The Pembrey Copper Cathode

Abstract

The world's first copper electrorefinery started production in 1869 at Pembrey in South Wales and was closed in March 1912. Refining principles pioneered there form the foundation of modern electrorefining practice. A cathode recovered at closure and now in the collection of the Swansea Museum, Wales, is the earliest authenticated British example of electrorefined copper as cathode. This unique artefact was sampled and assayed to establish its composition and market quality and to help elucidate refining capability at that time. The sampling method was based upon drilling into the edge of the cathode plate in order to protect its display integrity; assaying was by inductively coupled plasma mass spectrometry, the present received method for refined copper. Comparison with contemporaneous cathode and wire bar assays indicates that the Pembrey cathode would have been competitive in the copper market of its day, but with questions about its relatively high levels of silver and, to a lesser extent, arsenic.