| 摘要 |
<p>Aqueous solutions of cyanide complexes of metals other than gold are contacted at pH above 7 with a nitrogeneous anion exchange resin containing strongly and weakly basic groups in proportion such that the R ratio of strongly basic to total basic (i.e. strongly plus weakly basic) groups is between 10-75%, thereby effecting preferential absorption of metals other than Cu and/or fe and thereafter recovering from the resin a product having a reduced concentration with respect to Cu and/or fe. The pH of aqueous solutions, for example residual liquors from the cyanide process for the extraction of gold, containing cyanide complexes of described metals e.g. Ni, Co, Ag, Pd, Pt, Ir, Os, Rh, Mn, or Se together with cyanide complexes of Cu and/or Fe is adjusted to above 7 preferably 8-11, and the solution passed through a bed of resin the R ratio of which may be 40-65% preferably 45-55% and which may be based on a crosslinked polystyrene resin, until Cu and/or fe initially adsorbed are displaced down the column. Depending upon the desired metal content of the effluent the process may be repeated using a series of columns to effect further absorption. Recovery of the desired metal values may be achieved by elution or by drying and ashing the adsorbate resin. Eluting agents specified are aqueous sodium thiocyanate, or aqueous sodium or ammonium nitrate containing sodium cyanide, the desired metal being recovered from the resulting solution by any convenient means e.g. recovery of nickel as nickel cyanide, silver as the metal by electrolysis, or as the cyanide and cobalt as the sodium cobalt cyanide complex. Specifications 808,909 and 808,910 are referred to.</p> |
