PROCESS FOR PROTECTING THE SORROUNDINGS ELABORATION OF ACIDIC AND/OR BASIC ETCHING LIQUID

摘要

Copper content of used etching fluids is pptd. by addn. of zinc in a form having a large surface area, pref. waste zinc. Zinc is added until the colour of the soln. disappears plus a little surplus. Meanwhile the temp. of the soln. may rise to boiling point. The pptd. copper and the surplus zinc are sepd. out, pref. by filtration. Then copper is melted on its own or together with the zinc to form brass. The filtrate is concentrated by evapn. to a fifth of its original volume and cooled to produce a zinc salt.