反应详情

In the drawing, a leach liquor containing for example 75 g/liter copper and 25 g/liter Zn in the form of sulfates is first adjusted, if necessary, to a pH of between 0.5 and 6 and then led in stream 1 where it is contacted with copper di-(2-ethylhexyl) phosphate (Cu(DEP)2) to extract zinc into the organic phase as Zn(DEP)2 leaving copper sulfate in the aqueous phase. The zinc-containing organic phase, Zn(DEP)2 in stream 2 is stripped with dilute sulfuric acid to recover the zinc as a zinc sulfate solution and to generate di-(2-ethylhexyl) phosphoric acid (DEHPA) in stream 7. The zinc sulfate solution can then be subjected to electrowinning to recover zinc metal in a zinc recovery stage. The aqueous phase containing copper sulfate in stream 3 is led to a copper electrowinning circuit where a copper drop down to about 30 g/liter is taken to produce cathode copper in stream 5. The exit solution from electrowinning in stream 6 is then contacted in a copper stripping stage with the generated di-(2-ethylhexyl) phosphoric acid (DEHPA) in stream 7, to produce Cu(DEP)2 in stream 4 which is recycled to the incoming leach liquor in stream 1. The spent dilute copper solution after reaction with DEPH is then either recycled to the leach (not shown) or discarded.