METHOD FOR RECOVERING HYDROCHLORIC ACID AND COPPER FROM COPPER ETCHING WASTE LIQUID

摘要

PPROBLEM TO BE SOLVED: To provide a method for recovering hydrochloric acid having a higher concentration, and a method for conveniently recovering also copper in the concentrated solution after evaporation of hydrochloric acid by electrolysis or the like. PSOLUTION: This method comprises adding phosphoric acid to a copper etching waste liquid containing copper chloride and hydrochloric acid as the main components, heating it to evaporate hydrochloric acid, and recovering hydrochloric acid by condensing the evaporated vapor, whereby hydrochloric acid having a concentration of 15% or higher can be recovered. Wherein it is preferable to evaporate a part of the hydrochloric acid and to recover it, and then to dilute the concentrated solution and to evaporate the rest hydrochloric acid and to recover hydrochloric acid having a lower concentration than the initial hydrochloric acid. Also it would be better to recover cupric phosphate by depositing crystal from the concentrated solution after evaporating hydrochloric acid or to recover a metallic copper by diluting the condensed solution and electrolyzing it. Moreover, it would be better then to circulate the electrolyte after recovering metallic copper to the copper etching waste liquid as a phosphoric acid component and to use it repeatedly. PCOPYRIGHT: (C)2006,JPO&NCIPI