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Global climate change related to anthropogenic CO2 emissions is one of the most significant challenges for the future of human life on Earth. There are many potential options for reducing or even eliminating atmospheric CO2 emissions including underground sequestration, carbon mineralization and ocean storage. One of the most promising materials for carbon mineralization is Mg(OH)2 which is highly reactive and capable of forming stable carbonates. Here we show a novel low-carbon method of producing Mg(OH)2, from globally abundant olivine-rich silicate rocks. A combination of acid digestion and electrolysis of olivine were used to produce Mg(OH)2 in a fully recoverable system. The use of Mg(OH)2 from olivine provides a viable pathway for significant industrial scale reductions in global anthropogenic greenhouse gas emissions.

The reduction of the clinker factor in cement has emerged as the most promising solution to reduce carbon dioxide (CO2) emissions and to improve sustainability. Limestone calcined clay cement (LC3) is a ternary cement where the synergy between calcined clay and limestone allows the reduction of clinker factors to 0·5. In order to understand practical issues in the production of LC3, such as the selection of raw material and production conditions, industrial production of LC3 has been carried out at three locations in India. A wide range of raw materials was collected from various parts of India and characterised to evaluate their suitability for the production of LC3. Both static and rotary calciners were used for the production of calcined clay. Open- and closed-circuit ball mills were used. Limestones with various impurities and compositions were utilised. It has been observed that lower-grade clay and limestone can be used and that the quality control during the production process can be carried out using widely available techniques. Field trials have shown that the cement can be used without any changes to the existing construction methodologies. This paper discusses the key lessons and insights gained from these trial productions.