A natural-recirculation dissolver closely approaching a stirred-tank reactor in "behavior has" been developed, and its feasibility has been demonstrated in the mercury-catalyzed dissolution of aluminum in nitric acid. It was designed to utilize the heat of reaction and evolution of gaseous reaction products for recirculation and mixing. The dissolvent was 5-molar nitric acid, containing mercury in concen-trations from 10-4to 10-3 molar as a catalyst. Dissolution rates for l/7 scale, simulated MTR fuel elements of 2-S aluminum ranged from 0.25 to 4.0 mg/(cm2)(min), depending on the catalyst concentration in the dissolvent and the dissolvent flow rate. For comparable catalyst and acid feed concentrations, dissolution rates, based on unit net super¬ficial velocities, were nearly 25 times those for dissolution of randomly-packed flat plates in a pilot plant, continuous, flooded dissolver.
展开▼
