A REUSING METHOD OF COPPER NITRATE WASTE WATER AS ETCHING SOLUTION AND COPPER INGOT BY ETCHING PROCESS

摘要

A method for recycling copper nitrate wastewater generated in an etching process is provided to recycle nitric acid and copper by recovering nitric acid by evaporating copper nitrate wastewater and recovering copper by using electrowinning, thereby reducing the treatment cost. Solid sludge is filtered from copper nitrate wastewater. The copper nitrate wastewater is evaporated to recover nitric acid so that copper wastewater with increased copper ion concentration is obtained. The copper wastewater is electrowinned to recover electrolytic copper under conditions of current density 300-560 A/m^2, copper ion concentration over 20g/l, initial concentration of free acid below 50g/l, pH over -0.18, and thermal conductivity over 100mS/cm.