The production of Portland cement, the industry-standard cement, contributes ∼8% of global CO₂ emissions through fossil-fuel heating and decomposition of limestone (the primary cement raw material). Decarbonization, e.g., via direct electrification, of this 200-year-old liming routine is extremely challenging at the industry scale. We propose a scalable electrochemical decarbonization approach to circumvent the limestone use by switching to carbon-free calcium silicates from abundant minerals and recycled concrete. Water electrolysis produces protons and hydroxides to drive a pH gradient that accelerates Ca²⁺ ion leaching from calcium silicates and captures atmospheric CO₂ to form carbon-negative CaCO₃, which serves as the feedstock for cement manufacturing or as the carbon-mineralized product for cement substitution with permanent carbon storage. Value-added co-products amorphous silica and green H₂ further enhance cement performance and supplant fossil fuels for net-zero transition, respectively. The products readily meet present-day regulatory standards and demands, and the approach readily synergizes with business-as-usual cement manufacturing and concrete construction, which are important for upscaling and structural safety, promising ready reception by the public and industries. Blended Portland cement produced through our approach with carbon-negative CaCO₃ and silica demonstrates enhanced resilience and achieves carbon neutrality or negativity when incorporating storage or circulation of CO₂ from cement plant flue gas, respectively. This low-cost, electrochemical cement production approach using abundant ubiquitous raw materials enables electrification, transition to clean fuel, and decarbonization at a gigaton scale.

中文翻译：

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可扩展的电气化胶凝材料生产和回收


波特兰水泥是行业标准水泥，其生产通过化石燃料加热和石灰石（主要水泥原料）的分解，约占全球二氧化碳排放量的 8%。这种有 200 年历史的石灰程序的脱碳，例如通过直接电气化，在工业规模上极具挑战性。我们提出了一种可扩展的电化学脱碳方法，通过从丰富的矿物和回收混凝土中改用无碳硅酸钙来规避石灰石的使用。水电解产生质子和氢氧化物以驱动 pH 梯度，从而加速 Ca²⁺ 离子从硅酸盐中浸出并捕获大气中的 CO₂ 以形成负碳 CaCO 3，该_{CaCO 3} 用作水泥制造的原料或作为碳矿化产品，用于替代永久碳储存的水泥。增值副产品无定形二氧化硅和绿色 H₂ 进一步提高了水泥性能，并分别取代了化石燃料以实现净零转型。这些产品很容易满足当今的监管标准和要求，并且该方法很容易与照常营业的水泥制造和混凝土施工协同作用，这对扩大规模和结构安全很重要，有望受到公众和行业的欢迎。通过我们使用负碳 CaCO₃ 和二氧化硅的方法生产的混合波特兰水泥在结合水泥厂烟气中 CO₂ 的储存或循环时表现出增强的弹性，并分别实现碳中和或负碳。 这种低成本的电化学水泥生产方法使用丰富无处不在的原材料，可实现十亿吨规模的电气化、向清洁燃料的过渡和脱碳。