Silicate-derived calcium as a pathway to low-carbon Portland cement
21 hours ago
- #low-carbon construction
- #silicate rocks
- #cement decarbonization
- Cement production contributes 4.4% of global greenhouse gas emissions, with decarbonization technologies like alternative cements and carbon capture existing but underutilized.
- Using carbon-free silicate rocks (e.g., basalt) instead of limestone for Portland cement production could reduce energy needs by 30%, eliminate process emissions, and offer cost benefits.
- Silicate rocks are abundant globally, with enough calcium to meet cement demand for hundreds of thousands of years, similar to limestone's supply longevity.
- Thermodynamic analysis shows producing cement from silicates requires less than half the energy of limestone-based methods, with potential for full decarbonization using renewable energy.
- A process using hydrochloric acid leaching, electrolysis, and calcination can produce cement and supplementary materials from silicates, though energy efficiency improvements are needed.
- Co-production of steel, aluminum, and supplementary cementitious materials from basalt could meet global demand for these materials, reducing mining waste and enhancing economic viability.
- Alternative cements face adoption barriers due to risks and lack of long-term data; thousands of demonstration projects may be needed for market confidence.
- Combining silicate-derived cement with renewable energy and material blending offers a path to net-zero emissions, potentially reducing reliance on costly carbon capture.