Processing acid solutions from metal or glass surface treatment plant

摘要

Acid solutions arising from metal or glass surface treatment plant are recovered and recycled into the treatment plant. As a first treatment step, the waste liquid is separated into an acid solution and a metal salts solution by diffusion dialysis or nanofiltration. In subsequent steps, the metal salts solution is crystallized to separate salts from the filtrate which is then returned to the solution from the 1st treatment step or H2SO4 is added to release acids such as HF, HCl and HNO3 as metal salts or it is subjected to a thermal process.