Investigation on the Phase Transformation and Floatability of Sulphidized Cervantite

Abstract

ABSTRACTThe surface physicochemical properties of cervantite are similar to the gangue minerals, so it is difficult to achieve the flotation separation of cervantite from them. In order to improve the floatability of cervantite, the phase and floatability changes of cervantite were investigated by the sulphidization roasting with element sulfur in reducing atmosphere and flotation tests. Cervantite did not float while using isoamyl xanthate as collector. But its floatability improved greatly by the sulphidization roasting with element sulfur, and a sulfide layer of Sb2S3 is found to be the key component which causes the hydrophobic of sulphidized cervantite. The flotation recovery of sulphidized cervantite increased from 5% to 95% while the molar ratio of S:Sb changed from 0 to 1.5. In other words, the floatability of the sulphidized cervantite increased with the increase of sulfide layer thickness. However, the sulfide layer thickness depended on the additive amount of element sulfur, roasting time and temperature. In the process of sulphidization roasting,element sulfur changed first from solid state to liquid state, then the liquid sulfur reacted with the surface of cervantite, and the stibium phase experienced the following change of Sb2O4→Sb2O3(O)/Sb2O3(C)→Sb2S3. In addition, the Sb2S3 phase will further react with Sb2O4 if there is lack of element sulfur in the sulphidization roasting system.