Composition-controlled NaOH/Na(2)CO(3) fusion activation of coal gasification slag: Structural reconstruction, cementitious reactivity, and environmental performance.

A composition-controlled NaOH/Na2CO3 fusion strategy significantly enhances coal gasification slag reactivity, with the H6-C2 formulation achieving a 94.1% 28-day strength activity index.

• Why it matters: Utilizing coal gasification slag in cementitious materials is limited by low accessibility of reactive Si- and Al-bearing species within its network, restricting sustainable material development.
• What they did: The study systematically varied NaOH/Na2CO3 ratios while fixing total alkali at 8 wt% of CGS, evaluating effects through strength tests, calorimetry, dissolution, phase analysis, and environmental assessments, identifying the optimal H6-C2 formulation.
• The result: H6-C2 increased Si and Al release, decreased network polymerization, and reduced embodied energy, warming potential, and costs by up to 75%, supporting its use as a lower-impact supplementary cementitious material.