METHOD FOR PRODUCING CALCIUM PHOSPHATE, TRIBASIC FROM MIXED WASTE ACID OCCUPIED IN PREPARING PROCESS OF LIQUID CRYSTAL DISPLAY

摘要

The present invention relates to a method for producing calcium triphosphate by recovering high purity phosphoric acid from mixed waste acid generated in a liquid crystal display device manufacturing process, wherein the mixed waste acid solution generated in a liquid crystal display device is vacuum evaporated to give nitric acid and acetic acid in the mixed waste acid solution. Removing the first vacuum evaporation step; A diffusion dialysis treatment step of removing the aluminum component by diffusion dialysis treatment of the residual liquid remaining after the first vacuum evaporation treatment; A second vacuum evaporation step of concentrating phosphoric acid by vacuum evaporation after the diffusion dialysis; Preparing a calcium triphosphate slurry by reacting the concentrated phosphoric acid with calcium carbonate and filtering the mixture, neutralizing and reacting the calcium hydroxide solution with the resulting filtrate; And it provides a method for producing calcium triphosphate using the LCD mixed waste acid comprising the step of drying, calcining and grinding the moisture of the calcium triphosphate slurry.