PROCEDIMIENTO PARA LA OBTENCION DE COBRE.

摘要

1528061 Recovery of copper M J MEIXNER 24 May 1976 [18 June 1975] 21343/76 Heading C1A Copper is extracted from mineral ore containing Cu, Fe and S by leaching with an aqueous solution containing H 2 SO 4 and one or more ferric salts so as to dissolve copper as Cu2+ ions and to oxidize sulphides to elemental S or FeS 2 , extracting Cu2+ ions from the aqueous solution by ion exchange with an equivalent amount of H+ ions and recycling the thus extracted aqueous solution to leach further ore, the ratio of Fe(II) to Fe(III) ratio in the recycled solution being adjusted to a value at which there is substantially no further oxidation of S-containing compounds to sulphates by aeration in the presence of oxidizing bacteria prior to recycle. The ion exchange is suitably effected using liquid ion exchangers in a counter current solvent extraction. The pH of the aqueous solution prior to exchange is preferably adjusted to less than 2À5 and following ion exchange is typically 1À3-2À2. The solution of Cu2+ obtained by the ion exchange may be electrolysed to recover the pure copper and generate the H+ ions which are required to replace the Cu2+ in the leaching solution. The total ion concentration of the aqueous solution is preferably maintained between 2 and 12 g/1, the amount of Fe(II) being maintained at a minimum value which is dependent upon pH, e.g. at least 0À2 g/1 at pH 1À7. The leaching solution may contain bacteria of one or both of the strains thiobacillus ferrooxidans and thio-oxidans. The leaching is preferably carried out at ambient temperature and a portion of the aqueous solution may be drawn off before the ion exchange and recycled directly to leach further ore. The residue from the leaching becomes enriched in S and the residues may be used as starting material in the production of sulphuric acid.