Anhydrous disodium phosphate prodn. - from soda ash and phosphoric acid in hot satd. disodium phosphate soln.

摘要

Anhyd. di Na phosphate is obtd. by reacting soda ash with 75-100 wt. % concd. phosphoric acid in a soln. satd. with diNa phosphate at a temp. of 90-105 degrees C. Solid phase anhyd. product is formed and recovered. Pref. the process is carried out at a solid : liquid vol. ratio of 1:3. Septd. liquid phase is recycled. Process may be operated continuously and yields the prod. directly in anhyd. form.