(Poster session/Short oral-presentation) Mineral processing / Recycling

[2309-27-18] Selective depression of Pb-activated sphalerite with oxalic acid in sphalerite-galena flotation System

○Doaa Ashraf Eladl^{1[Doctoral course]}, Gde Pandhe Wisnu Suyantara ¹, Hajime Miki¹, Okibe Naoko¹ (1. Kyushu University)

Chairperson：高谷 雄太郎（東京大学）

Keywords:Organic acid, Green flotation, Pb2+activated sphalerite, Pb-Zn separation, Oxalic acid

Galena (PbS) and sphalerite (ZnS) often coexist in sulfide mineral ores. Flotation is commonly used to separate these minerals, but depressing ZnS in the flotation process can be challenging, particularly when ZnS is activated by Pb²⁺ ions dissolved from Pb bearing minerals. In this study, oxalic acid was used as a selective, efficient, and environmentally friendly depressant to separate PbS from Pb²⁺-activated ZnS. Micro-flotation experiments, FTIR, and XPS analysis were conducted to investigate the depressant mechanism of oxalic acid. Single-mineral flotation results showed that sphalerite was selectively depressed in the presence of oxalic acid with a mineral recovery of 20 %. In addition, the mixed mineral flotation recoveries of PbS and ZnS were 83% and 17 %, respectively. This effect is attributed to the precipitation of Pb oxalate on the surface of ZnS, causing a change in its hydrophobic properties. Conversely, Pb oxalate precipitationon the PbS surface resulted in a significant increase in flotation recovery. The results indicate that the use of oxalic acid as a depressant allows for the selective flotation of Pb-activated ZnS, effectively separating it from PbS.