96 results about "Pressure oxidation" patented technology

A process for recovering nickel and cobalt values from nickel- and cobalt-containing laterite ores as an enriched mixed nickel and cobalt sulphide intermediate and for producing nickel and cobalt metal from the nickel and cobalt sulphide intermediate. The laterite ore is leached as a slurry in a pressure acid leach containing an excess of aqueous sulphuric acid at high pressure and temperature, excess free acid in the leach slurry is partially neutralized to a range of 5 to 10 g / L residual free H2SO4 and washed to yield a nickel- and cobalt-containing product liquor, the product liquor is subjected to a reductant to reduce any Cr(VI) in solution to Cr(III), the reduced product liquor is neutralized to precipitate ferric iron and silicon at a pH of about 3.5 to 4.0, and the neutralized and reduced product liquor is contacted with hydrogen sulphide gas to precipitate nickel and cobalt sulphides. The precipitated nickel and cobalt sulphides can be leached in a water slurry in a pressure oxidation leach, the leach solution subjected to iron hydrolysis and precipitation, the iron-free solution contacted with zinc sulphide to precipitate copper, the iron- and copper-free solution subjected to zinc and cobalt extraction by solvent extraction to produce a nickel raffinate, the nickel raffinate contacted with hydrogen gas to produce nickel powder and the cobalt strip solution from the solvent extraction step contacted with hydrogen gas to produce cobalt powder.

A method of treatment or purification of a molybdenum concentrate also containing copper, comprises the step of subjecting the molybdenum concentra te to pressure oxidation in the presence of oxygen and a feed solution containi ng copper (e.g. CuSO4) and halide (e.g. CuCl2) to produce a pressure oxidation solution containing copper and a solid residue containing molybdenum. The pressure oxidation solution may be combined with feed solution containing sulfuric acid to a second pressure oxidation in which a copper concentrate i s treated for the recovery of copper therefrom.

This invention relates to a hydrometallurgical process for extracting platinum group metals (PGMs), gold, silver and base metals from a flotation concentrate (10) containing sulphide minerals such as pentlandite and chalcopyrite, along with pyrite and pyrrohotite. The process includes a modified pressure oxidation step (12) to selectively separate base metals into sulphate medium (14), from the PGMs. The modified pressure oxidation step (12) partially or completely oxidizes sulphide minerals to produce a product slurry (14) containing base metal sulphates in solution and a solid residue containing PGMs along with sulphate and elemental sulphur. The solid residue is subjected to a thermal treatment (18) to remove sulphate and elemental sulphur from the solid residue, and to condition the PGMs to be soluble in chloride medium. The treated solid residue is the subjected to PGM recovery by leaching in chloride leaching medium (20) to recover the PGMs.