(254s) Metal Leaching from a Copper-Rich Derivative of E-Waste Using Selected Organic and Mineral Acids

Authors: 
Barford, J., Hong Kong University of Science and Technology

World over, e-waste is one of the fastest growing waste streams, growing at a rate approximately three times faster than normal municipal solid waste. The United Nations Environment Program (UNEP) estimates global e-waste generation to range between 20 - 50 million tons per year. This very large volume of e-waste is not the only major problem; the hazardous chemicals it contains are also of huge concern. E-waste contains such a substantial amount of hazardous chemicals that it is believed to generate approximately 70% of the heavy metals in municipal solid waste landfills. Further, due to its complexity, e-waste is rarely recycled.

A huge amount of e-waste is generated nowadays because of the frequency with which electrical/electronic gadgets are discarded and replaced with the latest models. In many locations, available landfills are rapidly filling up and therefore there is an urgent need to deal with the waste in other ways than simply dumping it. Besides, when landfilled, the many toxic chemicals contained in e-waste can leach into the environment.

Developing greener processes of solving the e-waste problem will not only alleviate the pollution, but it will also offer economic opportunities. E-waste can in fact be an economically viable source of metals and other materials.

Our research aims at developing integrated processes for recovery of metals from e-waste. It involves enhancing techniques for release of metals from e-waste and their subsequent recovery.

We are focusing on recovering metals from printed circuit boards (PCBs) because they are found in all electronic gadgets and they contain very many different metals. We are investigating techniques for sequential release of different metals from PCBs. Different acids are applied and we monitor the leaching processes in order to study the sequence in which the metals are leached from the e-waste. This we will help in downstream separation operations.

We hope to elucidate the mechanism by which dilute acids mobilize metals from e-waste. We also hope to recommend which acids can be used in industrial scale operations based on efficiency and cost effectiveness. We shall also design reactors for the process.