苯甲羟肟酸铅金属有机配合物在氧化矿浮选中的作用机理及其应用

摘要

在氧化矿浮选中,硝酸铅是最常用的活化剂.经典的活化浮选理论认为,溶液中铅离子及羟基配合物吸附在矿物表面,为阴离子捕收剂(脂肪酸、螯合捕收剂等)在矿物表面吸附提供活性位点.然而,溶液化学计算表明,在矿浆体系中金属离子与捕收剂会反应生成金属有机配合物,经典理论并未考虑溶液体系中金属有机配合物在浮选过程中的作用.研究发现:相比于传统的顺序加药,硝酸铅和苯甲羟肟酸(BHA)的预先混合对白钨矿和锡石具有更强的捕收能力,表明金属有机配合物在浮选过程中发挥了至关重要的作用.基于对经典活化浮选理论新的认识,提出金属离子-有机配合物配位调控分子组装吸附理论,通过金属离子-有机配合物结构的定向调控,改善捕收剂的捕收能力和选择性.基于金属有机配合物捕收剂的钨锡混合浮选新工艺成功应用于湖南柿竹园多金属选厂,大幅提高了钨、锡综合回收率,在生产实践中证明了金属有机配合物捕收剂在捕收能力和选择性方面具有巨大的优势.%Lead nitrate (LN) is most frequently used as the activator in the flotation of oxidized ores. The classical theory shows that lead ions and lead hydroxides firstly adsorbed on mineral surface.The lead species adsorbed on mineral surface provide active sites for the collector. However,solution chemistry calculation proved that both the metal species and collectors would react with each other and form some metal - collector complexes. And the classical theory did not consider the role of metal - collector complexes in flotation. Flotation results indicate that lead complexes of benzohydroxamic acid (BHA), generated by premixing of LN activator and BHA collector, play an important role in the flotation and exhibit a stronger collecting ability in the flotation of scheelite and cassiterite. Therefore, a new model, coordination of molecular assembly by metal ion, was proposed to improve the classical metal activated flotation theory. Some new collectors could be developed to improve the collecting ability and selectivity according to the new theory. A novel flotation process of tungsten and cassiterite minerals has been applied to Shizhuyuan Mine, where the recovery of tungsten and cassiterite minerals were significantly improved. All these results prove that metal -collector complexes play an important role in improving the collecting ability and selectivity.