SYSTEM FOR REFINING HIGHLY CONCENTRATED PHOSPHORIC ACID USING WASTE LIQUID FROM ETCHING PROCESS AND METHOD FOR REFINING THEREOF

摘要

PURPOSE: To provide a system for refining highly concentrated phosphoric acid from waste liquid from a manufacturing process of semiconductor or liquid crystalline display device and a method for refining thereof. CONSTITUTION: The system using waste liquid from etching process including 50-70 wt.% of phosphoric acid, 10-30 wt.% of acetic acid, 5-10 wt.% of nitric acid and the remaining amount of water comprises a waste liquid storage part (101) which stores the waste liquid from etching process, a vacuum concentration reaction part (102) which condenses the waste liquid at the temperature of 90-118 deg.C under pressure of 300-700 mmHg to separate a lower layer of a highly concentrated phosphoric acid solution from an upper layer of a side product and a phosphoric acid solution storage part (105) which extracts the highly concentrated phosphoric acid solution from the vacuum concentration reaction part and then stores it.