A sustainable closed-loop strategy for maximizing resource utilization: A case study of salt lake carnallite

Resource scarcity and environmental degradation pose formidable challenges for the sustainable development of human society. Although enhancing resource utilization efficiency represents a viable solution to these challenges, many strategic resources still suffer from substantial waste and environmental pollution owing to their single utilization form and non-environmentally friendly technologies. In this study, by employing salt lake carnallite as a representative example, we proposed an eco-friendly closed-loop strategy that integrated various chemical processes to maximize resource utilization. This innovation enables successive recycling and utilization of the waste brine generated at each chemical stage, resulting in minimized resource wastage and maximized eco-environmental benefits. Compared with the conventional carnallite utilization method, our strategy enhanced the KCl yield from 55.48% to 89.25%, achieved nearly 100% utilization efficiency of Mg, and improved the Rb recovery efficiency from 0% to 81.28%. Consequently, the overall utilization efficiency of carnallite increased from 20.91% to 87.37%. Additionally, this approach offers the added benefit of significantly improving the overall utilization of mineral resources and substantially reducing the cost of large-scale sample preparation. This work helps to construct a more sustainable and cost-effective utilization system for various mineral and brine resources.