Selective separation of copper by membrane-electro-winning and its application in etchant recycling

Abstract

A close-looped process based on the membrane separation and electrolysis is proposed to regenerate the copper etchant in-situ, recover copper on-site and reuse it. It is characterized by selective separation of copper from the spent etchant, which is accomplished by the ion exchange membrane-electrowinning, and at the same time the other components useful for etching are reclaimed. The experiments show that at least 90% of electricity efficiency for copper removal can be maintained and the optimum condition for membrane-electrowinning is: cell voltage 2–2.5 V, operating temperature 40–50 °C and current density 500–1500 A/m². The regenerated etchant can be successfully reused to etch copper after adjusting its composition to the normal range, and its recycling property is as good as that of the fresh etchant after 50 times of use-disposal-regeneration cycles.

Keywords

copper etchant / membrane-electrowinning(M-E) / recycle / selective separation