FI65808C - HYDROMETALLURGISKT FOERFARANDE FOER FRAMSTAELLNING AV KOPPAR - Google Patents

Description

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Ma W 01) utlAggningsskript odoOo c ^ Patcr.tu cy ”:; r. iy 13 C7 ICO! ^ ^ (S1) /mtci.3 C 22 B 15/08 ENGLISH —FINLAND (21) Ptt * nulh «k * mu« - PatantaiMMiiriiig 750070 <B) 13.01.75 '7 (23) AUmpiM — GlMglMtadai 13-01.75 ( 41) Interpreters} ulktMksl - Victims afftmUg 15-07.75 htmtti- it registry controlled ...,. ......

PMMT. och reglsterttyreltea (44) (3 ^ (33) (31) Fyydeity * Mellieiw - HIN prtprtt * 14.01.7 ^ USA (US) 1 * 33208 (71) Duval Corporation, 900 Southwest Tower, Houston, Texas, USA (US ) (72) George E. Atwood, Tucson, Arizona, Charles H. Curtis, Tucson,

Arizona, USA (US) (71 *) Oy Koi ster Ab (51 *) Hydrometal lurgical method for the production of copper -

Hydrometa11urgiskt förfarande för framstä11 Ning av koppar

In a broader sense, this invention relates to an improved hydrometallurgical process for producing metallic copper from copper-containing materials. In particular, this improved process relates to a metal chloride process starting from a copper sulfide ore concentrate.

French Patent Publication 2,157,835 (corresponding to Finnish Patent Application 2,753/72) describes a hydrometallurgical process for copper sulphide ore concentrates, especially those containing copper ore. This process consists of four basic steps: an oxidation step in which the copper-containing material is oxidized with a solution containing ferric chloride and copper chloride to prepare a solution containing ferric chloride and excess copper chloride, a reduction step in which they, in which metallic copper is obtained from a copper chloride solution, preferably by electrolysis, and a regeneration-purification step in which ferric chloride is regenerated by oxidation and at the same time removing excess iron and sulphate ions and other impurities.

65808

Further development of the process according to the present invention has provided additional information on alternative methods as well as aspects which improve the advantages achieved by the basic process described in Finnish application 2753/72.

The invention thus relates to an improved method for producing metallic copper. The process is characterized in that in the process variant in which the regeneration-purification step is combined with the oxidation step, the total chloride ion content, including reactive chloride ions in solution and chloride ions from the metal chloride compound added to the solution, is maintained at a level such that the reduction step reduced to more than 75% copper (I) chloride and minimizing the loss of copper from solution by adding a metal chloride compound which may be potassium chloride, magnesium chloride, a mixture of potassium chloride and magnesium chloride, or a mixture of any of the above compounds and sodium chloride, the total chloride is maintained at a level which exceeds the concentration which can be achieved by the addition of sodium chloride alone up to the point of saturation.

The invention thus provides the following advantages: A. the total chloride ion content in the process solution can be adjusted to advantageous, B. the amount of reactive chloride ions available in the process solution is adjusted, C. potassium chloride is added to the process solution to reduce and limit sulfate ion content by precipitating sulfate ions from solution during regeneration and purification. , D. preferably combining the oxidation and regeneration-purification steps 1. the iron content in the reacted solution is reduced to a level which is advantageous in the final electrolysis, 2. the precipitation of unwanted separated solids in the process equipment is slowed down and limited.

Other advantages of the present invention will become apparent from the following description, examples, and claims.

In the drawings related to the description of the invention, Figure 1 shows a simplified flow diagram of the process of the present invention with a combination of oxidation and regeneration-purification steps.

3 65808

Fig. 2 is a diagram showing the stoichiometric molar equilibrium which is the chemical basis of the method of Fig. 1 when applying the method to copper ore.

Figure 3 is a flow chart of an embodiment of a process according to the present invention in which the oxidation and regeneration-purification steps are combined.

Figure 1 * shows a simplified flow chart of the process of this invention with a separate oxidation and regeneration-purification step.

Figure p is a table of values showing the effect of chloride ion concentration on the reduction of copper chloride to cuprous chloride using a separate oxidation and regeneration purification step.

Figure 6 is a table of values showing the effect of chloride ion concentration on the reduction of copper chloride to copper chloride using a combined oxidation and regeneration-purification step.

Figure 7 is a graph showing the effect of chloride ion concentration on the reduction of copper chloride to cuprous chloride in the reduction step.

The curve shown in Figure G is based on pilot plant values comparing the concentrations of sulphate ions in the liquids entering the combined oxidation-regeneration step, starting when only sodium chloride is added to the process grate and when calcium chloride is added in addition to sodium chloride.

U.S. Pat. No. 3,750,900 describes alternative uses for the regeneration-purification step and the oxidation step, either separately or in combination. In the combined mode of operation, the reaction of the oxidation step is carried out in the presence of oxygen, which is a necessary operating condition of the regeneration-purification step. In such a process, the reaction of the copper ore, in contact with the purified liquid of the electrolysis step in the presence of oxygen, causes continuous oxidation of the reaction liquid, in particular oxidation of copper chloride to copper chloride and oxidation of ferric chloride to ferric chloride to the extent possible. If the stock of reactive chloride ion is insufficient to convert the entire amount of iron to ferric chloride, ferric hydrate will precipitate.

This is illustrated by the following chemical reactions

Reduction step 2CureÖ0 + 3CuCl_ - * äCuCl + FeCl_ + 2S + CuFeS.

2 - + ψ 2 i I -

For electrolysis For combined oxidation-regeneration purification approx

Electrolysis step 6 5 8 0 8) 4CuCl + i'eCl -> 2Cu + 2CuCl_ + FeCl „I i b

Product for Combined Oxidation-Regeneration-Pur.

Combined oxidation-regeneration-purification step

CuFe32 + 23 + 2CuCl2 + FeClg + | 02 + 3 ^ 0 - »

3CuClO + 2Fe (0il) + äS

Γ Γ

For reduction The addition of residual oxygen to the final dissolution reaction, as required by the combined oxidation and regeneration purification process, provides, in addition to copper chloride, the added advantage of better reactivity and ferrous chloride capacity during the reaction, thus ensuring possible dissolution of the copper boiling point. The simplified reaction equation shows that the residue is ferrinhydroxide, but according to a preferred embodiment of the process it may be in the form of jarosite.

By adjusting the reactive chloride ion stock of the process liquid, the final iron content of the reacted liquid can be allowed to approach zero at the same time, which is advantageous from the electrolysis step lid. However, it is preferable to leave a certain minimum amount of residual iron as ferric chloride completely in the reacted liquid to ensure that all the reacted copper is in solution as cupric chloride. This addition of additional reactive chloride ion to the process fluid is illustrated by the following reaction equations, which supplement the previously mentioned process reaction equation from the Reduction Step.

2CuFeS2 + 3CuCX24CuCl + FeCX2 + 2S + CuFeS2 O, 1CuFeS2 + 0.3FeCl3 Q.XCuCX + 0.4FeCX2 + 0.2S

2.XCuFeS2 + 3CuC12 + 0.3FeCX3- »4, XCuCX + X.4FeCX2 + 2.2S

+ CuFeSg

Electrolysis step 4CuCX + FeCl2 2Cu + 2CuC12 + FeCl2 O.ICuCl + 0.4 FeClg - ^. O.XCu + 0.3FeCX2 + O.XFeCX3 4.1CaCl + 1.4FeCl2 - * 2.XCu »20iClo + L $ FeClP + .0.XFeC 65808

Combined oxidation-regeneration-purification step: 2Fe (OH)

CuFeS + 2S + 2CuCl + FeCl. + 3 O. + 3 HO -> 3CuCl „+ -1- 2 2 l 2 2 ^ ^

+ 4S

0.2S + 0.1FeCl3 + 0.3FeCl2 + 0.15 02 + 0.15 ^ 0 -> 0.1FeCl., + 0.2FeCl_ + 0.1Fe (OH) „+ 0.2S 3 3 -J- 3

CuFeS2 + 2,2S + 2CuCl2 + 1,3FeCl2 + 0.1FeCl3 + 3.15 02

♦ 3.15 HJD -> 3CuCl „+ 0.3FeCl„ + 2.1Fe (OH), + 4.2S

2 2 3 JT 3

It is found that reserving the minimum concentration of residual iron in the final reacted liquid of the combined oxidation-regeneration step, FeCl 3, to ensure the presence of all the copper in solution as copper chloride, has a compensatory effect on the electrolysis. The copper which this ferric chloride residue dissolves from the process solids fed to the reduction step causes the stoichiometric amount of ferric chloride to regenerate in the anolyte upon settling in the electrolysis step. It should be noted that this amount is one third of the amount of ferric chloride initially present in the reacted liquid of the above combined oxidation regeneration-purification step.

Thus, means have been expressed by which the "combined" process allows the extraction power of ferric chloride to be exploited (to ensure maximum dissolution of copper ore) while limiting the iron content of the electrolyte in the desired manner by controlling the reactive chloride ion storage in the process liquid.

It should be noted that the basic oxidation-regeneration-purification process is basically similar to the process described in Duval Corporation's U.S. Patent 3,785,944, which utilizes an oxidizing power of ferric chloride greater than that of copper chloride to ensure the most efficient dissolution of copper ore. the reacted liquid of the oxidation step is contacted with the solid fed to the process (stoichiometrically in excess), whereby copper chloride is mainly reduced to cuprous chloride in the electrolysis preparation step. The information provided by this "combined" process is that the simultaneous oxidation-regeneration-purification reaction makes it possible to control the decrease in the iron content of the reacted liquid towards zero. In this way, the iron content of the electrolysis feed solution can be substantially limited to the amount that is soluble only in the reduction step, and this has a beneficial effect on the quality of the electrolytically produced copper.

The combined oxidation-regeneration-purification process further offers the advantage that jarosite-shaped iron hydrate precipitates, as do other compounds associated with the regeneration-purification reaction, in the presence of insoluble solid residues, and thus seeks to reduce and limit the tendency of the process equipment to flake.

(a) The irregular surface of the solids, which is considerably larger in size than the smooth surface of the apparatus with which they are in contact, provides crystallization sites that attract precipitated compounds.

b) The solids present in the system create a wear effect and as a result the dandruff tends to come off the surface of the equipment.

In addition, combining the oxidation and regeneration-purification steps has the advantage that the production steps are further simplified and the equipment requirements are reduced.

U.S. Patent 3,735,900 discloses the excellent advantages of maintaining the desired total chloride ion concentration in the process by increasing the stock of reactive chloride ions in the process fluid by adding to the process fluid a "suitable alkali metal salt such as sodium chloride, potassium chloride or magnesium chloride thereof". The preferred effects of sodium chloride described in U3A 3,785,9M are as follows: 1) the solubility of cuprous chloride is improved 2) the secondary reaction leading to copper losses from the solution of the reduction step (step A) is slowed down and thus the intensification of the reduction is achieved sulphate ions are slowed down 5) protection against oxidation of cuprous chloride by atmospheric treatment is obtained when the process solution is passed from the reduction step through the metal recovery step 6) the quality of the electrolytic copper product is preferably affected.

It has previously been found that the combined oxidation-regeneration purification process has the advantage that a significant reduction in the amount of iron at the same time reduces the total concentration of chloride ions in the process liquid. According to U.S. Pat. No. 3,750,9, the total concentration of chlorides should be maintained at the desired level by the addition of the appropriate metal chloride salt "sodium chloride, potassium chloride, magnesium chloride and mixtures thereof".

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Laboratory experiments and pilot plant experiments with blocked oxidation and regeneration purification in separate steps, as well as monitored process fluid iron content, show, as shown in Figure 2 of U.S. Patent 3,785,9M, that the desired total process chloride chloride ion concentration can be achieved under these conditions by adding metal chloride. chloride to near saturation. This has been considered a suitable practice and according to U.S. Pat. No. 3,785,9M this is a "preferred embodiment" because sodium chloride is usually the most economically preferred metal chloride salt.

Extended laboratory experiments and pilot plant experiments, in which the oxidation and regeneration purification steps were combined and performed simultaneously by the preferred procedures of the chemical reactions mentioned earlier in this specification, have shown that the desired total chloride ion concentration cannot be satisfactorily achieved by adding sodium chloride alone. However, the need to add chloride ions associated with the low iron content of the process fluid can be met by using magnesium chloride instead of sodium chloride as the metal chloride salt to be added, or preferably by adding potassium chloride to the process fluid already almost saturated with sodium chloride to a concentration close to

The use of potassium chloride in combination with sodium chloride as the metal chloride salt to be added to the process fluid is preferred because it has been found that to the extent that potassium chloride (along with iron) is present in the process fluid, virtually all Bulphate ions precipitate from the process fluid as potassium iron rosin in the regeneration purification reaction. This is a significant advantage in controlling the flaking of the process equipment.

Chemical data for the process fluid with respect to chloride ion concentration for alternative applications are shown in Figures 5 and 6.

The tables list the chemical values for the reduction step reaction from the process in which the oxidation and regeneration purification steps operate separately (according to Figure 2 of U.S. Patent No. 3,750,9 ^) compared to the combined process option, which is the subject of further consideration and development in this application.

The chemical structure of the reaction system is expressed in moles per 1000 moles of water as well as by weight.

The reaction time was kept constant at 1 hour and the temperature at 107 ° C in a sealed stirred vessel equipped with a reflux condenser.

It should be noted that the values are given for the progressively varying amounts of chloride ion, Cl> present in the feed to the reduction step of the different process options: 1. Separate oxidation and regeneration purification steps a) 175 moles keeping the sodium chloride content at 71 moles h ) 155 moles Cl due to reduction of sodium chloride to 51 moles, to increase efficiency c) 1 * * 0 moles Cl due to reduction of sodium chloride to 36 moles, to increase efficiency d) 125 moles Cl due to reduction of sodium chloride to regeneration to 21 moles, efficiency purification steps a) 122 moles Cl due to a decrease in the ferric chloride content from 32.5 moles FeCl 2, 0 moles FeCl 2 b) 140 moles Cl due to an increase in the sodium chloride content from 71.0 moles to 80.5 moles (very close to saturation) and potassium chloride , 5 moles of addition.

c) 155 moles Cl due to an increase in sodium chloride from 71.0 moles to 80.5 (very close to saturation) and an increase in potassium chloride of 23.5 moles d) 175 moles Cl due to an increase in sodium chloride from 71.0 moles to 80.5 (very close to saturation) and increasing the amount of potassium chloride to U3.5 moles e) 175 moles of Cl obtained by adding magnesium chloride alone as the metal chloride salt in an amount of 62.0 moles per 1000 moles of water.

It is found that the decrease in the total Cl content under the conditions described above resulted in a 100% reduction in the proportion of cuprous ions in the feed solution, through reduction to cuprous ions, in the reacted solution to a range of 97.3 '99.7 / »at 175 moles Cl 75.0-76 .9% at a concentration of 122-125 moles of Cl. The secondary reaction was not found to cause copper losses in the solution even when a high degree of reduction to cupro ions was achieved.

In summary, the tabular values shown in Figures 5 and 6 show the significant effect of the total concentration of chloride ions in the reduction step (Step A) in reducing copper chloride to cuprous chloride when the crude copper sulfide concentrate is reacted. When the oxidation and regeneration-purification steps operated separately, the total concentration of chloride ions was varied by adjusting the concentration of 9,680,808 sodium chloride, HaCl. In the combined process variant, where the iron content was reduced, a compensating chloride * ion addition was provided as shown by replacing with magnesium chloride, MgCl 2, sodium chloride, and alternatively adding potassium chloride, KCl, to achieve the desired total chloride ion concentration greater than that of NaCl alone. limited solubility of.

The data shown in the tables of Figures 5 and 6 are also graphically illustrated in Figure 7.

The progressive relationship between the concentration of chloride ion Cl 2 and the related reduction of cupric chloride to cuprous chloride in the reacted liquid is described in the total chloride ion concentration range of 122-175 moles Cl per 1000 moles of H 2 O, and alternatively expressed in the chloride ion concentration range of 16-21% Cl 2.

It is found that when using combined oxidation and regeneration purification, a low iron chloride system to which sodium and potassium chloride have been added, shown in the drawing by solid lines, offers more favorable conditions for reducing a chloride system to which only sodium chloride is added (shown in dashed lines in the drawing). This finding is a further justification for the fact that potassium chloride belongs to the salts added to the system as metal chlorides.

The stoichiometric molar equilibrium chemical basis of the process application in which the oxidation and regeneration purification steps are combined is shown in Figure 2 in connection with the treatment of copper ore.

The important finding mentioned earlier in this report that, to the extent that potassium ions (along with iron) are available in the process fluid, virtually all sulfate ions precipitate from the fluid as potassium iron jarosite by regeneration-purification reaction, is shown by the results of pilot plant experiments shown graphically in Figure 8. that the amount of sulfate ions in the liquid after oxidation, when sodium chloride is present as the only added metal chloride salt, drops sharply to near zero when potassium chloride is added to the process liquid of the system.

A simplified basic process for the treatment of copper-containing materials, in which the oxidation and regeneration-purification steps are combined, is clear from the diagram of Figure 1, and the stoichiometric molar equilibrium chemical values for this process are shown in Figure 2, applied to copper ore. However, with respect to a preferred embodiment of the process, reference is made to Figure 3 and the following detailed description.

In the case of copper sulphide ore concentrates containing mainly copper ore, fresh ore concentrate is added to reduction step 1, step A, via iodine 2, Figure 3. When the term "fresh" or "crude" is used herein, copper-containing materials have not previously reacted with any substance in the process. . Copper chloride, sodium chloride and potassium chloride are fed to reduction step 1, step A, via line 3. Sodium chloride and potassium chloride are fed to line 3 via line 3A.

In reduction step 1, step A, which is substantially closed from the atmosphere, the copper chloride in solution is reduced mainly to cuprous chloride by reaction with a sulfide ore concentrate near atmospheric boiling point, about o. ♦. ·. , 107 C. The partially reacted sulfide ore dew as well as the solution containing some unreacted copper chloride, cupric chloride, ferric chloride, sodium chloride and potassium chloride are passed via a line to a separator 5, where the solid is separated from the solution by gravity sedimentation.

The solution from the separator 5 containing copper chloride, cuprous chloride, ferric chloride, sodium chloride and potassium chloride is then passed via line 6 to reduction step 7, step B, to which cemented copper is also fed via line 3. Cemented copper is used to reduce substantially all of the remaining copper chloride to cuprous chloride near atmospheric boiling point, about 107 ° C. At the same time, the cemented copper dissolves into cuprous chloride.

In step 7 of reduction step 7, the solution containing cuprous chloride, ferric chloride, sodium chloride and potassium chloride is removed via line 9 and passed to a suitable filter 12, e.g. a sand filter, where suspended solids are removed.

If the calcium sulphate salt accumulates in the process liquid, its amount can be adjusted to an acceptable level by using a crystallization step to remove this compound from the system. The filtered electrolysis solution then passes through line 13 and enters the electrolysis cells Ik. In these cells, copper chloride is electrolysed and deposited as metallic copper on the cathodes while copper chloride is regenerated by anodes. Metallic copper as well as silver deposited with it is removed from electrolytic cells 1 ^ at 15 ·

A solution of electrolytic cells containing ferric chloride, sodium chloride and potassium chloride, as well as regenerated copper chloride, is then passed through line 16 11 65808 to the oxidation and regeneration-purification step. 19. A solid is also added to step 19 via line 17 with the partially reacted ore concentrate from separator 5. The reaction temperature is maintained at about 10 ° C and the pressure at about U, 2 kp / cm and air or oxygen is passed through line 18 to step 19, where ferric chloride oxidizes to ferric chloride with copper chloride in solution acting as a catalyst. At the same time, ferric chloride and copper chloride react with the solid so that substantially all of the copper in the solid dissolves. Excess iron dissolved in the process solution, sulfate ions, and other impurities present in the system simultaneously precipitate as basic iron oxide and potassium jarosite. This combined step is preferably performed at elevated temperature to reduce the time required for oxidation and regeneration-purification reactions. It is estimated that at a temperature above but below the melting point of sulfur, where the viscosity of sulfur rapidly rises, is in the temperature range of about 115 "159 ° C, the superheated aqueous solution removes sulfur from mineral surfaces and thus prevents" blinding ", exposing the mineral surface and The most suitable temperature range is about 100 DEG-150 DEG C. For example, in laboratory experiments carried out according to the above procedure at 11 DEG-140 DEG C. and at a pressure of 1 +, 2 kp / cm <2> using oxygen for a reaction time of 60 minutes, 99.5% was obtained. copper to dissolve from the copper sulfide ore concentrate, which was predominantly copper flux and had a typical particle size distribution.

After cooling below the atmospheric boiling temperature to prevent a sudden flash at which the elemental sulfur is in solid form, a slurry containing sulfur, insoluble residue, potassium jarosite precipitate, copper chloride, ferric chloride, sodium chloride is used. separating the insoluble residue, sulfur and potassium jarosite precipitate from a solution containing copper chloride, ferric chloride, sodium chloride and potassium chloride. This solution is then returned via line 3 to reduction step 1, step A. The solids are removed from the device 21 via line 22 to the wash filter 23, where substantially all of the remaining process liquid is removed. The filtered solid (sulfur, insoluble waste and potassium jarosite precipitate) is removed at 2h and the recovered liquid is added to the solution in line 3 via line 25. The solid can be further treated by conventional methods to remove elemental sulfur, potassium jarosite precipitate, and insoluble precious metals.

65808

It has been found that when the combined step is carried out at atmospheric boiling temperature, an extended reaction time of an average of 10 to 12 hours is required to achieve the desired dissolution of 99 .mu.l of copper from a conventional copper-pyrite concentrate. Carrying out the process at atmospheric pressure, which is advantageous for the mechanical operation of the equipment, can therefore only take place at the expense of an extended reaction time.

By adjusting the stock of chloride ions in the process liquid, the final iron content of the reacted liquid can be allowed to send a value of zero, thereby minimizing the amount of iron in the process liquid and improving the quality of the copper product obtained from the electrolysis step. However, it is preferable to leave a small amount of iron in the reacted liquid (as ferric chloride) to ensure that all the reacted copper is in solution as copper chloride.

Although one embodiment of the present invention has been described as being applied primarily to the treatment of copper ore copper sulphide ore concentrate, it has also been found that a mixture of such sulphide ore concentrate with non-sulphide materials such as natural copper and copper oxides, carbonates and silicates can be treated efficiently by this process. Since substantially all copper ores contain copper ore and most other copper-containing materials of such ores dissolve more readily, an excellent advantage of the process of this invention is that any ore concentrate or copper concentrate mixtures can be extracted on a commercial scale.

In another embodiment of the present invention, shown as a flow chart in Fig. U, it has been found advantageous to use potassium chloride alone or with sodium chloride in a process in which the regeneration-purification step and the oxidation step are performed separately. Addition of potassium chloride gives potassium ions to the process liquid and through it practically all sulphate ions can be doped from the liquid as potassium jaxosite regeneration-purification reaction. This is important when controlling the flaking of process equipment.

When the copper chloride of the oxidation step is reacted with fresh copper ore in the reduction step, it has been found that the degree of reduction achievable may be limited by the secondary reaction and this results in copper losses in the solution. It is considered probable that a stable copper sulfide will then precipitate.

It has further been found that the reaction is temperature sensitive and that limiting the temperature to atmospheric boiling point, about 107 ° C, allows the reduction of 13 65808 copper chloride without copper losses in solution or with minimal copper losses, with an average reaction time of about 1 hour. It is therefore understood that limiting the temperature of the reduction reaction may limit the reaction rate to such an extent that the reaction can be practically controlled in this way.

Further reduction of the copper chloride of the first stage of the reduction can be carried out with suitable reducing agents such as sulfur dioxide, sodium sulfite, metallic iron and materials containing metallic copper, idioc scrap copper or cemented copper is economically available, its use is obviously advantageous because the quality of such copper is improved. electrolytic copper in the electrolysis step. Copper chloride can actually be completely reduced to cuprous chloride using one of these reducing agents.

In the second step of the reduction (also referred to as Step 3), the preferred reaction temperature varies depending on the specific reducing agent used. When using, for example, cemented copper or metallic iron, a temperature close to the atmospheric boiling point, about 107 ° C, has been found to be suitable.

In both the oxidation and regeneration purification step and the reduction step, it has been found advantageous to carry out the reaction by preventing contact with the atmosphere in order to minimize evaporation losses and to avoid oxidation of cuprous chloride to cupric chloride during the reduction step.

It has been found advantageous to control the electrolysis temperature. Raising the temperature improves the electrical conductivity of the electrolyte and the solubility of the salts in solution, both effects being advantageous. In this case, however, the vapor pressure of hydrochloric acid in the electrolysis also increases, and this is disadvantageous. Laboratory experiments as well as pilot plant experiments have shown that a temperature suitable for electrolysis is about 30 to 60 ° C, and preferably a temperature of about 55 ° C is used.

It has also been found advantageous to clarify the complete solution before introducing it into the electrolytic cells. The trace method removes any small particles left in the solution that may adversely affect the quality of the metallic copper as the copper settles on the cathodes of the electrolytic cells. Such clarification can be performed with any suitable device such as a sand filter.

As a result of the electrolysis of a complete (feed) solution containing cuprous chloride and ferric chloride, the copper ions are transferred to the cathode as metallic copper and at the same time the chloride ions are transferred to the anode and released in the presence of the anolyte solution, oxidizing the cuprous chloride to copper chloride. When a separate oxidation and regeneration-purification step is used, it is preferable to adjust the process so that the amount of electrolytically alloyable copper is not more than about half the amount of the copper pair of the complete solution fed to the electrolysis.

However, it has previously been found that when using combined oxidation and regeneration purification, it is preferable to feed a small amount of ferric chloride to the reduction step with copper chloride obtained from the oxidation step. In this case, the amount of copper removed in the electrolytic cell should be more than half the copper content of the complete solution, and the amount in excess should be the same as the amount dissolved by the ferric chloride in the reduction step. A stoichiometrically equivalent amount of ferric chloride relative to the electrolyzed convex, one-third of the amount reduced to ferric chloride / reduced in the reduction step, is oxidized to ferric chloride in the anode section of the cell.

Desirable properties of diaphragms used in electrolytic chemistry are substantial inertness to the solution and the best possible resistance to the hydraulic flow of the solution and the lowest possible electrical resistance. Available materials that meet these requirements include Teflon, polyethylene, polyethylene, and polyacrylic when suitably structured, such as popped, woven, needle-like, or gas-expanded, and when these materials are made so that their solution permeability is limited while the electrical resistance is as low as possible. Other materials available include films used to electrically remove salts from water, such as chlorosulfonated polyethylene sheets.

The relative heights of the solution surfaces in the catholyte and anolyte compartments of the electrolytic cell are adjusted by dam devices so as to maintain a hydraulic gradient from the catholyte compartment to the anolyte compartment to prevent the anolyte solution from flowing through the diaphragm in the opposite direction to the catholyte compartment. The anolyte solution contains copper chloride. If this solution were allowed to flow back into the catholyte compartment, it would tend to dissolve copper back from the cathodes, which would impair the efficient use of electricity.

The application of this invention is not limited to any particular apparatus. The process steps described herein may be performed in batches or continuously in any suitable conventional equipment, such as, for example, reactors, tanks, and vessels, which may be conventionally open or closed from the atmosphere. The various steps described herein may further be performed in one or more reactors, vessels or tanks. The present invention further encompasses the use of compartmentalized, divided, or segmented device units.

Claims (9)

15 6 5 80 8 A hydrometallurgical process for the production of metallic copper, wherein the copper is dissolved in metal chlorides, e.g. by an extraction solution containing copper (II) chloride, followed by electrolysis of the formed copper (i) chloride, the method comprising the steps of: (l) oxidizing a copper sulfide-ore concentrate-containing materials in a solution containing ferric chloride and copper (II) chloride; until a substantial portion of the copper contained in these materials is dissolved as copper (II) chloride, (2) a reduction step separate from the oxidation step, wherein at least a substantial portion of the copper (II) chloride of the solution obtained from the oxidation step is reduced to copper (I) chloride, (3) an electrolysis step the metallic copper is recovered and the copper (II) chloride is regenerated by electrolysis of the copper (I) chloride solution obtained from the reduction step, and (U) a regeneration bubbling step which may be separate from or combined with the oxidation step it is given react with oxygen in the presence of regenerated copper (II) chloride, whereby the ferric chloride required in the oxidation step is regenerated and iron oxide compounds, e.g. those with jarosite iron / sulphate ratios are precipitated by hydrolysis to remove excess iron and sulphate ions and other impurities in the solution, the chloride content of the solution being controlled at all stages of the process by the addition of a metal chloride compound which may be potassium chloride, magnesium chloride or sodium chloride , characterized in that in the process variant, in which the regeneration-purification step is combined with the oxidation step, the total chloride ion content, including reactive chloride ions in solution and chloride ions from the metal chloride compound added to the solution, is kept at a level such that copper in reduction step II) reduced to more than 75% copper (I) chloride and minimizing the loss of copper from solution by the addition of a metal chloride compound which may be potassium chloride, magnesium chloride, a mixture of potassium chloride and magnesium chloride, or any a mixture of the above compound and sodium chloride, wherein the total concentration of chloride ions in the solution is maintained at a level which exceeds the concentration which can be achieved by adding sodium chloride alone to the point of saturation. Process according to Claim 1, characterized in that the chloride ion concentration in the process solution is kept close to the maximum solubility permitted by the metal chloride salts of the process solution. Process according to Claim 2, characterized in that the potassium chloride is present in the metal chloride addition in an amount which is preferably required for the precipitation of practically all sulphate ions from solution. Process according to Claim 3, characterized in that sodium chloride is used as the metal chloride salt with potassium chloride. Process according to one of Claims 1 to U, characterized in that the excess iron is doped from the solution by adjusting the amount of reactive chloride ions available in the process solution. Process according to one of Claims 1 to 5, characterized in that the residual iron content of the reacted solution obtained from the combination of the oxidation and regeneration purification steps is limited by adjusting the amount of reactive chloride ions available in the process solution. Process according to Claim 6, characterized in that the removal of iron from the chloride solution in the combination of the oxidation and regeneration purification steps is limited so that only sufficient iron remains in the solution as iron (III) chloride to ensure that all copper chloride is copper (II) in the finally reacted solution. ) chloride. Process according to Claim 7, characterized in that the amount of metallic copper formed on the cathodes in the electrolysis step is kept equivalent to the amount of copper soluble in the process solution, copper (I) chloride oxidized in the anolyte to copper II) chloride and ferric chloride oxidized in the anolyte to ferric chloride. and a combination of regeneration and purification steps with the amount of ferric chloride in the final reacted solution. A hydrometallurgical process for producing metallic copper from a copper sulphide ore concentrate containing mainly copper ore according to claim 1, the process comprising a reduction step of first feeding the copper concentrate to an aqueous chloride-containing chloride solution to dissolve and ) to chloride, and the metallic copper is recovered in the copper recovery step by electrolysis in electrolytic cells of dissolved copper (I) chloride from the reduction step to produce metallic copper in the cathode compartment and copper II) to regenerate the chloride in the anode compartment. - the precipitation of the desired separated solids in the equipment is reduced and the solution obtained from the copper recovery step is reacted with oxygen to obtain a solution containing ferric chloride while oxidizing the unreacted ore concentrate from the reduction step to dissolve virtually all of the copper remaining in said ore concentrate, the resulting solution containing 17,680,808 copper (II) chloride and a very small amount of ferric chloride and, at the same time, by hydrolysis, iron compounds and other impurities are mixed from the solution, and the chloride solution containing copper (II) chloride and a very small amount of ferric chloride is returned to the reduction step. ie 6 5 8 0 8