摘要
The magnetism of pentlandite surface was enhanced through the selective precipitation of micro-fine magnetite fractions on pentlandite surfaces. This was achieved through adjustment of slurry pH and addition of surfactants. The results showed that at pH 8.8 with the addition of 100 g/t sodium hexametaphosphate, 4.5 L/t oleic acid, and 4.5 L/t kerosene, significant amount of fine magnetite particles adhered to the pentlandite surface, while trace amount of coating was found on serpentine surfaces. Thus, the magnetism of pentlandite was enhanced and pentlandite was well separated from serpentine by magnetic separation under the magnetic field intensity of 200 kA/m. Scanning electron microscopy （SEM） and zeta potential measurement were performed to characterize changes of mineral surface properties. Calculations of the extended Derjaguin-Landau-Verwey-Ocerbeek （EDLVO） theory indicated that, in the presence of surfactants the total interaction energy between magnetite and pentlandite became stronger than that between magnetite and serpentine. This enabled the selective adhesion of magnetite particles to pentlandite surfaces, thereby enhancing its magnetism.
通过控制矿浆pH值和添加表面活性剂,实现微细粒磁铁矿在镍黄铁矿表面选择性粘附而使其表面磁性增强。结果表明,在pH=8.8时,添加六偏磷酸钠(用量为100 g/t)、油酸(用量为4.5 L/t)和煤油(用量为4.5 L/t)后,微细磁铁矿选择性粘附在镍黄铁矿表面,使其磁性增强;而蛇纹石表面几乎不被磁铁矿粘附。然后,在磁场强度为200 k A/m条件下磁选,实现了二者的良好分离。扫描电镜结果也进一步证实了微细粒磁铁矿在镍黄铁矿表面发生了选择性粘附,而蛇纹石表面未观察到磁铁矿的存在。Zeta电位测试和扩展DLVO理论计算结果表明,添加表面活性剂后,磁铁矿和镍黄铁矿颗粒间存在很强的吸引作用,从而使微细粒磁铁矿选择性粘附在镍黄铁矿表面,增强了其表面磁性。
基金
Project(51574061)supported by the National Natural Science Foundation of China
Project(N150106004)supported by the Fundamental Research Funds for the Central Universities,China
Project(2014SKY-WK011)supported by the Open Fund Project of Shaanxi Key Laboratory of Comprehensive Utilization of Tailings Resources,China
