DE1583898A1 - Process for purifying oxyder ores - Google Patents

Description

DIPL.-ING. Π. MARCH

PATENT Attorney U »D« fAimw «AM» »

ntiM

DESCRIPTION for the patent application

Yoland Pierre P & ul Mayor, Gommugrc / Switzerland, and Pierre Francois Tord, Paris / France

"concerning
"Procedure for cleaning

The present invention relates to a method for purifying oxydes and in particular iron ores. Iron ores include both natural oxides and those obtained by roasting the sulphide ores,

It is known that the roasted products rich in hematite, those used in roasting sulphurous iron ores, such as from pyrite and pyrrhotiae, among others, represent a very good3 iron ore, which is used in the iron and steel industry, however, in the majority of

, -, - .. · BaD OFaGINAL

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Cases frowned upon and difficult because of numerous impurities, never zinc »lead, copper, aluminum, Yismuth, antimony, selenium, arsenic ubw · which also besides other, less disadvantageous, but undesirable, such as silicon oxide, silicates or calcium carbonate. Certain naturally occurring iron oxides that are low in sulfur or free from sulfur contain analogues Impurities and therefore cannot be used as iron ores

For a long time, Kittel has been looking for the removal of these contaminants, including these BiSet products or you can use the other iron oxides] one of the * such use is of even greater interest than the rich ores are becoming increasingly rare. The "chlorinating Roasting "processes called allow the conversion of the non-ferrous metals into chlorides and sulfates, which then can be extracted by methodical leaching. Unfortunately, chlorinating bust consumes a lot Heat and leaching is a cumbersome operation that does not allow the content of certain non-ferrous metals down to the limits desirable for the modern iron and steel industry are. The salt solutions obtained always contain a considerable amount of iron in the form of chlorides

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Sulfateno

Ss has also already been proposed to let chlorinating agents act on the iron oxides to be purified, such as chlorine, thionyl chloride, sulfur chloride, etc., and at a sufficiently high temperature that the metal chlorides formed, entrained by a carrier gas such as air or vapors, distill off or sublimate. During the oxidation of the reaction mixture, all components were brought to their maximum degree of oxidation. The temperature must reach 900 ^° C. or exceed it. under these conditions, impurities such as arsenic, antimony, etc. are blocked in the form of arsenates, antimonates, etc. and are not volatile. In addition, heating to 900 ^° C. or above is particularly difficult due to material problems, such as the strong reactivity of chlorine. Otherwise, it requires high fuel consumption.

It was therefore proposed to first reduce the iron oxides, such as the hematite of the roasted products, to magnetite and this in a second phase at a relatively low temperature of the order of 500 ° with a gaseous chlorinating agents, such as chlorine or gaseous hydrogen chloride, treat what is the removal of the volatile chlorides, such as that of arsenic,

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Antimony, tin, etc. allowed. To remove the less volatile chlorides, such as those of zinc, copper, Lead, gold, etc. must, however, in a third phase, the iron oxides to a temperature of 900 ° or above heated in an oxidizing medium and in the presence of a chlorinating agent. The Magnetite is reoxidized to hematite and the result of this oxidation The heat released helps to achieve the necessary high temperature · However, if you subsequently by magnet sifting impurities such as silicon dioxide wants to remove the silicates, etc., one must remove the hematite in a fourth phase of the process by the action of a gaseous one Convert reducing agent back into magnetite. Such a procedure is due to the numerous The work phases it includes are not very economical; and, Experiments have shown that iron oxides are formed when iron oxides are mixed with an anhydrous chlorinating agent treated in a reducing medium, or if these iron oxides are reduced beforehand, always ferric chloride, that due to the temperature is carried away by the carrier gas or remains in the iron oxide where its presence is disadvantageous.

The different drying processes that make a chlorination assume use anhydrous chlorinating agents:

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diea is due to the fact that generally accepted becomes that the presence of water vapor hydrolysis of the formed by the chlorinating agents Chloride "causes and wholly or at least partially ensues Prevents extraction by distillation or sublimation.

A process for recovering copper by distilling the chloride at very high temperatures of the order of 90O ⁰ C is also known, in which, after using an anhydrous gaseous chlorinating agent, water vapor is introduced in the residue to prevent the iron from evaporating in the form of the chloride in the form of their oxides fixes the iron and possibly the aluminum of the Auagangserze. This method makes calibration the known fact is utilized that the anhydrous ferric chloride FeCl, from the salt Hydra t FeCl ^ ₀ Ohgo not be obtained kannj when this, even in the presence of free hydrochloric acid, heated, hydrolyzed in accordance with the following equation:

2FeCl ₃ + 3HgO - * Fe ₃ O ₅ + 6HCl

(Compare Z _O B "A _P F _O Holleman, Traite de Chimie Inorganique, 2nd French edition, Paris 1917, page 485 _f line 4 ff,)"

The inventive method allows the liberation of

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Iron oxides of all volatile chlorides forming ingredients, and at a temperature between 500 and 800 ° and preferably between 600 and 700 ⁰ C.

The process according to the invention for purifying iron oxides or oxyder ores of iron which contain combinations of other constituents as impurities is characterized in that the oxides are contacted in a reaction zone with a hot gas, such as a carrier gas, and with at least one halogen hydrogen gas, wherein the amount of hydrogen halide gas used is at least equal to the amount theoretically necessary to form halides of the constituents mentioned and the temperature in the reaction zone is sufficiently high and advantageously between 600 and 700 ^° C. to remove the halides with the carrier gas

The term "halogenated water st off gas" means here and hereinafter hydrofluoric acid, hydrochloric acid, Hydrogen bromic acid and hydrogen iodine acid, these acids are used according to the present invention for calibration alone or used in combination, preferably in an amount that equal to or slightly higher than that which is theoretically necessary for the formation of the corresponding volatile halides iüt, which result from the implementation of this Haiogen hydrogen

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original .wsk-gte

gases with the impurities present in the iron oxides come",

In general, hydrogen chloride is chosen as a hydrogen halide gas gas, but you can also use another hydrogen halide gas, if you prefer, the non-ferrous constituents in the form of fluorides, bromides or iodides.

A gas such as air or nitrogen can be used as the carrier gas, which has been preheated in a tube furnace, a regeneration furnace or with the help of other equivalent heating devices. hydrogen or Kohlenwasserstoffβο in this case, the combustion can be effected outside and he reaction chamber and it then supplies the hydrogen halide gas into the conduit, which connects the combustion chamber with the Reaktionasone. The combustion can also be effected inside the reaction chamber and the hydrogen halide gas is then introduced into the fuel or into the combustion air. In general, any achievement of a warm gas in which the required amount of hydrogen halide gas is evenly distributed satisfies the requirements of the present invention

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Invention.

If necessary, one can also use any known method preheat the roasted products before. them into the reaction zone The roasted products that leave the roasting oven warm can also be treated directly.

According to one embodiment of the process according to the invention, use is made of an anhydrous hydrogen halide gas and a carrier gas which does not contain water vapor or contains it only in very small quantities. In this case, at a temperature below 700 ^° C., all halides whose boiling point is below that of the corresponding iron halide are distilled off. A neutral or weakly oxidizing gas is preferably used as the carrier gas, since a reducing atmosphere facilitates the formation and transport of ferric chloride.

After a first modification of the method according to the invention 5 you can, instead of a hydrogen halide gas in the Introduce carrier gas, add a heat-decomposable halide, such as ammonium chloride, to the cold roasted products or another precursor compound of the Ilalogenehydrogen gas.

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According to a second modification of the method, a carrier gas is used, which consists entirely or in part of water vapor In the course of the investigations into the purification of iron oxides, the surprising finding was made, that contrary to the accepted theories cited above, water vapor causes the formation of Non-ferrous metal chlorides at high temperature not adversely affected at all »

In addition, it has been found that the water vapor, if it is present in sufficient quantity, considerably slows the removal of the metal chlorides formed outside the reaction mixture. It has been found that even without exceeding the temperature of 500 to 70o ⁰ G, the less volatile metal chlorides such as those can remove the copper, lead, gold etc _e, which is an important economic advantage is in terms of the known methods for the purification of iron oxides by chlorination, in which the removal of these less volatile chlorides in an anhydrous or almost anhydrous medium ^{requires heating the reaction mass to a temperature of at least 1000 °} C., the other recognized disadvantages of these processes not yet being taken into account.

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Corresponding studies have also shown that the water vapor inhibits certain adverse reactions, like ζ · Β. on the one hand the formation of iron chlorides - independently on the nature of the iron oxide treated (hematite Fe JD * »Magnetite Fe ~ 0., Eieen-II-Oxyd PeO or their various Mixtures) - and on the other hand the formation of free halogen $ n, which after the reaction of Deacon in particular then form if any of the contaminants arise the base is copper; finally did the investigations nor show that if the steam does not separate the arsenic chloride (boiling point 130.2 °) either relieved, he doesn't bother them either »

It can be stated that one if all to be removed Impurities form chlorides with a low boiling point, such as those of molybdenum, arsenic, and antimony. obtain the same results in the presence and absence of water vapor ·. When performing cleaning in Presence of water vapor one finds a “trace of Iron in the distillate and the purified iron oxides are absolutely free of soluble iron, which is still true when the treatment is carried out in a reducing environment, where, on the other hand, when working in an anhydrous environment, practically impossible for the formation of ferric chloride too

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prevent it, especially if it is a reducing Atmosphere, or if you use a completely or partially reduced oxide.

The amount of water vapor that is introduced with the hydrogen halide gas can vary within wide limits. If hydrogen chloride gas is used, 1/2 part by weight of waeeer per 1 part by weight of hydrogen chloride gas is sufficient to inhibit the formation of chlorine and ferric chloride. However, in order to get rid of the chlorides of the heavy metals, much larger amounts of water may be used, in the order of magnitude of 1 to 10 times the weight of the hydrochloric acid. It is particularly advantageous to use 4 parts by weight of water per 1 part by weight of hydrochloric acid, since these never ae behaves azeotropic mixture with 20 i »hydrochloric acid corresponds to the change in the composition otui.e, distilled at 110 ⁰ C

One can use the anhydrous hydrogen halide gas and the Introduce steam separately into the reaction zone. However, it is usually advantageous to use an aqueous acid, in particular 20% hydrochloric acid, which is present in the required carrier gas at the reaction temperature or a higher temperature -is introduced, either as steam or in the form of fine! droplets, due to the considerable

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Vaporize the heat of the carrier gas.

It is important to emphasize that when you have an excess applies to hydrochloric acid, this calibrates in the condensate finds again, this latter consists of water - that introduced with the acid, released by the reactants and is optionally present in the carrier gas - that dissolves the chlorides formed and the excess of hydrochloric acid contains. This acid is easily recovered by distillation in the form of 20% hydrochloric acid; it can be fed back into the circuit, if necessary without intermediate condensation » If in the course of treatments to increase the value of the distilled chlorides, the hydrochloric acid whole or is partially recovered, this takes place in the form of the 20 ^ igen azeotropic mixture, which is fed back into the cycle will. If, on the other hand, one works in an anhydrous medium, the recovered azeotropic mixture has to pass through concentrated sulfuric acid can be dehydrated, which limits the interest in such recovery.

According to a third modification of the method according to the invention the hydrogen halide gas is formed in situ from a halogen precursor such as ammonium chloride, which is then used as aqueous solution is applied o This latter can either

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Load stream of the carrier gas can be atomized, or 2tn pastes of the metalloids can be used, or can also be introduced into an evaporator, which is kept at a temperature of more than 35O ⁰ O by external heating, and then introduced into the treatment furnace in a gaseous state. Regardless of the form to be selected of the feed, the ammonium chloride from 35O ⁰ C is completely disosiiert. In this way, the ammonium chloride solution is converted into a mixture of water vapor, hydrogen chloride gas (HCl) and ammonia (NH,) ο

The ammonia behaves like an inert gas, but it does is flammable, its presence makes it impossible to carry out the treatment in an oxidizing environment.

When the gas mixture leaving the furnace is cooled below the melting point, the ammonia combines with the Excess hydrochloric acid with regression of Ammonium chloride, and with the metal chlorides forming of oxides or hydroxides and ammonium chloride. The ammonium chloride used is completely recovered as a result of this white "

The application of ammonium chloride offers a technological one important advantage, because as soon as a neutralization of the

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acidic products before or after the occurrence of condensation takes place, the reaction mixture is at no time corrosive In order to increase this advantage still further, a slight excess can be added to the solution of ammonium chloride Add ammonia.

In the reaction zone where the hydrogen halide gas is in the presence or absence of water vapor, with certain non-ferrous components reacts to form volatile halides, one must have close contact between the solid and gaseous phases "one can do" one Use rotary kiln, a preferred embodiment of the erfindungegemässen However, the process consists of pluidization the iron oxides in the gas stream.

The gas flow causing the fluidization is partially off Composed of vapors that provide the amount of heat required to achieve and maintain the temperature, and optionally partially from water vapor, the avs the evaporation of aqueous hydrohalic acid originates. However, if it is an iron oxide that is rich in Premd constituents and if it is used as a halogenating agent Wants to use 20 hydrochloric acid, the amount of water vapor can be greatly increased Ensuring a good pluidization while at the same time

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ORIGINAL INSPECTED

To prevent an excessive influx of fines into the cyclones, it is necessary that the velocity of the gas be kept within fairly narrow limits (which are a puncture of the grain structure of the pesticide), e.g. 15 to 20 a / so. If the volume of the gas is very high is large, it is necessary to choose an unduly large diameter furnace in view of the residence time required. This technological disadvantage can be circumvented by connecting two ovens in series, one with anhydrous hydrogen chloride gas and the other with aqueous hydrochloric acid, for example with a 20 # solution. In the first furnace, the components whose chlorides are most volatile are then completely or partially flushed away by a warm carrier gas, such as neutral or a small excess of oxygen-containing vapors, to which anhydrous chlorine <5s is added in an amount below that which is stoichiometrically required so that it is completely consumed. In the second furnace, the metals that form low volatile chlorides wereSen, sov? Ie the optionally remaining reads of components, the more volatile chlorides form, chlorinated and discharged through a hot carrier gas, which is mixed with 20 tigern Chlorwasserstoffsimredpjnpf ₀

In the following, some components are given for explanation

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listed, which are obtained from naturally occurring iron oxides or from those obtained during the roasting of sulfide ores when using the invention. Process can separate without ^{exceeding a temperature of 700 0} C:

(a) using anhydrous hydrogen chloride

Aluminum, the chloride of which is AlCl, ^{sublimed at 18O 0} C, arsenic, the chloride of which AsCl- evaporates at 150, 2 ° C, beryllium, the chloride of which BeCl ₂ evaporates at 488 ⁰ C,

Whose chloride BiCl, bismuth evaporates at 447 ° C, molybdenum, whose vaporized chloride MoCl- at 268 ⁰ C, antimony, its chloride SbCl- evaporated at 223 ⁰ C, selenium, its chloride Se ₃ Cl ₂ evaporated at 127 ° C,

Tin, the chloride of which SnCl ₂ evaporates at 6O6 ° C,

Zinc, the chloride of which ZnCl ₂ evaporates at 732 ° C ₉ and others «

(b) using 20 # hydrochloric acid

one can without ever 700 ⁰ C to exceed additionally deposited on the above or the following constituents: chromium, whose chloride CrCl evaporated at 1150 ° C, copper, evaporated its chloride CuCl at 1490 ⁰ C, lead, its chloride PbCl ₂ at 950 ⁰ C evaporates, manganese, the chloride of which MnCl ₂ evaporates at 119O ⁰ C,

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Nickel whose chloride NiCl ₂ sublimes at 1000 ⁰ C, and others.

The isolation and separation of the halides, in particular of the volatile chlorides can be carried out by any known method, such as fractional condensation, dissolving in water and chemical separation, etc. "You can, for example, if you have roasted pyrite products containing arsenic and zinc,

treated _o

/ Cool the carrier gas to 400 C to prevent condensation To effect the main amount of arsenic chloride · This can be achieved by re-distilling small amounts with zinc chloride · But it can also be dissolved in water, which causes its hydrolysis and the isolation of the Arsenic in the form of arsenic anhydride and hydrochloric acid in porin of the azeotropic 20 # Lgen mixture is permitted.

If preferred, the non-ferrous components can be converted to halides in two or more stages. So you can separate them one after the other in the order of their volatility. If one K ₀ B containing ₀ Pyritröstprodukte arsenic, molybdenum and zinc, discontinuously with a carrier gas, which is mixed with Chlorwasseretoffgas treated, while raising the temperature gradually from 250 to 700 ⁰ C, successively receives the

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Chlorides of arsenic, molybdenum and zinc "

The iron oxides freed from non-iron components in this way form volatile halides which leave the reaction chamber warm. One can benefit from their considerable heat value by converting them into magnetite by treatment with a gaseous reducing agent Removal of the impurities in the form of the halides and the conversion of the hematite into magnetite then takes place at the same time. However, it is recommended as a halogen! to use an aqueous solution of hydrohalic acid or an aqueous solution of a precursor for hydrohalic acid, such as ammonium chloride, to prevent the formation of iron chlorides.

One can also / Without departing from the scope of the present invention, first convert the haematite to magnetite by heating in a reducing atmosphere and treat _f anechliessend the magnetite by a neutral gas, which is laden with aqueous Halogenwasserstoffsäuredäiapfen to the volatile halides forming constituents deposit »

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The invention is illustrated by the following examples, in which reference is made to the attached figures, which mean:

1 is a diagram of a device for carrying out the method according to the invention in an anhydrous manner; Figo 2 is a modification of the gate direction again Carrying out the procedure with steam | Fig. 3 is a schematic of an arrangement in which ammonium chloride used;

FIG. ₀ 4 shows a modification of the arrangement for the use of ammonium chloride and water vapor; Figure 5 _s is a schematic of an arrangement in which the method is carried out in two series in gescheiteten furnace.

example 1

One introduces continuously via line 1 (see Fig. 1) into the fluidizing furnace 2 IO t / h of pyrite roasted products which contain 11 pounds of silicon dioxide (SiOg), 2 1 * zinc (Zn) and 1.7 $> arsenic oxide (ΑβρΟ,) and which lead to particles iait less than 0.1 mm. The flow occurs with the help of vapors from the combustion in the combustion chamber 3 of about 150 sr / h of natural gas

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over 4 is fed; the combustion air -is introduced via 5 "Fuel consumption is controlled so that the temperature is 65O ⁰ C Dess liquid bed. 450 kg / h of hydrogen chloride gas are fed into the line system which connects the combustion chamber 3 with the fluidization furnace 2 via 6.

Via 7, 2 pyrite roasted products are removed from the fluidization furnace, the 11 ^ silicon dioxide (SiO ₂ ), less than 0.05 $> ZXtCs. (Zn) and less than $ 0.001> contain arsenic anhydride (Ab ₂ O *). The vapors are dedusted in cyclones 8 and 9; they then pass through the Isolierkessel 10 where it is cooled to 35O ⁰ C and ansohliessend the column 11, whose head end is held by the cooling device 12 at 150 ⁰ C.

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"At 13,410 kg / h of zinc chloride which has " melted "is drawn off. It is solidified in the separator 14. The vapors leaving the column 11 via line 15 are passed into column 16, the top of which is passed through the cooling device 17 90 ⁰ C is maintained the originating from the combustion of the natural gas in 3 of water vapor is also condensed and zusaimaen with arsenic trichloride at the bottom of column 16 withdrawn An additional amount of water is introduced in. 19; thus, the vapors are washed in the tower 18, which finally the exhaust can be evacuated through the "ventilator 20"

The amount of water added at 19 is chosen so that a solution of arsenic chloride with 40gAeOl per 100 g of solution flows off via 21, if necessary after cooling in 17 t into the mixer 23, where it is mixed with as much water over 24 In order to adjust its content to 33gAsOly'100 g solution, »Under these conditions arsenic trichloride hydrolyses to arsenic acid & anhydride and hydrochloric acid» The latter is neutralized by a milk of lime listed at 25 »Dag arsenic anhydride is filtered (26) and dried (27). In this way one maintains at 28 165 kg / ho die. 29 outflowing mother liquors are fed to the sewer after they have previously pasalert habon a cleaning sump, where they

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treated with an excess of lime or calcium carbonate will · Me rubbish dumps are being buried.

Example 2

According to the exemplary embodiment, the arrangement of which in Pig. 2 bar is shown, one continuously introduces 10% / h of roasted pyrite products through a funnel 1 into the cooling furnace 2, the 11 ^c / ° silicon dioxide (SiO ₂ ), 0.93 3 * zinc (Zn), 0.94 $ Lead (Pb), 0.42 # copper (Cu) and 0.30 $> arsenic (As), and which are pounded into grains less than 0.1 mm in diameter. The fluidization is carried out by means of vapors AU3 of combustion in the combustion chamber 3 of about 150 m / h natural gas derived, which is supplied by pipeline and fan 4 ₀ The combustion air is supplied via 5 in such amounts that the vapors are neutral or contain a small excess of oxygen. The fuel supply is controlled so that the temperature of the liquid "bed 65O ⁰ C. The dimensions of the furnace are chosen so that the residence time of the ice oxides is 15 minutes. 6 1480 kgA of 20% hydrochloric acid are fed in via pump 6, which gives an excess of 15% based on the theoretically necessary quantity for the conversion of Zn, Pb , Cu and As in their chlorides means - The 20

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Hydrochloric acid is evaporated from 7 more in GraphitauBt and the steam obtained Deesen temperature is 110 ⁰ C, is mixed with the Trägergae ·

With the extractor 8 of known type, hematite is extracted from the fluidization furnace 2, the 11 # silicon dioxide, less than 0.05 # zinc, less than 0.05 $> lead, less than C, .02 $> copper and less than 0.002 i » arsenic contains ο

The vapors are dedusted in the cyclones 9 and 10 and ^{cooled to 35O 0} C in the exchanger 11, which is

fcann

Exchanger 7 can be combined in such a way / that the considerable The amount of heat in the reaction products is used to evaporate the 20% hydrochloric acid »

The gas leaving the exchanger 11 is fed into the scrubbing column 12 passed through which the pump 13 is an aqueous Circulating solution absorbs all chlorides and excess hydrochloric acid. Their temperature will kept constant by the cooling device 14. Their composition is kept constant by a continuous withdrawal via the line system 15 and a corresponding one Addition of water via the pipe system 16

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The solution withdrawn through line 15 contains all of them Chlorides and the excess of hydrochloric acid, theirs Further treatment is chosen depending on the derivatives one wishes to obtain.

Example 3

In the first example for the treatment with ammonium chloride, the system shown in FIG. 3 is used. 10 t / h Pyritrö st products with those of Example 2 are identical, with 1736 kg / h of a 25 follow solution of ammonium chloride with 10 kg / h 20 #igem ammonia is added, wetted. This operation takes place on the screw conveyor 1, which feeds the pluidizing furnace 2,

from

The fluidization takes place with the help of ^ vapors, which from the Combustion in the combustion chamber 3 of about 140 nr / h Natural gas, which is supplied via the line and fan 4 ο The combustion air is introduced via a fan 5 and preheated in heat exchanger 8 and is applied in such amounts that the dumps are neutral or contain a small excess of non-flammable components.

The fuel gas supply is regulated so that the temperature of the

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The liquid bed is 65O ⁰ C. The dimensions of the furnace are calculated so that the residence time of the iron oxide is 15 minutes.

Through, the drainage device 9 is pulled out of the pluidizing furnace cleaned off products, their content of impurities Was brought to the same level as in Example 1. The vapors are in the cyclones 6 and 7 dedusted and cooled in the exchanger 8, which is used to preheat the combustion air, and then ir the cooling device 9ο The pH value of the condensate is everywhere more than 8 and the exchanger 8 and cooler 9 are made of ordinary, non-alloyed steel

In the furnace, the ammonium chloride is determined according to the following equation disassociated:

NH ₄ Ol w HH ₅ + HGl (1)

and the hydrogen chloride gas combines with the metals in the following way:

MeO + 2 HCl «MeCl ₂ + H ₃ O (2)

In the exchanger 8, the excess of chlorine water combines

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Hydrogen acid with the ammonia lint he formation of ammonium chloride The metal chlorides react with the ammonia in the following way «

MeCl ₂ + 2 HH ₅ + 2 H ₃ O = Me (OH) ₂ + 2 NH ₄ Cl (5)

The sum equation of reactions (1), (2) and (3) shows the following picture:

MeO + H ₂ O «Me (OH) ₂

Ea is therefore one molecule of water per during the implementation two molecules of ammonium chloride are consumed and the solution does not tend to thin out, in spite of the feeding of water from the vapors.

A suspension of arsenic anhydride and hydroxides of zinc, lead and copper is obtained in the container 10 a solution of ammonium chloride. This suspension will filtered through the rotary filter drum 12. You get through the line system 13 the mixture of oxides and hydroxides, their further treatment according to the products, which one wishes to receive is chosen. The amoonium chloride solution is fed into the collecting container 14, from where it is reintroduced into the cycle.

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Example 4

A modification of the ammonium chloride process will be described with reference to FIG. 10 t / h of roasted pyrite products which are identical to those of Examples 1 and 2 are fed continuously through the funnel 1 into the fluidizing furnace 2. The fluidization takes place with the help of vapors, which originate from the combustion in the combustion chamber 3 of about 140 nr / h natural gas, (Taβ supplied via the pipe system and blower 4. The combustion air is supplied via blower 5 and preheated in exchanger 13 " It is used in such amounts that the ratio COg / CCO + H ₂ ) in the vapors is 85/15. To avoid the formation of soot, water vapor is introduced through the controllable opening 6 of the combustion chamber. The fuel gas supply is controlled so that the temperature of Fltiftsigbetts is 675 ⁰ C. The dimensions of the furnace are calculated for a residence time of the egg oxide of 60 minutes.

The pump 7 conveys 1736 kg / h of a 25% solution of ammonium chloride into the tube furnace 8, to which 10 kg / h 20% ammonia is added. This solution is heated to 100 to 11O ° C in the convection zone of the furnace and subsequently evaporated in the jet zone, where the vapors are brought to 400 to 450 ⁰ C. The fumes pass

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then the fluidization furnace with the carrier gas.

By the puller 10 is drawn from the furnace the magnetite from the 11 ^ silica, less than 0.05 $> zinc, less than 0.05 lead, less than $ 0.02> copper and less than 0.002 "h Contains arsenic.

The gases are cleaned of dust in cyclones 11 and 12, cooled in the exchanger 13 and cooler 14 and then v? ie treated in Example 2, the ammonium chloride solution being returned to the collecting container 9 »

Example 5

The arrangement given in FIG. 5 corresponds to the procedure according to which the hydrohaloene treatment is carried out in two in Series switched ovens is carried out, one of which is the one is charged with anhydrous hydrogen chloride gas and the other with 20% hydrochloric acid.

Is introduced continuously from the hopper 1 into the Pluidisierungeofen 2 10 t / h Pyritröstprodukte a containing 10.0 # Silioiumdioxyd (SiO _2), 1.10 $> zinc (Zn), 0.50 i "arsenic (Ae), 0 .75 i » aluminum (Al), $ 0.27 molybdenum (Mo), $ 0.18 # antimony (Sb), $ 0.72 tin (Sn), 0.82 # lead (Pb), and 0.63 # copper

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(Cu) contained the? Luidisierung carried out by means of vapors h from üqt combustion in the combustion chamber 3 of about I30 jor /. Natural gas st seeds, which is supplied through line and fan 4. The combustion air is introduced over 5 in such quantities that the vapors contain an excess of 0.5 to 1.0 yoluene of oxygen. The fuel supply is regulated so that the temperature of the liquid bed is 550 ° C. The dimensions of the furnace are chosen so that the iron oxide stays there for 15 minutes

500 kg / h of anhydrous hydrogen chloride gas is introduced via fan S, which corresponds to the stoehiometrically required amount for the conversion of: "gastric non-ferrous metals into chlorides. The liquid bed flows from the furnace 2 via line 7 into the. two-stage furnace 8 »The fluidization takes place with the aid of vapors which originate from the combustion in the combustion chamber 9 at 70 m * / h of natural gas, which is supplied via line and fan 10. The combustion air is fed in via fan 11 in such quantities that the ratio Co ₂ A CO -§ · H ₂ ) in the vapors is 85/15. To avoid the formation of pupils is carried water vapor through the adjustable opening "" the combustion chamber a "The fuel gas supply is controlled so that the! Temperature of the liquid bed is 675 ⁰ C · 'Iron oxide lingers average

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15 minutes on each floor of the oven. One leads over pump 13 1500 kg / n 20 # hydrochloric acid added to the exchanger 14 evaporated and supplied to the vapors · The Total amount of hydrochloric acid introduced into the In both ovens, this corresponds to an excess of 12 #, based on the theoretically necessary amount for transfer of the non-ferrous metals in chlorides.

A sample taken in line 7 shows that the iron oxide leaving the first furnace is still 10 $> SiO ₂ , 0.7 £ Zn, 0.08 $> As, 0.05 Ί » Al, 0.04 # Mo, 0, 02 # Sb, 0.4-3 i> Sn, 0.82 # Pb and 0.63 # Cu.

The magnetite is withdrawn from the lower level of the furnace 8 through the outlet 15, which contains a maximum of 10 $> SiO ₂ , 0.05 $> Zn, 0.002 i> As, 0.01 % Al, 0.01 i> Mo, Contains 0.005 # Sb, 0.03 # Sn, 0.05 1> Pb, and 0.02 # Cu. If you clean it by passing it over a magnetic sifter, you bring its content? E »0 ^ to 98.5 to 99.0 #.

The gases leaving the furnace 2 are freed of dust in the cyclones 16 and 17, and those leaving the furnace 18 in cyclones 18 and 19 <> You will be in exchanger 20 mixed and cooled. The chlorides are isolated in column 21 as in Example 1 »

109841/1343

Claims (1)

- 31 - "" "1583BS8 Patent claims: 1. Process for the purification of oxydes and in particular of iron ores, which occur naturally or are obtained by roasting sulphide ores, by removing impurities that are formed by combinations with other constituents, v? Ie ζ · Β ₀ zinc, lead, copper, Aluminum, arsenic, beryllium, bismuth, molybdenum, antimony, selenium, tin, chromium, Hangan or Hickel, by using a chlorinating agent and a carrier gas, characterized in that the oxides are in a reaction zone with a warm gas such as a carrier gas and contacted with at least one hydrogen halide gas, whereby the amount of halide gas used is at least equal to the theoretically necessary amount for the formation of halides of the constituents mentioned, and the temperature in the reaction zone is kept high enough so that the halides are in a vaporous state and removed by the carrier gas 2. The method according to claim 1, characterized in that that one frees the iron oxides contained in the ore from all .Kicht-Bisen constituents, their haloganides more volatile are than the corresponding halides of iron, the separation being carried out in a single process step in the Heaktionszone causes 109841/1343 3o method according to one or more of the preceding Claims, characterized in that the transfer the Hicht-Eisenbeotendteile in halides in several process stages "effected, the separation successively in the order of volatility of the corresponding halide is carried out. 4. The method according to one or more of the preceding claims, characterized in that the iron oxides preheated before exposure to the carrier gas are set. 5 «Procedure according to one or more of the preceding Claims, characterized in that the sisenoxyde mixed with ammonium chloride or another with heat decomposable with the release of hydrogen halide gas Halide or another precursor compound for hydrogen halide gas, rcobei then the carrier gas of hydrogen halide gas is free 6 »Procedure according to one or more of the previous ones Claims, characterized in that a neutral gas is used as the carrier gas and the degree of oxidation of the iron oxides not changed· 109841/1343 OHiGlNAL 7, method according to one or more of the preceding Claims, characterized in that the carrier gas uses an oxidizing gas and separates the iron oxides in Perm from hematite, 8. The method according to one or more of the preceding claims, characterized in that the iron oxides in the reaction zone · fluidized by the gas stream. Process according to one or more of the preceding claims, characterized in that the temperature in the reaction zone is kept between 500 and 800 ⁰ C and preferably between 600 and 700 ⁰ O if hydrogen chloride gas is used 10. The method according to one or more of the preceding Claims, characterized in that in the reaction zone the presence of an amount of water vapor from 0.5 to 10 Parts by weight and preferably 4 parts by weight per 1 part by weight Hydrogen halide ensures " 11 · The method of claim 10, characterized in that one so selects the zugafilhrte with the hydrogen halide gas steam amount that does between 0.5 and 10 Gqtv, parts by and preferably about 4 per 1 weight -TeUe GoW ₀ "portion Ilalogenwasser" 109841/1343 substance gas is, if it is hydrochloric acid acts « 12o method according to one or more of the preceding Address 1 to 11, characterized in that ammonium chloride as a 25 # solution. 13 · The method according to one or more of claims 1 to 12, characterized in that simultaneously with the Ananonium chloride adds a small amount of ammonia. 14. The method according to one or more of claims 1 to 13 »characterized in that the ammonium chloride solution is either atomized in the carrier gas stream, or used to make the metal oxides into a paste, or passed through an evaporator which is heated to a certain temperature by external heating is kept above 35O ⁰ C, and then passes in a gaseous state into the treatment furnace. 15. The method according to one or more of claims 1 to 14, characterized in that a 20 # strength hydrogen chloride acid used. 16o method according to one or more of claims 1 up to 15t characterized in that the Oxyderae are first 109841/1343 treated by hypohalogenation in a water-free environment and then by Hydrohalogeniemng in the presence of steam ". ORIGINAL INSPECTED 109841 / 13Λ3 Blank page