组合捕收剂浮选菱锌矿的分子头基尺寸响应

通过单矿物浮选、动电位测试以及荧光探针检测对比研究了不同头基尺寸捕收剂组合油酸钠/十二胺和油酸钠/溴代十六烷基吡啶在菱锌矿表面的吸附特性及其对矿物浮选行为的影响。单一捕收剂体系浮选试验结果表明,3种捕收剂体系下,随着捕收剂浓度增加,矿物浮选回收率均呈现先增加后下降的趋势,油酸钠、溴代十六烷基吡啶、十二胺分别在pH值为5.8、8.4和10.1处达到最大回收率,3种捕收剂对菱锌矿的捕收能力顺序为油酸钠>溴代十六烷基吡啶>十二胺。混合捕收剂体系中,固定油酸钠浓度为2×10^-4 mol/L,加入适量的十二胺可以大幅促进矿物浮选,而加入溴代十六烷基吡啶几乎没有影响。动电位测试结果表明,在pH=6时经2×10^-4 mol/L 油酸钠溶液处理的菱锌矿表面电位为-30.5 mV,随着十二胺用量增加,已吸附油酸钠的菱锌矿表面电位逐渐上升,在十二胺浓度2×10^-4 mol/L时其表面动电位升高到接近菱锌矿在纯水中的动电位值22.3 mV,这是由于十二胺阳离子在已吸附了油酸钠阴离子的菱锌矿表面发生吸附; 而溴代十六烷基吡啶的加入对菱锌矿表面电位几乎没有影响,说明溴代十六烷基吡啶阳离子基本没有在矿物表面吸附,这与浮选试验结果一致。矿物表面微极性测试结果验证了上述推论,在此基础上给出了两种组合捕收剂在菱锌矿表面的吸附模型。

Influence of Head-Group Size of Combined Collectors on Their Performance in Floating Smithsonite

A combined collector of sodium oleate (NaOl)/Cetyl pyridine bromide (CPB) and NaOl/Dodecylamine (DDA) with varied head-group size was taken for investigating their adsorption onto smithsonite and their influence on the mineral flotation performance through single mineral flotation tests, zeta potential and fluorescence probe measurements. According to the flotation tests with single collector, the recoveries show an increasing trend before decreasing with an increase in the concentration of the collector. The maximum recoveries are obtained respectively with NaOl, CPB and DDA correspondingly at pH 5.8, 8.4 and 10.1. The capabilities of NaOl, CPB and DDA to collect smithsonite follow a descending order. By using the combination of collectors, DDA can significantly promote the flotation of smithsonite with the addition of NaOl at a fixed dosage of 2×10^-4 mol/L. However, the addition of CPB shows almost no effect. The zeta potential measurement of the smithsonite treated with 2×10^-4 mol/L NaOl at pH 6 is -30.5 mV. With the increasing of the DDA dosage, the zeta potential of smithsonite that has NaOl adsorbed on the surface increases gradually. With the concentration of DDA amounting to 2×10^-4 mol/L, it can reach 22.3 mV, approaching the zeta potential value of smithsonite in pure water, due to the further adsorption of DDA cations onto the smithsonite surface. However, the addition of CPB hasn′t brought any remarkable effect on the zeta potential of smithsonite, indicating CPB cations almost haven′t been adsorbed onto the mineral surface, which is consistent with the flotation test results. Fluorescence probe measurement results can also approve the above deduction. Consequently, a model for the adsorption of a combination of two collectors onto smithsonite is presented.