PROCESS FOR UPGRADING TANTALUM AND NIOBIUM ORES AND CONCENTRATES WITH THE RECOVERY OF MANGANESE AND RARE EARTHS OXIDES

摘要

A process for upgrading tantalum and niobium ores and concentrates is described herein. The process comprising: a) submitting the ore or concentrate to a caustic fusion or an alkali fusion using a melt comprising at least one salt of an alkali metal to produce a solidified melt; b) submitting the solidified melt to an alkaline leaching step to produce an alkaline pregnant leaching solution comprising manganese values; c) recovering the manganese values from the alkaline pregnant leaching solution to produce a substantially manganese-free leach solution; and d) precipitating tantalum and niobium as an insoluble niobiate and tantalate from the manganese-free leach solution. The rare earth oxides are recovered from the insoluble residues obtained during alkaline leaching.