Abstract: A method of recovering copper from a copper sulfide concentrate comprising a copper arsenic sulfosalt or a copper antimony sulfosalt, using carbon as a catalyst. The concentrate and carbon are added to an acidic sulfate leach solution. The copper is leached from the concentrate, in the presence of an oxygen-containing gas. The operating potential is maintained above a selected level. The carbon copper sulfide ratio of the carbon being added to the copper sulfide present in the concentrate being added is at least 1:20. The carbon may be maintained above a selected concentration in the leach solution. The leached copper is recovered from the solution by conventional methods.

Abstract: A method of recovering copper from chalcopyrite concentrate by chemical leaching, using pyrite and silver. The catalytic properties of pyrite in the chalcopyrite leaching process are significantly enhanced by pretreating the pyrite with silver ions. Particulate pyrite is exposed to a solution containing silver ions to form silver-treated pyrite. Particulate chalcopyrite and the silver-treated pyrite are mixed in an acidic sulfate leach solution. The copper is leached from the concentrate in the leach solution in the presence of an oxygen-containing gas, under conditions whereby the pyrite is substantially unoxidized. The leached copper is recovered from the solution by conventional methods. The used silver-treated pyrite is recycled to the leaching process.

Abstract: A method of recovering copper from chalcopyrite concentrate by chemical leaching, using pyrite and silver. The catalytic properties of pyrite in the chalcopyrite leaching process are significantly enhanced by pretreating the pyrite with silver ions. Particulate pyrite is exposed to a solution containing silver ions to form silver-treated pyrite. Particulate chalcopyrite and the silver-treated pyrite are mixed in an acidic sulfate leach solution. The copper is leached from the concentrate in the leach solution in the presence of an oxygen-containing gas, under conditions whereby the pyrite is substantially unoxidized. The leached copper is recovered from the solution by conventional methods. The used silver-treated pyrite is recycled to the leaching process.

Abstract: A method of recovering copper from a copper sulfide concentrate comprising a copper arsenic sulfosalt or a copper antimony sulfosalt, using carbon as a catalyst. The concentrate and carbon are added to an acidic sulfate leach solution. The copper is leached from the concentrate, in the presence of an oxygen-containing gas. The operating potential is maintained above a selected level. The carbon copper sulfide ratio of the carbon being added to the copper sulfide present in the concentrate being added is at least 1:20. The carbon may be maintained above a selected concentration in the leach solution. The leached copper is recovered from the solution by conventional methods.

Abstract: A method of recovering copper from a copper sulfide concentrate comprising a copper arsenic sulfosalt or a copper antimony sulfosalt, using pyrite as a catalyst. The concentrate and pyrite are added to an acidic sulfate leach solution. The copper is leached from the concentrate, in the presence of an oxygen-containing gas, under conditions whereby the pyrite is substantially unoxidized. The pyrite:copper sulfide ratio of the pyrite being added to the copper sulfide present in the concentrate being added is at least 1:3. The pyrite may be maintained at a concentration in the leach solution of at least 9 grams per liter. The leached copper is recovered from the solution by conventional methods.

Abstract: The invention provides, in part, a process for extracting nickel from a source material including iron and nickel, by contacting the source material (e.g, an ultramafic ore) with an aqueous ammonia solution containing an iron-complexing agent (e.g., citrate) under suitable conditions, thereby extracting the nickel. The aqueous ammonia solution may optionally contain a sulfur-containing reductant, such as thiosulfate.

Abstract: A method of recovering copper from a copper sulfide concentrate comprising a copper arsenic sulfosalt or a copper antimony sulfosalt, using pyrite as a catalyst. The concentrate and pyrite are added to an acidic sulfate leach solution. The copper is leached from the concentrate, in the presence of an oxygen-containing gas, under conditions whereby the pyrite is substantially unoxidized. The pyrite:copper sulfide ratio of the pyrite being added to the copper sulfide present in the concentrate being added is at least 1:3. The pyrite may be maintained at a concentration in the leach solution of at least 9 grams per liter. The leached copper is recovered from the solution by conventional methods.

Abstract: A method of leaching copper from copper sulphide-containing concentrates, such as chalcopyrite, includes using pyrite as a catalyst for ferric reduction in order to eliminate passivation of the chalcopyrite surface, the process being carried out under conditions whereby the pyrite is not materially oxidized, for example by maintaining the operating solution potential at a suitable level. The leaching is carried out in an acidic sulphate medium and may include oxidation by oxygen-containing gas. The leached copper is then recovered, for example by solvent extraction and electrowinning. The leaching process can result in the virtually complete extraction of copper at atmospheric pressure in as little as four hours.

Abstract: The durability of a bonded aluminium alloy and/or Alclad (Trade Mark) material joint can be improved by a two stage pre-treatment process in which after the surfaces to be joined have been degreased, a first solution BTESE and/or BTMSE in water, with or without methanol and/or ethanol, is applied to the degreased surfaces dried and coated with a second solution of &ggr;-glycidoxypropyltrimethoxysilane, an amino silane, &ggr;-aminopropyltriethoxysilane and/or trimethoxyvinylsilane in water with or without methanol and/or ethanol and drying prior to the application of an epoxy adhesive coating to the dried second solution surfaces, bonding and curing.

Abstract: Apparatus and a method for restraining the movement of members due to magnetic fields in which a clamp made of magnetostrictive materials is used.