Portland cement from basalt-derived calcium could cut process emissions, reduce energy demand about 30%, and create iron and aluminum co-products, offering a scalable low-carbon route for construction material production worldwide.
Study: Silicate-derived calcium as a pathway to low-carbon Portland cement. Image Credit: Viacheslav Zhedankov/Shutterstock
In a recent research article published in the journal Communications Sustainability, researchers explore a novel approach to infrastructure development by producing ordinary Portland cement from carbon-free silicate rocks such as basalt, aiming to decarbonize cement production while potentially reducing costs and energy use.
Cement's Carbon Challenge
Portland cement (PC) is the fundamental binder used worldwide in concrete construction, underpinning much of the built environment. Traditionally produced by calcining limestone (CaCO3), PC accounts for approximately 4.4% of global greenhouse gas emissions, primarily due to CO2 released during calcination and the high energy required to maintain temperatures above 1500°C.
Despite decades of efforts to improve energy efficiency and blend PC with supplementary cementitious materials (SCMs) to reduce emissions, substantial carbon output remains because the calcium source, limestone, is intrinsically carbon-intensive.
This study explores an alternative calcium source: silicate rocks such as basalt, which do not emit CO2 during processing, potentially enabling the production of low-carbon PC and significant decarbonization of the cement sector.
Silicate Calcium as Solution
The researchers conducted a thermodynamic analysis to quantify the minimum energy requirements and carbon emissions for producing Portland cement from various feedstocks, including traditional limestone and silicate rocks.
They compared the energy intensity and emissions profiles under different scenarios involving fossil fuel, renewable energy, and electrochemical processing. A detailed compositional analysis was performed to compare the elemental make-up of typical basalts and gabbros against limestone and Portland cement clinker compositions.
To assess the practicality of deploying silicate-derived calcium at scale, the study estimated the global availability of silicate rock resources relative to current and projected cement demands. They identified known unit processes, such as hydro- and pyrometallurgical routes, for extracting and recombining calcium, silicon, aluminum, and iron into cement clinker and SCMs.
Additionally, the analysis considered the co-production potential of valuable metals such as iron and aluminum from basalt feedstocks, which could supply significant fractions of global steel and aluminum demand.
Finally, the research examined challenges related to alternative cement materials derived from calcium silicate sources, modeling the unknown risk costs associated with adopting novel building materials, given the long track record and market dominance of traditional Portland cement frameworks.
Basalt Viability and Benefits
The compositional analysis confirmed that typical basalt and gabbro contain approximately 9–12% CaO by mass, substantially less than high-grade limestone (~50% CaO), but with added iron and aluminum content absent in limestone.
Although more rock (around 16 gigatons annually) would need to be mined compared to limestone to meet global CaO demand for cement, the process eliminates intrinsic CO2 emissions from calcination and reduces overall energy demand by around 30%. This would lower both the operational costs and environmental impacts associated with cement production.
Thermodynamically, producing cement clinker from basalt is viable and can be accomplished with proven unit processes, including hydrometallurgical extraction combined with pyroprocessing. These methods avoid releasing CO2, which is inherent to limestone calcination, and can be powered by renewable or nuclear energy sources.
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The presence of iron and aluminum in the feedstock creates opportunities for integrated industrial symbiosis, in which steel and aluminum production would occur alongside cement manufacturing, further enhancing economic viability and reducing the environmental footprint of multiple sectors.
The analysis also underscored significant challenges in adopting alternative cements derived from silicate calcium. One major barrier is market inertia: Portland cement’s dominant status is reinforced by centuries of demonstrated performance, well-understood durability, and extensive construction codes.
The perceived risk of structural failure with new materials is nontrivial. Modeling indicated that for the construction industry to confidently adopt novel cements, approximately 13,000 buildings must be constructed and observed without failure, equating to decades of demonstration projects.
Furthermore, other practical challenges include differences in workability, curing behavior, availability, and requirements for safety and maintenance, all of which pose hurdles in widespread industry adoption. Until these barriers are addressed, alternative cements are likely to remain niche products despite their lower carbon footprints.
Pathway to Low-Carbon Cement
This study highlights the potential for a paradigm shift in cement production by replacing limestone with silicate rocks like basalt as the calcium source. Doing so can virtually eliminate process CO2 emissions inherent to limestone calcination.
Additionally, it can reduce energy requirements by about 30%, and produce valuable co-products such as iron and aluminum that meet other industrial needs. Silicate-derived calcium thus offers a cost-competitive and sustainable solution to decarbonize Portland cement while supporting the broader industrial ecosystem.
To realize this opportunity, research is urgently needed to develop scalable, energy-efficient extraction and processing technologies, including hydro- and pyrometallurgical pathways that integrate well with renewable energy systems.
Ultimately, integrating silicate-based PC with supplementary cementitious materials, renewable energy, and circular economy principles (such as cement recycling) could enable the construction industry to significantly reduce its climate impact without sacrificing performance or economic feasibility.
Journal Reference
Prancevic J.P., Finke C.E., eta l. (2026). Silicate-derived calcium as a pathway to low-carbon Portland cement. Communications Sustainability 1, 78. DOI: 10.1038/s44458-026-00056-4, https://www.nature.com/articles/s44458-026-00056-4