Recovery of copper from materials containing copper and acid soluble iron compounds

A method of preventing acid soluble iron from entering solution while preparing a solution of Cu(I) salts from a magnetite, particulate copper mixture comprising the steps of:

• (a) leaching said mixture with an acidic aqueous solution containing a Cu(II) salt and an organonitrile selected from the group consisting of acetonitrile, 2-hydroxycyanoethane, acrylonitrile and propionitrile, the amount of nitrile being sufficient to stabilize the resulting Cu(I) solution;
• and
• (b) controlling the ratio of Cu(II) to Cu(I), while maintaining the pH of the solution between about 2 and 5 to ensure that acid soluble iron does not dissolve as Fe(II).

A method of preventing acid soluble iron from entering solution while preparing a solution of Cu(I) salts from a material containing both copper and acid soluble iron comprising the steps of:

• (a) leaching said material with an acidic, aqueous copper sulphate solution and an organonitrile selected from the group consisting of acetonitrile, 2-hydroxycyanoethane, acrylonitrile and propionitrile, the amount of nitrile being sufficient to stabilize the resulting Cu(I) solution;
• and
• (b) controlling the ratio of Cu(II) to Cu(I) while maintaining the pH of the solution between about 2.5 and 4.5 to ensure that acid soluble iron does not dissolve as Fe(II).