Recovery of dissolved gold by sodium borohydride (NaBH.sub.4) reduction
AssigneeHer Majesty the Queen in right of Canada, as represented by the Minister of Energy, Mines and Resources
InventorKazi E. Haque
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Abstract
A process is disclosed for the direct recovery of gold from cyanide leach liquor, thiourea leach liquor or Bio-D leach liquor. The process comprises reduction precipitation of the gold from solution by the addition of stabilized alkali metal borohydride, preferably sodium, potassium, lithium or ammonium borohydride, at ambient temperature and pressure. High purity gold is obtained by heating the reduced precipitate to about 1200.degree. C. The barren solution is in a condition such that it can be recycled to the upstream process.
Claims10
A process for recovering metallic gold from an acidic solution containing gold values, which comprises:
- adding to the solution a stabilized sodium borohydride comprising a mixture of sodium borohydride and sodium hydroxide in an amount at least stoichiometrically equal to the amount of gold compounds in solution to cause precipitation;
- separating the metallic precipitate from the solution;
- and
- heating the precipitate to obtain high purity metallic gold.
A process for recovering metallic gold from an acidic solution containing gold values, which comprises:
- adding to the solution a stabilized alkali borohydride in an amount at least stoichiometrically equal to the amount of gold compounds in solution to cause precipitation;
- separating the metallic precipitate from the solution;
- and
- heating the precipitate to obtain high purity metallic gold;
- wherein the stabilized alkali borohydride is a stabilized alkali metal borohydride or ammonium borohydride;
- wherein the stabilized alkali borohydride employed is stabilized sodium borohydride;
- and
- wherein the stabilized sodium borohydride comprises a mixture of sodium borohydride and sodium hydroxide.
Dependencies are inferred from the claim text.