Evaluating the economics of and business models for metal recycling from waste printed circuit boards in a South African context

[摘要] ENGLISH ABSTRACT: Electronic waste is the fastest growing component of solid municipal waste in South Africa however limited processing capacity exists in the country to economically recover metals from printed circuit board (PCB) waste. Presently the majority of recycled e-waste is exported instead of adding value to the processed material.A hydrometallurgical process entailing the selective leaching of gold and copper from waste printed circuit boards was developed by the research group (Rossouw, 2015; de Waal, 2018). This study sought to evaluate the economic and business viability of the proposed hydrometallurgical process within the South African context.A PESTEL approach was used to evaluate the South African recycling landscape. In this approach the status of the political, economic, environmental, legal, social and technological aspects characterising e-waste recycling and management was undertaken.Different business models were developed around the main activities of the associated operations of the proposed process. Screening and selection was done on two levels. An assessment of the collection and dismantling of e-waste was done and used as the first basis for screening the business models. It was established that the reverse logistics and associated manpower requirements and efficiencies associated with this operation were economically and operationally restrictive.Detailed costing and profitability studies were done on the last eight business models. The recovery of copper and gold in the metallic state was found to be associated with the highest capital and annual operating expenditures.Profitability studies were conducted on two levels. Performance analysis over the life of the project was done on the basis of discounted cash flows, time, cash and interest. The profitability ratios that included return on investment (ROI), capital ratio (CR), terminal capital rate of return ratio (CRRterm), present value ratio (PVR), net profit margin (NPM) and the (fixed asset turnover ratio) FATR were used to assess the annual performance of each business model.Both assessments revealed that all the business models under the specified process conditions, were unviable and incapable of both capital and interest repayment. Detailed sensitivity studies of the group 4 business was done.The risk of failure within five years was certain as evidenced by the perpetually decaying plots of the recapitalization risk curves. Four additional significant areas of risk were identified and evaluated that had an impact on the performance of the business models. These included supply and demand constraints, key raw material, technological and market related risks.A consideration of alternative revenue streams from palladium, silver and tin recovery, did not improve the performance of the business models. Decreasing both the capital costs and operating costs by margins ranging between 48% and 65% shifted the performance of the business models. The success of this project was driven strongly by the gold business, evidenced by improved performance at elevated minimum gold concentrations ranging between 563ppm and 925ppm. These concentrations implied that a consistent supply of high grade WPCBs would have to be furnished to ensure project viability. It is necessary to consider alternative processing routes when using medium grade WPCBs.

[发布机构] Stellenbosch University