四丁基溴化铵-碘化钾体系浮选分离镉

Study on floatation separation of cadmium with tetrabutyl ammonium bromide-potassium iodide system

研究了四丁基溴化铵-碘化钾体系分离镉的行为及其与其他金属离子分离的条件。结果表明,在水溶液中,Cd(Ⅱ)与四丁基溴化铵和碘化钾形成不溶于水的三元缔合物[CdI4][TBAB]2,此三元缔合物沉淀浮于盐水相上层形成界面清晰的液-固两相。当四丁基溴化铵和碘化钾的浓度分别为5.0×10-4mol/L和8.0×10-3mol/L及在pH 3.0的克拉克-鲁布斯缓冲溶液中,Cd(Ⅱ)的浮选率达到99.2%以上。而Rh(Ⅲ),Ga(Ⅲ),Co(Ⅱ),Zn(Ⅱ),Al(Ⅲ),W(Ⅵ),V(Ⅴ),Mn(Ⅱ),Ni(Ⅱ),Mo(Ⅵ)和Cr(Ⅲ)在该体系中不被浮选,实现了Cd(Ⅱ)与这些金属离子的定量分离。对合成水样中Cd(Ⅱ)的分离和测定,结果满意。该方法在微量镉的分离和富集中有一定的实用价值。

The behavior and conditions for the floatation separation of Cd（Ⅱ） from other metal ions were investigated with tetrabutyl ammonium bromide （TBAB）-potassium iodide system. The results showed that Cd（Ⅱ） combines with TBAB and KI into a ternary ion association precipitate [CdI4 ] [TB- AB]2 in the aqueous solutions. The precipitate was floated well on the surface of water phase to make the system to divide into both liquid phase and sold phase with a distinct boundary layer. Cd（Ⅱ） could be quantiatively separated from Rh（Ⅲ）, Ga（Ⅲ）, Co（Ⅱ）, Zn（Ⅱ）, AI（Ⅲ）, W（Ⅵ） , V（Ⅴ）, Mn（Ⅱ）, Ni（Ⅱ）, Mo（Ⅵ） and Cr（Ⅲ） by floatation. The floatation yield of Cd（Ⅱ） was higher than 99.2 % when the concentrations of TBAB and KI in Clark-Lubs buffer solution （pH 3.0） were 5.0×10^-4 mol/L and 8.0×10^-3 mol/L, respectively. The floatation separation and determination of Cd（Ⅱ） in the synthetic water sample with satisfactory results. This method is practical to the separation and enrichment of trace cadmium.