Extraction of uranium in caustic sludge from the production of nuclear fuel components by countercurrent dissolution and acid curing

The uraniferous caustic sludge (UCS) produced in the production of uranium fuel components was hardly to leach directly, due to its very low-grade uranium(<10%). A two-step operation, consisting of the three-stage countercurrent dissolution and subsequent H₂SO₄ curing processes, was conducted to deal with UCS. The results of the three-stage countercurrent dissolution process showed that the uranium content in UCS was decreased from 8.66 to 1.06%, the residual ratio was less than 18%, and the leaching rate of uranium was 98% or more. The results of H₂SO₄ curing process showed that the leaching rate of uranium could be controlled at more than 99.9%, and the uranium content of UCS was decreased to 0.19%. The process may serve the purpose of recovering uranium from uranium-containing alkaline residues with complex source. (author)