Reactive CO2 capture and mineralization using alkaline industrial residues to produce sustainable construction materials

Construction and steel industries face challenges meeting ambitious sustainability targets set by businesses and government, as they generate high volumes of solid residues, in the form of cement kiln dust and slag, while also releasing flue gases high in CO2 and impurities into the atmosphere. While promising methods to capture and convert CO2 into value-added products including fuels and chemicals have been commercialized, these pathways are thermodynamically uphill, energy-intensive, and require temperatures above 75 ºC. The company is developing a novel single-step, low temperature (25-75 °C) adaptive process for the integrated capture and conversion of CO2 into valuable calcium and magnesium carbonates for use in construction materials. The single-step, thermodynamically downhill approaches developed by the company do not consume acids and bases for carbon mineralization, and instead use solvents that transfer CO2 from the gas to the liquid phase, and from the liquid phase to solid carbonates. These carbonates can be used as sustainable construction materials, tuned for specific applications by controlling process parameters to deliver high-value synthetic inorganic carbonates. Through this DOE project, the company seeks to develop methods to modularize, scale, and adapt this process for site- and application-specific deployment. Specifically, the company proposes to: (1) Investigate the impact of particle size of alkaline residues from iron and steel, and cement manufacturing on the extent of carbon mineralization using gas streams having compositions representative of industrial emissions, (2) Determine the physio-chemical properties of concrete mixes with different loadings of mineralized fine aggregates, (3) Prepare and characterize field-specific test specimens using fine-tuned parameters, (4) Identify and define the framework for life cycle assessment (LCA) development, and (5) Determine economical implementation pathways based on Techno Economic Analysis (TEA) of the input, process, and output conditions. Successful accomplishment of these objectives will inform operating principles needed for commercial deployment, positioning the technology for Phase II scaleup and market launch. This technology can be adapted to create a new market for synthetic inorganic carbonates from anthropogenic CO2 as opposed to mining naturally occurring carbonates. The company believes that this adaptive environmentally sustainable technology can meet the unaddressed need to simultaneously treat multiple heterogeneous waste streams and produce value-added products.