Solvent extraction of valuable metals from pregnant leach solutions of cupriferous shale
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Wroclaw University of Technology
Publication date: 2007-01-01
Physicochem. Probl. Miner. Process. 2007;41(1):365–372
The pregnant solution after atmospheric leaching of cupriferous shale (middlings from Lubin Concentrator) with sulphuric acid and/or with sulphuric acid containing Fe(III) in the presence of oxygen were applied for solvent extraction experiments with several extractants. The solutions containing soluble sulphates of Cu(II), Zn(II), Ni(II), Co(II), Fe(II), Fe(IIII) and As as a contaminant. Aromatic hydroxyoximes, LIX 84, LIX 612 and LIX 984, were investigated as copper(II) extractants to evaluate their extraction and reextraction abilities. From the copper free raffinate Zn(II) was next extracted with di-(2-ethylhexyl)phosphoric acid (D2EHPA). Additionally, cobalt(II) and nickel(II) were separated from the zinc-free raffinate with di-(2,2,4–trimethylpentyl)phosphinic acid (Cyanex 272). Industrial aromatic hydroxyoxymes used for copper(II) extraction were not sufficient selective and other metal ion species present in leach solutions were also transferred to the organic phase. The extractive recovery of Cu(II), Co(II) and Ni(II) was better for the solutions obtained from acidic leaching of shale in the absence of Fe(III) salts. The recovery of valuable metals was not satisfactory and further experiments are necessary to establish the optimal conditions of extraction and reextraction processes.