摘要
研究生物氧化产生的黄钾铁矾对酸性硫脲浸金的影响,并探讨草酸添加剂的作用机制。结果表明,黄钾铁矾会增加硫脲的消耗和阻碍金的溶解。黄钾铁矾能显著提高硫脲的分解,阻碍金的溶解。黄钾铁矾造成不利影响的主要原因可能是酸性溶液中黄钾铁矾释放的铁离子使溶液浆电位增加,从而加速硫脲的分解,并加剧硫脲分解产生的钝化物种对金表面的钝化作用。添加草酸盐可以有效削弱黄钾铁矾的不利影响,表现为明显降低硫脲的消耗和促进金的溶解。通过溶液电位、Zeta电位和XPS分析,揭示草酸的可能作用机理。草酸盐不仅可以通过与Fe^(3+)配位减弱Fe^(3+)与硫脲之间的相互作用,还可以通过无差别吸附和静电斥力阻止钝化产物在金表面包裹。
The effect of jarosite generated from bio-oxidation on gold leaching in acidic thiourea solution was studied,and the role of the oxalate additive was also investigated.The biogenetic jarosite was found to markedly raise the thiourea consumption and hinder the gold dissolution.The dominant cause for the detrimental effect of jarosite is likely that iron ions were released from jarosite dissolution in the acidic solution and thus increased the solution potential,resulting in the accelerated decomposition of thiourea and the aggravated passivation of gold surface by the passivating species from thiourea decomposition.However,the addition of oxalate to solution was shown to be effective in weakening the adverse effect of jarosite manifested as much reduced thiourea consumption and enhanced gold dissolution.The possible acting mechanisms of oxalate were revealed by the analyses of solution potential,Zeta potential and XPS.Oxalate could not only weaken the interaction between Fe^(3+)and thiourea via complexing with Fe^(3+)but also prevent the passivation species from coating on gold surface through indiscriminate adsorption and electrostatic repulsion.
作者
李科
李骞
姜涛
杨永斌
徐斌
许瑞
张雁
Ke LI;Qian LI;Tao JIANG;Yong-bin YANG;Bin XU;Rui XU;Yan ZHANG(School of Minerals Processing and Bioengineering,Central South University,Changsha 410083,China)
基金
Financial supports from the National Key Research and Development Program of China (No. 2018YFE0110200)
the Key Research and Development Program of Hunan Province, China (No. 2020SK2125)。
关键词
生物黄钾铁矾
金浸出
硫脲消耗
草酸盐
biogenetic jarosite
gold leaching
thiourea consumption
oxalate
