Problems with residual elements and their control through specifications

Abstract

This article is a summary of a paper presented at the symposium entitled 'International Conference on Residuals Additives and Materials Properties' sponsored by the National Physical Laboratory, the Royal Society and the Metals Society and held on 15–17 May 1978. The problem of residual elements in materials is one which is likely to be given greater emphasis as a greater proportion of industrial raw materials are produced by secondary (recycled) routes. The sensible specification of residual elements and the various means by which this can be achieved will take on increasing importance as the proportion of trace elements in recycled materials increases.