JP2018178201A - Method of separating copper or zinc from leaching object - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for separating copper or zinc from an object for an exudation treatment small in agent used amount and small in energy used amount.SOLUTION: There is provided a method for separating copper or zinc from an object for an exudation treatment, which has a process for generating an exudation post liquid containing an ammine complex ion of one or both of copper and zinc and a solid residue, by contacting a solid object for the exudation treatment containing one or both of copper and zinc and containing iron with an exudate containing ionized ammonium salt and having pH of 7.5 to 11.5 in a first closed vessel, a process for solid-liquid separating the exudation post liquid, a process for adding a sulfidizing agent to the exudation post liquid after solid-liquid separation to prepare a regenerated post liquid containing sulphide of one or both of copper and zinc and ammonium salt in a second closed vessel, and a process for solid-liquid separating the regenerated post liquid to separate solid sulfide containing one or both of coper and zinc and the regenerated post liquid after the solid-liquid separation containing ionized ammonium salt, and uses the separated regenerated post liquid as the extrude.SELECTED DRAWING: None

Description

  The present invention is a solid that contains an iron component and contains one or both of copper and zinc, such as scrap that is a raw material of steel production and scale, dust, or sludge that is a by-product of the steel production process. The present invention relates to a method of separating one or both of copper and zinc from a leaching target.

  The scrap used as the raw material of steel manufacture has high copper content in many cases mainly due to the mixing of the copper wire used as an electric wire or conducting wire, and other copper or copper alloy parts. Moreover, scrap contains surface treatment steel plates, such as a galvanized steel plate, and the scrap contains a small amount of zinc which is a surface treatment component of a steel plate. As ferro scrap, there are, for example, waste cars, waste electric products, machine scraps, etc., and cutting scraps generated during processing.

  Dust, which is a by-product of the iron and steel manufacturing process, is generated in sintering, blast furnaces, converters, etc. in an integrated steel mill, and in an electric furnace, and its main component is iron, but it contains zinc in addition to iron components. The scale is continuous casting or hot rolling, and is an iron oxide generated when the surface of the steel material is oxidized in a hot condition. The main component is iron oxide, but may contain copper although in a small amount.

  Sludge, which is a by-product of the steel manufacturing process, is a sludge generated when neutralizing acid waste liquid and plating waste liquid generated at the time of plated steel sheet manufacturing, and zinc as a plating component other than iron in the base material It contains nickel, and these metals are present as hydroxides.

Copper is an element that adversely affects the performance of steel products such as mechanical properties and processability, and when scraps mixed with copper are used as a raw material for steel melting, only low quality steel can be produced. Therefore, it is preferable to remove copper from scrap, and various copper removal methods have been studied conventionally. For example, in Patent Document 1, the scrap is treated with a leaching solution containing NH ₃ and ammonium salt ((NH ₄ ) ₂ CO ₃ or (NH ₄ ) ₂ SO ₄ ) in the presence of oxygen, and copper in the scrap is anmined It is disclosed to dissolve as complex ion and separate decopper scrap. At this time, it is supposed that the obtained leachate is heated to decompose complex ions, and copper oxide crystallized when (NH ₄ ) ₂ CO ₃ is used is recovered. When (NH ₄ ) ₂ SO ₄ is used, the obtained aqueous solution of copper sulfate is electrolyzed to recover metallic copper.

  Further, copper is a metal element which is more difficult to oxidize than iron once mixed in the iron making process, and there is a problem that it is very difficult to separate.

  Since zinc has a boiling point and a melting point of 907 ° C. and 420 ° C. respectively, it is reduced and volatilized in the lower part of the blast furnace at 1400 to 1600 ° C. when introduced into the furnace, particularly in the blast furnace, and the blast furnace is 400 to 800 ° C. It is said that precipitation occurs at the top of the furnace, and if the amount of input of zinc is increased, zinc adheres to the blast furnace wall, which is said to have an adverse effect on stable operation. For zinc separation in dust, various dezincification methods have been studied conventionally. For example, in Patent Document 2, a zinc-containing material is brought into contact with a leaching solution containing ammonia, ammonium carbonate and ammine copper (II) complex ions while blowing in an oxygen-containing gas to dissolve zinc as an ammine zinc complex ion. The disclosed leachate is purified by the addition of metallic zinc to decompose ammine zinc complex ions in the purified leachate and to recover the precipitated basic zinc carbonate.

JP-A-5-195103 JP-A-6-49556

However, according to Patent Document 1, in order to recover copper oxide crystallized when (NH ₄ ) ₂ CO ₃ is used, the leaching waste solution is heated to evaporate ammonia gas and carbon dioxide gas and absorb the gas. In order to achieve this, water for absorption (also referred to as a gas absorption liquid) is required. In order to recover (NH ₄ ) ₂ CO ₃ in the leachate, it is necessary to partially discharge the leachate waste liquid or the gas absorber out of the system, since the amount of gas absorption liquid to be treated exceeds the amount of leachate required. There is a problem that the processing equipment is required. In addition, there is a problem that the ammonia component and the carbon dioxide component run short as the leaching waste liquid or the gas absorbing liquid is partially discharged to the outside of the system, and these components must be constantly replenished. Further, the concentration of (NH ₄ ) ₂ CO ₃ in the leaching waste solution is high, and in order to evaporate it to ammonia gas and carbon dioxide gas, much energy is required, which is not economical. When electrolytic copper sulfate solution obtained using (NH ₄ ) ₂ SO ₄ is electrolyzed to recover metallic copper, only the ammonia component in the leachate is evaporated by heating and recovered by the absorbing solution, but heating is carried out In addition to the fact that the amount of energy used is large, only the ammonia component is evaporated only when the leachate is on the alkali side, it becomes difficult to evaporate when it is on the acid side, and the recovery rate of the ammonia component decreases. was there. Moreover, although it is described in patent document 1 that oxygen is blown in in the leaching step, the control method for the input of oxygen is unclear, and if it is continuously input without controlling oxygen, it is a component that is easy to evaporate There is a problem that some (NH ₄ ) ₂ CO ₃ evaporates.

Moreover, in patent document 2, in order to heat up a leachate, evaporate ammonia gas and carbon dioxide gas, and absorb the gas similarly to patent document 1, a gas absorption liquid is needed. In order to recover (NH ₄ ) ₂ CO ₃ in the leachate, it is necessary to partially discharge the leachate or the gas absorber out of the system since the amount of gas absorption liquid to be treated exceeds the amount of leachate. There was a problem that was necessary. In addition, the ammonia component and the carbon dioxide component run short as part of the leachate or the gas absorbing liquid is discharged out of the system, and there is a problem that these components must be constantly replenished.

  Therefore, an object of the present invention is to provide a method for separating one or both of copper and zinc from an object to be leached, in which the amount of use of a drug such as ammonium salt is small and the amount of energy used is small.

  The inventor of the present invention is a solid leachable target containing an iron component and containing one or both of copper and zinc in the form of at least one of metal, oxide, hydroxide and chloride. In the method of leaching and separating one or both of copper and zinc as an ammine complex ion, the amount of drug used can be suppressed in a method for obtaining a residue of a leaching object having a small content of one or both of copper and zinc, And as a result of repeating examination about a method which can control a process which consumes much energy, such as heating, it came to make the present invention.

The summary is as follows.
(1) In the first closed container, containing an iron component, and one or both of copper and zinc in the form of any one or more of metal, oxide, hydroxide and chloride The solid leaching target contained in the step (b) is brought into contact with a leaching solution containing an ionized ammonium salt in the range of pH 7.5 to 11.5, and one of the copper and zinc in the solid leaching target or Leaching step of eluting both into the leaching solution as an ammine complex ion to form a leaching solution containing the ammine complex ion and the balance of the solid leaching object;
A first solid-liquid separation step of solid-liquid separation of the liquid after leaching to separate the liquid after leaching after solid-liquid separation, which is a liquid phase containing the ammine complex ion, and the remaining part of the solid leaching target When,
In a second closed vessel, the liquid after leaching after solid-liquid separation contains a gas containing hydrogen sulfide, lithium sulfide, sodium sulfide, sodium hydrogen sulfide, potassium sulfide, potassium hydrogen sulfide, magnesium sulfide, and calcium sulfide At least one sulfiding agent selected from among them is added to decompose ammine complex ions in the solution after leaching after the solid-liquid separation to precipitate one or both of copper and zinc as a solid sulfide and to ionize it. A leaching solution regeneration step of regenerating the recovered ammonium salt into a post-regeneration solution containing the solid sulfide and the ammonium salt;
The liquid after liquid regeneration is separated into solid and liquid to separate into solid sulfide containing one or both of copper and zinc and liquid after liquid / solid separation which is liquid phase containing the ionized ammonium salt 2 solid-liquid separation step,
A method for separating copper or zinc from an object to be leached, comprising using the liquid after regeneration of the liquid phase separated in the second solid-liquid separation step as a leachate used in the leaching step.

(2) The method for separating copper or zinc from a leaching target according to (1), wherein the solid leaching target is an iron component as a main component.

(3) The solid leaching target is at least one selected from scrap, which is a raw material of steel production, and scale, dust, and sludge which are by-products from the steel production process. The separation | isolation method of copper or zinc from the leaching process target object as described in (2).

(4) The method for separating copper or zinc from an object to be leached according to the above (3), wherein the object to be leached is at least one pulverized material selected from scale and dust.

(5) The method for separating copper or zinc from the object to be leached according to any one of (1) to (4), wherein an oxygen-containing gas is blown into the leaching solution in the leaching step.

(6) When the dissolved oxygen concentration in the leachate in the first closed vessel falls below a predetermined value A within the range of 1 to 40 mg / L, and oxygen in the gas phase in the first closed vessel When the concentration falls below a predetermined value B in the range of 2 to 98% by volume, the presence or absence of blowing is controlled such that the oxygen-containing gas is blown into the leachate, when at least one of the conditions is satisfied.
A state in which the dissolved oxygen concentration in the leachate in the first closed vessel is not less than the predetermined value A in a state where the blowing of the oxygen-containing gas is not performed, and the gas phase in the first closed vessel The method for separating copper or zinc from the object to be leached according to (5), wherein the leaching step is judged to be complete when the oxygen concentration in the medium continues to be the predetermined value B or more for a predetermined time or longer. .

(7) In the leaching step, controlling the free ammonia concentration in the leachate in the first closed vessel in the range of 3 to 50 g / L, and in the gas phase in the first closed vessel The method for separating copper or zinc from the object to be leached according to any one of the above (1) to (6), wherein at least one of controlling the ammonia concentration in the range of 0.6 to 12% by volume is performed. .

(8) In the leaching solution regeneration step, the sulfurizing agent to be added to the leaching solution in the second closed vessel so as to be within the range of the redox potential for forming the solid sulfide obtained in advance. The method for separating copper or zinc from the object to be leached according to any one of the above (1) to (7), wherein the amount of addition is adjusted.

(9) In the leachate regeneration step, a portion of the leachate in the second closed vessel is continuously taken into the third closed vessel to adjust the pH to 7 or less, and then the third The concentration of hydrogen sulfide in the gas phase in the closed vessel is continuously measured, and when the concentration of hydrogen sulfide in the gas phase rises and reaches a predetermined value, the addition of the sulfurizing agent into the second closed vessel is carried out. The method for separating copper or zinc from a leaching target according to any one of the above (1) to (8), which is stopped.

(10) The leaching target according to any one of (1) to (9) above, wherein the gas containing hydrogen sulfide is at least one selected from hydrogen sulfide gas and coke oven gas. Method of copper or zinc from waste.

(11) Separation of copper or zinc from the object to be leached according to any one of the above (1) to (10), wherein the hydrogen sulfide-containing gas is a gas from which a hydrogen cyanide component has been separated and removed in advance Method.

  According to the present invention, in the method for separating copper or zinc from a leaching target, the leaching solution can be regenerated while suppressing the amount of energy used, and the amount of medicine used can be reduced.

It is a graph which shows the change of the oxidation-reduction potential and the gaseous-phase part hydrogen-sulfide concentration in simulation liquid after leaching. It is a graph showing the relationship between the total ammonia -N concentration with soluble copper concentration and S ^2- concentration in the leaching after simulant for hydrogen sulfide gas input. It is a figure explaining the separation | isolation method of copper or zinc from the leaching process target object which concerns on this embodiment. It is a graph which shows a change of hydrogen sulfide, hydrogen cyanide, and ammonia concentration in coke oven gas. It is a figure explaining the method to isolate | separate a hydrogen cyanide component from coke oven gas. It is a figure explaining reaction in the 1st airtight container. It is a graph which shows the time-dependent change of the oxidation-reduction potential (ORP) and dissolved oxygen (DO) concentration in a 1st airtight container. It is a graph which shows the time-dependent change of the oxidation-reduction potential (ORP) and dissolved oxygen (DO) concentration in a 1st airtight container. It is a flowchart of the separation | isolation method of copper or zinc from the leaching process target object which concerns on this embodiment. It is a graph which shows the relationship between the presence form of sulfide ion, and pH. It is a graph which shows the relationship between dissolved oxygen concentration and Cu leaching rate. It is a graph which shows the relationship between a gaseous-phase part oxygen concentration and Cu leaching rate. Is a graph showing the relationship between the leaching solution f-NH ₃ concentration and Cu leaching rate. It is a graph showing the relationship between the gas phase NH ₃ concentration and Cu leaching rate. It is a graph which shows the relationship between the leaching waste liquid ORP and the Cu leaching rate. It is a graph showing the relationship between the third closed container (H 2 _S measurement vessel) in the Cu leaching rate. It is a graph which shows the relationship between untreated COG and Zn leaching rate of treated COG. It is a diagram illustrating a third closed container (H 2 _S measurement vessel). It is the graph which showed typically the time-dependent change of the dissolved oxygen concentration (DO) in a leachate. It is the graph which showed the oxygen concentration change of the gaseous-phase part in a leachate typically. Change the dissolved oxygen concentration (DO) in the leaching solution with time when the object to be leached is placed in a closed vessel and the oxygen concentration gas (DO) is blown when the dissolved oxygen concentration (DO) in the leaching solution falls below a predetermined value A It is the graph which showed typically.

  Hereinafter, an example of the embodiment of the present invention will be described in detail.

In the present specification, a numerical value range represented using “to” means a range including numerical values described before and after “to” as the lower limit value and the upper limit value, unless otherwise specified. However, when there is a notice such as “super” and “less than”, it means that the numerical values described before and after “to” are not included as at least one of the lower limit value and the upper limit value.
In addition, in the present specification, when referring to “one or both of copper and zinc”, it may be simply referred to as “copper / zinc”.

<Separation method of copper or zinc from leachable object>
The leaching target in the present embodiment contains an iron component, and one or both of copper and zinc (copper / zinc) is any one of metal, oxide, hydroxide, and chloride. Contain in the form of species or more. The objects to be leached include electronic devices and machines used in composite devices such as motors, electronic components, batteries, electronic boards, heat exchangers, electric wires, plated steel plates, etc., and discarded electronic devices and machines are also included. It becomes. In addition, as the leaching target, at least one selected from scrap, which is a raw material of steel production, and scale, dust, and sludge, which are by-products from the steel production process, is also applicable.

  It is preferable that the leaching target is mainly composed of an iron component. Here, being a main component means that the ratio (mass ratio) in the leaching target is 50% by mass or more.

First, the overall outline of the present embodiment will be described with reference to the flowchart (FIG. 9) of the separation method according to the present embodiment.
In the leaching step, a first sealed container which is a container in which a vapor phase portion is sealed, which is a container to be subjected to leaching treatment containing copper / zinc in the form of at least one of metal, oxide, hydroxide and chloride When placed in a container (hereinafter also referred to as "leaching tank" or "first container") and immersed in the leaching solution in the first closed container containing an ammonium salt, as shown in the following (formula 1), Copper / zinc reacts with ammonium ions and NaOH in the leachate in the first closed vessel and is oxidized to divalent ions to form and dissolve ammine complex ions. At this time, oxygen is used as an oxidant and consumed. This reaction tends to proceed in the alkaline region of pH 7.5-11.5. More preferably, it is easy to advance in the alkaline area of pH 9.5-10.5.

Me + 2 (NH ₄ ) ₂ SO ₄ + 2 NaOH + 1/2 O ₂
→ Me (NH ₃ ) ₄ SO ₄ + Na ₂ SO ₄ + 3H ₂ O − (1 equation)
(Here, Me is Cu or Zn)

  In addition, in the leachate in the first closed vessel containing ammonia (ammonium ion), copper / zinc forms an ammine complex ion and dissolves easily, while iron has a larger ionization tendency than copper. Nevertheless, because the surface layer is passivated, it hardly dissolves. By utilizing such properties of copper, zinc and iron, copper / zinc can be selectively leached from the object to be leached.

  Also, copper / zinc in dust and scale is often present as metal, oxide and chloride, and copper / zinc in sludge is often present as hydroxide. When copper / zinc is present as a hydroxide, (1) becomes (1−1) and no consumption of oxygen occurs. Similarly, no consumption of oxygen occurs in the case of oxides and chlorides.

Me (OH) ₂ +2 + 2 (NH ₄ ) ₂ SO ₄ + 2 NaOH
→ Me (NH ₃ ) ₄ SO ₄ + Na ₂ SO ₄ + 4H ₂ O − (formula 1-1)
(Here, Me is Cu or Zn)

  When the object to be leached containing copper / zinc metal is introduced into the first closed vessel, the reaction of formula (1) proceeds until the oxygen in the first closed vessel is consumed, and most of the oxygen is consumed. Then, the reaction of equation (1) stops. Therefore, the oxygen initially present in the first closed vessel is consumed, and copper / zinc in the object to be leached which is a metal of copper / zinc becomes an ammine complex ion and elutes to some extent.

  Next, in the first solid-liquid separation step, the leaching solution, which is an aqueous solution containing the remaining portion (residue) of the leaching object to which copper / zinc has been leached and the ammine complex ion, leaches the solid in this step. The residue to be treated is separated into a liquid after leaching after solid-liquid separation containing an ammine complex ion. Moreover, the residue of the object of the leaching process which has as a main component the iron content in which the content rate of copper / zinc fell after isolation | separation can also be collect | recovered, and it can also be used as an iron raw material for steel manufacture.

  The liquid after leaching after solid-liquid separation is an ammonia-containing aqueous solution containing an ammine complex ion of copper / zinc, and the ammonium ion concentration is lowered, so the reaction of formula (1) becomes difficult to proceed to the right. The leaching ability of zinc is reduced. When copper / zinc is selectively separated from the liquid after leaching after solid-liquid separation, the ammonia-containing aqueous solution can restore the copper / zinc leaching ability again, and again, the first sealed container ( It can be used as a leachate of a leacher).

  Therefore, in the leachate regeneration step, the leached solution after solid-liquid separation is also referred to as a second closed vessel (hereinafter, also referred to as “leach regeneration vessel” or “second vessel”) which is a vessel in which the gas phase portion is sealed. By mixing with a sulfiding agent (for example, the sulfiding agent in the formula 2 is hydrogen sulfide), copper ion and zinc ion react with sulfide ion to form sulfide (copper sulfide, zinc sulfide) An ammonium salt and NaOH are formed (Formula 2), and the mixture after regeneration is sent to the second solid-liquid separation step.

_{Me (NH 3) 4SO 4 +} H 2 S + Na 2 SO 4 + 2H 2 O
→ MeS +2 + 2 (NH ₄ ) ₂ SO ₄ + 2 NaOH-(2 formulas)
(Here, Me is Cu or Zn)

  In the second solid-liquid separation step, the liquid after regeneration is solid-liquid separated into a sulfide and an aqueous solution containing an ammonium salt and NaOH (liquid after regeneration after solid-liquid separation). The separated sulfide is recovered, and the separated copper sulfide and zinc sulfide can be used as a copper / zinc refining raw material. In addition, the separated aqueous solution containing ammonium salt and NaOH can regenerate the leaching ability of copper / zinc, and it is again put into the first closed vessel (leaching tank) and used as a leaching solution in the leaching step. used.

  When the reaction (1) in the leaching step and the reaction (2) in the leachate regeneration step for regeneration of the leachate are combined, it becomes (3), and when hydrogen sulfide and oxygen are supplied from the outside, the leaching target The copper / zinc in the product eventually precipitates out as sulfide to form water. After leaching, ammonium ions and sulfate ions, which are counter ions of ammonium ions, in the solution are recovered and theoretically hardly discharged out of the system. However, water and ammine complexes are present in the gaps of the residue of the object to be leached separated in the first solid-liquid separation step and in the gaps of the copper / zinc sulfide separated in the second solid-liquid separation step. Since ammonium ions to be formed and sulfate ions, which are counter ions of ammonium ions, are also mixed, they are partly discharged out of the system.

Me + + H ₂ S + _1/2 O ₂ → MeS + + H ₂ O − (3 formulas)
(Here, Me is Cu or Zn)

  From the above, in the flow of the separation method according to the present embodiment, the heating time and temperature can be reduced even if the heating step with a large amount of energy consumption is not performed or performed, and the leaching solution, the leaching solution It can be seen that the amount of drug used can be reduced because the amount of liquid taken out of the system after regeneration can be reduced.

・ Completion of the leaching process (oxygen concentration)
Next, it is explained that the separation method according to the present embodiment can reduce the amount of carried out of the leachate, the solution after leaching, and the solution after regeneration outside the system by appropriately controlling, and can reduce the use amount of the drug. Do.
In the first closed vessel of the leaching step, as shown in FIG. 6, the copper / zinc metal is oxidized in the leaching solution by the dissolved oxygen in the leaching solution or Cu ²⁺ ions described later, and then in the leaching solution. It reacts with ammonium ion to form an ammine complex ion. The ammine complexation reaction is easy to occur and takes almost no time, but the copper / zinc metal oxidation reaction is slower and more time-consuming than it. In addition, copper / zinc in the leaching target which is a solid substance becomes copper ions or zinc ions and slightly dissolves in the leaching solution, but the dissolution amount is small and the dissolution reaction also takes time. On the other hand, the dissolved oxygen in the leachate is in equilibrium with the oxygen concentration in the gas phase, and it can be said that the dissolved oxygen concentration in the leachate and the oxygen concentration in the gas phase are substantially proportional to each other.

  In order to determine whether the leaching of copper / zinc from the material to be leached has ended, it may be determined whether the ammine complexation reaction has ended. Since the oxidation reaction is rate-limiting, it is judged whether the oxidation reaction has ended by continuously or intermittently measuring the oxygen concentration in the gas phase or the dissolved oxygen concentration in the leachate, because the ammine complexation reaction is rate-limiting. Can.

Preferably, an oxygen-containing gas (oxygen or a gas containing oxygen) is introduced into the first closed vessel for the oxidation of the metal. At this time, if it is the dissolved oxygen concentration in the leachate in the first closed vessel, the oxygen concentration in the gas phase in the first closed vessel is made to be a predetermined value or more in the range of 1 to 40 mg / L. If so, it is preferable to control the presence or absence and the amount of oxygen or a gas containing oxygen so as to be a predetermined value or more in the range of 2 to 98% by volume. That is, when the dissolved oxygen concentration in the leachate falls below a predetermined value A in the range of 1 to 40 mg / L, and the oxygen concentration in the gas phase in the first closed vessel is in the range of 2 to 98% by volume. It is preferable to control the presence or absence of the blowing so that the oxygen-containing gas is blown into the leaching solution when at least one of the conditions below the predetermined value B is satisfied, and the amount thereof is preferably controlled.
The state in which the dissolved oxygen concentration in the leachate in the first closed vessel is a predetermined value A or more without the oxygen-containing gas being blown in, and the oxygen concentration in the gas phase in the first closed vessel It can be determined that the leaching step has been completed when the state in which is greater than or equal to the predetermined value B continues for a predetermined time or more.

There are ON / OFF control, PI (Proportinal Integral) control, PID (Proportal Integral Differential) control, and the like as a control method of the presence or absence of oxygen or gas containing oxygen and the amount thereof. On the other hand, the ammine complexation reaction is easy to occur and takes almost no time, but the oxidation reaction of copper / zinc metal is slower and time-consuming as compared with that, so the reaction rate of equation (1) is small and the oxygen consumption rate is also small. The oxygen input rate also decreases. Therefore, even in the case where PI control or PID control is adopted in the present embodiment, the oxygen input tends to be intermittent and in most cases almost the same as the ON / OFF control. When the dissolved oxygen concentration is 1 mg / L or more, or the oxygen concentration in the gas phase is 2% by volume or more, the oxidation rate does not become too small, and the time required for the leaching step becomes short. When the dissolved oxygen concentration is 40 mg / L or less or 98 volume% or less, the oxygen partial pressure in the gas phase is suppressed to 1 atm or more, and there is no need to make the first closed container have high pressure resistance. The cost of the device is suppressed.
The predetermined value A is selected from the range of 1 to 40 mg / L as described above, and is more preferably selected from the range of 5 to 20 mg / L.
The predetermined value B is selected from the range of 2 to 98% by volume as described above, and is more preferably selected from the range of 10 to 40% by volume.
The predetermined time is preferably, for example, in the range of 3 to 60 minutes.

The object to be treated with metal copper or metal zinc (metal plate) is placed in a closed vessel containing oxygen-containing gas and leachate, and the dissolved oxygen in the leachate is stirred in the closed vessel in batch mode. FIG. 19 schematically shows the change with time of the concentration (DO), and FIG. 20 schematically shows the change in oxygen concentration in the gas phase part. In addition, the surface area of the metal plate is sufficiently large, and it is assumed that the rate of oxygen consumption is not limited.
The dissolved oxygen concentration (DO) decreases with a constant gradient until point a in FIG. 19, but the gradient gradually decreases after point a. This is because as the dissolved oxygen concentration decreases, the oxygen on the left side of Formula 1 decreases and the reaction rate decreases. Therefore, it is preferable that the predetermined value A is a change in the graphed oxygen concentration (point a) or a dissolved oxygen concentration (DO) larger than the point a, by determining the change with time of the dissolved oxygen concentration (DO) shown in FIG. .
The oxygen concentration in the gas phase portion decreases with a constant gradient until point b in FIG. 20, but the gradient gradually decreases after point b. This is because as the oxygen concentration in the gas phase portion decreases, the dissolved oxygen concentration (DO) also decreases, the oxygen on the left side of Formula (1) decreases, and the reaction rate decreases. Therefore, it is preferable that the predetermined value B be the oxygen concentration of the gas phase part where the graph gradient changes (point b) or the point where the graph gradient changes (point b) by obtaining the temporal change of the oxygen concentration in the gas phase part .
Place the object (metal plate) for leaching treatment of either metallic copper or metallic zinc in a closed vessel, continuously measure the dissolved oxygen concentration (DO) in the leachate while stirring the leachate, and measure a predetermined value A It is FIG. 21 which showed typically the time-dependent change of the dissolved oxygen concentration (DO) in a leachate when blowing in oxygen-containing gas in a closed container when it became less than. At the initial stage of leaching, the dissolved oxygen concentration (DO) falls below the predetermined value A every Δt time, and oxygen-containing gas is supplied, but the metallic copper and metallic zinc in the leaching object in the leachate form an ammine complex As it ionizes, the rate of consumption of dissolved oxygen decreases. As a result, the blowing time interval of the oxygen-containing gas becomes long. Therefore, it is preferable to set the predetermined time used to determine whether or not the leaching of copper / zinc from the leaching target is finished to be 5 to 10 times Δt.

Here, an example is given and demonstrated.
In the first sealed container which is adjusted to pH 10 and contains an aqueous ammonium sulfate solution containing sufficient ammonium ions, scraps serving as a raw material for steel production mixed with metallic copper are introduced, and the copper ions are leached. It is FIG. 7 which showed the dissolved oxygen concentration in the leachate in 1 airtight container, and the change of the oxidation-reduction potential. The pH was almost constant at pH 10, and the dissolved oxygen concentration was controlled to be 1 mg / L or more, that is, when it was less than 1 mg / L, pure oxygen was introduced into the first closed vessel. Copper metal was oxidized and dissolved oxygen concentration was less than 1 mg / L and pure oxygen was added up to 680 minutes, but after 680 minutes, dissolved oxygen becomes more than 1 mg / L, and the input of pure oxygen is lost and metal The copper oxidation reaction and the ammine complexation reaction have ended. When a sample was taken out after about 1000 minutes, although all the metallic copper mixed in the scrap had leached, a portion of metallic iron was hardly leached.

Next, instead of scraps, galvanized steel sheets were used and leached.
Adjust the pH to 10, put a galvanized steel sheet instead of scrap into a closed first closed container containing ammonium sulfate aqueous solution containing sufficient ammonium ions, and leach out zinc ions in the first closed container It is FIG. 8 which measured the change of the dissolved oxygen concentration in the leachate, and the oxidation-reduction potential. The pH was almost constant at pH 10, the dissolved oxygen concentration was controlled to be 10.3 mg / L or more, and when it was below 10.3 mg / L, pure oxygen was introduced into the first closed vessel. The metal zinc in the plating layer was oxidized until the dissolved oxygen concentration fell below 10.3 mg / L until 600 minutes and pure oxygen was added, but after 600 minutes, the dissolved oxygen comes to exceed 10.3 mg / L, The input of pure oxygen almost disappeared and the oxidation reaction and ammine complexation reaction of metallic zinc were completed. When a sample was taken out after about 900 minutes, almost the entire plated portion of the surface layer portion of the galvanized steel sheet was leached, but almost no metallic iron portion was leached under the plated layer. From this, it can be said that, when copper / zinc is contained as a metal in the object to be leached, it is possible to determine whether the leaching reaction has ended by measuring the concentration of dissolved oxygen.

  When the form of copper / zinc in the object to be leached is only oxides, hydroxides and chlorides, no metal oxidation reaction occurs, so no oxygen consumption occurs and only the ammine complexation reaction As it occurs, the decrease in dissolved oxygen concentration hardly occurs. Since an oxidation reaction is not necessary, it is only an ammine complexation reaction, which is likely to occur and takes almost no time. That is, when the form of copper / zinc in the object to be leached is only oxides, hydroxides, and chlorides, the ammine complexing reaction is usually completed in about 5 to 120 minutes, so 5 to 120 After contacting with the leachate for a minute, it is possible to determine whether the leaching reaction has ended by measuring the concentration of dissolved oxygen.

  Further, since the concentration of dissolved oxygen in the leachate in the first closed vessel and the concentration of oxygen in the gas phase in the first closed vessel are substantially proportional, the concentration of oxygen in the gas phase in the first closed vessel is By measuring, it can be determined whether the leaching reaction has ended.

Ammonia concentration When the ammine complexation reaction proceeds in the leaching step, the free ammonia concentration (also described as the concentration of ammonia present as NH ₃ , the concentration of fr-NH ₃ ) in the leachate in the first closed vessel decreases. At the same time, the concentration of ammonia in the gas phase in the first closed vessel also decreases. Also, the ammonium ion concentration in the leachate in the first closed vessel is in equilibrium with the free ammonia concentration in the leachate in the first closed vessel at a constant pH, and in the leachate in the first closed vessel The ammonium ion concentration in the leachate in the first closed vessel is equal to the gas phase in the first closed vessel, since it is in equilibrium with the free ammonia concentration in the first closed vessel and the ammonia concentration in the first closed vessel. It can be said that there is a proportional relationship with the ammonia concentration inside. If the free ammonia concentration in the leachate in the first closed vessel becomes too low, the ammine complexation reaction becomes difficult to proceed. In addition, when the concentration of free ammonia in the leachate in the first closed container becomes too high, the moisture is also removed when discharging the object to be leached after removing copper sulfide, zinc sulfide or copper and zinc described later. Although the water is simultaneously discharged, the water also contains an ammonia component, which is carried out of the system, which reduces the economic efficiency. Therefore, it is preferable to properly control the free ammonia concentration in the leachate in the first closed vessel. Specifically, the free ammonia concentration in the leachate in the first closed vessel is preferably in the range of 3 to 50 g / L.
The free ammonia concentration in the leachate in the first closed vessel is preferably in the range of 5 to 20 g / L.

In addition, since the free ammonia concentration in the leachate in the first closed vessel is substantially in equilibrium with the ammonia concentration in the gas phase in the first closed vessel, the free ammonia concentration in the vapor phase in the first closed vessel is Preferably, the ammonia concentration is in the range of 0.6 to 12% by volume.
The concentration of ammonia in the gas phase in the first closed vessel is preferably in the range of 1.2 to 4.8% by volume.

  In addition, dust and copper / zinc in the scale are not homogeneously dispersed but often segregated. The blast furnace dust or converter dust discharged from the blast furnace or converter has iron oxide or metallic iron portions scattered as solids or melt from the furnace and a portion volatilized as zinc vapor, and is cooled in the dust collection stage Often exist around blast furnace dust particles. Dust often adheres to one another at the time of cooling and is in an aggregated state. In addition, when a steel material to which copper is added is hot-rolled, a copper-containing scale is generated, but the copper component is often dispersed in the scale surface without being uniformly dispersed in the scale. This is because the melting point of metallic copper (1,085 ° C.) is lower than the melting point (1,370 ° C.) of iron oxide (FeO), which is the main component of scale, and therefore copper components having a low melting point 1,200 ° C.) is a melt and it is easy to segregate. On the other hand, in the present embodiment, only the portion exposed to the copper / zinc portion and in contact with the leaching solution can be removed. Therefore, in the case of dust or scale, the rate of removal of copper / zinc often increases if the particle size is reduced by crushing.

  In the leachate regeneration step of recovering the solution after leaching after solid-liquid separation, copper / zinc is precipitated as a sulfide from the leachate after solid-liquid separation containing copper / zinc ammine complex ion as in equation (2) When the sulfide ion is introduced in excess, the excessively charged sulfide ion is introduced into the first closed vessel of the leaching step through the second solid-liquid separation step. As a result, a dense sulfide layer more stable than ammine complex ions is formed on the surface layer of copper / zinc contained in the object to be leached, making it difficult to leach out the copper / zinc in the lower part of the sulfide layer, copper / The zinc leaching rate may be low or leaching may not be possible.

On the other hand, by performing the following measures, the sulfide ion hardly remains in the regenerated leachate in the leachate regeneration step, and the leachate can be stably used repeatedly.
As a first method, a sulfurizing agent (gas containing hydrogen sulfide, lithium sulfide, sodium sulfide, sodium hydrogen sulfide, potassium sulfide, potassium hydrogen sulfide, magnesium sulfide) in the leached solution in the second closed vessel of the leachate regeneration step When charging at least one sulfurizing agent selected from calcium sulfide), the redox potential of the solution after leaching in the second closed vessel is measured, and the redox potential (also described as ORP) is calculated. When the value falls below a certain value (for example, the redox potential (standard potential) is -100 mV or less at pH 9.3), the addition of the sulfiding agent is stopped, and in the second solid-liquid separation step, solid-liquid such as precipitation or filtration When sulfides deposited by the separation operation are separated from the solution after regeneration, the unreacted solution is hardly present in the solution after regeneration (leaching solution) after solid-liquid separation. Even when reused in closed container, since that does not form a sulfide on the surface layer of the copper / zinc contained in the leaching object, a copper / zinc becomes ammine complex ions, easily leached. Oxidation of the solution after leaching in the second closed vessel, because the value (predetermined value) of the redox potential changes under the influence of pH and depending on the concentration of copper / zinc dissolved as an ammine complex, etc. The set value of the reduction potential is preferably determined by experiment or the like.

As a second method, a part of the liquid after leaching (for example, several tens to several hundreds of ml / min) in a second sealed container (leaked liquid regeneration tank) is sealed in another third sealed container 70 (FIG. 18, The solution is continuously collected in about 10 to 5000 ml, and the extracted solution 21 from the second closed container is stirred with a stirrer 72, and the solution 21 is extracted with acid, such as hydrochloric acid or sulfuric acid (acid aqueous solution And 78) to adjust the amount of the aqueous acid solution 78 with the pH adjusting valve 74 while measuring the pH of the liquid 21 after leaching with the pH meter 73, thereby making the pH 7 or less, more preferably 5 or less. At the same time, the hydrogen sulfide concentration in the gas phase in the third closed vessel 70 is continuously measured with a hydrogen sulfide (H ₂ S) concentration meter 77, and the hydrogen sulfide concentration becomes a certain value (for example, 1 ppm) Up to the second closed vessel, at least one selected from a sulfiding agent (gas containing hydrogen sulfide, lithium sulfide, sodium sulfide, sodium hydrogen sulfide, potassium sulfide, potassium hydrogen sulfide, magnesium sulfide, calcium sulfide Charge the sulfiding agent).

  When the hydrogen sulfide concentration rises and reaches a certain value (predetermined value), the introduction of the sulfiding agent into the second closed vessel is stopped. By doing so, in the next second solid-liquid separation step, when sulfides precipitated by solid-liquid separation operation such as precipitation or filtration are separated from the liquid after regeneration, in the liquid after regeneration after solid-liquid separation (leaching liquid) In addition, unreacted sulfide ions can be made to remain only at low concentrations. Therefore, the sulfide ion is oxidized when maintaining the dissolved oxygen concentration in the leachate of the first closed vessel of the leaching step, even when it is reused as the leachate in the first closed vessel. Since copper and zinc do not form sulfides in the surface layer of copper / zinc contained in the object to be leached, copper / zinc is most preferred because it becomes an ammine complex ion and tends to leach out.

  Hydrogen sulfide differs in the form of the compound depending on the pH (FIG. 10), and the ratio to become molecular hydrogen sulfide is increased by setting the pH to 7 or less, more preferably 5 or less, and the air in the third closed vessel Since the hydrogen sulfide gas is easily evaporated in the phase part, the pH of the solution after leaching in the third closed vessel is adjusted to 7 or less, more preferably 5 or less. Since the hydrogen sulfide concentration in the gas phase in the third closed vessel is affected by pH, the predetermined value (the above value) of the hydrogen sulfide concentration in the gas phase in the third closed vessel is determined by experiment or the like It is preferable to determine. If the setting value of the hydrogen sulfide concentration in the gas phase part in the third closed vessel is increased too much, an excess of the sulfiding agent is charged into the second closed vessel, and the sulfide ions will be present in excess. The sulfide ion, which has been excessively introduced, is introduced into the first closed vessel of the leaching step through the second solid-liquid separation step, and the ammine complex ion is deposited on the surface of the copper / zinc contained in the object to be leached. It may form a more stable dense sulfide layer, make it difficult to leach out the copper / zinc in the lower part of the sulfide layer, and the leaching rate of copper / zinc may decrease or may not leach out. Therefore, the smaller the setting value of the hydrogen sulfide concentration in the gas phase part in the third closed vessel, the better, and the vicinity of the detection lower limit of the hydrogen sulfide concentration meter is most preferable. In addition, since the liquid after the measurement discharged | emitted from the 3rd airtight container is a small amount, you may discard it and you may return it in the 2nd airtight container.

Change in oxidation-reduction potential in simulated liquid after leaching and hydrogen sulfide concentration in gas phase part Here, simulated liquid after solid-liquid separation described in Table 1 is used as liquid after leaching after solid-liquid separation The oxidation-reduction potential in the simulated liquid after leaching in the second closed vessel when preparing and introducing hydrogen sulfide gas which is one of the sulfiding agents while stirring in the second closed vessel, The change of the hydrogen sulfide concentration in the gas phase part in the closed container of the above is shown in FIG.
Further, the relationship between the total ammonia state-N concentration in the simulated liquid after leaching after solid-liquid separation, the solubility Cu concentration, and the S ^2- concentration with respect to the hydrogen sulfide gas input amount is shown in FIG.

  As the amount of hydrogen sulfide gas input increases, the oxidation-reduction potential gradually decreases, and when the amount of hydrogen sulfide gas input is about 155 mmol / L, the oxidation-reduction potential rapidly decreases, and at the same time, the inside of the second closed vessel The concentration of hydrogen sulfide in the gas phase portion of is detected. Although the pH of the simulated liquid after leaching in the second closed vessel is not shown, it remains at pH 9.1 to 9.4 and there is no significant change. The concentration of hydrogen sulfide in the gas phase part in the second closed vessel can be detected immediately after the redox potential falls below 0 mV and rapidly rises.

In addition, the solubility Cu (D-Cu) concentration in the simulated liquid after leaching in the second sealed container is also determined as the redox potential in the simulated liquid drops below 0 mV after the leaching in the second sealed container. It became about mg / L, and it became possible to detect the sulfide ion (S ²⁻ ) concentration in the simulated liquid after leaching in the second closed vessel. This is because the soluble Cu was changed to sulfide by hydrogen sulfide gas which is a sulfiding agent.

When an aqueous solution containing sulfide ions such as sodium hydrogen sulfide aqueous solution and sodium sulfide aqueous solution is used as the sulfiding agent, the pH of the leachate is on the alkali side of 9.1 to 9.4, and therefore the sulfide ion is H in molecular form _The ratio of change to 2S is very small (Fig. 10), and the concentration of hydrogen sulfide in the gas phase portion hardly increases.

However, when the sulfiding agent is in a gaseous state such as hydrogen sulfide gas, after the leaching in the second closed vessel, the reaction of the sulfidation of Cu ions in the simulated liquid is almost completed, and at the same time the gas phase in the second closed vessel Since the rate of absorption into the simulated liquid after the leaching of H ₂ S in the _second part significantly decreases, the H ₂ S concentration in the gas phase part in the second closed vessel rises.

The regenerated solution after regeneration at points (a) and (b) in FIG. 2 is filtered, and the regenerated solution after solid-liquid separation which is the liquid phase (hereinafter also referred to as “regenerated leachate”) is collected in a closed container. did. A copper plate was put in the regenerated leachate, and the leaching amount of the copper plate of the regenerated leachate was measured. As a result, 3.1 g of copper plate was leached and dissolved in 1 liter of regenerated leachate (point a) in which soluble Cu remained. Was able to measure.
On the other hand, the surface of the copper plate turned black in the regenerated leaching solution (point b) in which the soluble Cu did not remain and contained sulfide ions, and no leaching of the copper plate was observed. From the results of X-ray diffraction and the like, this black material was found to be copper sulfide, and the copper sulfide film prevented the leaching solution from contacting the copper plate under the copper sulfide film, so the leaching of the copper plate proceeded. It is thought that it was not.
That is, when all the copper ions and zinc ions in the solution after leaching in the second closed vessel are precipitated as sulfides, there is a possibility that sulfide ions may remain in the solution after leaching in the second closed vessel. high. Therefore, after solid-liquid separation, if it is reused as a leachate, it can be said that a coating of sulfide is easily formed on the copper / zinc metal part, and the function as a leaching agent is slightly reduced.

In addition, metallic copper and metallic zinc are directly oxidized by dissolved oxygen, and in addition to leaching while forming an ammine complex ion, they are indirectly dissolved as shown in (Formula 4) to (Formula 6) With oxygen, metallic copper and metallic zinc are oxidized and leached while forming an ammine complex ion. That is, if Cu ²⁺ ion remains, direct oxidation and indirect oxidation of one or both of metallic copper and metallic zinc work to form an ammine complexing ion, so that copper / zinc metal is easily leached out. Become.

Cu ²⁺ + Cu → Cu ⁺ − (equation 4)
Cu ⁺ + O ₂ → Cu ₂ ⁺ -(5 formulas)
Cu ²⁺ + Zn → Zn ²⁺ + Cu − (6)

  From the above, not all the copper ions and zinc ions in the solution after leaching in the second closed vessel are precipitated as sulfides, but copper ions and zinc ions are partially left as a sulfide while remaining in the leachate. It is preferable to precipitate.

Control Means A specific control means will be described with reference to FIG. When using a gas containing hydrogen sulfide as the sulfiding agent, the control of the amount of introduction of the sulfiding agent may be performed by using the oxidation-reduction potential of the leached solution 21 in the second closed vessel 20 or the second closed vessel 20. It can be judged by the concentration of hydrogen sulfide in the gas phase part of Each value is preferably adjusted by experiment, but taking FIG. 1 as an example, the redox potential of the liquid 21 after leaching in the second sealed container 20 is 100 to 130 mV, and the second sealed container 20 is The hydrogen sulfide concentration in the gas phase portion is preferably 1 to 5 ppm.

When at least one sulfiding agent selected from hydrogen sulfide-containing gas, lithium sulfide, sodium sulfide, sodium hydrogen sulfide, potassium sulfide, potassium hydrogen sulfide, magnesium sulfide, and calcium sulfide is used, the sulfiding agent is used. The timing to stop the addition of can be determined, for example, by the following method. A part of the solution after leaching in the second closed vessel 20 is collected in a closed third closed vessel (H ₂ S measurement vessel), and the collected solution in the second closed vessel 20 is collected The pH can be 7 or less, more preferably 5 or less, and stirring can be performed in the third closed vessel, and it can be judged by the concentration of hydrogen sulfide in the gas phase part in the third closed vessel.

Hydrogen sulfide-containing gas As the hydrogen sulfide-containing gas, high-purity hydrogen sulfide gas can be used, but the cost of the gas is generally high. On the other hand, there is coke oven gas as a gas containing hydrogen sulfide, and the coke oven gas originally contains hydrogen sulfide and ammonia, and these components can not be used as fuel gas without separation.

  Therefore, the inventor of the present invention works on using coke oven gas as the gas containing hydrogen sulfide of the present invention, and copper / zinc ammine complex ion reacts with hydrogen sulfide contained in coke oven gas to be copper / It was found to precipitate as a sulfide of zinc. In addition, it was also found that the ammonia component in the coke oven gas is partially absorbed in the leachate, which results in the replenishment of the ammonia component in the leachate. That is, the coke oven gas deposits copper / zinc, which is an ammine complex metal in the liquid after leaching in the second closed vessel, as a sulfide, and supplements the ammonia component necessary to form an ammine complex ion. It has been found that the solution after leaching in the second closed vessel can be regenerated as leachate.

In addition, it has been found that since coke oven gas contains CO ₂ , it can also be used to supplement carbonate ion which is a counter ion of ammine complex ion.

The coke oven gas may contain hydrogen cyanide. Hydrogen cyanide, cyanide ions in leach solution after in the second closed vessel (CN ^-) is dissolved in next liquid phase. After solid-liquid separation, cyanide ion is contained in the leachate, and cyanide ion is stabilized with zinc ion, copper ion, iron ion when the leachate containing cyanide ion is used as leachate in the first closed vessel. And dense complex layer (for example, Cu ₂ Fe (CN) ₆ ) is formed on the surface layer of copper / zinc contained in the leaching object to make it difficult to leach copper / zinc in the lower part of the complex layer .

  In addition, in the leaching step, the liquid phase portion contained in the gap in the residue of the leaching object recovered after the separation of copper / zinc is likely to contain cyanide ions, which is also from the viewpoint of work safety It is more preferable to separate hydrogen cyanide from coke oven gas in advance.

  Then, when the method of separating hydrogen cyanide in coke oven gas in advance was examined, it was found that hydrogen cyanide gas in coke oven gas can be selectively separated in advance by bringing coke oven gas into contact with an iron-based slurry.

  Hydrogen sulfide in coke oven gas when a coke oven gas (also referred to as COG, see Table 2 for the component) is aerated at 120 mL of an iron hydroxide slurry (see component 3 for the component) at a rate of 4.3 NL / min. FIG. 4 shows changes in hydrogen cyanide and ammonia concentrations.

  As shown in FIG. 4, as the COG flow rate increases, the removal rate of hydrogen sulfide in COG decreases and gradually disappears. On the other hand, hydrogen cyanide in COG maintains a high removal rate, and although ammonia is not as low as hydrogen sulfide, its removal rate gradually decreases. This is because iron hydroxide (trivalent) in the absorbent is reduced to divalent iron ion by hydrogen sulfide and oxidation-reduction reaction (formula 7), and divalent iron ion is stable cyanide complex with cyanide ion (8) to be separated.

Fe ³⁺ , S ^2- → Fe ²⁺ , S, S ₂ O ₃ ^2- , SO ₃ ^2- , SO ₄ ² --(7)
^{_{3 [Fe (CN) 6]}} 4- + 4Fe 3+ → Fe 4 [Fe (CN) 6] 3 - (8 type)

  Ammonia hardly forms an ammine complex ion with iron ion, and is hardly absorbed as ammine complex ion, but when hydrogen cyanide and hydrogen sulfide are absorbed, the pH of the absorbing solution decreases, so the ammonia component is absorbed. The ammonia component is removed because it is easy to do. That is, when the alkali is added to the absorbing solution to raise the pH of the absorbing solution, the absorptivity of ammonia decreases, and when the acid is added to the absorbing solution to lower the pH of the absorbing solution, the absorptivity of ammonia increases.

-Equipment used for the separation method FIG. 3 shows an example of equipment and flow according to the method for separating copper or zinc from the object to be leached according to the present embodiment.
In FIG. 3, the leaching step of leaching copper / zinc by ionization of ammine complex from the leaching object and the ammine complex ionizing copper / zinc in the leaching waste solution from the leaching step are precipitated as sulfide, It shows in detail the leachate regeneration step of reclaiming the leachate by separating it from the leachate waste.

Each process will be described including the equipment configuration.
First, the basic equipment configuration in the present embodiment will be described. However, the present embodiment is not limited to the following equipment configuration.
In the leaching step, for example, a first closed vessel (leaching tank) 2 containing the leachate 1, a stirrer 3 for stirring the inside of the first closed vessel 2, and oxygen or air in the leachate 1. There is used a device having an oxygen gas supply device 9 and a diffusion valve 17 for dissipating excess gas from the inside of the first closed container when the internal pressure in the first closed container is a closed container. For the first solid-liquid separation step, for example, a solid-liquid separation device 10 that separates solids in the liquid 32 after leaching is used. In the leachate regeneration step of regenerating the leached solution 33 after solid-liquid separation, for example, a second closed vessel (leach regeneration tank) 20 containing the leached solution 21 after solid-liquid separation and its second A stirring device 22 for stirring the inside of the container 20, a diffusion valve 25 for dissipating excess gas from the inside of the second sealed container when the internal pressure in the second sealed container 20 rises, and a second sealed container 20. An apparatus having a sulfiding agent feeding device 28 for feeding a sulfiding agent is used. For the second solid-liquid separation step, for example, a solid-liquid separation device 30 that separates solid matter in the regenerated liquid after regeneration 34 is used.

  The solid-liquid separation device 10 used in the first solid-liquid separation step and the solid-liquid separation device 30 used in the second solid-liquid separation step include, for example, a sedimentation tank, a strainer, a filter, a cyclone, a filter press, and Although an apparatus such as a centrifugal separator can be applied, a strainer, a filter, a centrifugal separator, and the like having high sealing property are preferable because of the pH range in which the ammonia component evaporates.

  Furthermore, the amount of medicine used can be further suppressed by adding the following device. In the leaching step, a pH meter 4 for measuring the pH of the leachate 1 in the first closed container (leach tank) 2 containing the leachate 1, and a pH adjuster charging the pH adjuster for pH adjustment of the leachate 1 At least one of the device 5, a dissolved oxygen concentration meter 7 for measuring the dissolved oxygen concentration of the leachate 1 and an oxygen concentration meter 8 for measuring the oxygen concentration of the gas phase in the first closed vessel 2, At least one of a dissolved free ammonia concentration meter 15 for measuring the dissolved free ammonia concentration and an ammonia concentration meter 16 for measuring the ammonia concentration of the gas phase in the first closed vessel 2 and ammonia for replenishing the leachate 1 A solution replenishment device 11 may be added. In the leachate regeneration step, a pH meter 23 for measuring the pH of the leached solution 21 in the second closed vessel 20 containing the leached solution 21 and a pH adjuster for adjusting the pH of the leached solution 21 are added. PH adjuster charging device 24, an oxidation-reduction potentiometer 26 for measuring the redox potential in the leached solution 21, and a hydrogen sulfide concentration meter 27 for measuring the hydrogen sulfide concentration in the gas phase in the second closed vessel 20. And at least one of them may be added. By adding these devices, it becomes possible to control the process in a more appropriate state, and it is possible to further suppress the amount of medicine used.

Operation Next, an operation according to the present embodiment will be described by way of an example.
In the leaching step, a pH adjuster such as an aqueous solution of sodium hydroxide and a dilute aqueous solution of sulfuric acid is added to an aqueous solution of ammonium sulfate, which is one example of the leachate 1, and pH 9.5 to 11.5 in advance, more preferably pH 9.5 The leachate 1 adjusted to ̃10.5 is charged into the first closed vessel 2. Thereafter, while stirring with the stirring device 3, the leaching object 12 is put into the first closed container 2, and the first closed container 2 is covered and sealed. Stir for 30 minutes to 15 hours, supply oxygen or oxygen containing gas (air or the like) from oxygen or similar gas supply device 9 to oxidize one or both of metallic copper and metallic zinc in leaching object 12 And form a complex ion with the ammonium ion (equation 1) to leach out the copper / zinc component in the object to be leached 12. When the internal pressure in the first closed container 2 rises, the excess gas is dissipated from the diffusion valve 17. Thereafter, from the inside of the first closed vessel 2, the post leaching solution 32 containing the residue of the leaching object 12 is subjected to the next first solid-liquid separation step, filter press, centrifuge, and settling tank And the like to be separated into the residue 14 of the object to be leached and the liquid 33 after leaching after solid-liquid separation containing copper / zinc ammine complex ion. The liquid after leaching after solid-liquid separation is sent to the second closed vessel 20 which is a closed vessel in which the next leachate regeneration step is performed, and a sulfiding agent is charged by the sulfiding agent feeding device. As the sulfiding agent, at least one sulfiding agent selected from gas containing hydrogen sulfide, lithium sulfide, sodium sulfide, sodium hydrogen sulfide, potassium sulfide, potassium hydrogen sulfide, magnesium sulfide and calcium sulfide is used it can. The leached liquid 21 in the second closed vessel 20 is stirred by the stirring device 22, and the copper / zinc ammine complex ion is decomposed to precipitate sulfide, and the ammonium ion is dissolved to form the regenerated liquid 34 (2 formula). When the internal pressure in the second closed container rises, the excess gas is released from the release valve 25. The second leaching solution 21 in the second closed vessel 20 is subjected to the next second solid-liquid separation step as the regeneration liquid 34, such as a second solid-liquid such as a filter press, a centrifuge, and a settling tank The solution is sent to the separation device 30 and separated into a leachate (liquid after regeneration after solid-liquid separation) 35 in which sulfide 31 and ammonium ions are dissolved. The separated leachate 35 is again introduced into the first closed container 2 where the leaching process is performed, and reused as the leachate 1 of copper / zinc in the leaching object 12. In this way, heating time and temperature can be reduced even when a process using a large amount of energy such as heating is not performed or performed, and the amount of the leachate carried out of the system is reduced. By doing this, the amount of drug used can be reduced. The separated copper sulfide and zinc sulfide can be used as a copper / zinc refining material.
Furthermore, by controlling the above-described operation within the control range described below, the amount of drug used is further reduced.

  The copper / zinc ammine complex ion can be formed at a pH of 7.5 to 11.5, and a more preferred pH is pH 9.5 to 10.5. Therefore, the pH of the leachate 1 in the first closed vessel 2 is measured with a pH meter 4, and a pH adjuster such as an aqueous sodium hydroxide solution or a dilute aqueous sulfuric acid solution is charged by a pH adjuster charging device 5, pH 7.5 It is effective to maintain the pH at 11.5, more preferably at pH 9.5-10.5.

  Furthermore, controlling the dissolved oxygen concentration in the range of 1 to 40 mg / L while measuring the dissolved oxygen in the leachate 1 in the first closed vessel 2 with the dissolved oxygen concentration meter 7, and Controlling at least one of controlling the oxygen concentration in the gas phase to be in the range of 2 to 98% by volume while measuring the oxygen concentration in the gas phase part in the closed container 2 with the oximeter 8 In order to carry out, it is preferable to introduce oxygen or a gas containing oxygen (such as air) into the first closed container 2 by means of the oxygen or the like gas supply device 9. Thereby, one or both of the metallic copper and the metallic zinc in the leaching object 12 can be easily oxidized, and the ammine complex ion can be made more easily.

  Furthermore, control the dissolved free ammonia concentration to be in the range of 3 to 50 g / L while measuring the dissolved free ammonia concentration in the leachate 1 in the first closed vessel 2 with the dissolved free ammonia concentration meter 15 Controlling the ammonia concentration in the gas phase to be in the range of 0.6 to 12% by volume while measuring the ammonia concentration in the gas phase in the first closed vessel 2 with the ammonia concentration meter 16 The ammonia solution is replenished into the first closed vessel 2 by the replenishing device 11 in order to perform at least one of the above control, so that the copper / zinc in the leaching object 12 can be more easily converted to the ammine complex ion. can do. The ammonium salt in the ammonia solution is preferably at least one selected from ammonium sulfate, ammonium chloride and ammonium carbonate.

  Furthermore, in the leachate regeneration step, the pH of the leached solution 21 in the second closed vessel 20 is measured with a pH meter 23, and a pH adjuster such as an aqueous sodium hydroxide solution and a dilute aqueous sulfuric acid solution is It is preferable to charge and maintain the pH at 7.5 to 11.5, more preferably at pH 9.5 to 10.5. This is because the liquid after regeneration after solid-liquid separation separated by the solid-liquid separator 30 (leaching liquid) is used again as the leaching liquid 1 in the first closed container 2.

  Furthermore, the oxidation-reduction potential of the leached solution 21 in the second closed vessel 20 is measured by the oxidation-reduction potentiometer 26, and a sulfurizing agent is introduced until the oxidation-reduction potential falls below a certain value, and the second closing. It is preferable to measure the concentration of hydrogen sulfide in the gas phase in the container 20 with a hydrogen sulfide concentration meter 27, and to charge the sulfiding agent until the concentration of hydrogen sulfide becomes a certain value or less. As a result, the copper / zinc ammine complex ion in the leaching solution 21 can be more stably decomposed into copper / zinc sulfide and ammonium ion. It is preferable to obtain the above-mentioned certain value of the redox potential and the certain value of the hydrogen sulfide concentration by experiments in advance.

By controlling within the above control range, the amount of drug used is further reduced.
During the progress of the reactions (4) to (6), which are oxidation reactions, oxygen is consumed, while when the leaching reaction is completed, the oxygen consumption rate decreases, but the oxygen consumption rate Often not zero. When metallic iron and the like are contained in the leaching object, oxidation is performed while consuming a small amount of dissolved oxygen. As a means to determine the termination of the leaching reaction, a method is used in which the presence or absence of oxygen or oxygen-containing gas from the oxygen inflow device 9 and the control of the amount thereof are performed by the dissolved oxygen concentration meter 7 or 8 However, when the feed rate of oxygen or a gas containing oxygen becomes zero (when no feed is performed), it can be determined whether the oxidation reaction has ended. Since oxidized copper / zinc forms an ammine complexing ion in a short time, it may be determined that the ammine complexing reaction has ended when the input rate of oxygen or a gas containing oxygen becomes zero.

The sulfiding agent charged by the sulfiding agent feeding device 28 is at least one selected from a gas containing hydrogen sulfide, lithium sulfide, sodium sulfide, sodium hydrogen sulfide, potassium sulfide, potassium hydrogen sulfide, magnesium sulfide, and calcium sulfide. Although a species of sulfiding agent can be used, it is more preferred to use hydrogen sulfide gas. That is, since aqueous solutions such as sodium sulfide solution and sodium hydrogen sulfide solution contain alkali and water in addition to sulfide ions, it is necessary to add acid for pH adjustment and to separate excess water. It is because there is. In addition, when coke oven gas is charged from the sulfiding agent feeding device 28, hydrogen sulfide and ammonia components are absorbed by the leached liquid 21 in the second closed vessel 20, but hydrogen (H ₂ ) and methane ( Components such as CH ₄ ) are hardly absorbed. In this case, since the internal pressure in the second closed vessel 20 is increased, coke oven gas from which the hydrogen sulfide component has been separated can be recovered from the diffusion valve 25.

  The first closed container 2 in which the leaching step is performed and the second closed container 20 in which the leachate regeneration step is performed may be of a simple closed type. For example, a container in which the first sealed container and the second sealed container are connected to the outside air by an elongated pipe, and it takes a very long time for the gas in the gas phase in the container and the outside air to mix, When the closed container or the second closed container of 1 and the outside air are connected by piping, a water seal may be installed at the end of the pipe to simply shut off the container from the outside air.

  In the leaching step, since the ammine complexation reaction takes time, particularly when oxygen is blown, the ammine complexation reaction is completed by measuring at least one of the dissolved oxygen concentration in the leachate and the oxygen concentration in the gas phase. It is preferable to determine whether it has been done, so batch processing or batch multistage processing is preferable. On the other hand, the leachate regeneration step may be either batch processing or continuous processing. This is because the reaction rate of the sulfide reaction is large.

Method of separating hydrogen cyanide component from coke oven gas Next, one embodiment of a method of separating hydrogen cyanide component from coke oven gas containing hydrogen sulfide will be described based on FIG.
First, the equipment configuration will be described. In the decyanation step, a decyanizing tank 50, a pump 59 for charging the iron-based slurry 57 into the decyanating tank 50, an iron cyanide slurry 58 which overflows from the decyanating tank 50, a coke oven gas before decyanizing ( The line into which COG before decyanation 51 is charged, the post decyanation coke oven gas (also referred to as COG after decyanation) 52 discharged from decyanation tank 50, the oxidation reduction potential in decyanization tank 50, pH And a pH meter 55, and a hydrogen cyanide concentration meter 56 for measuring the concentration of hydrogen cyanide in the COG 52 after decyanation. The pump 59 for feeding the iron-based slurry 57 controls the operation according to the hydrogen cyanide concentration value by the hydrogen cyanide concentration meter 56.

Next, the operation will be described.
In the decyanizing tank 50 filled with the iron-based slurry 57, the COG 51 before decyanation is aerated, and brought into gas-liquid contact, and hydrogen cyanide in the COG 51 before decyanation and iron ions in the iron-based slurry 57 are stable cyanide. The iron cyanide complex is formed, and hydrogen cyanide in COG 51 before decyanation is separated. The concentration of hydrogen cyanide in the COG 52 after decyanation is measured by a hydrogen cyanide concentration meter 56. When the concentration of hydrogen cyanide exceeds a predetermined value, the iron-based slurry 57 is charged into the decyanation tank 50 by the pump 59. The COG 52 after decyanation is introduced into the second closed vessel 20 from the sulfiding agent introduction device 28, and the hydrogen sulfide in the COG 52 after decyanation is copper / zinc in the leached solution 21 in the second closed vessel 20. Can be reacted with the ammine complex ion to form copper sulfide and zinc sulfide, and the solution after leaching can be regenerated into a leachate. In the second closed vessel 20, the decyanated COG 52 from which the hydrogen sulfide component has been removed can be taken out from the diffusion valve 53.

  EXAMPLES Hereinafter, the present invention will be more specifically described by way of examples, but the present invention is not limited to these examples. It is obvious that those skilled in the art can conceive of various modifications or alterations within the scope of the idea described in the claims, and they are naturally within the technical scope of the present invention. It is understood that.

Example 1
Using the apparatus shown in FIG. 3, one of the ammonium sulfate, ammonium carbonate and ammonium chloride shown in Tables 4 and 5 contains a leaching target containing each of iron, copper and zinc shown in Table 4 and Table 5. The aqueous solution containing the above and a sulfiding agent such as sodium hydrogen sulfide aqueous solution as a sulfiding agent are treated according to the following method to leach and separate copper / zinc, and copper / zinc is separated from the solution after leaching, and leaching solution Were regenerated, and the same leaching object was again dipped using the regenerated leaching solution to leach and separate copper / zinc. .

(1) Step 1 (leaching step and first solid-liquid separation step)
2 L (38 g-NH ₃ / L) of an aqueous ammonium solution shown in Tables 4 and 5 were placed in the first closed vessel 2, and the pH was adjusted to the values shown in Tables 4 and 5 with a 20 mass% aqueous NaOH solution. The target for leaching treatment described in Table 4 and Table 5 is placed in the first closed vessel 2, the leachate 1 in the first closed vessel is stirred by the stirring pump 3, and the leachate 1 and the gas phase portion are brought into contact I did. In addition, the dissolved oxygen concentration of the leachate 1 in the first closed vessel 2 is continuously measured with the dissolved oxygen concentration meter 7, and the dissolved oxygen concentration is lower than the dissolved oxygen concentration (DO) described in Table 4 and Table 5 ON-OFF control was performed so that pure oxygen was introduced (30 mL / min) into the closed container 2 of 1). Also, a free ammonia concentration of the leaching solution 1 was continuously measured with an ammonia concentration meter 15, when the free ammonia concentration falls below 5 g / L, Table 4 and aqueous ammonium described in Table 5 (76g-NH 3 / _L) It replenished and the free ammonia concentration in the leachate 1 in the 1st airtight container 2 was hold | maintained for 10 hours so that it might become 5000 ppm or more. After 10 hours, the stirring pump 3 was stopped, and the inside of the first closed container 2 was allowed to stand. The unleached metal iron plate, metal copper plate and metal zinc plate were taken out from the first closed container 2, their weights were measured, and the leaching rate (first time) was calculated.
In addition, when powder such as zinc oxide powder or copper oxide powder is a sample, the solution after leaching is subjected to pressure filtration with solid-liquid separator 10 (pressure filtration apparatus), and after leaching after solid-liquid separation The iron, copper and zinc concentrations were measured, and the leaching rate (first time) from each powder was calculated. The leached solution from which the metal plate was removed, or the leached solution after filtration (after solid-liquid separation) was introduced into the next second closed vessel 20.

(2) Step 2 (Leachate regeneration step and second solid-liquid separation step)
The sulfurization described in Tables 4 and 5 until the oxidation reduction potential (ORP) reaches the values described in Tables 4 and 5 while stirring the leached solution 21 in the second closed vessel 20 by the stirring pump 22. The agent was added to precipitate copper ions and zinc ions forming an ammine complex as sulfides. At that time, the pH of the leached solution 21 in the second closed vessel 20 is measured by the pH meter 23, and the pH of the leachate 1 in the first closed vessel 1 (pH described in Table 4 and Table 5) ± Maintained at 0.5. After the oxidation reduction potential reaches a predetermined value, the leached solution 21 in the second closed vessel 20 is pressure-filtered (solid-liquid separation) with a filtration device to remove the deposited sulfide, and the regenerated leachate is obtained. Obtained. It was confirmed that the metal ion concentration in the regenerated leachate decreased to 10 to 110 mg / L, the total ammonia concentration hardly changed, and that no sulfide ion was present. In Comparative Examples 1-1 and 1-6, since the leaching rate in the leaching step was small, the steps after the leaching solution regeneration step were not performed.

(3) Step 1 (second time, leaching step and first solid-liquid separation step)
Next, the regenerated leachate 35 was re-introduced into step 1, and the objects to be leached described in Table 4 and Table 5 were introduced into step 1, and step 1 was repeated. The leaching rate (second time) at that time is shown in Table 4 and Table 5.

  From Comparative Example 1-1, Examples 1-2 to 1-5, and Comparative Example 1-6, when the pH of the leaching solution is 7 or less or 12 or more, although the metallic zinc plate and the metallic copper plate hardly leach out, the pH of the leaching solution is It turns out that it is good to control to 7.5-11.5.

  From Examples 1-4, 1-7, 1-8 and 1-11, it can be said that leaching with ammonium sulfate, ammonium carbonate and ammonium chloride is possible.

  Moreover, it can be said that metal, an oxide, a hydroxide, and a chloride are applicable as an existence form of copper and zinc from Examples 1-4, 1-7, 1-8, and 1-9.

  Moreover, it can be said from Examples 1-7 and 1-10 that, in the case of metals and oxides, iron hardly leaches out in the leaching solution as the existence form of iron.

  Further, from Examples 1-4, 1-12, and 1-13 to 1-17, sodium sulfide aqueous solution, sodium sulfide aqueous solution, calcium sulfide aqueous solution, lithium sulfide aqueous solution, potassium sulfide aqueous solution, potassium hydrogen sulfide aqueous solution as a sulfurizing agent It can be said that a high leaching rate of copper and zinc can be obtained even using an aqueous solution of magnesium sulfide.

In addition, the amount of the leachate or leachate waste carried out in each example is small, and in Example 1-7, the amount of the leachate adhering when taking out the leaching object from the leaching step is 2 ml, and it is removed from the leachate regeneration step The amount of water in the resulting sulfide was 2 mL, for a total of 4 mL. That is, 0.2% (= 4 mL ÷ 2000 mL) of the leachate is discharged out of the system. On the other hand, the object to be treated for leaching described in Example 1-7 is treated with a leaching solution containing NH ₃ and (NH ₄ ) ₂ CO _{3 in the} presence of oxygen, which is the method described in Patent Document 1, and leaching treatment When copper and zinc in the object are dissolved as ammine complex ions and the residue is removed by filtration, the leaching waste solution is heated to decompose the complex ions, the ammonia and carbonic acid are evaporated, and copper oxide and zinc oxide are recovered. Although the amount of leaching waste liquid adhering when taking out the leaching object from the leaching process is 2 mL, in the leachate regeneration step where the leachate is regenerated into leachate, water is used to absorb the evaporated ammonia and carbonic acid. The amount of water needed was 120 mL. The liquid corresponding to the amount of added water needs to be discharged from the system, so a total of 122 mL will be discharged from the system. That is, 6% of the leachate (= 122 mL 浸出 2000 mL) is discharged out of the system. In Example 1-7, the reaction was performed at normal temperature, and as in Patent Document 1, it was not necessary to heat the leaching waste solution to decompose the complex ions and evaporate the ammonia and carbonic acid, so the energy used was also reduced. . From the above, according to the present invention, it can be said that the amount of the leachate and the solution after leachate discharged out of the system is small, the amount of chemical replenishment is small, and the amount of energy used is small.

(Example 2)
Iron scrap, hot-rolled scale, finely ground hot-rolled scale, blast furnace secondary ash, finely ground blast furnace secondary ash, neutralized sludge shown in Table 6 is a leaching object and leachate 2L described in Table 6 The mixture was leached for 10 hours in (38 g-NH ₃ / L), and the sulfiding agent was charged to a ORP described in Table 6 using the sulfiding agent described in Table 6. As in Example 1, Step 1, Step 2, and Step 2 of the second time were performed, and the leaching rate (first time, second time) was measured. The volume-based average diameter of the hot-rolled scale is 180 μm (hereinafter, the average diameter is indicated on the basis of volume), the finely-grounded hot-rolled scale is obtained by milling the hot-rolled scale, and the average diameter is 21 μm. there were. Similarly, the average diameter of the blast furnace secondary ash was 130 μm, and the average diameter of the blast furnace secondary ash after milling was 24 μm.

  From Examples 2-1 to 2-6, one or more components of iron scrap, hot rolled scale, blast furnace secondary ash, copper and zinc in neutralized sludge can be leached out, and sodium hydrogen sulfide aqueous solution is used. It can be said that the leachate can be regenerated.

  By comparing Examples 2-2 and 2-3, and 2-4 and 2-5, it can be said that the leaching rate of copper or zinc is improved by pulverizing.

(Example 3)
A metallic iron plate and a metallic copper plate shown in Table 7 were treated as leaching targets, and leached for 10 hours in 2 L of leachate (38 g-NH ₃ / L) described in Table 7. The dissolved oxygen concentration (DO) in the leachate at the time of leaching was changed to 0.5 to 50 mg / L. The sulfiding agent was used until it became ORP of Table 7 using the sulfiding agent of Table 7. As in Example 1, Step 1, Step 2, and Step 2 of the second time were performed, and the leaching rate (first time, second time) was measured. The measurement results are shown in FIG.
When the dissolved oxygen concentration is 1 mg / L or more, it can be said that the leaching rate of copper from the metal copper plate is increased. Therefore, it can be said that the dissolved oxygen concentration is preferably 1 mg / L or more.

(Example 4)
A metallic iron plate and a metallic copper plate shown in Table 8 were treated as leaching targets, and leached for 10 hours in 2 L of the leaching solution (38 g-NH ₃ / L) described in Table 8. The oxygen concentration of the gas phase part in the leachate at the time of leaching was changed to 1 to 98% by volume. The sulfiding agent was used until it became ORP of Table 8 using the sulfiding agent of Table 8. As in Example 1, Step 1, Step 2, and Step 2 of the second time were performed, and the leaching rate (first time, second time) was measured. The measurement results are shown in FIG.
When the oxygen concentration in the gas phase portion is 2% by volume or more, it can be said that the leaching rate of copper from the metal copper plate is increased. Therefore, it can be said that the oxygen concentration in the gas phase part is preferably 2% by volume or more.

(Example 5)
A metallic iron plate and a metallic copper plate shown in Table 9 were treated as leaching targets, and leached for 10 hours in 2 L of leachate described in Table 9. The dissolved oxygen concentration (DO) in the leachate at the time of leaching was adjusted to 10 mg / L, the f-NH ₃ concentration in the leachate was changed to 1 to 70 g / L, and the metal copper plate was leached.
The sulfurizing agents listed in Table 9 were charged until the ORP listed in Table 9 was reached. As in Example 1, Step 1, Step 2, and Step 2 of the second time were performed, and the leaching rate (first time, second time) was measured. The measurement results are shown in FIG.
When the f-NH ₃ concentration in the leaching solution is 3 g / L or more, it can be said that the leaching rate of copper from the metal copper plate becomes extremely high. Therefore, it can be said that the f-NH ₃ concentration in the leachate is preferably 3 g / L or more.

(Example 6)
A metallic iron plate and a metallic copper plate shown in Table 10 were treated as leaching targets, and leached for 10 hours in 2 L of leachate described in Table 10. The dissolved oxygen concentration (DO) in the leachate at the time of leaching was adjusted to 10 mg / L, and the NH ₃ concentration in the vapor phase of the leaching tank was changed to 0.3 to 15% by volume to leach the metal copper plate.
The sulfurizing agents listed in Table 10 were charged until the ORP listed in Table 10 was reached. As in Example 1, Step 1, Step 2, and Step 2 of the second time were performed, and the leaching rate (first time, second time) was measured. The measurement results are shown in FIG.
It can be said that the leaching rate of copper from the metal copper plate becomes extremely high when the NH ₃ concentration in the vapor phase of the leaching tank is 0.6% by volume or more. Therefore, it can be said that the NH ₃ concentration in the gas phase of the leaching tank is preferably 0.6% by volume or more.

(Example 7)
A metallic iron plate and a metallic copper plate shown in Table 11 were treated as leaching targets, and leached for 10 hours in 2 L of leachate described in Table 11. The metallic copper plate was leached by adjusting the dissolved oxygen concentration (DO) in the leachate to 10 mg / L, the pH of the leachate to 10, and the NH ₃ concentration in the vapor phase of the leacher to 10% by volume at the time of leaching. The sulfurizing agents listed in Table 11 were charged until the ORP reached −70 to −230 mV. Step 1, Step 2, Step 2, Step 2, Step 1, Step 2, Step 3, Step 3 were carried out by the method according to Example 1, and the leaching rate (first, second, third) was measured. . The measurement results are shown in FIG.
It can be said that the leaching rate of copper from the metal copper plate becomes extremely high after the second leaching when the ORP of the solution after leaching at pH 10 is -150 mV or more. Moreover, precipitation of copper sulfide could be observed in the region where ORP is -100 mV or less. Since the ORP changes with pH and dissolved components, it is preferable to set it by experiment, but in Example 7, it may be preferable to manage ORP at -150 mV to -100 mV.

(Example 8)
A metallic iron plate and a metallic copper plate shown in Table 12 were treated as leaching targets, and leached for 10 hours in 2 L of leachate described in Table 12. The metallic copper plate was leached by adjusting the dissolved oxygen concentration (DO) in the leachate to 10 mg / L, the pH of the leachate to 10, and the NH ₃ concentration in the vapor phase of the leacher to 10% by volume at the time of leaching. Using the sulfurizing agent listed in Table 12, extract a portion of the leached solution in the second closed vessel, place it in a third closed vessel (H ₂ S measurement vessel) which is a closed vessel, and adjust its pH to Adjusted to 10. The sulfiding agent described in Table 12 was charged until the hydrogen sulfide concentration in the gas phase of the third closed vessel was 1 ppm. Step 1, Step 2, Step 2, Step 2, Step 1, Step 2, Step 3, and Step 1 were performed according to the method according to Example 1, and the leaching rate (first, second, third) was measured. The measurement results are shown in FIG.
When the pH of the third closed vessel is 7 or less, more preferably 5 or less, the hydrogen sulfide component in the solution after leaching is easily evaporated, and the sensitivity to the amount of hydrogen sulfide input is increased, and sulfurization is caused. Excessive input of hydrogen gas is likely to be reduced, and copper is likely to leach out of the metal copper plate after the second leaching. From this, it can be said that it is preferable to set the pH of the hydrogen sulfide concentration measurement tank to 7 or less, more preferably 5 or less.

(Example 9)
The blast furnace secondary ash shown in Table 13 was subjected to leaching treatment, and was leached for 10 hours in 2 L of leachate described in Table 13. Zinc was leached by adjusting the dissolved oxygen concentration (DO) in the leachate to 10 mg / L, the pH of the leachate to 10, and the NH ₃ concentration in the vapor phase of the leacher to 10% by volume at the time of leaching. ORP is -150 mV using coke oven gas (also referred to as COG before decyanation) containing hydrogen sulfide and cyanide as a sulfiding agent, or coke oven gas from which cyanide is removed (also referred to as COG after cyanide) Until then, the gas which is a sulfiding agent was introduced. Step 1, Step 2, Step 2, Step 2, Step 1, Step 2, Step 3, Step 3 were carried out by the method according to Example 1, and the leaching rate (first, second, third) was measured. . Table 14 shows the composition of COG before decyanation and COG after decyanation. The measurement results are shown in FIG. After decyanation, COG is COG from which decyanation COG is aerated from an iron slurry (iron hydroxide, Fe concentration 8.2 g / L) to remove the cyan component.
By degassing the iron slurry from the components before decyanizing COG and after decyanating COG (Table 14), the cyan component is absorbed by 96% while the ammonia and hydrogen sulfide are only 12% and 17% respectively It can be seen that it has changed to hydrogen sulfide required to regenerate the liquid after leaching and COG after decyanation containing an ammonia component which is a leaching agent.
When COG before decyanation was used as the sulfiding agent, the Zn leaching rate after the second time decreased, but when COG after decyanizing was used as the sulfiding agent, the Zn leaching rate hardly decreased even after the second time. From this, it can be said that it is easy to regenerate the leached solution with COG after decyanation by removing the cyan component in advance.

1 leachate in the first closed container 2 first closed container (leaching tank)
3 Stirring device 4 pH meter 5 pH adjusting agent feeding device 7 dissolved oxygen concentration meter 8 oxygen concentration meter 9 oxygen etc. air feeding device 10 first solid-liquid separation device 11 replenishment device 12 leaching object 14 residue of leaching object 15 dissolved free ammonia concentration meter 16 ammonia concentration meter 17 diffusion valve 20 second closed vessel (leaching liquid regeneration tank)
21 Second leached liquid in the closed vessel 22 Stirrer 23 pH meter 24 pH adjuster charging device 25 Spreading valve 26 Redox potentiometer 27 Hydrogen sulfide concentration meter 28 Sulfurizing agent charging device 30 Second solid-liquid separator 31 Sulfide (CuS, ZnS)
32 Liquid after leaching 33 Liquid after leaching after solid-liquid separation 34 Liquid after regeneration 35 Liquid leaching (liquid after regeneration after solid-liquid separation)
36 Measurement sample (to third sealed container)
50 Decyanation tank 51 Coke before coke oven gas (COG before cyanide removal)
52 After decyanating coke oven gas (after decyanizing COG)
53 release valve 54 oxidation-reduction potentiometer 55 pH meter 56 hydrogen cyanide concentration meter 57 iron-based slurry 58 iron cyanide slurry 59 pump 70 third closed vessel 72 stirrer 73 pH meter 74 pH adjustment valve 77 hydrogen sulfide (H ₂ S) concentration Total 78 acids (acid aqueous solution)

Claims (11)

In the first closed container, containing an iron component, and containing one or both of copper and zinc in the form of any one or more of metal, oxide, hydroxide and chloride A solid leaching object is brought into contact with a leaching solution containing an ionized ammonium salt in the range of pH 7.5 to 11.5, and one or both of the copper and zinc in the solid leaching object are A leaching step of eluting in the leaching solution as an ammine complex ion to form a leaching solution containing the ammine complex ion and the balance of the solid leaching target;
A first solid-liquid separation step of solid-liquid separation of the liquid after leaching to separate the liquid after leaching after solid-liquid separation, which is a liquid phase containing the ammine complex ion, and the remaining part of the solid leaching target When,
In a second closed vessel, the liquid after leaching after solid-liquid separation contains a gas containing hydrogen sulfide, lithium sulfide, sodium sulfide, sodium hydrogen sulfide, potassium sulfide, potassium hydrogen sulfide, magnesium sulfide, and calcium sulfide At least one sulfiding agent selected from among them is added to decompose ammine complex ions in the solution after leaching after the solid-liquid separation to precipitate one or both of copper and zinc as a solid sulfide and to ionize it. A leaching solution regeneration step of regenerating the recovered ammonium salt into a post-regeneration solution containing the solid sulfide and the ammonium salt;
The liquid after liquid regeneration is separated into solid and liquid to separate into solid sulfide containing one or both of copper and zinc and liquid after liquid / solid separation which is liquid phase containing the ionized ammonium salt 2 solid-liquid separation step,
A method for separating copper or zinc from an object to be leached, comprising using the liquid after regeneration of the liquid phase separated in the second solid-liquid separation step as a leachate used in the leaching step.   The method for separating copper or zinc from a leaching target according to claim 1, wherein the solid leaching target is mainly composed of an iron component.   The solid leaching object is at least one selected from scraps serving as raw materials for steel production, and scale, dust, and sludge as by-products from the steel production process. The separation | isolation method of copper or zinc from the leaching process target object as described.   The method for separating copper or zinc from a leaching object according to claim 3, wherein the leaching object is at least one pulverized material selected from scale and dust.   The method for separating copper or zinc from a leaching target according to any one of claims 1 to 4, wherein an oxygen-containing gas is blown into the leaching solution in the leaching step. When the dissolved oxygen concentration in the leachate in the first closed container falls below a predetermined value A in the range of 1 to 40 mg / L, and the oxygen concentration in the gas phase in the first closed container is 2 When it falls below a predetermined value B in the range of -98 vol%, the presence or absence of blowing is controlled so that the oxygen-containing gas is blown into the leachate, when at least one of the conditions is satisfied,
A state in which the dissolved oxygen concentration in the leachate in the first closed vessel is not less than the predetermined value A in a state where the blowing of the oxygen-containing gas is not performed, and the gas phase in the first closed vessel The method for separating copper or zinc from the object to be leached according to claim 5, wherein the leaching step is judged to be complete when the state where the oxygen concentration in the substance is the predetermined value B or more continues for a predetermined time or more.   In the leaching step, the free ammonia concentration in the leachate in the first closed vessel is controlled to a range of 3 to 50 g / L, and the ammonia concentration in the gas phase in the first closed vessel is determined. The method for separating copper or zinc from the object to be leached according to any one of claims 1 to 6, wherein at least one of controlling in the range of 0.6 to 12% by volume is performed.   In the leachate regeneration step, the addition amount of the sulfurizing agent to be added to the leached solution in the second closed vessel is within the range of the redox potential for forming the solid sulfide, which is obtained in advance. The method for separating copper or zinc from a leaching object according to any one of claims 1 to 7, wherein the method is adjusted.   In the leachate regeneration step, a portion of the leachate after leaching in the second closed vessel is continuously taken into the third closed vessel to adjust the pH to 7 or less, and then the inside of the third closed vessel is obtained. The concentration of hydrogen sulfide in the gas phase part is continuously measured, and when the concentration of hydrogen sulfide in the gas phase part rises to a predetermined value, the addition of the sulfiding agent into the second closed vessel is stopped. A method of separating copper or zinc from a leaching object according to any one of claims 1 to 8.   The copper from the object to be leached according to any one of claims 1 to 9, wherein the hydrogen sulfide-containing gas is at least one selected from hydrogen sulfide gas and coke oven gas. Or a method of separating zinc.   The method for separating copper or zinc from the object to be leached according to any one of claims 1 to 10, wherein the gas containing hydrogen sulfide is a gas from which a hydrogen cyanide component has been separated and removed in advance.