Selective flotation separation of galena from sphalerite via chelation collectors with different nitrogen functional groups

Abstract

Nitrogen functional groups often provide excellent collecting selectivity and efficiency for collector molecules because of the rational alkalinity as Lewis base and the delicate affinity for metal ions. In this work, 1,3-diphenylthiourea (DPTU), 2-acetylhydrazine-1-carbothioamide (ADCT), (E)-1,5-diphenylthiocarbazone (DPTZ) were used as novel selective collectors for the flotation of galena/sphalerite mixed system, and universal collector sodium ethyl-xanthate (SEX) was used as the reference collector. The flotation results showed that collector with more nitrogen atoms (DPTZ) offered better selectivity for the flotation separation of galena from a galena/sphalerite mixed mineral system. Separation selectivity, FTIR and XPS studies showed, in the case that collector solution environment pH value < pKa value, N atoms did not participate in the coordination reaction. But in the opposite case, almost all N atoms in the collector molecule participated in the coordination reaction. As a result, there is stronger interaction between the collector molecule and the lead ion on the surface of galena, which was conducive to the selective flotation separation. The contact angle results showed that suitable hydrophobic groups were also critical to efficient separation.