Leaching of a Low-grade Refractory Tantalum-Niobium Ore by KOH Sub-molten Salt
KOH亚熔盐浸出低品位难分解钽铌矿的实验

A new leaching process for a low-grade refractory tantalumniobium ore by KOH sub-molten salt was studied. The effects of leaching temperature, initial KOH concentration, leaching time and mass ratio of alkali to ore on the leaching rate of Nb and Ta were investigated. The results show that the leaching rates of Nb and Ta can be raised as high as 98% and 96% respectively, 10% higher than those of the hydrofluoric acid process. Thus, the utilization rate of the refractory tantalumniobium resource was greatly improved. In the process, KOH sub-molten salt was used as reaction medium to substitute the highly concentrated and toxic HF solution of the traditional process. Consequently, the pollution of F was eliminated at the source. This provides a new way for extracting NbTa from the tantalumniobium ore.