From carbonation chemistry to structural performance: Sulfur concrete from brine salts and carbide lime

This study presents an integrated physical–chemical approach for brine desalination, carbon dioxide (CO₂) capture, and the production of high-performance sulfur concrete (SC) utilizing industrial by-products. A novel aqueous carbonation process was developed, in which carbide lime waste (CLW), a highly alkaline byproduct of acetylene production, reacts with CO₂ and desalination brine salts under optimized hydrodynamic and thermodynamic conditions. The process simultaneously reduces brine salinity, sequesters CO₂ as stable carbonates, and yields solid products enriched in CaCO₃ and NaHCO₃. Thermodynamic analysis confirmed the spontaneous and exothermic carbonation over the temperature range of 10–90 °C, while Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), and Raman spectroscopy characterized the morphology, crystallinity, and functional groups of the recovered solids. These carbonated brine salts were incorporated as aggregates in molten sulfur matrices to produce SC with compressive, tensile, and flexural strengths of 60 MPa, 4 MPa, and 12 MPa, respectively, surpassing the benchmarks of Portland cement concrete (PCC). SC exhibited low porosity (1.569%) and moisture absorption (0.17%), with SEM confirming dense microstructural integration and Raman analysis verifying the incorporation of CaCO₃. This waste-to-resource methodology couples carbonation chemistry with sustainable material synthesis, offering a scalable pathway for CO₂ sequestration, brine management, and the production of durable, water-free construction materials suitable for harsh environments.