Eco-efficiency of a novel construction material produced by carbon capture and utilization

Carbon capture and utilization, CCU, has a great potential for the improvement of the environmental profile of products and services. This is the case for construction materials, which are able to sequester an enormous amount of carbon dioxide in the form of usable products, providing a long-term capacity for storage of CO2. In a recent approach, a solid carbonate, MgCO3·3H2O (nesquehonite) was discovered to have cementitious behaviour, similar to gypsum plaster, in its phase transitions in dehydration-rehydration cycles, or during direct conversion to other carbonates. This solid can be obtained by reacting, in alkaline environments, CO2 from industrial gas streams and magnesium from desalination brines. This study aims the life cycle and eco-efficiency of such material using a standardised approach. The geographical scope is the State of Qatar, where desalination and power generation are located in the same facility for heat integration, and where the current market conditions of construction material imports provide an excellent framework for a competitive case study. The results show that the production of a plasterboard-like construction material based on the hardening of magnesium carbonate trihydrate is associated with less CO2 emissions than conventional gypsum-plasterboard production. For such achievement, the production system should introduce renewable energy as the source of electricity in the manufacture of the alkali used for the CO2 absorption in the carbon capture process. Also, process optimisation towards less demand of energy resources and the substitution of plaster and plasterboard products in real-life applications are essential to improve the eco-efficiency of the product.