Optimization on the purification of cassiterite from low-grade cassiterite concentrate

Abstract

Optimization on the purification of cassiterite from low-grade cassiterite concentrate has been successfully done. The concentrate used came from the mine site in the Delas area, Bangka Island with an element content of Sn was 31.60% wt and the impurity phases including zircon, ilmenite, quartz, hematite, and monazite. The purification process consists of two steps: mechanical-magnetical separation and acid leaching. The mechanical-magnetical separation step started by color separation (bright sand removal) and removed the magnetic elements of the concentrate subsequently. The content of the Sn element in acid leaching residue increased significantly was up to 90.28% with cassiterite as the dominant phase. The X-ray diffraction (XRD) revealed that the impurity phase of the filtrate after crystallization in all varying pH consists of cassiterite, ilmenite, and ammonium chloride. The solubility of cassiterite concentrate in the acid leaching process is very low at 4.4%, this indicates that the Sn element is difficult to decompose under these conditions.