Recycling of lithium ion batteries with microwave technology

The growing consumption at global level of lithium ion batteries (LIBs) in portable electronics, electric vehicles and renewable energy storage is determining a rapid increase in the amount of e-waste generated from end-of-life spent LIBs. Due to the materials that make up LIBs, landfilling and incineration pose environmental and safety concerns. The scarcity of metal resources needed to manufacture LIBs and the possibility of valorising them through their recovery has increased the interest in recycling wasted LIBs. The state of the art of recycling spent LIBs mainly consists of pyrometallurgical and hydrometallurgical processes, but both generate considerable environmental problems. The aim of the thesis is to study an innovative recycling method of spent LIBs, based on the use of microwave technology. Microwave has been applied on different samples, varying the exposure time and the percentage amount of reductant, graphite. Microwave in fact, beyond the usual application in the kitchens, in the last years has received a lot of attention as an effective technology in various fields. This is due to the excellent performances in chemical reactions, that can be attributed to its unique heating mechanism. Some environmental applications where it can be exploited are: remediation of contaminated soil, purification of air, organic wastewater treatment and sewage sludge pre-treatment. The process reported in this thesis is mainly focused on the recovery of the two elements with higher demand share in Li-ion battery sector, lithium and cobalt. After microwave application, XRD and SEM-EDS analysis have been performed to characterize the tested samples and observe the effects of the occurred reactions. XRD analysis allows to determine the crystalline structure of the samples, while with SEM-EDS analysis the surface topography and chemical composition can be obtained. Finally, water leaching and wet magnetic separation are carried out in order to extract and recover Li and Co in an expendable form.