无捕收剂浮选的半导体能带理论讨论

用量子力学计算得到了方铅矿(PbS)和黄铁矿(FeS_2)的半导体能带图,以及分子氧和HS-离子的HOMO和LUMO的能量。计算结果画成方铅矿和黄铁矿半导体与分子氧和HS-离子作用的能级图,从电子转移微观层次上解释这两类矿物的无捕收剂浮选机理(包括自诱导浮选和硫化钠诱导浮选)。结果表明,P型半导体(以黄铁矿为典型代表)具有良好硫化钠诱导浮选行为,N型半导体(以方铅矿为典型代表)具有良好自诱导浮选行为。电子载流子浓度(n_e)与空穴载流子浓度(n_p)之比值可以作为一个参数来判断无捕收剂浮选行为:n_c/n_p值大,自诱导浮选行为好;n_p/n_e值大,硫化钠诱导浮选行为好。

CONSIDERATIONS OF SEMICONDUCTOR ENERGY BAND THEORY ON COLLECTORLESS FLOTATION OF SULPHIDE MINERALS

The energy band structure diagrams of galena and pyrite semiconductors and the energy of HOMO and LUMO for oxygen molecule and HS- ion were obtained through quantum-mechanics calcluations. The energy level diagrams showing the interactions between the two mineral semiconductors and O2 and HS-were drawn and used to explain the micro-mechanisms of electron transfer involved in the collectorless flotation process of galena and pyrite, which includes self-induced flotation and lsa2S-indured flotation. The results have shown that the P-type semiconductor (pyrite as a typical one) displayed a good Na2S-induced flotation behavior, but the N-type one (galena as a typical one) a good self-induced flotation behavior. The electron carrier density (ne) to cavity carrier density (np) ratio was considered as a parameter of evaluating the collectorless flotation. The self-induced flotation becomes better with the increase of ne /np ratio, while the Na2S-induced flotation improves with the increase of np/we ratio.