METHOD OF REGENERATING PHOSPHORIC ACID-CONTAINING TREATMENT LIQUID

摘要

A method of regenerating a phosphoric acid-containing treatment liquid, in which without any residue of other substances affecting the properties of phosphoric acid-containing regenerated liquid, a phosphoric acid-containing treatment liquid can be regenerated with low energy and with high efficiency. The method of regenerating a phosphoric acid-containing treatment liquid is adapted to regenerate a phosphoric acid-containing treatment liquid produced by silicon nitride treatment, characterized in that the phosphoric acid-containing treatment liquid is first mixed with a hydrophobic organic solvent containing a specified organophosphorus compound, subsequently a phase separation is carried out to thereby attain precipitation separation of any silicon compound of the phosphoric acid-containing treatment liquid from the phosphoric acid-containing treatment liquid, and thereafter the phosphoric acid-containing regenerated liquid is recovered.