E-waste recycling: Integrated life cycle assessment and techno-economic analysis unravels pyrometallurgy’s edge and delivers an optimization framework for recovering waste printed circuit boards

Abstract

With electronic waste growing at 3 %–5 % annually, metals can be recycled. Pyrometallurgy, while effective for recovering crude copper from waste printed circuit boards (WPCBs), faces significant challenges in environmental impact mitigation and economic feasibility. This study implemented life cycle assessment (LCA) and techno-economic analysis (TEA) based on first-hand industrial data from an enterprise in China to compare environmental-economic performance and policy adaptability across present pyrometallurgy (BAU), three optimized technologies (T1: Natural gas substitution for diesel, T2: Waste heat recovery for power generation, T3: Integrated optimization of “T1 + T2”) and hydrometallurgy. It was revealed that significant electricity consumption dominated the environmental hotspots in pyrometallurgy due to China’s reliance on coal-fired power grids, contributing 31.84 %–64.25 % and 31.85 %–49.86 % across all midpoint and endpoint indicators. While T1 achieved <5 % per-ton environmental gains, its emission reduction benefits became notable at 3614 tons/year. T2 reduced environmental burdens by 7.18 %–51.58 % through waste heat-to-energy conversion that cut electricity demand. Furthermore, T3 achieved optimal performance in 17 midpoint indicators and three endpoint categories, reducing environmental impact by 7.26 %–51.73 % and 30.22 %–40.46 %, respectively. From techno-economic perspective, T3 delivered the highest economic feasibility with a payback period of 4.69 years and remained viable under stricter environmental taxes or corporate tax hikes. Sensitivity analysis revealed that grid decarbonization could reduce environmental burden of traditional pyrometallurgy by 20.44 %–40.92 %, highlighting the synergistic necessity of energy transition and process optimization. This study provides a technical selection framework and policy insights for green recycling of WPCBs, advancing circular economy and dual carbon goals.