Water and Resource Recovery from Lithium-Ion Battery Recycling with Membrane Distillation Crystallization

Description

Lithium-ion batteries (LIBs) represent a significant secondary resource for critical materials like cobalt, nickel, manganese, and lithium. However, established LIB recycling processes, particularly those employing liquid-liquid extraction for metal separation, generate valuable resources and wastewater streams containing diluted sulfuric acid and metal sulfates. This study shows the application of Membrane Distillation Crystallization (MDC) as a novel approach for efficient water reclamation and resource recovery from LIB recycling. MDC presents a sustainable and energy-saving solution for concentrating saline solutions, enabling the simultaneous recovery of high-purity water and valuable metal sulfates in solid form. MDC operates in a moderate temperature range of 45 - 65°C. This energy-saving feature contributes to the overall sustainability of the process. This innovative approach significantly contributes to the establishment of a circular economy for LIBs and promotes responsible water management within the LIB recycling industry.

A series of MDC experiments were performed at 50 ± 2°C to investigate the effects of seed crystallization, as well as water and salt recovery of cobalt sulphate (CoSO₄), and lithium sulphate (LiSO4) solutions from an artificial lithium-ion battery leachate. Silicon dioxide (SiO₂) was added as a seed crystal to facilitate the growth of crystals on the existing particles and to enable their subsequent separation in a classifier section. Different solutions were prepared, the first solutions contained 30 g L- 1 and 90 g L-1 of CoSO4, respectively. The second solution contained 100 g L-1 of Li2SO4 and the last one 1 g L-1 of H2SO4. The MDC experiments were first conducted in a lab setup and then in a mini-plant using a tubular polypropylene (PP) membrane.

Firstly, varying concentrations of CoSO₄ solutions were examined. The MDC permeate flux remained relatively constant between 2.5 - 2.0 kg m-2 h-1, with a water recovery of about 30 %. Subsequent experiments investigated the treatment of a Li₂SO₄ solution. Similar to the CoSO₄ experiments, the permeate flux showed relative stability between 2.9 - 2.5 kg m-2 h-1. In this case, a water recovery of 40% and a salt recovery of 10% were achieved, demonstrating the capability to recover both water and valuable Li₂SO₄. The rejection rate, a key indicator of the efficiency in removing CoSO₄ and Li2SO4 from the feed solution, remained consistently high at 99.9% throughout the operation times. The rejection rate demonstrates the effectiveness of the MDC process in producing a high-quality permeate devoid of CoSO₄ and Li2SO4 contamination, respectively. Finally, the separation of H2SO4 from water was investigated. Here, the permeate flux was between 4 - 3.7 kg m-2 h-1 during the operation time and a water recovery of 30% was achieved.

Period	16 Mar 2025 → 19 Mar 2025
Event title	IWA Water Reuse Conference 2025
Event type	Conference
Location	Kapstadt, South AfricaShow on map
Degree of Recognition	International