Sustainable ammonia production from waste via chemical looping and mechanochemical synthesis: A comparative life cycle and techno-economic analysis

This study investigates the feasibility of producing ammonia from waste-derived resources through four pathways: the reference incineration process (INCI), the Haber–Bosch route using imported nitrogen (HB), a mechanochemical ball milling process (BM), and an integrated chemical looping–ball milling system (CLBM) that internally supplies hydrogen and nitrogen. All scenarios were conducted at a scale of 2000 kg/day, followed by life cycle assessment using the ReCiPe 2016 Midpoint method and techno-economic analysis that included capital cost, operating cost, carbon tax, and net profit. BM achieved the lowest GWP on a waste-treatment basis (2.330 kg CO₂-eq/kg-waste), while CLBM showed the lowest product-based emissions (5.439 kg CO₂-eq/kg-NH₃). Although none of the routes achieved positive profitability at the evaluated scale, CLBM recorded the smallest annual deficit (−103.6 k$), outperforming HB and BM due to higher ammonia productivity and internal resource generation. Overall, CLBM demonstrated the most favorable balance between environmental and economic performance.