From Hazardous Waste to Functional Materials: A Critical Review on the Environmental Valorization of Zinc-Bearing Electric Arc Furnace Dust

Zinc-bearing electric arc furnace dust (ZEAFD) is a large-volume hazardous byproduct of steelmaking, whose complex composition and fine particulate nature pose significant environmental management challenges. While conventional pyrometallurgical and hydrometallurgical approaches focus on recovering individual metals, they largely overlook the functional value embedded within the complex oxide system. This critical review provides a systematic assessment of recent advances in transforming ZEAFD into functional materials from an environmental valorization perspective, advocating for a paradigm shift from waste disposal to value-added utilization. The formation mechanisms, physicochemical characteristics, and phase compositions of ZEAFD are first analyzed to establish its potential as a functional-material precursor. Two primary conversion strategies are then examined: (1) extraction-reconstruction routes that isolate and resynthesize ZnO/ZnFe2O4-based materials and (2) direct whole-dust conversion approaches that preserve the native oxide framework. The derived materials demonstrate promising applications across multiple domains relevant to environmental sustainability, including energy storage (lithium-ion battery anodes and supercapacitors), environmental remediation (desulfurization, heavy-metal adsorption, and photocatalysis), electromagnetic devices, and biomedicine. Key challenges are identified, including feedstock variability, inconsistent performance metrics, and the inherent trade-off between the purification depth and process sustainability. Future research directions are proposed, emphasizing standardized performance evaluation, mechanistic understanding, expansion into high-demand applications such as aqueous zinc-ion batteries, and the development of closed-loop, low-carbon transformation processes. This review establishes a framework for the sustainable conversion of ZEAFD from an environmental liability into a valuable resource for functional material synthesis, with implications for reducing industrial waste burdens and advancing circular economy principles.