【Ten Years of Great Progress in Chemical Technology】China led the world in technologies for the high-value utilization of calcium carbide slag from 2015 to 2023

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Ten years of rapid development in chemical technology – praise for China’s prosperity and strength. By contributing our ideas, we can foster more active participation from everyone. HaiChuan becomes even better with your involvement; we welcome everyone to take part more actively in the forum discussions. Everyone should focus on safety and know how to handle emergencies. ********************************************* Recently, the project \"Deep purification of calcium carbide slag for the production of low-carbon calcium-based materials and their applications\", led by the Institute of Process Engineering of the Chinese Academy of Sciences, passed the evaluation of scientific and technological achievements organized by the China Circular Economy Association. The evaluation committee, chaired by Professor He Kebin from Tsinghua University and an academician of the Chinese Academy of Engineering, believes that the overall technology of this project is at the international leading level, and efforts should be accelerated to promote its industrialization. 　　This project was carried out through collaboration between the Institute of Process Engineering of the Chinese Academy of Sciences, Zhejiang University, Anhui Huasu Co., Ltd., Qinghai Salt Lake Yuanpin Chemical Co., Ltd., Inner Mongolia Yili Chemical Industry Co., Ltd., and other organizations. In 2011, the Research Department of Green Process Engineering for Resources and Environment at the Institute of Process Engineering, Chinese Academy of Sciences, initiated research on technological innovations for the large-scale and high-quality utilization of calcium carbide slag. Building on years of research experience in the high-quality utilization of calcium-based solid wastes, it developed key technologies such as high-volume vortex separation for rapid acetylene removal, multi-field-enhanced depolymerization for thorough impurity removal, enhanced desulfurization and control of gypsum crystallization, and low-temperature calcination to produce metallurgical-grade active calcium oxide. 　　The expert group assessed that this technology achieves an acetylene removal rate of over 90% during the eddy current separation process; the calcium hydroxide content in the components of high-calcium calcium carbide slag is above 94%. Fine-grained calcium carbide slag is suitable for desulfurization of high-sulfur coal in power plants, with a desulfurization rate of over 99%, and the metallurgical-grade active calcium oxide products meet the relevant standard requirements. This project has developed a comprehensive set of low-carbon technologies for the advanced purification of calcium carbide slag to produce calcium-based materials. Five demonstration projects have been established, and over the past three years, approximately 3.6 million tons of calcium carbide slag have been utilized in high-quality applications. Significant reductions in carbon dioxide emissions have been achieved during the utilization of each ton of calcium carbide slag, enabling a shift from its use as a low-end building material to its high-value utilization as a medium-to-high-end calcium-based mineral material through low-carbon production processes. 　　The implementation of this technology can comprehensively address issues such as low reaction efficiency in the current utilization processes of calcium carbide slag, as well as safety risks related to combustion and explosion. It helps to overcome the key challenges associated with the high-value, low-carbon utilization of calcium carbide slag, and facilitates the development of new low-carbon pathways for the deep purification and cross-industrial, high-quality recycling of this waste material. This provides technical support for the sustainable, green, and low-carbon utilization of large quantities of coal-based solid wastes, thereby contributing to the achievement of the **\"dual carbon\" strategic goals. 　　Relevant research has been funded by projects such as the \"863\" Program, the **Key R&D Program, self-funded projects of the Chinese Academy of Sciences’ Institute for Innovation in Green Process Manufacturing, and the **National Natural Science Foundation. The research results were included in the \"Catalog of Advanced and Applicable Process Technologies and Equipment for Comprehensive Utilization of Industrial Resources (2021 Edition)\” as well as in the exhibition on scientific and technological achievements during the 13th Five-Year Plan period; 13 invention patents were granted by the **Intellectual Property Office**. The research team edited and published 2 group standards, and contributed to 1 industry standard.