Selectively leaching Cu(Ⅱ) and Ni(Ⅱ) from acid mine drainage sludge by using ethylenediamine-ammonium sulfate

来源期刊：中国有色金属学报(英文版)2002年第6期

论文作者：李德良 王淀佐 J A Finch

文章页码：1176 - 1179

Key words：ethylenediamine(EDA); AMD sludge; selective extraction; waste treatment; nickel; copper

Abstract: A method based on controlling the complexation-precipitation equilibrium of metal ions was proposed to selectively recover nickel and copper from hydroxide sludge formed by lime neutralization of acid mine drainage(AMD). Ethylenediamine(EDA) and ammonium sulfate were chosen as complex reagent and precipitating reagent, respectively, to dissolve target metal hydroxides from sludge and limit useless metal ions in the pregnant solution. Results from both synthetic and natural samples show the excellent selectivity for the target metals(copper and nickel) against Fe(Ⅱ), Ca(Ⅱ) and Mg(Ⅱ), 99% recovery of Cu(Ⅱ) and Ni(Ⅱ) and shorter leaching time can be reached by this process, and the resultant solution can be used for direct electrowinning. The optimum operating conditions are: pH=9~11, ρ(EDA)=40g/L, ammonium sulfate 50g/L, leaching time 5h(for natural sample) and 2.5h(for synthetic sludge), liquid to solid ratio being 4 with mechanical stirring at room temperature.