Patent ID: 7559971

Claim:
A method for the removal of silver from a cuprous chloride solution in a copper recovery process, comprising removing, in at least two stages, silver from the cuprous chloride solution with soluble mercury, wherein fine-grained copper powder is fed countercurrently to the cuprous chloride solution, the method comprising: feeding mercury into the cuprous chloride solution at preselected stages in a preselected molar ratio to the silver in the solution; precipitating silver amalgam onto the surface of fine-grained copper powder; removing the precipitated silver amalgam from the cuprous chloride solution for the separation of mercury and silver; recycling soluble mercury back to silver removal; and treating the removed precipitated silver amalgam for the recovery of silver; wherein the treating step comprises leaching the precipitated silver amalgam into a dilute chloride solution using an oxidant, whereby the mercury dissolves as mercury chloride and the silver precipitates as silver chloride.