Process for recovering gold

Patent metadata

Field	Value
Publication number	US-2017247777-A1
Application number	US-201515521790-A
Country	US
Kind code	A1
Filing date	Oct 29, 2015
Priority date	Oct 29, 2014
Publication date	Aug 31, 2017
Grant date	—

Abstract

Provided is a process for recovery of gold from gold-bearing raw materials comprising (a) leaching said gold-bearing raw material in a chloride containing leaching solution containing a total concentration of less than 120 g/L of halide ions, whereby the total concentration of chloride ions is less than 120 g/L of to dissolve gold and to obtain a leach solution comprising gold in solution; and simultaneously contacting the leach solution comprising gold in solution with a re-sorptive material to obtain a leach solution comprising gold-bearing re-sorptive material; and (b) recovering gold and optionally silver from the said gold-bearing re-sorptive material.

First claim

1 - 21 . (canceled)

22 . A process for recovery of gold from gold-bearing raw materials comprising (a) leaching said gold-bearing raw material in a chloride containing leaching solution comprising a total concentration of 1 to 35 g/L of halide ions, whereby the total concentration of chloride ions is from 1 to 35 g/L , to dissolve gold and to obtain a leach solution comprising gold in solution, wherein the oxidation-reduction potential of the leaching solution in the leaching step (a) is at least 400 mV vs. Ag/AgCl; and simultaneously contacting the leach solution comprising gold in solution with a re-sorptive material to obtain a leach solution comprising gold-bearing re-sorptive material, wherein the re-sorptive material is selected from carbon comprising chemicals and materials; and (b) recovering gold and optionally silver from said gold-bearing re-sorptive material.

23 . A process as claimed in claim 22 , wherein the total concentration of bromide ions is less than 10 g/L, and a total concentration of cupric and/or ferric ions is at least 1 g/L.

24 . A process as claimed in claim 22 , wherein the chloride containing leaching solution comprises a total concentration from 1 to 20 g/L of halide ions, whereby the total concentration of chloride ions is from 1 to 20 g/L.

25 . A process as claimed in claim 22 , wherein the oxidation-reduction potential of the leaching solution is 400 mV to 750 mV vs. Ag/AgCl.

26 . A process as claimed in claim 22 , wherein the total concentration of dissolved cupric and/or ferric ions in the chloride containing leaching solution is at least 0.26 g/L.

27 . A process as claimed in claim 22 , wherein the total concentration of ferric ions in the chloride containing leaching solution is 0 g/L to 10 g/L.

28 . A process as claimed in claim 22 , wherein the total concentration of cupric ions in the chloride containing leaching solution is less than 20 g/L.

29 . A process as claimed in claim 22 , wherein the method comprises using oxygen-containing gas as oxidant for oxidizing iron and/or copper in the leach solution.

30 . A process as claimed in claim 22 , wherein the gold-bearing raw material comprises preg-robbing material.

31 . A process as claimed in claim 22 , wherein the temperature of the leaching step (a) is at or below the boiling point of the leaching solution.

32 . A process as claimed in claim 22 , wherein the leach solution has a pH of less than 4.0.

33 . A process as claimed in claim 22 , wherein the leaching is carried out in the absence of bromide ions.

34 . A process as claimed in claim 22 , wherein the leaching is carried out in the absence of copper.

35 . A process as claimed in claim 22 , wherein the leaching is carried out in the absence of iron.

36 . A process as claimed in claim 22 , wherein the re-sorptive material is selected from the group consisting of activated carbon, resin, organic solvents, organic substances, inorganic carbon, rubber, plastics, biopolymers, and combinations thereof.

37 . A process as claimed in in claim 22 , wherein the re-sorptive material comprises one or more of activated carbon, resin in leach, solvent in leach, organic substance, inorganic carbon, rubber, plastic, ion-exchange resin and polymeric resin.

38 . A process as claimed in claim 22 , wherein the method comprises removing excess water from the leach solution by one or more of evaporation, reverse osmosis, and other water removal technology.

Assignees

• Outotec Finland Oy

Inventors

• Lundström Mari
• O'Callaghan John
• Haakana Timo
• Ahtiainen Riina
• Karonen Janne

Classifications

• C22B11/06 Primary

  Chloridising · CPC title

• C22B3/10

  Hydrochloric acid {, other halogenated acids or salts thereof} · 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

• Y02P10/20

  Recycling · CPC title

• C22B3/24 Primary

  by adsorption on solid substances, e.g. by extraction with solid resins · CPC title