PRODUCTION OF POTASSIUM PERRHENATE

PURPOSE:To easily obtain high-purity potassium perrhenate by adding hydrogen sulfide to the oxidation leaching liquid of crude rhenium sulfide to obtain high- purity perrhenic acid and thereafter adding potassium hydroxide. CONSTITUTION:High-purity perrhenic acid is obtained in the following residual liquid by oxidizing and leaching crude rhenium sulfide and adding hydrogen sulfide in a residual liquid after the leaching. Then potassium perrhenate is produced by adding potassium hydroxide thereto. Ordinally used crude rhenium sulfide contains 10-40% Re, 0.02-0.08% Mo, 0.01-0.5% Bi, 2-10% Hg, 0.1-0.3% Cu, 0.01-0.30% Se, 2-10% As and 30-50% S. Oxidation is performed in an early stage and complete oxidation is performed by using especially hydrogen peroxide as an oxidizing agent.