Abstract: The present invention relates generally to a process for the production of sulfuric acid and liberation of precious metal values from materials containing sulfur through pressure leaching operations. In accordance with various aspects of the present invention, the sulfur-bearing materials may comprise residues from pressure leaching operations, such as those carried out at medium temperatures. The process of the present invention can be advantageously used to convert such sulfur-bearing materials to sulfuric acid by means of pressure leaching. The sulfuric acid so produced can be used beneficially in other mineral processing operations, for example those at the site where it is produced. Metals, such as precious metals, that are contained within the sulfur-bearing materials advantageously may be recovered from processing products by established precious metals recovery technology.

Abstract: The present invention relates generally to a process for recovering copper from a metal-bearing ore, concentrate, or other copper-bearing material using pressure leaching and direct electrowinning. More particularly, the present invention relates to a substantially acid-autogenous process for recovering copper from chalcopyrite-containing ore using pressure leaching and direct electrowinning in combination with a leaching, solvent/solution extraction and electrowinning operation.

Abstract: A system and process for recovering copper from a copper-containing ore, concentrate, or other copper-bearing material to produce high quality cathode copper from a leach solution without the use of copper solvent/solution extraction techniques or apparatus. A process for recovering copper from a copper-containing ore generally includes the steps of providing a feed stream containing comminuted copper-containing ore, concentrate, or other copper-bearing material, leaching the feed stream to yield a copper-containing solution, conditioning the copper-containing solution through one or more physical or chemical conditioning steps, and electrowinning copper directly from the copper-containing solution in multiple electrowinning stages, without subjecting the copper-containing solution to solvent/solution extraction prior to electrowinning.

Abstract: A multi-layer hunting mask adapted to be close fitting at least over the nose and mouth of a wearer for eliminating odorous compounds from the exhaled breath of a wearer is disclosed. The mask includes an inner air-permeable fabric mesh layer, a middle activated carbon fiber fabric mesh layer, and an outer air-permeable fabric layer having a camouflage pattern. The inner, middle and outer layers are fastened together to provide a continuous, flexible nose and mouth covering mask for the wearer. The mask has at least one elastomeric loop for securing the mask over the mouth and nose of the wearer. A method of making the mask and a method of using the mask are also disclosed.