硝酸钠-硫氰化铵-溴化十六烷基吡啶体系浮选分离和富集铑

研究了硝酸钠-硫氰化铵-溴化十六烷基吡啶(CPB)体系浮选分离富集铑的新方法。探讨了酸度、硝酸钠、硫氰化铵和溴化十六烷基吡啶的浓度等对Rh³⁺浮选率的影响,确定了浮选分离Rh³⁺的最佳条件,并讨论了Rh³⁺的浮选分离机理。结果表明,在最佳条件下,Rh³⁺与硫氰化铵和溴化十六烷基吡啶生成不溶于水的三元缔合物[CPB⁺]₃[(Rh(SCN)₆^3-],此三元缔合物浮于盐水相上层形成界面清晰的液-固两相。控制溶液酸度为pH 2,在0.2 g/mL硝酸钠、8.0×10^-3mol/L硫氰化铵和3.0×10^-3 mol/L溴化十六烷基吡啶(CPB)的条件下,实现了Rh³⁺与Al³⁺、Mn²⁺、Ga³⁺、Fe²⁺、Cd²⁺、Mg²⁺、V、Ni²⁺、和Cr³⁺的定量分离。方法用于合成水样中微量Rh³⁺的浮选分离,回收率为97.6%～99.1%。

Flotation separation and enrichment of rhodium by sodium nitrate-ammonium thiocyanate-cetylpyridinium bromide system

The new flotation separation and enrichment method of rhodium by sodium nitrate-ammonium thiocyanate-cetylpyridinium bromide system (CPB) system was studied. The influence of acidity as well as the concentration of sodium nitrate, ammonium thiocyanate and CPB on the flotation rate of Rh³⁺ was investigated. The optimal conditions for the flotation separation of Rh³⁺ were obtained. Moreover, the flotation separation mechanism of Rh³⁺ was also discussed. The results showed that Rh³⁺ could react with ammonium thiocyanate and CPB under optimal conditions to form water insoluble ternary complex [CPB⁺]₃[(Rh(SCN)₆^3-], which was floated on the upper layer of salt-water phase and formed liquid-solid phase with clear interface. The acidity of solution was controlled at pH 2. When the concentration of sodium nitrate, ammonium thiocyanate and CPB was 0.2 g/mL, 8.0×10^-3 mol/L and 3.0×10^-3 mol/L, respectively, the quantitative separation of Rh³⁺ from Al³⁺, Mn²⁺, Ga³⁺, Fe²⁺, Cd²⁺, Mg²⁺, V, Ni²⁺ and Cr³⁺ was realized. The proposed method was applied to the flotation separation of trace Rh³⁺ in synthetic water samples. The recoveries were between 97.6% and 99.1%.