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Techno-economic analysis on the mass production of vaterite-type calcium carbonate using SWRO brine and cement kiln dust – A carbon utilization and storage case study in Saudi Arabia

Abstact

This study presents a comprehensive techno-economic and environmental assessment of producing high-purity vaterite-type precipitated calcium carbonate (PCC) using seawater reverse osmosis (SWRO) brine, cement kiln dust (CKD), and captured carbon dioxide (CO₂). A 50-ton-per-annum (TPA) pilot plant operated in Jubail, Saudi Arabia demonstrated stable production of spherical vaterite CaCO₃ with ≥97% purity, ≥ 80% vaterite content, ≥ 99% whiteness, and ≤ 3 μm particle size. The process employs CKD (CaO 40–60%) as a low-cost calcium source and SWRO brine as a natural solvent, avoiding synthetic extraction chemicals. Techno-economic modeling for a 100,000 TPA commercial vaterite PCC plant indicates strong profitability (IRR > 70%, ROI < 1.4 years) across CO₂ price scenarios up to 750 SAR/ton, with NaOH as the dominant cost driver. An environmental assessment incorporating allocation and sensitivity analyses for CKD, SWRO brine, NaOH, and electricity yields a footprint range of −272 to 974 kgCO₂-eq/t PCC. Under three representative scenarios, the footprint is 566, 148, and − 272 kgCO₂-eq/t PCC, corresponding to 23,200–107,000 t/y annual GHG reductions for a 100,000 TPA plant relative to a conventional PCC plant. Integration with SWRO infrastructure further enables an “integrated seawater hub” concept, supporting circular-economy linkages across the water and cement sectors.