METTHOD OF REGENERATION METHOD OF ACID CUPPER(II)CHLORIDE ETCHING WASTE

摘要

The present invention relates to regeneration of acidic copper(ll)chloride etching wastes (CuCI₂) formed in printed circuit board industry. The regeneration process yields high quality liquid hydrochloric acid and pure copper sulfate or copper sulfate containing sodium sulfate as impurity. In the present method, acidic CuCI₂ etching waste together with sulfuric acid is fed to a distillation column, thereby yielding, from the top of the column, concentrated, liquid, 30-35% hydrochloric acid and, as secondary flow, more dilute, liquid 20% sulfuric acid having azeotropic composition. Metal sulfates are crystallized from the metal-containing sulfuric acid flow obtained from the bottom of the column. Sulfuric acid flow, from which metal sulfates have been separated, may be recycled back to the column as sulfuric acid feed.