应用选择性磁罩盖法磁选分离镍黄铁矿与蛇纹石

针对镍黄铁矿和蛇纹石浮选难分离,提出采用磁罩盖法进行磁分离.结果表明,控制一定的矿浆物化条件,随着磁种磁铁矿的添加,镍黄铁矿的磁选回收率随之升高,而蛇纹石的回收率基本保持很低,可实现两者的良好分离.人工混合矿分离结果表明,磁种质量分数为5%时,获得的精矿Ni品位为19.89%,回收率为92.46%,MgO质量分数为4.72%;X射线衍射和扫描电镜分析结果显示磁铁矿在镍黄铁矿表面产生了罩盖,在蛇纹石表面未产生明显的罩盖;Zeta电位测试和DLVO理论计算结果表明,添加六偏磷酸钠后,蛇纹石表面电性由正变负,而对镍黄铁矿和磁铁矿表面电性未产生显著影响,从而使磁铁矿与蛇纹石间的相互作用变为排斥,而与镍黄铁矿之间仍为吸引,因而磁铁矿选择性罩盖在镍黄铁矿表面,增强其磁性,实现与蛇纹石的磁分离.

Separation of pentlandite from serpentine using the selective magnetic coating-magnetic separation technology

Magnetic coating magnetic separation method was proposed to separate pentlandite from serpentine, which is difficult to separate them using flotation. Results show that under certain physical and chemical conditions of slurry, the pentlandite recovery increases with the amounts of magnetite increasing, while the recovery of serpentine remains at a low level, indicating that their separation could be realized. The separation results of the artificial mixtures show that with addition of 5% magnetite, a concentrate of 19.89% Ni with a recovery of 92.46% and MgO mass content of 4.72% are obtained. The results of X-ray diffraction (XRD) and scanning electron microscopy (SEM) demonstrate that quantities of magnetite particles adhere to the pentlandite surfaces whereas the surface of serpentine is not clearly coated by the magnetite. The Zeta potential analyses and DLVO calculations suggest that with the addition of sodium hexametaphosphate (SHMP), the Zeta potential of serpentine reverses from positive to negative while those of pentlandite and magnetite are not affected significantly. Thus, it made the interaction of magnetite-serpentine become repulsion while that of magnetite-pentlandite remain attraction. Consequently, magnetite particles selectively adhere to the surface of pentlandite and enhance its magnetism, resulting in the magnetic separation of pentlandite from serpentine.