• • At 250 °C under micro-oxidation, red mud-coal product pH dropped from 10.29 to 8.47, meeting the alkaline regulation target (5.5–9.0) for in-situ remediation, enabling growth of alkali-tolerant plants.
• • Organic matter content reached 12.98% (SOC 7.53%) at 250 °C, classified as 'high' by soil organic matter grading standards, providing a stable organic-inorganic complex for soil microecology.
• • Water-stable aggregates of 0.250–2.000 mm increased from 10% to 28% at 250 °C, with capillary porosity of 22%, enhancing soil structure and water retention.
• • The process leverages endogenous humic acid generation via coal oxidation, avoiding high-cost external organic amendments and achieving synergistic dealkalization and aggregation in a single step.