A review in calcium carbide slag utilization for carbonation: from methods to applications

Global CO 2 emissions, exceeding 40 billion tonnes annually, drive critical ecological challenges, necessitating effective mitigation strategies like carbon capture, utilization, and storage (CCUS). CO 2 mineralization, a promising CCUS pathway, utilizes alkali-rich industrial wastes such as carbide slag (CS) to form stable carbonate minerals, ensuring permanent CO 2 sequestration with minimal leakage risks. CS, primarily composed of Ca(OH) 2 , offers high alkalinity and calcium content, making it an ideal precursor for CO 2 mineralization. Various carbonation methods, including direct, indirect and advanced techniques, could produce construction materials, high-value nano-calcium carbonates and energy storage solutions. Operational parameters such as temperature, concentration, humidity, and additives significantly influence carbonation efficiency and product properties. Direct carbonation yields CaCO 3 suitable for large-scale industrial uses, while indirect and advanced methods enhance product purity and functionality for specialized applications. This integration sequesters CO 2 while producing valuable by-products, thereby enhancing economic viability. This article provides a comprehensive analysis of CS carbonation mechanisms, methods, and applications, emphasizing the interplay between process parameters and product outcomes to optimize sustainable CO 2 management and material innovation.