In a significant leap towards decarbonizing one of the world's most carbon-intensive sectors, Chinese researchers have unveiled a catalytic process that leverages steel waste and methane to slash Carbon Dioxide (CO2) emissions in cement production by up to 80%. This innovative approach, developed by experts at the Dalian Institute of Chemical Physics (Huawusuo), part of the Chinese Academy of Sciences, tackles the long-standing challenge of high emissions associated with the fundamental chemistry of Cement Manufacturing.

For decades, the decomposition of calcium carbonate (CaCO3) during cement production has been a major source of CO2 emissions, accounting for approximately 60% of the industry's total carbon footprint.

Preliminary findings indicate that this novel catalytic process drastically reduces carbon emissions by approximately 80% compared to conventional Calcium Carbonate decomposition. This significant reduction offers a promising pathway for achieving deep decarbonization within the Cement Industry, which currently accounts for roughly 8% of global CO2 emissions.

The research team, led by Dr. Zhenggang Liu and Dr. Rui Lu, drew inspiration from the metallic composition of byproducts from the steel industry, including ironmaking slag, steelmaking slag, dust, and sludge. They engineered a simulated steel-derived solid waste composed of iron (Fe), aluminium (Al), and zinc (Zn) to act as a catalyst. When this catalyst is introduced into a methane (CH4) atmosphere alongside calcium carbonate, it triggers a co-thermal reaction. This reaction efficiently breaks down the calcium carbonate, producing calcium oxide (CaO) – a key component of cement – and valuable syngas, a mixture of hydrogen (H2) and carbon monoxide (CO) widely used in energy and chemical industries.

A particularly exciting aspect of this innovation is that the catalytic materials do not need to be removed after the reaction. Instead, they can be directly incorporated into the cement clinker, the granular material that forms the basis of cement. This seamless integration with existing production lines minimizes disruption and reduces waste generation.

The study identified two distinct reaction pathways underpinning this efficient process. The direct pathway involves adsorbed methane interacting with the carbon-oxygen bond at the calcium-iron interface, directly yielding carbon monoxide and hydrogen. The second pathway involves the traditional decomposition of CaCO3 into CaO and CO2, followed by the CO2 reacting with activated methane. The researchers also discovered that adding aluminium and zinc enhances the catalyst's surface area and the distribution of active iron oxide sites, further boosting the process's performance.

Initial life cycle analysis (LCA) suggests substantial environmental benefits if this method is scaled up for industrial application, without requiring a complete overhaul of existing cement plants.