MANUFACTURE OF AMORPHOUS SELENIUM HAVING LOW SULFUR CONTENT

摘要

PURPOSE:To obtain high purity amorphous selenium having a dense structure and a low S content by blowing gaseous SO2 into an aqueous selenious acid soln. after adding sulfuric acid to the soln. to a specified concn. and by carrying out refining by distillation. CONSTITUTION:Sulfuric acid is added to an aqueous selenious acid soln. having 100-200g/l concn. at <=50 deg.C so as to adjust the concn. of sulfuric acid to >=50g/ l, and about 1.1 equiv. gaseous SO2 is blown into the soln. with slight stirring. A formed precipitate is separated and refined by distillation to obtain amorphous selenium having <=5ppm S content.