Electrolytic process for the preparation of lead sulfonate and tin sulfonate for use in lead / tin plating baths

摘要

An electrolytic process for producing lead and tin sulfonates which comprises applying a DC voltage to an anode (2) and a plurality of cathodes (4) in an electrolytic cell and thereby dissolving lead or tin in an electrolytic solution. The electrolytic cell is partitioned by cation- and anion-exchange membranes (5,6) into anode and cathode chambers. The electrolytic solution is a solution of an organic sulfonic acid, and the anode is lead or tin. The process reduces contents of radioisotopes such as uranium and thorium to a level of less than 50 ppb, and therefore the coatings formed by solder plating using the lead and tin salts in accordance with the invention show radioactive α particle counts of less than 0.1 CPH/cm2.