RECOVERY OF NITRIC ACID FROM RAFFINATE AND CONDENSATE SOLUTIONS BY STEAM DISTILLATION/PYROHYDROLYSIS AND FRACTIONAL DISTILLATION IN A GLASS COLUMN

摘要

Potential processes for the pilot-plant-scale purification and concentration of nitric acid condensate and raffinate solutions were studied. As a result, a process was developed where condensates were continuously purified by an aluminum nitrate-calcium nitrate trap to reduce 200 - 300-ppm fluoride concentrations to less than one ppm. Next, the condensates were fed to an all-glass rectification column to concentrate nitric acid to 14 molar and to reduce 200 - 400-ppm chloride concentrations to less than one ppm. Finally, raffinates were steam distilled and pyrohydrolized to recover greater than 90 percent of the nitrates as nitric acid.