FI117138B - Production of metallic copper by reducing copper (I) oxide by hydrogen - Google Patents

Description

MANUFACTURE OF METAL COPPER BY REDUCING OXY WITH DIA VEDY

FIELD OF THE INVENTION

The invention relates to a process for the production of metallic copper in connection with chloride-based hydrometallurgical production. M <tb> Copper raw material is dissolved in a solution of copper (II) chloride-alkali chloride to provide a solution of copper (II) chloride. Copper is doped as copper (I) oxide and the resulting alkali chloride solution is subjected to electrolysis in the leaching of the raw material and recovery of the copper to produce chlorine, alkali hydroxide and hydrogen. The metal is made from copper (I) oxide by reducing it clearly with alkaline hydrogen at elevated pressure, either as a batch or as a Continue process.

15

BACKGROUND OF THE INVENTION

U.S. Patent No. 6,007,600 describes a process for the hydrometallurgical production of copper-containing ra; V ·! such as copper sulphide concentrate. According to the method, r ** *: 20 is dissolved in a countercurrent solution with concentrated alkali chloride-cup * im: solution in several steps to form a solution of copper (I) chloride: Since impurities of both divalent copper and memory 9 »» »: * always remain in the solution, ·· * Reduction and solution purification. Pure copper (l) chloride solution precipitated with hydroxide to copper (i) oxide and the oxide is further reduced * ;;; copper. During the precipitation of copper (I) oxide, the form • 9 • 9 ....... _.

2 pyro m etai 11 u rg in i or autoclave. The autoclave reduction was not further described.

The production of metallic copper from cuprite (Cu20) with its> 5 autoclave reduction is described in the congress presentation He Wadsworth, M.E.: '' Hydrothermal Reduction of Copper Oxides '' in EPD Congress 1994, The Minerals, Metals &Mated; Warrendale, 1994. According to the studies described in the presentation, naturally occurring copper (I) oxide is reduced to metal by hydrogen reduction. The hydrogen reduction is carried out in an autoclave at 150 ° C and 1900 kPa (19 bar). Reduction-related time, or induction period, before the reaction is close Dead time is several hours. By using certain excipients such as hy anthraquinone, the incubation time can be reduced.

15

Copper (I) oxide dip, which is mainly used for pigmentation, appears to be quite pure in tests conducted by Hevia and Wadsworth. In practice it is Thu 4 *: Λ: Ku | * · ·: 20 reduction is more difficult than the reduction tests described in the commercial, pure Cu «* 4 2 V presentation have not been able to evaluate the effect of * impurities. In the reduction experiments, the pH of the slurry is v 7-9 and the article states that the pH is irrelevant.

• I

• 4 «44

PURPOSE OF THE INVENTION

The object of the method of the present invention is game 3

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a simple process for the production of metallic copper from copper (I) oxide formed during the production of copper hydronr 5. the preferred copper concentrate used in hydrometallurgical production. The copper concentrate is dissolved in alkali chloride-copper (li) chlo and the resulting copper (l) chloride solution is purified directly from the copper (l) chloride solution by alkali hydroxide doping with copper (l) oxide. In the precipitation of copper (I) oxide, an alkali chloride solution is passed to a chlor-alkali electrolysis to produce the chlorine, an alkali hydrogen, required for the dissolution of the n and the copper recovery. The pH of the Kupah (l) oxide slurry is adjusted to v alkaline by the alkali hydroxide produced by the electrolysis, already the reduction of the copper (I) oxide to the metallic copper is carried out in the presence of hydrogen from the electrolysis.

One essential aspect of the invention is that the reduction * *: voim: is strongly alkaline. The pH value of the slurry is preferably in the range of 9 »» »: V 20 * · *: V Due to the preparation method, copper (I) oxide always contains 1 µl which, when reacted with an alkali hydroxide, produces? The amount of chloride is of the order of 0.1-1 · · • # # 25 The precipitated Cu20 slurry in concentrated alkali chloride solution can • · · in a pressurized state as such without thickening or lie ft. . . __ _____II _____ ___L. _ 11 4

The reduction of copper (I) oxide can be carried out either as a batch process in a continuous process.

5 DETAILED DESCRIPTION OF THE INVENTION In the hydrometallurgical preparation of copper, which takes place as described in U.S. Patent 6, C previously mentioned, it is preferable to obtain copper in solution as monovalent copper (I) chloride. When a chlor-alkali electrolyte is incorporated into the process; The alkali chloride solution formed in the steps is derivatized with a chlor-alkali electrol to produce chlorine gas, which is used as a raw material for the precipitation of copper (I) oxide and hydrogen for the production of the metal.

15

Copper (l) oxide is reduced to mc metal copper according to the invention under hydrogen-elevated pressure, autoclave technology has advanced, and even at higher pressures j *: / ·: use does not cause major problems, copper (l) oxide reduction can 50 bar and at 14 (IV preferably 170-220 ° C.

The main problem with the hydrogen reduction of copper (l) oxide is the * ··· * time, ie the reactions start out rather slowly. It has been mentioned in technique 25 that this incubation time may have been reduced by the use of • · * · ;; for example, hydrazine or anthraquinone. The hydrazine is classified as 4 # f · 5, the pH is preferably adjusted to 9.5-13.5 in the process with alkali hydroxide. The pH adjustment of the slurry can be made already by the coupling hydroxide of the precipitation linkage with cup alkali hydroxide, or it can also be added to the slurry prior to its autoclave, or the α-hydroxy hydroxide can be directly introduced into the autoclave.

Raising the pH of the solution going to the reduction to the alkali hydroxide process is also advantageous in a ratio other than in l <l. In the preparation of chloride-based copper (I) chloride or copper (I) oxide, a small amount of 1.5% chloride is always left in the oxide powder. When the oxide slurry to be reduced does not contain alkali hydroxide, the chloride present in the oxide powder is dissolved to react with its salt with hydroxide. When sodium is preferably used in chlor-alkali electrolysis, sodium chloride is formed which does not precipitate with the copper but remains in the slurry from the reduction, and the copper powder is recycled to leach the copper concentrate. Although: it is sodium, other s • * potassium can be used instead.

• · * * * *:, · 20 *: V It is advantageous for the process economy that copper (l) oxide p <* · can also be carried out either directly from the alkali chloride slurry without filtration, washing and precipitation * · '· ·· * dipping in water. Of course, it is clear that the method developed. Copper (I) oxide can also be filtered, washed and slurried in aqueous solution before reduction. Reduction of the copper (I) oxide cannot be * 6 The hydrogen required for the reduction is obtained by chlor-alkali electrolysis as described in U.S. Patent No. 6,007,600.

EXAMPLES 5 Example 1

An aqueous slurry of copper (I) oxide was introduced into an autoclave to determine the method of the invention. Copper (l) oxides in each test 100 g / l. The hydrogen partial pressure was all experimental! temperature 200 ° C. The starting material had a chloride content of about 1 * 3 µl to the pH of the solution fed into the autoclave, ranging from 8.3 to 13.2. was performed by introducing sodium hydroxide into an aqueous solution e into an autoclave. Other results can be found in the appendix t; An indicator of the success of the experiment can be taken as the oxygen concentration of ki produced, that is, the lower the oxygen content, the better the success.

Table 1 "Röe ΓΪ 2 3 4 5 6 ~: Λ: Grain size, pm 50 50 50 3Ö 50 50 50 ~

: V "pH iT" 12.5 12.5 12.5 12.5 12.5 "TÖX

: Hydrazine, 0 250 1000 0 0 0 0 * · mg / l • __ _ ___ _ · «*! Duration of the test, ···. 120 60 60 60 60 60 60 · ... · min

Cl2-. a / 0.54 0.007 <0.005 0.007 0.035 0.037 0.011 Concentration% ·· ____ __ _ _ _

Product O ·, -

Claims (17)

11 A process for recovering metallic copper from a copper chloride-based hydrometallurgical preparation) wherein the copper raw material is dissolved in an alkali chloride-cup solution to form a copper (I) chloride solution, followed by treatment with an alkali hydroxide to form copper (I) oxide Chlorfale electrolysis for the lysis of the raw material to produce the chlorine alkali hydroxide required for the recovery of copper, characterized in that the copper (I) oxide slurry has a pH of 9.5 to 13.5 in the process followed by reduction of the copper (I) oxide to the metal. 15 2, The process according to claim 1, the known reduction is carried out at a hydrogen partial pressure of 40 to 50 bar. . . 3. A process according to claim 1 or 2, wherein the reduction temperature is adjusted to a temperature in the range of 140 to 220 °. 3. Förfarande enligt patent krav 1 eller 2, stump deck 11 The process according to claim 3, wherein the known reduction temperature is adjusted to a temperature in the range 140 to 220 ° C. • * 5. Förfarande enligt face av patentkraven 1 - 4, carry bucket (l) oxiden som leds account reduktionen innehaller chlorid A process according to any one of claims 1 to 4, in the turn: that the copper (I) oxide to be introduced into the reduction contains the corresponding salt dissolved in solution when reacting with chloric 11 alkali hydroxide. 6. Förfarande enligt patentkrav 5, incl. 7. Förfarande enligt patentkrav 5 eller 6, kännetecknat av koppar (l) oxiden löser sig och bildar vid reactionen med <motsvarande sait som kvarkär upplöst i lösningen. 8. Förfarande enligt face av patent kraven 1-7, apply detergent alkaline and sodium. A process according to any one of claims 1 to 7, wherein the alkali used is sodium. 9. Förfarande enligt face av patentkraven 1-7, apply 15 det of the alkaline and potassium. The process according to any one of claims 1 to 7, wherein the alkali used is potassium. A process according to any one of claims 1 to 9, wherein the copper (I) oxide is reduced from a concentrated alkali chloride solution 10. Förfarande enligt face av patentkraven 1 - 9, carry bucket (l) oxiden reduce ra ur ur concentrate alkaline chloride · v; 20 11. Förfarande enligt näget av patentkraven 1-9, carry * 9 bucket (l) oxiden har före reduktionen utfällts ur en · *: ··; alkalikloridlösning. • • 99 9 9999 The process according to any one of claims 1 to 9, wherein the copper (I) oxide is precipitated from the alkali chloride solution prior to reduction. 12. Förfarande enligt face av patentkraven 1 - 9, carry 25 buckets (l) oxiden har före reduktionen utfällts ur en alkalichlorideslösning, filtrate, tvättats och uppslam • ··· * vattpnlnsninn reduktionen av koppar (l) oxide genomförs continuinligt. The process according to any one of claims 1 to 9, wherein the copper (I) oxide is precipitated before reduction. . of alkaline chloride solution, filtered, washed and slurried aqueous solution • · »• *«. · 20 • ψ ft m The process according to any one of claims 1 to 12, wherein the reduction of the copper (I) oxide is carried out in a batch process. The process according to any one of claims 1 to 12, wherein the reduction of the copper (I) oxide is carried out in a continuous operation by supplying an alkali hydroxide in a pressurized state to the copper (I) oxide slurry. Process according to one of Claims 1 to 14, characterized in that the pH of the copper (I) oxide slurry is adjusted to a value by supplying an alkali hydroxide to a pressurized state. ίο 1. Förfarande f utvinning av metallisk hood ur ko samband med chloridebaserad hydrometallurgisk fram hood, colors ramaterial för hopp loses upp med hood (ll) chloridlösning f att attadkomma en koppar (l) l wilkning behandlas med alkalihydroxid för att b den alkichloride solution for sodium chloride (l) oxiden Eeds account for chloral alkaline electrolysis for alkaline hydroxide and for use in the treatment of pH and pH adjustment of the pH 9.5 - 13.5 rr • *: v. 20 alkali hydroxide som picture vid farfarandet, varefter r Γ * ': bucket (l) oxiden account metal bucket bucket i tricksatt u * * ·: **: hjälp av. ♦ ··· • * »*: [[[: 2. Förfarande enligt patentkrav 1, kännetecknat av att red 25 under ett deltryck av 40 - 50 bar pa va. • m · • · ♦ ** # 15. Förfarande enligt face av patentkraven 1-14, oxidizing capsule (l) oxuppslamningens pH regulatoras account of the samband med utfällningen av koppar (l) oxiden. 16. Förfarande enligt face av patentkraven 1-15, the bucket bucket (l) oxiduppslamningen pH adjuster account 9.5 without an alkaline hydroxide bucket (l) oxiduppslamningen and ice bucket det trycksatta utrymmet. 17. Förfarande enligt face av patent kraven 1 -14, the pH-regulator of the bucket (l) oxiduppslamntngens accounted for 9.5 without the addition of an alkaline hydroxide detergent. 15 • · • 0 0 • 0 «• 0 00 0 0 0 0 0 0 0 0 00 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 * 11 0 0 0 0 0 0 0 00 0 0 0 0 0 0 0 0 • 00 000 0 · • 0 0 00