PRODUCTION OF ALUMINUM SULFATE HAVING EXCELLENT SOLID- LIQUID SEPARATION FROM ALUMINUM NITRATE GENERATED AS BY-PRODUCT

摘要

PROBLEM TO BE SOLVED: To provide a method for producing aluminum sulfate having excellent solid-liquid separation from aluminum nitrate generated as a by-product in a regeneration process for a waste electrolytic etching solution consisting essentially of nitric acid contaminated with aluminum. SOLUTION: Aluminum nitrate generated as a by-product in a process for regenerating a waste electrolytic etching solution consisting essentially of nitric acid contaminated with aluminum is dissolved in water firstly. The solution is mixed with a concentrated mother liquor after aluminum sulfate crystal separation and sulfuric acid to form a solution having an adjusted concentration of sulfuric acid. The solution is made to have 15-35 wt.% apparent total sulfuric acid concentration and heated to 60 deg.C and then cooled to 0-25 deg.C. Aluminum sulfate crystal is precipitated/separated to produce aluminum sulfate having excellent solid-liquid separation.