A novel scheme of tungsten minerals: flotation by Pb-BHA complexes for pre-enrichment and gravity separation for cleaning process

摘要

Pb-BHA complexes has been proved to be selective for the separation of scheelite and wolframite from calcium minerals without depressants. And a new process has been developed to significantly improve the recovery of tungsten minerals. However, the flotation results show that it's difficult to further improve the concentrate quality and recovery of tungsten minerals and cassiterite due to the differences in flotation rate and sensitivities to depressants. The super fine particles also created some challenges for cleaning flotation process. Some advanced gravity separators for super fine particles were introduced for the cleaning process based on the similar density of scheelite, wolframite, and cassiterite. Both the similarities and diferenties in floatability and density of different minerals have been fully considered in the new process, pre-enrichment using Pb-BHA flotation and upgrading using gravity separation. A concentrate with 61% WO3 and 3.12% Sn was obtained, and the recovery of tungsten minerals was the same to the previous process. And gravity separation is of high efficiency, low capital and low capital operating costs, and no chemicals, which is beneficial to the environmental. This study indicates that a combination in-depth of flotation and physical separation may provide some solutions for problems of complex refractory ores.