METHOD FOR RECOVERING LIQUID NITRIC ACID WASTES HAVING SULFATE-IONS IN THEIR COMPOSITION Russian patent published in 2003 - IPC

FIELD: recovery of liquid radioactive wastes such as nitric-acid wastes having radioactive materials in their composition. SUBSTANCE: method involves treatment of sulfate-ion containing wastes with potassium and/or sodium bichromate in amount sufficient to attain concentration of hexavalent chromium in liquid wastes between 0.001 and 0.02 g per 1 g of sulfuric acid. Nitric solution obtained in this way is evaporated including its nitric acid stripping followed by its concentration, for instance rectification, bottoms solution being neutralized by alkali and/or sodium to medium pH value 6-8; after that this solution is conveyed for storage or vitrification by using existing method. EFFECT: ability of extracting nitric acid for industrial processes. 3 cl