Sustainable production of lithium salts extraction from ores in China: Cleaner production assessment

Abstract

As the largest lithium consumer globally, China's lithium supply is primarily stored in ores, which have a greater environmental burden than brines. However, China has yet to promulgate cleaner production standards for lithium extraction from ores. This study proposes a comprehensive evaluation system for the lithium ore extraction industry, based on the National Cleaner Production requirements and other industry standards. The 36 indicators included in the evaluation system were categorized into 6 criteria layers, and the importance of each indicator and criterion layer were verified by 21 experts from 11 institutions and enterprises. We collected data regarding these indicators system from 16 ore-based lithium extraction plants and calculated the weight of each indicator with regard to the overall cleaner production level of the plants. Subsequently, we compared and analyzed the cleaner production level of the plants according to the interview and survey data. The results indicate that Shehong Tianqi Lithium (ST) and Chengdu Rongjie Lithium (CR) are the two cleanest plants, with values of 0.800 and 0.789 respectively, placing them at the international leading level (ILL). Overall, China's ore-based lithium extraction industry score's 0.678 in our evaluation system, which is the domestic advanced level (DAL). Sensitivity analysis revealed that of the 6 criteria layers, process technology and equipment (C1) (37.9%), resources and energy consumption (C2) (20.3%), and intensity of pollutants produced (C4) (20.9%) had the greatest impact on the level of cleaner production. The variations in the cleaner production level of different plants is primarily due to the following evaluation indicators: evaporation device (I16), cooling system (I14), fuel type (I12) in the C1 criteria layer, comprehensive energy consumption intensity (I26), water consumption intensity (I25) in the C2 criteria layer, SO2 produced (I46), wastewater produced (I44), sulfuric acid mist produced (I48), and dust produced (I45) in the C4 criteria layer. Finally, based on these variations, this study suggests improving production equipment and technology, using clean fuels, and unifying emission standards as potential policies that can help achieve cleaner production levels in China's ore-based lithium extraction industry.