A Northwestern University lab has demonstrated a method to produce the mineral feedstocks for cement, concrete, plaster, and paint from seawater, electricity, and captured CO2, with CEMEX actively funding and co-authoring the research as part of its industrial decarbonization strategy.
The global construction industry mines approximately 50 billion metric tons of sand and gravel annually, a figure the UN Environment Programme projects will climb another 45 percent by 2060. The price of sand and gravel in the United States has more than quintupled since 1978. In Vietnam, domestic demand already exceeds total national reserves. Sand is the second most consumed commodity on Earth after water, and in many regions it is running out faster than it can be replaced. Into this supply crisis steps a laboratory at Northwestern University's McCormick School of Engineering, with a method that doesn't mine these raw materials at all. It grows them from seawater, electricity, and CO2.
The research, published in the journal Advanced Sustainable Systems on March 19, 2025, was led by Alessandro Rotta Loria, Louis Berger Associate Professor of Civil and Environmental Engineering at Northwestern's McCormick School. Co-advised with Jeffrey Lopez, an assistant professor of chemical and biological engineering, the lab produced a deceptively simple system: insert electrodes into seawater, apply a low electrical current, and bubble CO2 through the water. What follows is a cascade of electrochemistry. The current splits water molecules into hydrogen gas and hydroxide ions. The CO2 injection transforms the water's chemistry, increasing concentrations of bicarbonate ions. Those bicarbonate and hydroxide ions react with calcium and magnesium dissolved naturally in seawater, precipitating into solid minerals: calcium carbonate and magnesium hydroxide. The hydrogen is released as a clean gas. The solid minerals remain.
Those minerals, composites of calcium carbonate and magnesium hydroxide, are not byproducts. They are construction materials. Calcium carbonate acts as a direct carbon sink. Magnesium hydroxide sequesters additional CO2 through further interactions with the gas. Together, with a composition split evenly between the two minerals, one metric ton of the resulting material can hold over half a metric ton of CO2. The material can substitute directly for sand and gravel in concrete, which relies on aggregate for 60 to 70 percent of its volume. It can also serve as a raw feedstock for cement, plaster, and paint manufacturing, covering much of what the construction supply chain currently pulls from the ground.
Rotta Loria describes the chemistry as nature's own method, borrowed and electrified. Coral and mollusks use metabolic energy to convert dissolved seawater ions into calcium carbonate shells. His lab uses electrical energy to do the same, then pushes the mineralization further by injecting CO2. The lead author on the paper is Nishu Devi, a postdoctoral fellow in the lab. PhD students Xiaohui Gong and Daiki Shoji, and former graduate student Amy Wagner, also contributed. The work was financially supported by CEMEX and Northwestern's McCormick School.
That CEMEX funded and co-authored this research is the signal worth reading carefully. CEMEX is the world's third-largest cement company by production capacity, headquartered in Monterrey, Mexico, operating in over 50 countries with roughly 41,000 employees. Its Global R&D department is housed at CEMEX Innovation Holding AG in Zug and Brugg, Switzerland. The researchers named on the Northwestern paper from that department are Alexandre Guerini and Davide Zampini, CEMEX's vice president of global R&D.
Zampini's involvement is not nominal. His name appears on both the 2024 mechanistic precursor paper and the March 2025 study with CO2 injection. He is the executive responsible for evaluating whether emerging materials science can be made commercially viable at industrial scale, and his active participation in the research rather than a passive endorsement signals that CEMEX views the process as a serious development candidate.
The company's position on decarbonization provides the strategic context. Under its "Future in Action" program, CEMEX has committed to becoming net-zero CO2 by 2050 and has validated 1.5 degrees Celsius-aligned 2030 targets with the Science Based Targets initiative. It estimates annual investment of approximately $150 million toward its 2030 goals. Its corporate venture capital arm, CEMEX Ventures, backs more than 23 startups across low-carbon materials, carbon capture, and digitalization. In March 2026, CEMEX Ventures was named "Sustainability Investor of the Year" at the BuiltWorlds Awards. The Northwestern collaboration sits within this architecture: open university research, funded by the company, with company scientists embedded as co-authors.
From a natural resources standpoint, what makes the Northwestern method noteworthy is what it doesn't require. Sand mining is one of the most environmentally destructive extraction industries on the planet. River dredging destroys riverbank stability and downstream fisheries. Coastal mining erodes shorelines and eliminates protective buffers against storm surge. Ocean floor dredging disrupts benthic ecosystems at scale. The UN has documented organized crime networks controlling illegal sand trades in India and Italy, conflicts over maritime extraction rights between Singapore and its neighbors, and governments moving to outright ban certain forms of extraction. This is not a mature, stable commodity market. It is a resource under pressure, with a demand curve that continues to rise.
Seawater, by contrast, covers 71 percent of the Earth's surface and is inexhaustible at any human-relevant timescale. It contains naturally dissolved calcium and magnesium ions in concentrations sufficient to feed mineral precipitation reactions continuously. The Northwestern process does not disturb marine ecosystems directly: Rotta Loria envisions modular, land-based reactors positioned at shorelines near existing cement plants, drawing in seawater, running it through the electrolytic mineralization process, treating the effluent before returning it to the ocean. The ocean functions as a feedstock reservoir, not a mining site.
The CO2 input adds another resource dimension. The process consumes CO2 as a raw material, permanently locking it into the mineral structure of the product. For a cement plant positioned on a coastline, the possibility Rotta Loria describes is a closed loop: CO2 released by cement manufacturing enters a shoreline reactor, reacts with seawater and electricity, and emerges as solid aggregate ready for the next concrete pour. Every batch of concrete produced under such a system would be a net carbon storage event. The building becomes the sequestration facility.
The clean hydrogen produced alongside the minerals deserves its own accounting. Industrial hydrogen production today depends heavily on steam methane reforming, a process that emits significant CO2 of its own. Green hydrogen, produced by electrolyzing fresh water with renewable electricity, is cleaner but expensive and constrained by freshwater availability. The Northwestern process produces hydrogen as a byproduct of electrolyzing seawater, using no freshwater input and generating a saleable energy product alongside the construction material. The economics of the system shift meaningfully when the hydrogen is valued: the same electrical input that grows the mineral aggregate also manufactures fuel.
The research as published is laboratory scale. Rotta Loria's team has demonstrated proof of concept and established that mineral properties can be precisely controlled by adjusting voltage, current, CO2 flow rate, and seawater recirculation timing. The materials can be grown denser or flakier depending on intended application. What remains undemonstrated at this stage is the full techno-economic model: the energy cost per ton of aggregate produced, the capital requirements for modular reactor deployment, the net carbon accounting under realistic grid conditions, and the performance of the material in full-scale structural concrete over time. These are scaling questions, not chemistry questions.
Rotta Loria directs the SOIL lab (Subsurface Opportunities and Innovations Laboratory) at Northwestern and has co-founded two startups, GEOEG and ENERDRAPE, indicating a track record of moving laboratory discoveries toward commercial application. The broader CEMEX collaboration, which this paper describes as ongoing rather than concluded, provides the industrial development pathway a university lab alone cannot.
For the natural resources sector, the implication is structural rather than incremental. A viable industrial process for growing concrete aggregate from seawater and CO2 would not merely reduce the environmental cost of sand mining. It would replace the commodity category entirely for one of its largest end uses, substituting an exhaustible, geographically constrained resource with an effectively unlimited one, while converting an industrial waste gas into a durable product. The chemistry has been demonstrated. The scale-up is where CEMEX's involvement becomes decisive.