Improving xanthate flotation of fine pyrite using SPAM and the mechanism

ABSTRACT This paper focuses on the promotion mechanism of sulfonated polyacrylamide (SPAM) on SBX flotation performance on fine pyrite, and verifies the positive effect for a gold ore with pyrite as the main Au-bearing mineral. Micro flotation showed that fine pyrite (−26 + 15 μm) floated poorly compared with coarser ones (−74 + 38 μm), and this cannot be completely filled through increasing the SBX dosage; however, by adding moderate SPAM into the pulp after SBX the flotation of fine pyrite was obviously improved. The real ore flotation revealed that SPAM decreased total reagent dosage and improvement on the concentrate indexes. SBX/SPAM system enabled faster settlement of fine pyrite compared with only SBX or SPAM system, indicating that larger particle size was obtained through hydrophobic and bridging flocculation. Zeta potential results showed that the pre-adsorbed SBX had little effect on the further adsorption of SPAM. Contact angle measurements suggested that the addition of moderate SPAM (50 μg/L) had almost no effect on pyrite surface hydrophobicity, illustrating that SPAM just bridged different fine particles adsorbed SBX rather that covered them. FTIR results showed that the amount of SPAM participating in bridging action was few.