Abstract: Metal values are recovered from mattes containing nickel, cobalt and iron by first suspending the mattes in water, oxygen pressure leaching and then chlorine leaching the residue from the oxygen leach.

Abstract: A process is provided for treating a matte for selective extraction of nonferrous metals using a single stage oxidative pressure leach wherein leaching is carried out in a continuous manner and relatively mild conditions on an aqueous slurry of the matte having a specific sulfur adjustment, having copper present in the aqueous phase, and having a final pH of less than .about.4 but not less than .about.3.

Abstract: A slurry, such as might be obtained from acid leaching nickeliferous ores having a high iron content, is treated to separate dissolved nickel or cobalt from iron oxide solids. The treatment involves a controlled precipitation of the non-ferrous metal with the aid of calcium sulfide or barium sulfide followed by flotation to recover a high grade concentrate of the non-ferrous metal.

Abstract: Anode slimes from an electrorefining operation are fed, together with sulfuric acid, into a heated pelletizer wherein a sulfation reaction occurs, simultaneously with pellet formation, to solubilize copper, nickel and tellurium contained in the slimes.

Abstract: A process for treating anode slimes containing silver in which the silver is converted to a form soluble in dilute nitric acid, and in which after dissolution in dilute nitric acid, the silver is electrowon from solution. The process can be carried out by a route which is entirely hydrometallurgical. In addition to recovery silver, other values such as Se, Te, Ni and precious metals can be recovered.

Abstract: A nickel matte in which the atomic ratio of S:(Ni+Co+Cu) is less than 0.7 is fragmented and slurried with water or an aqueous nickel sulfate solution to ensure that the S:(Ni+Co+Cu) ratio for the slurry as a whole exceeds 0.4, the slurry is heated under pressure in the presence of oxygen to form a basic nickel sulfate and the reacted slurry is treated with lime to convert the basic nickel sulfate to nickel hydroxide. The nickel hydroxide is then separated from gypsum by physical separation and thereafter dissolved in spent sulfate electrolyte to generate fresh electrolyte from which nickel can be electrowon.

Abstract: A hydrometallurgical process for treating copper refinery anode slimes containing selenium, lead and precious metals in which a selenium product of better than 99.7% purity can be produced and the final residue is suitable for smelting to produce anodes for silver refining.