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A critical review on Na+ removal and immobilization in construction materials from synergistic utilization of red mud and biomass ash
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DOI:10.1016/j.resconrec.2026.109090.png)
Abstract
En 中文
The large-scale utilization of red mud, a highly alkaline by-product of alumina refining, is critically hindered by its substantial Na+ content. This poses significant environmental and engineering risks. In environmental contexts, the high mobility of Na+ contributes to soil salinization and groundwater contamination. Within cementitious systems, excessive Na+ induces deleterious effects such as efflorescence, alkali-silica reaction, and long-term durability degradation. These issues collectively identify Na+ as a critical bottleneck restricting the safe application of red mud in construction materials. To address this, a novel synergistic strategy is explicitly stated in which biomass ash serves as both a reactive Si-Al source and a Na+ regulator to develop low-carbon cementitious materials. Material performance is critically evaluated, focusing on the sources and migration behavior of Na+ in red mud-biomass ash systems. The mechanisms and applicability of Na+ removal technologies are assessed, with a focus on physical, chemical, and biomass ash-assisted approaches. Furthermore, multi-scale immobilization mechanisms within key gel phases (e.g., N-A-S-H) are elucidated, focusing on ion exchange and microstructural modulation. Biomass ash is confirmed as a vital regulator that enhances system reactivity and reinforces the gel network. Finally, future research directions are outlined to provide a theoretical foundation for sustainable, low-alkalinity construction materials.
Journal
R
IF:
10.9
Papers:
7.0K
Citations:
5.3W
