Co-Calcination of Bauxite Residue With Kaolinite in Pursuit of a Robust and High-Quality Supplementary Cementitious Material

The present article investigates the potential of co-calcination with kaolinite as a sector-wide solution for transformation bauxite residue into an effective supplementary cementitious material (SCM). Bauxite residues from eight alumina refineries were co-calcined 30 wt% at 750°C. SCMs moderately high reactivities obtained. Mortars replacement Portland cement (CEM I) by had relative strengths 73 ± 4%, 87 and 88 2% after 2, 7, 28 days compared to CEM I reference mortar. reactivity contribution strength development shown scale linearly dosage. Most require only 20 substitution reach performance targets. Co-calcination reduced mobility heavy metals significantly. negative effect on workability that some BRs higher content free sodium exhibited was mitigated co-calcination. This positive also observed calcination 10 kaolinite. same found leaching metals. inherent mainly stemmed desilication products such sodalite cancrinite. During co-calcination, sodium-containing phases reacted kaolinite, delivering low free-sodium content.