Abstract:
High-alumina coal is widely distributed in coalfields of the central and western Inner Mongolia, and is rich in valuable elements such as aluminum, silicon, lithium, and gallium. Comprehensive and efficient utilization of high-alumina coal is expected to greatly improve the resilience of China's aluminum supply system and improve the utilization rate of solid waste, alleviating the environmental pollution problems such as fly ash storage in coal-fired power plants with considerable economic benefits. This study takes the high-alumina fly ash demonstration production line in the Datang Group Tuodian Park as an example, and analyzes the distribution of various inorganic resources in high-alumina coal. On the basis of comprehensively combing the matching mechanism of "raw material-production process-technology-product/by-product", an integrated industrial chain of high-aluminum coal recycling system is established, which consists of "clean combustion process of high-alumina coal—multi-stage pre-desilication process—low-energy-consumption extraction process of alumina". By adopting material metabolism analysis, the migration and transformation law of valuable elements in the industrial chain is studied, and the distribution model of associated valuable elements is established to identify key links in material metabolism optimization of the industrial chain. In addition, the economic, environmental and social benefits of the industrial chain, compared with the traditional bauxite and aluminum smelting industry, is calculated. The results provide support for the promotion of high value-added, cascade recycling patterns of high-alumina coal in Inner Mongolia. The results show that (1) the overall recycling rate of valuable elements in the entire industrial chain of high-alumina coal recycling system exceeds 80%; (2) the promotion and application of this industrial chain in Inner Mongolia Autonomous Region can produce 1303 10
4t alumina and co-produce 964 10
4t active calcium silicate and 3192 10
4t calcium silicate slag, creating an annual income of 38.95 billion yuan. A quarter of the annual consumption of bauxite resources and 766 10
4t limestone resources can be saved, and 1150 Hectares of vegetation can be protected while increasing 426 10
4t of carbon sequestration. The economic, social and environmental benefits of the industrial chain are huge.