Acid Leaching of Thorium Carbide

Overnight acid leaching experiments were carried out on ThC/sub 2/ with HCl, H/sub 2/SO/sub 4/, and HNO/sub 3/. For 0.5 to 12 N HCl at room temperature, ThC/sub 2/ disintegrated spontaneously and dissolved 100%. For H/sub 2/SO/sub 4/ at room temperature, ThC/sub 2/ dissolved 100% in 0.5 to 3 N, but at higher concentrations, the solubility decreased to zero. At 80 deg C in 12 N H/sub 2/ SO/sub 4/, however, the solubility increased to 6.1%, as compared with 1.8% at room temperature. For HNO/sub 3/ at room temperature, the solubility decreased from 100% in 0.5 N to a minimum in 6 N and thereafter increased to a limit of 50% in 12 N. The solubility in 8 N HNO/sub 3/ increased from 19% at room temperature to 99% at 80 deg C. A mechanism for the redissolving of ThC/sub 2/ in HNO/sub 3/ at concentrations above 6 N is proposed. (D.L.C.)