Effect of pyrolysis and comminution on copper extraction and techno-economic assessment for resource recovery from...

Waste printed circuit boards (WPCBs) are resourceful waste materials that comprises of a combination of organic and inorganic materials. Material recovery from WPCB is necessary for both environmental and economic reasons. The current study investigated the effect of comminution and/or pyrolysis on the leaching efficiency of copper using WPCB of two sizes: S1 (1 × 1 cm²) and S2 (<100 μm), and their pyrolyzed versions, S3 and S4. The grinding and pyrolysis of WPCB before leaching increased the efficiency. The S3 sample exhibited the highest recovery efficiency, and copper was subsequently recovered in solid phase through zinc cementation, achieving a purity of 97.4 %. Based on the performance of sample S3, an Aspen Plus® simulation was conducted for a plant integrating comminution, pyrolysis, and metal extraction, designed for a feed capacity of 500 kg/h and an operational lifetime of 20 years. Economic evaluation parameters were determined using discounted cash flow analysis, and the minimum selling price (MSP) of oil was calculated for four different scenarios. A net present value of $2.87 M, payback period of 5.4 years, internal rate of return of 29 % and profitability index of 2.25 was obtained. Overall, this study demonstrates an integrated approach for WPCB valorization through pyrolysis and copper recovery.