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

The invention relates to a method of controlling acid soluble iron while obtaining solutions of copper (I) salts in water containing an organo nitrile (selected from the group consisting of acetonitrile, 2-hydroxycyanoethane, acrylonitrile and propionitrile) from materials containing copper and iron compounds, said solutions having a low iron content, which method comprises leaching the material with a solution of copper (II) salt in water containing the selected organo nitrile, the amount of nitrile present being sufficient to stabilize the resulting copper (I) solution and the pH of the mixed solution being controlled in relation to the relative concentrations of the copper (II) salt, copper (I) salt and nitrile to ensure that the iron compounds are not significantly soluble therein, and then separating the copper (I) solution from the insoluble materials.