Gold recovery from jewellery waste

This paper explores the potential of gold concentration from "handwashing w aste" from jewellery workshops. Experiments were carried out by means of gr avity separation equipment (in particular utilising the Knelson concentrato r) after ascertaining that the gold occurs in the waste in the form of free particles and that the shape and size of the gold particles are suitable t o separation, compared to other pollutant particles. Special blending of the handwashing waste with inert particles were adopted in order to control the stability of feed to the concentrator. Equivalence relations were used to simulate the gold particles behaviour in the origin al waste and to find out the best operative conditions for the concentrator . Experimental results demonstrated the suitability of gravity beneficiatio n procedures for the preconcentration of gold particles in the sink and the elimination of much of the contaminants: it was possible to obtain a theor etical recovery up to 90% for gold particles bigger than 35 mu m. practical application on the real handwashing sample has led to a maximum recovery o f up to 68%. (C) 2000 Elsevier Science Ltd. All rights reserved.