Patent ID: 6770249
Filing Date: 2004-08-03
Classification: C22B,Y02P

Abstract:
A leach process utilizing a chloride leach solution for leaching a selected metal from a metal bearing feed stock to produce a pregnant chloride leach solution suitable for selective metal recovery, comprising the steps of:providing a metal bearing feed stock containing iron oxides and containing a metal oxide (MO) wherein M is selected from the group consisting of Zn, Cd, Cu, Ag, Sn, Ni, and Pb; contacting said feed stock with a chloride leach solution comprising CaCl2 and water with a specific gravity in a range of 1.45 to 1.55 wherein the specific gravity of the chloride leach solution is controlled by the addition or removal of water to form a complex solution; and maintaining the concentration of CaCl2 in said complex solution so that the CaCl2 will react, at atmospheric pressure and at a temperature below the boiling point of the complex solution, with the MO to form a calcium-metal-chloride complex according to the formula: 3CaCl2+2MO+2H2Oâ†’[Ca+++2MCl3âˆ’]+2CaOH2without solubilizing substantially all of the Fe present in the complex solution.