Abstract: The invention provides a recycling step in an oxidative pressure leaching process for recovery of metals using halide ions, in which a portion of the leached solids are recycled back to the feed to the autoclave, to allow two or more passes through the high temperature leaching step.

Abstract: The invention provides a recycling step in an oxidative pressure leaching process for recovery of metals using halide ions, in which a portion of the leached solids are recycled back to the feed to the autoclave, to allow two or more passes through the high temperature leaching step.

Abstract: A method of extracting a halide and sulphate from an aqueous sulphate solution, such as a zinc sulphate solution, comprises subjecting the solution to solvent extraction to extract halide and sulphate from the solution and controlling the amount of sulphate extracted by selective adjustment of the acidity of the aqueous solution.

Abstract: A method of extracting a halide and sulphate from an aqueous sulphate solution, such as a zinc sulphate solution, comprises subjecting the solution to solvent extraction to extract halide and sulphate from the solution and controlling the amount of sulphate extracted by selective adjustment of the acidity of the aqueous solution.

Abstract: A method for extracting copper from a mineral feed containing copper sulphide mineral 1, which involves crushing and blending the feed 2, 6, 10 followed by leaching of the feed in an autoclave 20. The conditions in the autoclave are controlled so that the presence of oxygen at superatmospheric oxygen pressure maintains the ratio of ferrous to ferric ions at a level so as to facilitate the leaching of copper from the feed. The leaching is carried out in the presence of acid which may be itself generated by oxidising conditions in the autoclave. Further leaching is carried out in a series of tanks 22, 24, 26 and 28 after which the solids are separated from solution in a series of steps including treatment in a hydroclassifier 30, a clarifier 32 and a polishing filter 38. Copper is extracted from the resultant leachant at a copper extraction station 44 with a final copper product 54 being retrieved in electrowin cells 52.

Abstract: An ion exchange separation, recovery and regeneration process for the control of iron is disclosed that can replace the conventional bleed stream process used in copper electrowinning. The disclosed process minimizes the loss of cobalt from the electrowinning circuit and can effect a lowering of the total iron concentration in the electrolyte circuit with an associated increase in current efficiency. The process captures the iron as iron(III) on an ion exchange medium containing a plurality of --CH(PO.sub.3 R.sub.2).sub.2 or --C(PO.sub.3 R.sub.2).sub.2 -- groups through which the divalvent metal ions pass. The iron(III) is then reduced with copper(I) to form iron(II) that is freed from the exchange medium, thereby permitting regeneration of the medium.

Abstract: A sulfur dioxide free process for the production of high purity metallic copper from copper-matte wherein copper-matte is leached under oxidizing conditions in a ferric-containing acid copper sulfate electrolyte leach assembly including one or more leach reactors to yield a copper-rich electrolyte, and copper cathode is produced in an electrowinning assembly which is physically decoupled from the leaching assembly and may include one or more electrowinning cells. The process operates at ambient pressure and temperatures less than the boiling point.

Abstract: An ion exchange separation, recovery and regeneration process for the control of iron has been developed to replace the conventional bleed stream process used in copper electrowinning. The process minimizes the loss of cobalt from the electrowinning circuit and strips the iron into a sulfate-based solution suitable for leach solution makeup. In addition, this process can effect a lowering of the total iron concentration in the electrolyte circuit with an associated increase in current efficiency.

Abstract: The present invention is concerned with a method for selectively removing antimony and bismuth from an impure sulphuric acid solution containing at least 50 g/L of acid and some concentration of ferric ion (for example copper refinery electrolyte), is disclosed. The method involves contacting the impure solution with a sufficient quantity of finely divided metallic copper so as to prereduce all ferric ion present in the solution to the ferrous oxidation state. The prereduced solution is then contacted with a chelating resin. The method avoids the deleterious loading of ferric iron onto the ion exchange resin and prevents the return of excessive amounts of chloride ion with the purified electrolyte.