MANUFACTURING OF SODIUM PHOSPHATE FROM MIXED WASTE ACID

摘要

PURPOSE: A method for manufacturing sodium phosphate from mixed wasted acid is provided to improve the purity of refined phosphoric acid by eliminating nitric acid, acetic acid, aluminum from mixed wasted acid. CONSTITUTION: Mixed wasted acid is generated from a liquid crystal display manufacturing process and a semiconductor manufacturing process. The mixed wasted acid is processed with a vacuum evaporation process in order to eliminate nitric acid and acetic acid. Aluminum is separated and eliminated from residual mixed wasted acid in order to obtain phosphoric acid aqueous. The content of the aluminum in the phosphoric acid aqueous is between 10 and 30ppm. The vacuum evaporation process is additionally processed. Sodium hydroxide is added to the phosphoric acid aqueous in order to form sodium phosphate. Moisture in the sodium phosphate is eliminated.