Development, properties, and resource utilization of delithiated β spodumene as new-type building materials: Recent progress and future challenges

The rapid growth of lithium extraction from spodumene ores has resulted in the large-scale accumulation of delithiated β -spodumene (D β S), an emerging industrial by-product with increasing environmental pressure. This review critically synthesizes the formation mechanisms, physicochemical properties, activation strategies, and cementitious reutilization potential of D β S, with emphasis on its intrinsic reactivity and performance relative to conventional supplementary cementitious materials (SCMs) Lithium extraction routes significantly modify the oxide composition, phase assemblage, and amorphous structure of D β S, resulting in high sulfate content, low CaO availability, and heterogeneous aluminosilicate networks that govern its hydration behavior. Quantitative R3 results position D β S as a moderate-reactivity SCM (≈440–450 J/g at 168 h), exceeding fly ash, comparable to calcined clay, and below metakaolin and GGBFS, with a dissolution-controlled, slow but sustained pozzolanic response. Activation strategies, including mechanical and chemical approaches, effectively enhance reaction degree and geopolymerization efficiency. In blended systems, DβS contributes predominantly to medium- and later-age strength development rather than early performance. Key limitations restricting large-scale implementation, including early-age reactivity, sulfate-related effects, and compatibility with conventional cement systems, are identified. Finally, future research directions are proposed to facilitate the integration of D β S into low-carbon cementitious systems and circular construction practices. This review establishes D β S as a viable secondary aluminosilicate resource and provides a mechanistic framework to guide its sustainable application in cement and concrete composites.