Patent ID: 7547348
Filing Date: 2009-06-16
Classification: C22B,Y02P

Abstract:
1. A method for recovery of copper from copper-bearing raw material further containing other valuable metals, iron, and sulphur, the method comprising: leaching said raw material into an aqueous solution of copper chloride and hydrochloric acid in a leaching stage; adjusting a redox potential of a copper-containing raw material leach in the leaching stage using a feed of an oxidizing agent to the range of 480-500 mV with regard to a Ag/AgCl electrode, whereby iron and sulphur remain in a deposit formed in leaching and the copper in the aqueous solution is mainly divalent; feeding the aqueous solution coming from the leaching stage to the first extraction stage of a two-stage liquid-liquid extraction stage; extracting, in the first extraction stage, copper from the aqueous solution coming from the leaching stage into a first organic extraction solution while the other valuable metals remain in the aqueous solution coming from the leaching stage; partitioning the aqueous solution coming from the first extraction stage into a first part and a second part; feeding the first part of the aqueous solution back to the leaching stage; neutralizing the second part of the aqueous solution; feeding the neutralized aqueous solution into the second extraction stage; extracting, in the second extraction stage, copper from the neutralized aqueous solution into a second organic extraction solution while the other valuable metals remain in the neutralized aqueous solution; transferring the first and second organic extraction solutions to a stripping stage where copper is transferred from the first and second organic extraction solutions into an aqueous solution of sulphuric acid forming a copper-depleted organic extraction solution; feeding the aqueous solution of sulphuric acid from the stripping stage to an electrowinning stage for recovery of elemental copper.