PROCEDURE FOR PROCESSING SPENT SALT-ACID ETCHING MIXTURE WHICH IS A RESIDUE IN ETCHING PRINTED CIRCUITS

摘要

The invention refers to the processing of salt-acid etching mixture which is a residue after etching printed circuits. A novel procedure for the recuperation of spent salt-acid etching mixture is proposed which consists of adding copper into the spent salt-acid etching mixture while supplying air. After that the solution is neutralised with Cu(OH)2 and the suspension is filtered, while the paste-like residue is processed to obtain copper fungicide and the filtrate is transferred through a suitable outlet.