PROCESS FOR REGENERATION OF PHOSPHORIC ACID CONTAINING ETCHANT FOR METALS OR PHOSPHORIC ACID

摘要

The invention provides a process for regenerating efficiently a phosphoric acid containing etchant for metals which further contains volatile impurities such as volatile and hydrophilic etching inhibitor substances and other impurities such as metal ions into an etchant free from these impurities. The process comprises the step (1) of ridding a phosphoric acid containing etchant for metals which further contains at least one acid other than phosphoric acid and volatile and hydrophilic impurities of the volatile components by heating, vacuumization, blasting, or a combination of two or three of them and the step (2) of extracting metal ions from the residue obtained in the step (1) which contains phosphoric acid as the main component by the use of an extractant containing both a phosphoric monoester and a phosphoric diester.