The sustainable and competitive recovery of materials from spent batteries is becoming an urgent issue due to the increasing popularity of hybrid and fully electric vehicles. In this present study, flowsheet simulation was combined with life cycle assessment to investigate the environmental impacts of a conceptual, experimentally proven hydrometallurgical battery recycling process, where nickel metal hydride (NiMH) battery waste is used as reductant for lithium-ion battery (LIB) waste, synergistically improving the extraction of valuable metals from both waste types. Various options for sodium circulation in the precipitation of rare earths were considered in different scenarios. The results showed that the main benefit of the process was the reduced consumption of leaching chemicals. Of the investigated sodium management scenarios, crystallization of sodium sulfate was found to be the most environmentally feasible option, allowing the use of Na as a precipitation chemical for rare earth recovery. Significant potential reductions in climate change, acidification, freshwater eutrophication, and human toxicity were also achievable when compared to the life cycle impacts of the primary production of battery metals, mainly due to the high environmental footprint of primary nickel and cobalt sulfate production. Although further improvements to the process were found to be possible, the future availability of waste NiMH batteries may limit the application of the described process concept on an industrial scale.

由于混合动力和全电动汽车的日益普及，从废电池中可持续地，有竞争力地回收材料已成为迫在眉睫的问题。在本研究中，将流程模拟与生命周期评估相结合，以研究概念性，经实验验证的湿法冶金电池回收过程的环境影响，其中镍氢电池（NiMH）被用作锂离子电池（LIB）的还原剂废物，协同改善两种废物中有价值金属的提取。在不同的情况下，考虑了稀土沉淀中钠循环的各种选择。结果表明，该工艺的主要好处是减少了浸出化学品的消耗。在调查的钠管理方案中，发现硫酸钠结晶是最环保的选择，允许使用Na作为沉淀化学品进行稀土回收。与电池金属一次生产的生命周期影响相比，还可以实现气候变化，酸化，淡水富营养化和人类毒性的显着减少，这主要是由于一次镍和硫酸钴生产的环境足迹较高。尽管发现可以对该方法进行进一步的改进，但是废NiMH电池的未来可用性可能会限制所描述的方法概念在工业规模上的应用。与电池金属一次生产的生命周期影响相比，还可以实现气候变化，酸化，淡水富营养化和人类毒性的显着减少，这主要是由于一次镍和硫酸钴生产的环境足迹较高。尽管发现可以对该方法进行进一步的改进，但是废NiMH电池的未来可用性可能会限制所描述的方法概念在工业规模上的应用。与电池金属一次生产的生命周期影响相比，还可以实现气候变化，酸化，淡水富营养化和人类毒性的显着减少，这主要是由于一次镍和硫酸钴生产的环境足迹较高。尽管发现可以对该方法进行进一步的改进，但是废NiMH电池的未来可用性可能会限制所描述的方法概念在工业规模上的应用。