次亚磷酸盐在电解铜氰废液同时回收铜和氰过程中的作用

Effect of hypophosphite during the recovery of copper and cyanide from high concentration copper-cyanide wastewater by electrodeposition

  • 摘要: 以高浓度铜氰溶液为研究对象,通过添加次亚磷酸盐,进行了高碱条件下电积回收铜与氰化物的研究.研究了次亚磷酸盐用量、温度对铜和氰化物沉积过程的影响;利用线性循环伏安、恒电位电解并结合X射线衍射分析阳极沉淀物的物相,分析了阳极反应机理和次亚磷酸盐抑制氰化物分解的机理;采用电解后余液进行金的氰化浸出实验.结果表明:次亚磷酸盐可有效抑制电沉积过程中氰化物的分解,其抑制效果随温度升高而增强.电解过程中阳极表面生成的Cu2+是造成氰化物分解的主要原因;次亚磷酸盐通过优先与Cu2+发生氧化还原反应从而抑制氰化物的分解.处理后余液对金的氰化浸出无不良影响,通过电解可综合回收铜氰废水中金属与氰化物,处理后废水可循环利用.

     

    Abstract: The recovery of copper and cyanide from high concentration wastewater was conducted by electrodeposition with high basicity. The effect of hypophosphite dosage and temperature on recycling copper and cyanide from wastewater was investigated. The linear cyclic voltammetry, potentiostatic electrolysis and X-ray diffraction analysis were used to research the anodic reaction and precipitate phase, the mechanisms of cyanide decomposition and hypophosphite inhibition were also analyzed. The experiment of cyanide leaching of gold was done in residual liquid after electrolysis. The results indicate that the damage of cyanide is effectively suppressed by hypophosphite. The inhibitory effect is enhanced gradually with increasing temperature. The Cu2+ forming on the anode surface is the main reason to degrade cyanide. Hypophosphite restrains cyanide from degradation by preferential oxidation. The tail liquid has no effect on leaching of gold, and the copper-cyanide wastewater can be comprehensively recovered the valuable metals and cyanide by electrodeposition.

     

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