| 摘要 |
<p>1494990 Leaching zinc sulphides SHERRITT GORDON MINES Ltd 15 Oct 1976 [22 Oct 1975] 42970/76 Heading C1A Zinc and iron-containing mineral sulphides in finely divided form are pressure leached with sulphuric acid under a positive partial pressure of oxygen at 135-175‹ C. in two counter-current stages, with the mineral sulphides being fed to the first stage to produce a zinc sulphate leach-end solution which after purification, is subjected to electrolysis to recover cathode zinc, and the return electrolyte containing residual zinc values and sulphuric acid being fed to the second stage, wherein the quantity of sulphide fed to the first stage is adjusted relative to quantity of acid fed to second stage to provide at least one mole of zinc in first stage per mole of acid in second stage, and controlling the quantity of return electrolyte entering the second stage to give about 1 mole of acid per mole of zinc that has to be dissolved in the electrolyte to provide a suitable solution for said electrolysis, wherein the first stage leach solution has a pH above 1À0, less than 3 g.p.l. H 2 SO 4 , and less than 2 g.p.l. dissolved iron, and wherein the second leaching extracts all the zinc from the first leach residue, and the resultant second stage leach residue containing unreacted sulphides, elemental sulphur and precipitated iron is separated from the second stage leach solution containing extracted zinc, the latter solution being passed to the first stage.</p> |
