In oder to get the fundamental conditons on the removal of impurity of metallic ions such as Fe
2+, Mn
2+, Cu
2+ and Zn
2+ ions, synthetic sulphuric acid solution was used.
NaCIO was used as oxidation reagent for Fe
2+→Fe
3+ and Mn
2+→Mn
4+. Selective optimum ORP was+1, 000-1, 150 mv, pH was 3.3-3.4 and oxidation temperature was 50-70°C for oxidation of Fe
2+→Fe (OH)
3 and Mn
2+→MnO
2 while Ni
2+, Co
2+, Cu
2+ and Zn
2+ ions were remained in the solution. After removal of Fe
2+ and Mn
2+ ions, as secondary stage, Cu
2+ and Zn
2+ ions were selectively sulphurized and precipiteted with H
2 S while Ni
2+ and Co
2+ ions were remained in the solution. Selective optimum ORP was -130--140 mv and pH was 3.4-3.5.
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