Removal of surface layers from plated materials: upgrading of scrap

In this paper a description is given of a method developed for the purpose of removing surface layers from plated materials. The principle of separation is based on the difference in vapour pressures and stabilities with the formation of metal chlorides. A series of pyrolytic experiments was carried out with different combinations of electroplated materials in an atmosphere of gaseous HCI. The HCl was produced by pyrolyzing scrap polyvinyl chloride. Specimens of tinplated copperwire and steelplate, galvanised steel and chromed copper, were treated in this way with the result that most of the tin, zinc and chromium were preferentially removed, leaving the steel and copper almost unattacked.