WO2018117771A1 - Method for recovering nickel and cobalt from nickel, iron, and cobalt-containing raw material - Google Patents

Abstract

The present invention relates to a method for recovering nickel and cobalt from a nickel, iron, and cobalt-containing raw material. According to the present invention, high concentrations of valuable metals, such as nickel and cobalt, can be recovered from a raw material containing nickel, iron, and cobalt, and especially, the concentrations of nickel and cobalt are low and the concentration of iron is high, and thus when nickel is leached, a relatively large amount of iron is leached, whereas a small amount of nickel is leached. Therefore, the present invention can be more suitably applied in the smelting of nickel ore in which the separation of iron and nickel is difficult.

Description

Recovery of nickel and cobalt from nickel, iron and cobalt containing raw materials

The present invention relates to a process for recovering nickel and cobalt from nickel, iron and cobalt containing raw materials.

Ore containing nickel and iron is laterite (Laterite), which is a nickel oxide ore, and may be classified into limonite, saprolite, and the like according to the mineral phase. These ores are passivated and therefore resistant to acids, resulting in slow dissolution reactions to acids. Therefore, as a method for effectively leaching nickel, methods for recovering nickel by dissolving it in an acid in an autoclave under high temperature and high pressure have been proposed, which is called 'HPAL (High Pressure Acid Leaching)'.

When the nickel leaching reaction is performed at room temperature, the nickel recovery rate does not exceed 85% even after leaching for several months or more.However, the HPAL method enables the leaching of 90% or more of nickel within two hours. It can be called a method. As a technique regarding nickel recovery by such an HPAL method, patent documents 1 and 2 are mentioned.

However, HPAL method should be carried out under the high temperature and high pressure of the autoclave, and it is known that it can be mainly used only for the titanium material due to its strong acidity, and thus has the disadvantage of very high equipment cost and high maintenance cost. In addition, since a caustic soda, which is an expensive precipitant, or an environmentally harmful precipitant such as H ₂ S must be used for nickel concentration, there is also a problem in that a facility cost for treating this is increased. In addition, when leaching limonite nickel ore using the above method, high-speed leaching is possible, but limonite ore has a high iron content and a low nickel content, and when leaching nickel by acid dissolution, iron is leached relatively. On the other hand, nickel is leached in small amounts, there is a problem that it is difficult to separate iron and nickel from the leach.

As a technique for improving said problem, the technique disclosed by patent document 3, 4, 5 etc. is mentioned. Patent Documents 3 and 4 disclose methods for effectively concentrating nickel by recovering nickel and iron from ore with low nickel quality and recovering ferronickel from these concentrates, and Patent Document 5 discloses a process by-product. A method of improving the nickel content of a nickel concentrate after precipitation by using the obtained roasted iron ore as a slurry for precipitation after reduction is disclosed.

However, in the case of the above method, a large amount of impurities such as Mg and Si, in addition to nickel and iron, are still included in the reducing raw material for precipitation, so that by-products such as slag are generated when recovering ferronickel after precipitation. In addition, although the iron content is higher than nickel after precipitation, it can be used as ferronickel, but there is a disadvantage that it is not suitable for producing high-purity nickel having a high nickel content.

[ Prior Art Document ]

[ Patent Literature ]

(Patent Document 1) Korean Unexamined Patent Publication No. 10-2007-7020915

(Patent Document 2) Japanese Unexamined Patent Publication No. 2010-031341

(Patent Document 3) Korean Registered Patent No. 10-1353721

(Patent Document 4) Korean Registered Patent No. 10-1359179

(Patent Document 5) Korean Registered Patent No. 10-1657810

The present invention has been made to solve the above problems, and an object thereof is to provide a method for efficiently recovering nickel and cobalt from a raw material containing nickel, iron, and cobalt.

According to one aspect of the invention, the step of reducing the raw material containing nickel, iron and cobalt to a reducing gas containing hydrogen; Adding acid to the reduced raw material and leaching to obtain a solution containing nickel, iron and cobalt ions; Preparing a purified solution from which impurities are removed by adding a hydroxide containing iron or magnesium to the solution; Depositing nickel and cobalt by administering reduced iron for precipitation to the tablet solution containing nickel and cobalt ions; Adding an acid to the precipitate obtained in the precipitation step and leaching to obtain a solution containing nickel, iron and cobalt ions; Adding an alkaline agent to the nickel, cobalt and iron-containing solution and oxidizing with a gas containing oxygen to remove iron; And adding an alkali agent to the solution to obtain nickel and cobalt hydroxides.

The amount of the reduced iron for precipitation may be 1.5 to 2.5 times the molar sum of nickel and cobalt ions present according to the following relational formula.

[Relationship 1]

Reduced iron input (seed ratio) = (Metal Fe content in reduced iron for precipitation) / (Ni + Co ion content in the leaching solution)

The reduced iron for precipitation may be obtained by indirectly reducing the iron chloride roasted iron ore obtained from the by-product of the nickel smelting process with solid carbon or reducing gas.

The reduction rate of the reduced iron for precipitation may be 80 to 99%.

A particle size of the reduced iron for precipitation may be 5 μm or less.

When reducing the iron chloride roast iron ore with a reducing gas, the reduction temperature may be 500 ~ 950 ℃.

When reducing the iron chloride roast iron ore with a reducing gas, the reduction temperature may be 500 ~ 950 ℃.

The iron chloride roast iron ore is obtained by evaporating and concentrating a solution containing iron and chlorine ions generated as a filtrate in the nickel smelting process to obtain a concentrated solution; Crystallizing the concentrated solution to obtain iron chloride crystals; Solid-liquid separation of the iron chloride crystals and the slurry; And roasting the iron chloride crystals to obtain iron chloride roasted iron ore.

The solution containing iron and chlorine ions generated as a filtrate in the nickel smelting process is

A leaching step of dissolving nickel ore containing nickel and iron with hydrochloric acid to obtain a leaching solution in which nickel and iron ions are leached; PH adjustment step of adjusting the pH by adding an alkali agent to the obtained leachate, and solid-liquid separation of the solid phase impurities in the leachate; Adding nickel ore containing nickel and iron to the leaching solution and then depositing nickel with ferronickel; And it may be a filtrate generated in the nickel smelting process comprising a precipitate recovery step of filtering and recovering the solid precipitate by filtration.

The acid introduced into the reduced raw material may be a precipitated filtered filtrate with an ion exchange resin to recover residual nickel and cobalt, and the ion exchange resin may be stripped with an acid to include an acid containing nickel and cobalt. have.

Acids containing nickel and cobalt obtained by the ion exchange may be re-introduced into the leaching process.

The alkaline agent may be at least one selected from calcium hydroxide or calcium carbonate.

The nickel and cobalt hydroxides may be leached into sulfuric acid and solvent extracted to prepare nickel sulfate and cobalt sulfate.

In the step of obtaining nickel cobalt hydroxide by adding alkali, the chlorine component and calcium component in the leachate may be removed in the form of calcium chloride.

It may be to add H ₂ S instead of an alkaline agent.

According to the present invention, valuable metals such as nickel, cobalt, and the like can be recovered from a raw material containing nickel, iron, and cobalt. In particular, the nickel concentration is low, the iron concentration is high, and iron is relatively high when leaching nickel. While leached, nickel may be more suitably applied in the case of small leaching, which makes it difficult to separate iron and nickel.

Figure 1 schematically shows a flow chart of the nickel and cobalt recovery method according to an embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described with reference to various examples. However, embodiments of the present invention may be modified in various other forms, and the scope of the present invention is not limited to the embodiments described below.

The present invention relates to a method for producing a high concentration of nickel concentrate from nickel, iron and cobalt-containing raw material, according to one aspect, reducing the raw material containing nickel, iron and cobalt with a reducing gas containing hydrogen; Adding acid to the reduced raw material and leaching to obtain a solution containing nickel, iron and cobalt ions; Preparing a purified solution from which impurities are removed by adding a hydroxide containing iron or magnesium to the solution; Depositing nickel and cobalt by administering reduced iron for precipitation to the tablet solution containing nickel and cobalt ions; Adding an acid to the precipitate obtained in the precipitation step and leaching to obtain a solution containing nickel, iron and cobalt ions; Adding an alkaline agent to the nickel, cobalt and iron-containing solution and oxidizing with a gas containing oxygen to remove iron; And adding an alkali agent to the solution to obtain nickel and cobalt hydroxides.

The nickel iron-containing raw material to which the present invention can be applied is not particularly limited, and may be applied as long as it contains nickel and iron, and preferably nickel ore, for example, nickel ore such as limonite and sapolite Can be mentioned.

Nickel ore varies depending on the type of ore, but usually contains 1-2.5% Ni and 15-55% Fe. Among these, limonite ore has a low nickel concentration of 1-1.8% and an iron concentration of 30-55. High in% The present invention can be effectively applied even in recovering nickel from such relatively low nickel content of limonite. Hereinafter, a method for producing a nickel concentrate from the nickel, iron and cobalt-containing raw materials of the present invention will be described in detail.

Pretreatment of raw materials containing nickel, iron and cobalt

In recovering nickel from the nickel, iron, and cobalt-containing raw materials, the nickel, iron, and cobalt-containing raw materials can be effectively reduced in the reduction step, and may be subjected to a pretreatment step as necessary. This pretreatment process includes drying, grinding and firing steps.

Nickel, iron, and cobalt-containing raw materials typically contain about 20-40% adhered water and about 10% crystalline water. In the state containing such adhering water, the grinding efficiency is lowered, and when the nickel iron-containing raw material is fired and then pulverized, there is a risk of causing a load on the grinding equipment due to high heat. Therefore, it is preferable to dry a nickel iron containing raw material before grind | pulverizing to microparticles | fine-particles, and it will not specifically limit, if the said adhering water can evaporate. For example, it can carry out in the temperature range of 100-200 degreeC.

In the case where the nickel, iron and cobalt-containing raw materials are pulverized after drying, the particle size is preferably 1 mm or less. Pulverizing the particle size to 1 mm or less is preferable for reducing and leaching efficiency improvement. The lower limit of the particle size is not particularly limited, but is preferably 10 µm or more for the efficiency of the grinding step.

On the other hand, the crystal water may not be removed in the drying process, and may cause a decrease in the reaction efficiency in the reduction reaction. The calcining treatment may be performed in a range of 250 to 850 ° C. depending on the kind of ore.

Reducing the raw material containing nickel, iron and cobalt with a reducing gas containing hydrogen

The nickel, iron, and cobalt-containing raw materials are reduced to obtain nickel, iron, and cobalt-containing raw materials. The reduction can be performed at a temperature range of 550 to 950 ° C. using a reducing gas containing hydrogen as the reducing agent.

If the reduction temperature is less than 550 ° C, the reduction is not sufficient, the recovery rate during subsequent leaching is low, the precipitation efficiency may also be lowered. As the reduction temperature is increased, the leaching yield and precipitation efficiency may be increased. However, when the reduction temperature is increased, additional reduction efficiency may not be increased, and workability due to intergranular sintering may be reduced.

It is preferable to use the gas containing hydrogen as said reducing gas. CO gas may be used instead of hydrogen, but should be reduced at a high temperature of 1000 ° C. or higher, and the activity of the powder reduced at high temperature is lowered, thereby lowering the leaching rate and further lowering the precipitation efficiency.

The reducing gas may be a gas containing hydrogen, hydrogen may be used alone, and inert gas may be used together. Helium, argon, carbon dioxide, nitrogen, etc. are mentioned as said inert gas. Other examples that can be used as the hydrogen-containing reducing gas include Cokes Oven Gas (COG) containing 50% or more of hydrogen generated in an iron ore smelting process, or gas generated in a methane hydrogen reforming reaction. And hydrogen-containing LNG reformed gas containing 65% or more.

Hydrogen contained in the reducing gas is reduced by reacting with oxygen of nickel and iron present in an oxidized state in nickel, iron and cobalt-containing raw materials to generate water. As an example, the theoretical reduction reaction when using limonite ore is shown in the following formula (1).

_{(Ni 0. 1 Fe 0.} 9) OFe 2 O 3 + 4H 2 = (Ni 0. 1 Fe 0 .9) + 2Fe + 4H 2 O Equation (1)

The amount of hydrogen included in the reducing gas may be added in excess of the theoretical equivalent ratio for efficient reduction reaction. However, in consideration of the increase in the process cost, it may be included in the number of moles of 1 to 5 times, 2 to 5 times or 2 to 4 times the theoretical equivalent ratio.

The nickel, iron, and cobalt-containing raw materials reduced by such a reaction can be obtained, and hydrogen which has not participated in the reaction of the added hydrogen can be recovered and re-introduced into the process.

An acid is added to the reduced raw material and leached to form nickel, iron and Cobalt ions  Step of obtaining a solution

In the present invention, after slurrying the reducing material, acid is added to the slurry to dissolve and leach nickel, iron, and cobalt contained in the reducing material in the slurry, so that nickel is nickel ions, iron is iron ions, and cobalt is cobalt. Ionize with ions. As the leaching acid, hydrochloric acid or sulfuric acid may be used.

In addition, the acid is an acid obtained by treating the filtered filtrate after the precipitation step described below with an ion exchange resin to recover residual nickel and cobalt, and removing the resin with an acid to mix an acid containing nickel and cobalt with a leaching acid. Can be. The ion exchange resin may be typically bis-picolylamine (Bis-picolylamine), in addition to the resin that selectively adsorbs nickel and cobalt may be used. As such, by using an acid containing nickel and cobalt with the leaching acid to dissolve the nickel and iron cobalt, the nickel and cobalt filtered without precipitation in the precipitation step may be further recovered.

In general, when the reducing raw material reduced by the reduction reaction of the formula (1) is leached into an acid, the reaction is carried out as shown in the following formulas (2) and (3) to dissolve the ferronickel in the reducing raw material by the acid to ferronickel ion. Is leached.

_{(Ni 0. 1 Fe 0 .9} ) + 2Fe + 6HCl = (Ni 0. 1 Fe 0. 9) Cl 2 + 2FeCl 2 + 3H 2 Equation (2)

_{(Ni 0. 1 Fe 0 .9} ) + 2Fe + 3H 2 SO 4 = (Ni 0. 1 Fe 0. 9) SO 4 + 2FeSO ₄ + 3H ₂ formula (3)

In order to leach such reducing raw materials into an acid, when hydrochloric acid is used as the acid, hydrochloric acid must be added at a molar number not less than twice the number of moles of (Fe + Ni) as shown in the above formula (2). However, when adding hydrochloric acid more than four times the number of moles of (Fe + Ni), no further leaching efficiency improvement is obtained. Therefore, it is preferable to add in the range of two times to four times the number of moles of (Fe + Ni). Do. On the other hand, when sulfuric acid is used as the acid, as can be seen from the above formula (3), it is preferable to add a mole number of one or more times and two times or less of the number of moles of (Fe + Ni) of the nickel iron-containing raw material.

Preparing a purification solution from which impurities are removed by adding hydroxide containing iron or magnesium to the solution;

On the other hand, oxides such as Al ₂ O ₃ , SiO ₂ , and Cr ₂ O ₃ contained in nickel, cobalt, and iron-containing raw materials hardly occur by acid, and remain as solid residues, but some are dissolved by acid. And elutes into the leach solution. Eluted Al, Si, Cr, and the like are elements that may degrade the precipitation ability and the quality of nickel, cobalt and iron precipitates in the subsequent precipitation step, it is preferable to remove before the precipitation step.

Elements such as Al, Si, Cr, and the like dissolved in the leach liquor can be removed by precipitation with a solid hydroxide by adding an alkaline agent to the leach liquor to change the pH of the leach liquor. At this time, the alkali agent added for adjusting the pH of the leaching solution is not particularly limited, and may be used without limitation as long as it can increase the pH of the leaching solution. For example, hydroxides of metals such as Ca, Mg, Fe, and Ni, and oxides such as CaO and MgO may be used alone or in combination.

Although the quantity of the alkaline agent added to a leach liquid is not specifically limited, It is preferable to add to the extent which can adjust pH of a leach liquid to the range of 1.5-3.5. The pH of the leaching solution is generally high in acidity of 1 or less by the added acid, and when the pH is adjusted in the above range, impurities such as Al, Si, Cr, etc. in the solution are effectively precipitated as hydroxides. However, if the pH exceeds 3.5 when the alkaline agent is added, nickel, cobalt, and iron in the solution may precipitate out of the hydroxide, thereby reducing the recovery rate.

The alkali agent added for adjusting the pH of the leachate is not particularly limited and may be used without limitation as long as the pH of the leachate may be increased. For example, hydroxides of metals such as Ca, Mg, Fe, and Ni and oxides such as CaO and MgO may be used alone or in combination.

The solid residue precipitated as described above is very easy to be separated by filtration, so that a leaching solution containing nickel, cobalt, iron, and ions can be obtained by separating with a solid-liquid separator such as a filter press or a decanter.

Precipitating nickel and cobalt by administering reduced iron for precipitation to the tablet solution containing nickel and cobalt ions.

The concentrated nickel, iron and cobalt ions are precipitated into a nickel concentrate. In the present invention, when the nickel concentrate is precipitated, reduced iron, which is indirectly reduced by solid carbon or a reducing gas, is used as a seed material for precipitation, and may be preferably in powder form.

When the precipitated reduced iron is added to the nickel, iron and cobalt ion-containing solution (leaching solution), the nickel of iron and nickel ions dissolved by the reaction as shown in the following formula (4) or (5) is reduced to Substitution precipitates with nickel concentrate metal by iron.

(FeCl ₂ + NiCl ₂ + CoCl ₂ ) + 3Fe = FeNiCo + 3FeCl ₂ Formula (4)

(FeSO ₄ + NiSO ₄ + CoSO ₄ ) + 3Fe = FeNiCo + 3FeSO ₄ Formula (5)

The principle of the substitution reaction as described above is due to the natural potential difference between iron, nickel and cobalt, and the battery is formed by the natural potential difference between the iron in the iron and nickel ion-containing solution and the iron in the precipitated iron powder. The dissolution reaction by oxidation is progressed, and the reaction in which nickel ions in the iron and nickel ion-containing solution are reduced and precipitated at the negative electrode site proceeds. The reaction proceeds by a mechanism such as cobalt and railroad, and a reaction in which cobalt ions are reduced and precipitated proceeds.

The reduced iron for precipitation requires very high activity to enable efficient precipitation recovery of nickel. Reduced iron having such a high activity can be obtained by reducing the iron oxide obtained by roasting the iron chloride crystals in the process at 700 to 900 ℃ hydrogen.

More specifically, iron chloride roast iron ore obtained from the by-product of the nickel smelting process can be directly reduced with solid carbon or reducing gas to obtain reduced iron for precipitation.

The iron chloride roasted iron ore may be obtained from a solution containing iron and chlorine ions generated as a filtrate in a nickel smelting process for recovering nickel using a hydrochloric acid solution from a nickel ore containing nickel and iron.

An example of a process for obtaining iron chloride roasted iron ore used in the present invention is as follows. Obtaining a concentrated solution by evaporating and concentrating a solution containing iron and chlorine ions generated as a filtrate in a nickel smelting process of recovering nickel using a hydrochloric acid solution from a nickel ore containing nickel and iron; Crystallizing the concentrated solution to obtain iron chloride crystals; Solid-liquid separation of the iron chloride crystals and the slurry; It may be obtained by a process comprising the step of roasting the iron chloride crystals to obtain iron chloride roasted iron ore.

The iron ion and chloride ion containing solution can be obtained by the following process. That is, a leaching step of dissolving nickel ore containing nickel and iron with hydrochloric acid to obtain a leaching solution in which nickel and iron ions are leached; PH adjustment step of adjusting the pH by adding an alkali agent to the leaching solution, and solid-liquid separation of the solid phase impurities in the leaching solution; Adding nickel ore containing nickel and iron to the leaching solution and then depositing nickel with ferronickel; And it may be a filtrate generated in the nickel smelting process comprising a precipitate recovery step of filtering and recovering the solid precipitate by solid-liquid separation from the precipitate.

On the other hand, when reducing the iron chloride roast iron ore using a reducing gas, a temperature of 500 ~ 950 ℃ is preferred. If the reduction temperature is less than 500 ° C, Fe ₂ O _{3, which} is the Fe oxide of roasted iron ore, does not go through FeO, which is a reducing intermediate phase, and has a long reduction time due to kinetic problems such as reduction from Fe ₃ O ₄ to Fe. When the temperature is higher than 950 ° C, reduction occurs, so that Fe, which is reduced to an excessive temperature, is sintered or energy is excessive. As the reducing gas, a gas containing hydrogen, CO, or a mixed gas thereof, or at least one of hydrogen and CO may be used. For example, the reducing gas may be 100% hydrogen or 100% CO or mixed gas such as hydrogen and CO mixed gas or hydrogen + CO + LNG reforming gas or COG.

When the iron chloride roast iron ore is reduced using solid carbon as the reducing agent, the reduction temperature is preferably 700 to 1200 ° C. If the reduction temperature is less than 700 ℃ there is a problem that takes a long reduction rate, if the 1200 ℃ or more, reduced Fe is sintered or excessive energy takes a problem in terms of economics. Coal, coke, or the like may be used as the solid carbon.

The precipitated reduced iron may contain 5 wt% or less of elements such as Fe, Ni, Mg, Si, and Al, and preferably 3 wt% or less. For example, the precipitation-reduced iron for reducing is Fe: 58 ~ 72% by weight, Ni: 1% by weight or less, the total content of Mg, Si and Al: 5% by weight or less, preferably 3% by weight or less, the rest is oxygen and It may contain other impurities.

On the other hand, the reduction rate of the reduced roasted roast iron is preferably 80 to 99%. When the reduction rate is less than 80%, it is easy to secure a deposition rate of Ni of 97% or more in the precipitation process, but the Ni content of the Ni concentrate after precipitation is low due to the high content of impurities such as unreduced oxygen in the precipitation roasting iron. There is a disadvantage that the cost of the process increases. When the reduction rate exceeds 99%, there is a low impurity advantage, but after the reduction, the metal Fe in the roasting metal for reduction after precipitation has a disadvantage in that the precipitation rate is reduced due to the large particle size due to sintering, etc., and also 95% considering the additional reduction cost High reduction rates in excess of are undesirable.

It is preferable that the average particle size of the said roasting reduced iron is 5 micrometers or less. The reason for limiting the particle size of the precipitated roasted reduced iron is to increase the specific surface area for the smooth reaction of the metal Fe in the precipitated roasted reduced iron in the solution and Ni ions in the leached solution during the precipitation process. Particle size can be controlled through a general dry / wet crushing process.

In addition to iron oxide obtained from the iron chloride crystals, if the specific surface area, etc. is high, iron oxide or reduced iron having high activity after reduction may be applied to the present invention.

The amount of reduced iron used for precipitation added to the iron, nickel, and cobalt ion-containing solution to reduce the nickel and cobalt may be adjusted according to the amount of the reduced raw material used for leaching, and the use ratio of the iron powder may be precipitated. It is very important as a factor in determining the recovery rate and the nickel concentration of the final product obtained and the ratio of iron and nickel.

In the present invention, the input amount of the reduced iron for precipitation is input differently according to the amount of nickel in the iron and nickel ion-containing solution, and in order to satisfy the nickel recovery rate of 95% or more, the input amount defined by the following Equation 1 is 1.5 to 2.5 times by weight. It is desirable to satisfy.

Seed ratio = (Fe content in reduced iron for precipitation) / (Ni + Co ion content in leaching solution)

Equation 1 is a formula defining the amount of the iron powder for precipitation in consideration of the content of nickel and cobalt in the solution to be precipitated, the metal iron in the reduced iron for precipitation of the formula (4) and (5) and leaching In consideration of the precipitation reaction of the nickel ions in the solution, it is preferable to add a reduced iron for precipitation containing 1.5 to 2.5 times the metal iron of nickel and cobalt content in the leaching solution.

When the input amount is less than 1.5 times, the amount of precipitated iron powder is small, so that the nickel content of the nickel concentrate after precipitation is very high such that 40% or more is possible, but there is a possibility that nickel ions which do not participate in the precipitation reaction in solution may exist. It is not good in terms of recovery rate, and when it is 2.5 times or more, a high recovery rate of nickel can be as high as 99%. However, the nickel content in the nickel concentrate after precipitation is so low that additional costs increase such as iron removal in subsequent processes. .

remind At the precipitation stage  Obtained On precipitate  Acid and leached to form nickel, cobalt and Iron ions  Step to get a solution

After preparing nickel, cobalt and iron precipitates, acid is added to dissolve and releach nickel, cobalt and iron precipitates so that nickel is ionized to nickel ions, cobalt to cobalt ions and iron to iron ions. The acid used in the acid leaching step is not particularly limited, but hydrochloric acid or sulfuric acid may be used.

In general, when the reducing raw material reduced by the reduction reaction of the formula (1) is leached into an acid, the reaction is performed as shown in the following formulas (6) and (7) so that nickel, cobalt, and iron in the nickel, cobalt, and iron precipitates are added to the acid. And are leached with nickel, cobalt and iron ions, respectively.

(Ni, Co, Fe) + 6 HCl = (Ni, Co, Fe) Cl ₂ + + 3H ₂ Formula (6)

(Ni, Co, Fe) + 3H ₂ SO ₄ = (Ni, Co, Fe) SO ₄ + 3H ₂ Formula (7)

In the nickel cobalt and iron-containing solution obtained in the above step Alkaline  Adding and oxidizing with a gas containing oxygen to remove iron

The method for removing iron from the acid leaching solution containing nickel, cobalt and iron obtained through the releaching is accompanied by the following oxidation and reduction reactions. That is, the present invention comprises a step of that accompanying the oxidation precipitation, neutralization and precipitation of a solid precipitate such as FeOOH process and Fe ^{3 +} ions for the oxidation of Fe ^{2 +} ions Fe ^{3 +} ions, such as below scheme .

Oxidation: Fe ^{2 +} + 1 / 4O ₂ + 1 / 2H ₂ O = Fe ^{3 +} + OH ^- Formula (8)

Neutralization reaction: Fe ^{3 +} + 3OH- = FeOOH + H ₂ O Formula (9)

General ^{reaction: Fe 2 + + 1 / 4O} 2 + 2OH - = FeOOH + 1 / 2H 2 O (10)

The input of oxygen can be obtained by the input of air as well as pure oxygen. However, the addition of the oxygen is preferably carried out at a rate of 0.01 L / min to 0.2 L / min per 1 L of leaching liquor, when the air is introduced at a rate of 2 to 10 times the input rate It is preferable. For example, the input of air may be performed at a rate of 0.02 L / min to 2 L / min per 1 L of leachate.

If the feed rate of oxygen and air is less than the above range, the Fe ^{2 +} ions Fe ^{3 +} ion process is oxidized to be insufficiently performed, and, if the feed rate of oxygen and air exceeds the above range, the oxygen and air Since the consumption of is increased, it is not preferable in terms of cost.

For the oxidation of the Fe ^{2 +} ions of hydrogen peroxide, it is possible to use an oxidizing agent such as NaOCl, since such an oxidant is the Fe removal achieved in a short time has higher is the oxidation velocity, but whereas high price thereof Fe a Ni in the leachate, When present in a higher concentration than Co has a problem that the cost of the oxidant excessively higher than Ni, Co. Therefore, in the present invention, although the oxidation rate is lower than that of hydrogen peroxide, NaOCl, etc., inexpensive oxygen or air is used as the oxidant.

Furthermore, in order to increase the reaction efficiency between the gas and the solution, such as oxygen and air, it is necessary to increase the interfacial area of the bubble. For this purpose, it is preferable to decrease the bubble size to increase the interfacial area between the bubble and the solution.

In the present invention, the bubble refinement method is not particularly limited and may be achieved by, for example, using a microbubble generator. There are many types of microbubble generators, such as spiral liquid flow type, venturi type, ejector type, and pressurized dissolution type. In the present invention, any one may be used.

The temperature of the acid leaching solution is preferably maintained at 40 to 99 ℃, if less than 40 ℃ there is a problem that the reaction rate is lowered, if it exceeds 99 ℃ water is evaporated there is a problem that the energy consumption increases.

When Fe ^{2 +} ions are oxidized to Fe ^{3 +} ions, neutralization precipitation is possible in a solid form at a lower pH range than Ni ^{2 +} ions and Co ^{2 +} ions. Thus, by adding a neutralizing agent capable of supplying OH ^- ions, Fe Precipitate ^{3 +} ions in solid form. The neutralizing agent in the form of a solid powder is preferably mixed with water to be added in the form of a slurry, and the neutralizing agent is preferably mixed with 1 to 10 times the weight of water based on the weight of the neutralizing agent.

The neutralizing agent may be a Ca-based neutralizer, Mg-based neutralizer or a mixture thereof, wherein the Ca-based neutralizer is, for example, at least one selected from the group consisting of limestone, CaCO ₃ , CaO and Ca (OH) ₂ . For example, the Mg-based neutralizing agent may be at least one selected from the group consisting of magnesite, MgCO ₃ , MgO and Mg (OH) ₂ .

Fe ^{3 +} ions are precipitated in a solid form by the neutralizer, and there is a possibility that Ni and Co are co-precipitated with Fe, and the higher the pH of the solution, the greater the coprecipitation loss. On the other hand, keeping the pH low to minimize Ni and Co losses reduces the rate of decarburization and lowers productivity, so it is very important in terms of Ni / Co loss and productivity that the pH remains within the appropriate range during decarburization.

Therefore, in the present invention, the step of depositing the oxidized Fe ^{3 +} ions as a solid by adding the neutralizing agent is preferably maintained at a pH of 2 to 4, when the pH is less than 2 to reduce the iron removal rate to lower the productivity If the pH exceeds 4, the coprecipitation loss in which Ni and Co are co-precipitated with Fe increases.

On the other hand, the neutralizing agent is added as soon as the supply rate than the oxidation rate of the ion of Fe ^{2 +} Fe ^{3 +} ions OH ^- ions will be the loss of Ni and Co increases, so to increase the pH of the solution. On the contrary, if the neutralizer input rate is lower than the oxidation rate, the pH of the solution is decreased, but the overall decarburization rate is decreased.

Therefore, it is desirable to maintain the pH of the solution by matching the oxidation reaction rate and neutralizing agent feed rate of the Fe ^{2 +} of the ions Fe ^{3 +} ions into the appropriate region, and for this purpose the present invention in the same molar amount and content of Fe of the neutralizing agent Preferably, Ca, Mg, or a mixture thereof is introduced. This minimizes Ni and Co losses while attaining a certain level of iron removal rate. Preferably, the neutralizing agent may be added at a rate of 0.05g / min to 0.2g / min per 1L of leachate.

For example, when the Fe concentration in the solution is 1 mol, 1 mol of CaCO ₃ is added. However, in the latter part of the process where the Fe concentration is lowered, since the decarburization rate may be significantly lowered, it is preferable to remove most of Fe by oxidative precipitation using oxygen and to remove a small amount of Fe with fast fruit, NaOCl, and the like. However, since a small amount of remaining Fe can be removed by other methods such as solvent extraction in the post-stage process, it is not necessary to use fruit or NaOCl.

In the solution Alkaline  Adding to obtain nickel and cobalt hydroxides

Nickel and cobalt in the nickel-free and cobalt-containing solution from which the iron is removed are preferably manufactured from a solid hydroxide for commercialization. Nickel and cobalt dissolved in the nickel and cobalt-containing solution may be precipitated as a solid hydroxide by changing the pH of the nickel and cobalt-containing solution in the same manner as the method of removing impurities such as Al, Si, and Cr in the leach solution. The alkali agent to be added to the nickel and cobalt-containing solution is not particularly limited, but is preferably added to the extent that the pH of the nickel and cobalt-containing solution can be adjusted in the range of 8 to 10. The pH of the nickel and cobalt-containing solution is usually 2 to 4 by adding an alkalizing agent, which is a neutralizing agent, while removing iron. When the pH is adjusted to the above range, nickel and cobalt in the solution are effectively precipitated as hydroxides of Ni (OH) ₂ and Co (OH) 2, respectively.

When the alkaline agent is added, if the pH is 8 or less, nickel and cobalt in the solution may remain in the solution rather than precipitate as a hydroxide, thereby reducing the recovery rate. The alkali agent added for adjusting the pH of the leachate is not particularly limited and may be used without limitation as long as the pH of the leachate may be increased. For example, hydroxides of metals such as Ca, Mg, Fe, and Ni and oxides such as CaO and MgO may be used alone or in combination.

The precipitated solid nickel and cobalt hydroxides are very easy to be separated by filtration, and the nickel and cobalt hydroxide solid phases can be obtained by separating them with a solid-liquid separator such as a filter press or a decanter.

The obtained nickel and cobalt hydroxides can then be manufactured in various products such as nickel, cobalt metal, nickel, cobalt sulfate, nickel, cobalt chloride, etc. according to a target wet product, a reduction process, and the like.

For example, nickel and cobalt hydroxides may be leached with sulfuric acid to purify trace impurities by known techniques such as solvent extraction, and nickel and cobalt sulfates of NiSO ₄ and CoSO ₄ may be prepared through evaporation crystals, respectively. It can be used as a raw material.

In addition, nickel and cobalt hydroxides may be calcined at 600 ° C. or higher to prepare nickel and cobalt oxides such as NiO and CoO, respectively, and then reduced to a reducing agent such as hydrogen, carbon monoxide, or coal, thereby producing nickel and cobalt metals, respectively.

Hereinafter, an Example is given and this invention is demonstrated more concretely. The following examples are intended to illustrate the present invention in more detail, and the present invention is not limited thereto.

Example

Limonite ore having the composition shown in Table 1 was dried in a rotary kiln furnace at 150 ° C. for 30 minutes, and then pulverized using a super mill to obtain a powder having an average particle size of about 15 μm. The powder obtained was calcined in a calcination furnace maintained at 700 to 800 ° C. for 1 hour to remove crystal water from the ore powder.

The calcined nickel ore was discharged from the kiln and introduced into a rotary kiln reduction furnace cut off of oxygen, and then the ore was used at 850 ° C. using twice the number of moles of hydrogen relative to the number of moles of (Ni + Fe) contained in the prepared ore powder. Reduced ore was prepared by reducing. The components of the reduced ore obtained by such reduction are shown in Table 1 below. In Table 1, the content of each component represents weight%, and the balance is oxygen and trace amounts of Cr, Mn, and the like. The reduced ore prepared as described above was cooled in an anoxic tank filled with nitrogen gas, and then 150 ml of water was added to 150 g of the reduced ore to prepare a slurry.

Ni Fe Mg Si Al Co Dry light 1.33 44.2 1.7 3.9 2.4 0.18 Reduced ore 1.85 61.6 2.4 5.4 3.3 0.25

Meanwhile, iron and chlorine ion-containing solutions, which are by-products of the nickel smelting process, were evaporated and crystallized at a temperature of 80 and 1 atm to obtain iron chloride crystals, and then solid-liquid separation was carried out. Ready.

The composition of the iron oxide is shown in Table 2 below.

Iron oxide having a composition of Table 2 was indirectly reduced under the conditions of Table 3 to prepare reduced iron for precipitation.

The composition of the reduced iron for precipitation prepared as described above is shown in Table 4,

In addition, Table 4 also shows the composition of the conventional reduced ore. In Tables 2 and 4, the content of each component represents weight percent, and the balance is oxygen and trace amounts of Cu, Zn, and the like.

Mg Ca Mn Fe Si Al P S Cl Iron oxide 0.60 0.015 1.32 69.0 0.012 <0.005 <0.005 <0.005 0.068

Reducing Agent Type Reduction temperature () Reduction time Precipitation Reduced Iron Hydrogen gas 850 degrees 60 minutes

Precipitation Type Mg Ca Mn Fe Co Ni Si Al Precipitation Reduced Iron 0.81 0.02 1.79 93.7 0.10 0.33 0.02 0.01 Precipitation reduction 2.35 0.13 1.00 61.6 0.29 1.85 5.41 3.33

20% of hydrochloric acid was added to the slurry in the slurry prepared as described above, to prepare a solution of 1 l, followed by stirring, thereby performing an acid leaching reaction for leaching nickel, cobalt and iron ions from the reduced ore. The leaching solution obtained by the leaching reaction was concentrated to have a leaching solution having various contents of Ni and Co components as shown in Table 5 below.

In order to precipitate nickel, cobalt and iron precipitates from the leach solution prepared as described above, the precipitated reduced iron and precipitation minerals prepared as described above were added to the leach solution to carry out the substitution precipitation reaction of nickel, cobalt and iron precipitates. The amount of the reduced iron for precipitation and the reduced ore for precipitation are shown in Table 5 below. After performing the substitution precipitation reaction for 2 hours, the nickel, cobalt and iron precipitate cake (cake) and the solution was separated, and then investigated the Ni and Co content of the cake (cake), the precipitation rate was investigated and the results 5 is shown. The precipitation rate was calculated by the following equation.

Precipitation rate (%) = {(metal content of leachate-metal content of solution after precipitation) / (metal content of leachate)} × 100

division Leachate Composition (mg / l) Precipitation seed Precipitation seed input (seed ratio) Nickel Concentrate Composition (wt%) Precipitation rate (%) Ni Co Ni Co Ni Co Inventive Example 1 2783 283 Precipitation Reduced Iron 3.0 19.9 1.67 96.2 57.8 Inventive Example 2 4448 442 Precipitation Reduced Iron 2.3 27.9 2.02 97.9 64.2 Inventive Example 3 5338 511 Precipitation Reduced Iron 1.9 33.1 2.2 96.3 57.3 Comparative Example 1 4044 336 Precipitation Iron Powder 0.5 11.4 0.2 91.3 6.9 Comparative Example 2 2730 436 Precipitation reduction 4.0 7.6 0.39 93.7 13.4

As shown in Table 5, in the case of the invention example that satisfies the conditions of the present invention it can be seen that more than 96% Ni and 50% or more Co is precipitated. In particular, it is possible to secure a high concentration of precipitate containing Ni at least about 20% by weight.

On the other hand, as shown in Table 5, the Ni concentrate of Comparative Examples 1 and 2 outside the conditions of the present invention does not contain 20%, the precipitation rate is also low, having a high Ni, Co content as in the present invention Difficult to secure precipitates

The nickel, cobalt and iron precipitates obtained above were leached with hydrochloric acid and iron was removed using CaCO ₃ and oxygen as neutralizing agents. As shown in Table 6, the recovery of each element in the leaching process was more than 99%, the iron removal rate in the subsequent de-ironing process can secure more than 99.9%.

division Ni Co Fe Precipitate 20.4% 1.24% 43.2% Liquid after leaching 16.0 g./L 0.90 g / L 34.8 g / L Leaching Recovery 99.9% 99.8% 99.5% After decontamination 13.0g / L 0.68 g / L 0.033 g / L Recovery rate of degassing process 99.0% 96.2% 0.1% or less

The iron obtained above was removed, and alkali was added to the obtained nickel and cobalt solutions to prepare nickel and cobalt hydroxides. Alkaline, a neutralizing agent, used slaked lime. Table 7 shows the recovery rate of both nickel and cobalt hydroxides was 99.99% or more.

division Ni Co After decontamination 13.0g / L 0.68 g / L Nickel, Cobalt Hydroxide 32.46% 1.88% Hydroxide recovery rate > 99.99% > 99.99%

Although the embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and changes can be made without departing from the technical spirit of the present invention described in the claims. It will be obvious to those of ordinary skill in the field.

Claims (15)

Reducing the raw material containing nickel, iron and cobalt with a reducing gas containing hydrogen; Adding acid to the reduced raw material and leaching to obtain a solution containing nickel, iron and cobalt ions; Preparing a purified solution from which impurities are removed by adding a hydroxide containing iron or magnesium to the solution; Depositing nickel and cobalt by administering reduced iron for precipitation to the tablet solution containing nickel and cobalt ions; Adding an acid to the precipitate obtained in the precipitation step and leaching to obtain a solution containing nickel, iron and cobalt ions; Adding an alkaline agent to the nickel, cobalt and iron-containing solution and oxidizing with a gas containing oxygen to remove iron; And Adding an alkali agent to the solution to obtain nickel and cobalt hydroxides. The method of claim 1, Input amount of the reduced iron for precipitation is nickel and cobalt recovery method, characterized in that 1.5 to 2.5 times the number of moles of nickel and cobalt ions present according to the relationship [Relationship 1] Reduced iron input (seed ratio) = (Metal Fe content in reduced iron for precipitation) / (Ni + Co ion content in the leaching solution) The method of claim 1, The method for recovering nickel and cobalt is obtained by indirectly reducing the iron chloride roasted iron ore obtained from the by-product of the nickel smelting process by solid carbon or reducing gas. The method of claim 1, Nickel and cobalt recovery method characterized in that the reduction rate of the reduced iron for precipitation is 80 ~ 99%. The method of claim 1, Nickel and cobalt recovery method characterized in that the precipitated reduced iron particle size is 5㎛ or less. The method of claim 3, The method for recovering nickel and cobalt is characterized in that when reducing the iron chloride roast iron ore with a reducing gas, the reduction temperature is 500 ~ 950 ℃. The method of claim 3, When the iron chloride roast iron ore is reduced to solid carbon, the reduction temperature is 700 ~ 1200 ℃ nickel and cobalt recovery method characterized in that. The method of claim 3, The iron chloride roast iron ore is Evaporating and concentrating a solution containing iron and chlorine ions generated as a filtrate in a nickel smelting process to obtain a concentrated solution; Crystallizing the concentrated solution to obtain iron chloride crystals; Solid-liquid separation of the iron chloride crystals and the slurry; And Roasting the iron chloride crystals to obtain iron chloride roasted iron ore. The method of claim 8, The solution containing iron and chlorine ions generated as a filtrate in the nickel smelting process is A leaching step of dissolving nickel ore containing nickel and iron with hydrochloric acid to obtain a leaching solution in which nickel and iron ions are leached; PH adjustment step of adjusting the pH by adding an alkali agent to the obtained leachate, and solid-liquid separation of the solid phase impurities in the leachate; Adding nickel ore containing nickel and iron to the leaching solution and then depositing nickel with ferronickel; And The method of recovering nickel and cobalt, characterized in that the filtrate generated in the nickel smelting process comprising a precipitate recovery step of filtering and recovering the solid precipitate by filtration. The method of claim 1, The acid introduced into the reduced raw material is precipitated and the filtered filtrate is treated with an ion exchange resin to recover residual nickel and cobalt, and the ion exchange resin is stripped with an acid to include an acid containing nickel and cobalt. Nickel and cobalt recovery methods The method of claim 10, Acid containing nickel and cobalt obtained by the ion exchange is re-introduced to the leaching process, nickel and cobalt recovery method The method of claim 1, The alkaline agent is nickel and cobalt recovery method characterized in that at least one selected from calcium hydroxide or calcium carbonate. The method of claim 1, The nickel and cobalt hydroxide leaching with sulfuric acid and solvent extraction to produce nickel sulfate and cobalt sulfate, characterized in that for producing nickel and cobalt sulfate The method of claim 1, A method for recovering nickel and cobalt, wherein the chlorine and calcium components in the leachate are removed in the form of calcium chloride in the step of obtaining nickel cobalt hydroxide by adding alkali. The method of claim 1, Nickel and cobalt recovery method characterized in that the addition of H ₂ S instead of an alkaline agent.

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