【摘要】 硫脲对金、银、铜的反萃取能力和体系的酸度有关。利用此特点,通过调节体系酸度并采用分段反萃取可达到金与银、铜的基本分离。反萃取过程的适宜工艺条件为:温度60℃;反应时间大于5min;流比1/3;硫脲浓度1.2mol/L;酸度0.5mol/L HCl(反萃液Ⅰ)和1.5mol/L HCl和(反萃液Ⅱ)。负载有机相经两段共五级逆流反萃取后,金、银、铜的反萃率均达99.8%以上。将反萃体系在高流比混合澄清器中进行小规模生产性试验,结果与模拟平衡值相近,级效率达95%。用电沉积法将硫脲液中金和银、铜按不同的槽电压进行分离,所得硫脲贫液经调整后可返回反萃体系,反萃能力不受影响。更多还原

【Abstract】 Both theoretical analyses and experimental results showed that SC（NH₂）₂ can replace CN- in R₃CH₃NM（CN）₂ forming R₃CH₃N⁺ and M（SC（NH₂）₂）₂⁺ under acidic condition. The stripping ability of thiourea is related to acidity and Au can be separated from Ag, Cu by controlling acidity and adopting two-step successive stripping. It was found that when the concentration of SC（NH₂）₂ was 1.2 mol/L; that of HCl was 0.5 mol/L（stripping solution Ⅰ） and 1.5 mol/L（stripping solution Ⅱ）; t>5 min and flow ratio of V_A/V_O = 1/3, at a temperature of 60 ℃ under moderate agitation, the stripping effeciencies of Au, Ag, Cu were all over 99.8% with five-stage countercurrent stripping. The small-scale test of stripping in a high flow ratio vertical mixer-settler was carried out and it is concluded that the experimental results agree with the simulated equilibrium data, the stage effeciecy would reach 95%. Au, Ag and Cu were finally recovered and completely separated from each other by electrowinning using different bath voltages and the acidified thiourea solution can be used again for recycling.更多还原