Technoeconomic Assessment of Organic Halide Based Gold Recovery from Waste Electronic and Electrical Equipment

Waste Electronic and Electrical Equipment (WEEE) is one of the fastest growing waste streams worldwide, with significant economic value due to the precious metals contained within. Currently, only a small share of the total globally produced quantity produced is treated effectively and a large amount of valuable non-renewable resources are being wasted. Moreover, the methods currently applied in industry on a large scale are not always environmentally friendly. Thus, an economically viable and environmentally friendly method that would achieve high recovery of certain elements is sought. The objective of this paper is to assess four different organic halides as leaching agents for gold recovery from WEEE. Two of them have been previously tested (namely N-bromosuccinimide, NBS, and N-chlorosuccinimide, NCS) and have shown promising results, whereas the other two are novel and were selected due to their lower toxicity levels (trichloroisocyanuric acid, TCICA, and tribromoisocyanuric acid, TBICA). Both commercially supplied pure gold powder and WEEE dust from a recycling company were used as the gold source. Results show that from a technical standpoint, the NBS is a superior solution with both substrates, reaching 61% and 99% extraction efficiency from WEEE dust and pure gold, respectively. The other three methods recorded lower recovery efficiency (with the highest value reaching 36% for NCS, 53% for TCICA and 29% for TBICA). However, taking into account the price of gold and the expenses of the extraction process, only three of the lixiviants tested (NBS, NCS and TCICA) could be potentially profitable and viable on a larger scale.