Electrolytic regeneration of acidic copper etch solns. - using two-compartment cell sepd. by cation-selective membrane for the generation of chlorine@ for oxidising etching agent and oxygen@

摘要

Process for electrolytically regenerating acid copper etch solns. contg. FeCl3 or CuCl2 includes the cathodic deposition of Cu and anodic oxidn. of the etch soln. The electrolysis is carried out in two separate cells. Chlorine is produced in one cell, and oxidises the etching agent. The anode of the other cell is placed in an. aq. sulphuric acid soln. sepd. from the etch soln. by a cation-selective membrane. This results in the formation of gaseous anodic oxygen. The ratio of chloroxidation to oxidn. by oxygen is controlled, leading to a reversal of the changes which have arisen during etching. Also claimed is the device for carrying out the process, comprising an electrolysis cell with cathode and anode compartments sepd. by a diaphragm, with feed and discharge lines for the etch soln. to the two compartments. Metallic Cu from the etch soln. is deposited on the cathode, and chlorine is formed at the anode and reoxidises the etch soln. A further anode is provided, which is immersed in aq. sulphuric acid and is sepd. from the etch soln. by a cation-selective membrane. There are separate control elements for the electrolysis at the two anodes, and further control elements for the feed and discharge of the etch soln. to the cathode and anode compartments. USE/ADVANTAGE - Used in the etching of excess Cu from printed circuit boards, etc. Permits accurate control of the compsn. of etch solns. for recycling. No chemicals have to be added which would be removed from the system due to residues adhering to the etched products or deposited Cu.