# US 8,540,950 B2 · Method for the removal of chloride from zinc sulphate solution

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- Number: US 8,540,950 B2
- Document ID: US8540950B2
- Status: Granted
- Kind: B2
- Application number: 13/511,091
- Filed: 2010-11-22
- Published: 2012-11-15
- Granted: 2013-09-24
- Earliest claimed: 2009-11-23
- Assignees: Outotec Oyj
- Applicants: Mikko Ruonala; Kurt Svens; Antti Arpalahti; Karoliina Lepistö
- Inventors: Mikko Ruonala; Kurt Svens; Antti Arpalahti; Karoliina Lepistö
- Web page: https://patentgrep.com/patent/US8540950B2

## CPC

- C22B 19/22: {with leaching with acids}
- C01G 9/06: Sulfates
- C22B 3/46: by substitution, e.g. by cementation
- C22B 19/26: {Refining solutions containing zinc values, e.g. obtained by leaching zinc ores (treatment or purification of solutions by liquid-liquid extraction, by ion exchange or by adsorption C22B3/00)}
- Y02P 10/20: Recycling
- C22B: PRODUCTION AND REFINING OF METALS (electrolytic C25); PRETREATMENT OF RAW MATERIALS
- C01G: COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F (metal hydrides {monoborane, diborane or addition complexes thereof} C01B6/00; salts of oxyacids of halogens C01B11/00; peroxides, salts or peroxyacids C01B15/00; thiosulfates, dithionites, polythionates C01B17/64; compounds containing selenium, or tellurium C01B19/00; binary compounds of nitrogen with metals C01B21/06; azides C01B21/08; {compounds containing nitrogen, other non-metals and metal C01B21/082}; metal amides C01B21/092; nitrites C01B21/50; {compounds of noble gases C01B23/0005}; phosphides C01B25/08; salts of oxyacids of phosphorus C01B25/16; carbides C01B32/90; compounds containing silicon C01B33/00; compounds containing boron C01B35/00; compounds having molecular sieve properties but not having base-exchange properties C01B37/00; compounds having molecular sieve and base-exchange properties, e.g. crystalline zeolites, C01B39/00; cyanides C01C3/08; salts of cyanamide C01C3/16; thiocyanates C01C3/20)
- Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS

## Abstract

The invention relates to a method for removing chloride from zinc sulphate solution in conjunction with zinc production. According to the method, the chloride is removed from solution by means of monovalent copper, which is produced in a separate copper(I) oxide formation stage, in which the pH is regulated to the region of 4.5-5.

## Claims

### Claim 1

A method for removing chloride from concentrated zinc sulphate solution with copper(I) oxide, whereby a sidestream is taken from the zinc sulphate solution, which is cooled and routed to a chloride removal stage, wherein chloride removal is performed with copper(I) oxide, which is produced in a separate copper(I) oxide formation stage by reducing the copper sulphate contained in the zinc sulphate solution fed into the copper(I) oxide formation stage and the copper sulphate additionally fed into the copper(I) oxide formation stage into copper(I) oxide with zinc powder, said reducing the copper sulphate being conducted at a pH in the range of 4.5-5.

### Claim 2 (depends on 1)

A method according to claim 1, wherein the solution exiting the chloride removal stage is subjected to liquid/solids separation and that the copper chloride residue formed is routed to hydroxide washing in order to form sodium chloride solution and a precipitate containing copper(I) oxide and metallic copper.

### Claim 3 (depends on 2)

A method according to claim 2, wherein the precipitate exiting hydroxide washing is leached in a copper leaching stage with sulphuric acid and oxygen-containing gas and that the acidic copper sulphate solution that is formed is routed either wholly or partly to the chloride removal stage.

### Claim 4 (depends on 3)

A method according to claim 3, wherein part of the copper sulphate solution formed in the copper leaching stage is routed to the copper(I) oxide formation stage.

### Claim 5 (depends on 2)

A method according to claim 2, wherein part of the precipitate exiting hydroxide washing is routed to the copper(I) oxide formation stage.

### Claim 6 (depends on 1)

A method according to claim 1, wherein the pH of the copper(I) oxide formation stage is regulated with sodium hydroxide.