Innovative two-step synthesis design approach in developing vanadium incorporated low-carbon binder system

Abstract

A novel two-step synthesis approach was developed to create a low-carbon C2S binder system incorporating vanadium, utilizing thermodynamic modeling and subsequent experimental validation. The modeling identified 1 wt% V2O5 as the ideal dosage since excessive V2O5 led to Ca2V2O7 generation, depleting CaO in C2S phases. Additionally, 1400 °C was the optimal clinkering temperature for C2S synthesis as higher temperatures favored C3S formation while lower temperatures reduced the C2S content. Experiments confirmed that clinkering at 1400 °C could produce high β-C2S content in V2O5-doped binders, with V5+ ions stabilizing β-C2S and inhibiting its transformation to γ-C2S. Small amounts of Ca2V2O7 formation during clinkering could also promote the V2O5 passivation. After 1-day carbonation, vanadium-dosed pastes prepared at 1400 °C possessed low porosity and dense morphologies, contributing to superior strength by forming CaCO3 and gel phases. This approach offers a sustainable direction to maximize the performance of low-carbon binder systems by recycling heavy metal-derived solid wastes.