Resourceful Treatment of Battery Recycling Wastewater Containing H2SO4 and NiSO4 by Diffusion Dialysis and Electrodialysis

Facing the increasing demand for batteries worldwide, recycling waste lithium batteries has become one of the important ways to address the problem. However, this process generates a large amount of wastewater which contains high concentration of heavy metals and acids. Deploying lithium battery recycling would cause severe environmental hazards, would pose risks to human health, and would also be a waste of resources. In this paper, a combined process of diffusion dialysis (DD) and electrodialysis (ED) is proposed to separate, recover, and utilize Ni2+ and H2SO4 in the wastewater. In the DD process, the acid recovery rate and Ni2+ rejection rate could reach 75.96% and 97.31%, respectively, with a flow rate of 300 L/h and a W/A flow rate ratio of 1:1. In the ED process, the recovered acid from DD is concentrated from 43.1 g/L to 150.2 g/L H2SO4 by the two-stage ED, which could be used in the front-end procedure of battery recycling process. In conclusion, a promising method for the treatment of battery wastewater which achieved the recycling and utilization of Ni2+ and H2SO4 was proposed and proved to have industrial application prospects.