Zero-waste valorization of feldspathic minerals: Technical, economical, and environmental assessment

Feldspathic minerals, though abundant, are underutilized for metal extraction. This study presents a techno-economic and environmental assessment of the novel POTASSIAL process, an integrated, near-zero-waste flowsheet designed to recover potassium chloride (KCl), aluminum oxide (Al 2 O 3 ), and silicon carbide (SiC) from a K-feldspar concentrate. An alternative route producing Ca-silicate from marble sludge residues was also considered. The process, which combines mechanical activation, hydrometallurgical leaching, and thermochemical reduction, was modeled at an industrial scale of 100 tons/day. The economic analysis estimates a total fixed capital investment of $76 million and annual operating costs of $39.7 million, driven primarily by high energy and reagent consumption. Under baseline assumptions and maximum market pricing, the process is marginally profitable, with a payback period of 11.4 years and an internal rate of return (IRR) of 6.1%. A sensitivity analysis reveals that economic viability is highly dependent on revenue from the high-value SiC co-product, challenging the traditional research focus on potash-only extraction from feldspar. A cradle-to-gate Life Cycle Assessment (LCA) demonstrates that while the process has a higher carbon footprint than conventional routes to produce KCl, Al 2 O 3 , and SiC, due to high thermal energy demand, it offers significant qualitative environmental advantages. These include the elimination of hazardous by-products such as red mud and brine tailings, and the potential to utilize bio-based carbon reductants. This assessment quantifies the primary economic and environmental barriers, concluding that future work must focus on energy integration and reagent recycling to unlock the process's potential as a sustainable alternative for mineral valorization.