Talc deposits from different sources: genesis and quality

摘要

Talc as a secondary mineral is derived from various parent rocks. Three types of rocks, serpentinized ultramafic, metavolcanic and carbonate were selected for the present study. The comparison of talc deposits derived from these rocks reflects the existence of significant differences in the mode of occurrence, mineralogy, geochemistry and quality. The ultramafic-derived talc (UM-T) contains Fe, Al, Ca, Cr and Ni as major impurities. Enrichment in MgO (and less commonly SiO_2) occurred during the talcification of metavolcanic and caronate rocks while SiO_2 is largely and solely added to the UM-T. Both metavolcanic- (MV-T) and carbonate-derived talc(C-T) are much purer than UM-T and, therefore, have a greater range of uses without treatment in cosmetics, ceramics and paint. However, the UM-T can be beneficiated using magnetic separation and froth flotation for paint, ceramic and paper industries.