A case study of flotation of chalcopyrite-molybdenite ore using a mixture of pyrogallic acid and o-isopropyl ethylthiocarbamate: Insights from ab initio calculations

To date, lime-free flotation processes are increasingly advocated due to many problems caused by the traditional process using lime (CaO) as a depressant and xanthate (BX) as a collector. In this work, we developed a combination of pyrogallic acid (PGA) and o-isopropyl ethylthiocarbamate (Z200) as an eco-friendly alternative to the lime-xanthate process for chalcopyrite-molybdenite (ccp-mlb) flotation. Roughing flotation experiments showed that this process yields ccp-mlb concentrate with similar recovery and grade of Cu and Mo as in the traditional lime-xanthate process. However, the huge advantage of the novel process is that it requires ten times lower dosages of sodium sulfide in the subsequent separation of ccp-mlb concentrate. The ab initio calculations explained this trend at the atomistic level, where hydrogen sulfide ions could desorb collector more easily from the Z200@ccp complex compared with BX@ccp. The same method could be applied for environmentally friendly separations of other resources with similar composition.