Silver recovery by ion exchange

Patent metadata

Field	Value
Publication number	US-2017175224-A1
Application number	US-201515315534-A
Country	US
Kind code	A1
Filing date	Jun 4, 2015
Priority date	Jun 5, 2014
Publication date	Jun 22, 2017
Grant date	—

Abstract

The present invention according provides a method of recovering silver from silver containing halide solutions, comprising the steps of: (a) providing an ion exchange column comprising a weak anion exchange resin; (b) introducing the silver containing halide solution to the ion exchange column to absorb silver in the weak anion exchange resin; (c) washing the loaded ion exchange resin with a first washing solution to rinse off absorbed zinc and optionally at least part of copper; (d) washing the loaded ion exchange resin with a second washing solution to rinse off remaining copper; and (e) optionally washing the loaded ion exchange resin with a third washing solution to rinse off absorbed lead; and (f) eluting the loaded ion exchange resin with an eluent to remove silver from the resin and to obtain a silver containing solution.

First claim

1 . A method of recovering silver from silver containing halide solutions, comprising:
(a) providing an ion exchange column comprising a weak anion exchange resin; (b) introducing the silver containing halide solution to the ion exchange column to absorb silver in the weak anion exchange resin; (c) washing the loaded ion exchange resin with a first washing solution to rinse off absorbed zinc and optionally at least part of copper; (d) washing the loaded ion exchange resin with a second washing solution to rinse off remaining copper; and (e) optionally washing the loaded ion exchange resin with a third washing solution to rinse off absorbed lead; and (f) eluting the loaded ion exchange resin with an eluent to remove silver from the resin and to obtain a silver containing solution.

2 . The method as claimed in claim 1 , further comprising:
(g) treating the ion exchange resin with an acidic solution to protonate the resin and to obtain a protonated resin.

3 . The method as claimed in claim 1 , wherein the silver containing halide solution comprises 0.1 to 1500 mg/L silver.

4 . The method as claimed in claim 1 , wherein the silver containing halide solution comprises 100 to 300 g/L.

5 . The method as claimed in claim 1 , wherein the halide is chloride.

6 . The method as claimed in claim 1 , wherein the silver containing halide solution further comprises 0 to 80 g/L bromides.

7 . The method as claimed in claim 1 , wherein the silver containing halide solution is obtained by leaching silver containing ore and/or concentrate with an acidic aqueous leaching liquor comprising 10 to 110 g/L Cu 2+ , 50 to 300 g/L Cl − , and 1 to 80 g/L Br − .

8 . The method as claimed in claim 1 , wherein the pH of the silver containing halide solution is below 3.

9 . The method as claimed in claim 1 , wherein the backbone of the weak anion exchange resin is a macroporous matrix.

10 . The method as claimed in claims 9 , wherein the backbone of the weak anion exchange resin is amorphous silica.

11 . The method as claimed in claim 1 , wherein the weak anion exchange resin comprises amine groups as the anion-exchange functional groups.

12 . The method as claimed in claim 1 , wherein the first washing solution is water or an aqueous solution comprising NaCl and/or CaCl 2 .

13 . The method as claimed in claim 1 , wherein the second washing solution is an aqueous solution comprising a hydrochloric acid.

14 . The method as claimed in claim 1 , wherein the third washing solution is an aqueous solution comprising an aminopolycarboxylic acid or salt thereof.

15 . The method as claimed in claim 14 , wherein the aminopolycarboxylic acid is ethylenediaminetetraacetic acid (EDTA).

16 . The method as claimed in claim 1 , wherein the eluent is an acidic solution comprising thiourea (SC(NH 2 ) 2 ).

17 . The method as claimed in claim 16 , wherein the concentration of thiourea is from 1 to 5 wt %.

18 . The method as claimed in claim 1 , wherein the acidic solution in step (g) is a hydrochloric acid solution.

19 . The method as claimed in claim 1 , wherein the eluent is an aqueous solution containing one or more thiosulfate salt, and optionally Na 2 SO 3 .

20 . A method for recovering silver with a weak anion exchange resin from a pregnant leach solution resulting from hydrometallurgical treatment of silver containing ores and/or concentrates, which pregnant leach solution is silver containing halide solution having pH below 3.

21 . The method according to claim 20 for recovering silver from a pregnant leach solution resulting from chloride based leaching of copper and gold ores and/or concentrates.

22 . The method for recovering silver with a weak anion exchange resin from a pregnant leach solution resulting from hydrometallurgical treatment of silver-containing ores and/or concentrates, which hydrometallurgical treatment is chloride based leaching of copper and gold ores and/or concentrates.

Assignees

• Outotec Finland Oy

Inventors

• Valkama Kari
• Haapalainen Mika
• Tyster Mikko
• Virolainen Sami

Classifications

• C22B3/00

  Extraction of metal compounds from ores or concentrates by wet processes · CPC title

• C22B3/42 Primary

  by ion-exchange extraction · CPC title

• C22B11/04 Primary

  by wet processes (extraction of metal compounds by leaching in organic solutions C22B3/16; treatment or purification of solutions by liquid-liquid extraction C22B3/26) · CPC title

• C22B3/06

  in inorganic acid solutions {, e.g. with acids generated in situ; in inorganic salt solutions other than ammonium salt solutions} · CPC title

• C22B11/00 Primary

  Obtaining noble metals · CPC title