The growth of the lithium-ion battery industry requires a secure supply of raw materials and appropriate end-of-life management of batteries. In almost five years, global cobalt consumption has increased by nearly 30%, driven mainly by rechargeable batteries. Consequently, several risks have been identified for cobalt, in particular the growing demand for electric vehicles, which could exceed current production. Therefore, research into the recovery of this critical metal, from industrial or urban waste, is particularly important in the years to come. In this study, cobalt is recovered from a lithium-ion battery leachate in hydroxide form. The thermodynamic simulations performed with Visual Minteq showed that it was possible to recover 99.8% of cobalt (II) hydroxide at 25 °C. Based on these results, experiments were conducted to validate the hypotheses put forward and to compare the results obtained with the simulations performed. Experimentally, several operating parameters were studied to determine the optimal conditions for cobalt recovery, in terms of yield, filterability, and selectivity. Results obtained in a batch reactor allowed the determination of the temperature conditions to be applied in continuous reactor. The cobalt (II) hydroxide precipitation in continuous reactor was carried out under different pH conditions. It was then possible to determine the optimal conditions for cobalt recovery in terms of yield and filterability. Results showed that working at pH 9 would effectively meet the desired criteria. Indeed, cobalt recovery is close to 100% and filtration flow rate is three times higher. Results obtained allow a better understanding of cobalt (II) hydroxide precipitation.

Among pollutants, petroleum hydrocarbons are recognized as the priority pollutants of the environment. Petroleum hydrocarbons can cause changes in the physical and chemical properties of soils, leading to a decrease in the functional activity of the microbiota of soil biocenoses. The aim of the study was to develop ways and methods of oil-contaminated soil remediation with the new generation sorbents based on organomineral biofertilizer “Kazuglegumus” and aluminum alloys activated by indium, gallium, and tin. The structure and composition of the organomineral reagents, as well as soils with different degrees of contamination were proved by Fourier transform infrared spectroscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy, differential scanning calorimetry, and thermogravimetry. As a working hypothesis, it was accepted that the aluminum alloy activated by gallium, indium, and tin forms complex compounds with humic or fulvic acids, which are low-toxic or non-toxic for plants. The efficiency of cleaning oil-contaminated soils with organomineral sorbents was evaluated. The reduction of oil concentration in soil samples by 12–22% depending on the concentration of reagents and oil content in soil was revealed. The character of oil pollution impact on plants of legume families alfalfa, melilot, and sainfoin, which are characterized by the ability to accumulate and then give nitrogen to the soil, was studied. The phytotoxicity of uncontaminated and non-oil-contaminated soils was studied in laboratory and field conditions. Significantly accelerated plant growth was observed in samples of oil-contaminated soil after treatment with sorbent based on activated aluminum alloy Rau-85 and fertilizer “Kazuglegumus”. The plants had stronger root systems. These experiments are explained by the effect of Rau-85 alloys in favor of reducing the oil concentration to the normalized limits, as well as the transformation of natural humic substances and additionally applied fertilizer “Kazuglegumus” (potassium humates), which increased their biological activity.