BREAKDOWN OF ARTIFICIAL TANTALUM CONCENTRATE BY HYDROFLUORIC-ACID

The destructive action of hydrofluoric acid on artificial tantalum con centrates obtained in processing wastes from solid-alloy production is studied. The effectiveness with which tantalum is leached by hydroflu oric acid depends on the drying temperature of the concentrate and fal ls from 92 to 74% with increase in treatment temperature from 20 to 50 0 degrees C. This is due to change in phase composition of tantalum an d titanium compounds (the basic phase components of the concentrate). When tantalum concentrate dried in air at ordinary temperatures is tre ated with hydrofluoric acid, the degree of tantalum extraction in the acidic solution is > 95%; in this case, even milder conditions are req uired than in the processing of natural tantalum raw materials. The re sults obtained indicate that the artificial tantalum concentrate is hi ghly reactive and that it is not expedient to dry the concentrate, esp ecially above 200 degrees C.