Abstract
Phosphogypsum (PG), a significant by-product of the wet phosphoric acid production process, poses environmental and utilization challenges due to its harmful impurities, including heavy metals, fluorides, and phosphates. This review aims to evaluate the stabilization/solidification (S/S) methods for these hazardous impurities to enhance PG recycling in road engineering and other applications. A comprehensive bibliometric analysis was conducted using data from the Web of Science Core Collection, covering publications from 1985 to 2024. The review assesses the types and impacts of PG impurities on composite material performance and environmental health, detailing various S/S methods and their underlying mechanisms. Key findings suggest that blending PG with inorganic cementitious materials, incorporating additives, and using PG-based geopolymers are effective strategies for S/S. Blending PG with electrolytic manganese residue (EMR) and granulated blast furnace slag (GBFS) shows significant potential in immobilizing heavy metals and reducing environmental risks. The use of polymer materials, surface modifiers, and curing agents enhances the physical encapsulation and chemical stabilization of harmful impurities. PG-based geopolymers, formed through unique hydration reactions, offer robust encapsulation and adsorption capabilities for heavy metals. Additionally, biological treatment methods and biochar adsorption present innovative approaches for PG remediation. The main S/S mechanisms include physical encapsulation, chemical precipitation, ion exchange, and adsorption. Future research should focus on optimizing these S/S techniques, exploring synergistic combinations, and developing cost-effective and scalable solutions to improve PG recycling and promote sustainability in industrial practices.