چكيده انگليسي :
The growing application and use of lithium-ion batteries in household, industrial, transportation, and medicine have made their production and disposal significant challenges in today's world. The need for raw materials for production, the increasing speed of production and consumption, the environmental risks posed by used lithium-ion batteries and the high grade of precious and industrial metals in the composition of batteries containing lithium, cobalt, nickel, manganese and aluminum oxide are all reasons for recycling. Therefore, it was started with the aim of recovering valuable and industrial metals from the cathode composition of used lithium-ion batteries, eliminating or reducing environmental risks, providing raw materials and creating a closed loop from production to consumption, and reducing the use of primary resources. Among the methods of pyrometallurgy, hydrometallurgy and biohydrometallurgy, hydrometallurgy method was recognized as the optimal and most appropriate method due to its high efficiency and production speed, greater compatibility with the environment and lower production of pollutants. In the step of sample preparation, and with the help of electrical discharge processes, the battery was opened, and the cathode was separated from the other constituent parts through, mechanical crushing and sieving, resulting in a suitable powder prepared for the leaching process. In the mentioned process, acidic and alkaline solutions were used, among the two types of acids, inorganic and organic, organic acids are preferred due to their properties such as high acidity, low pollution and the possibility of recovery and reuse. Dissolved metals in the solution were precipitated through the sedimentation process and by adding another metal salt compound, while other metals in the solution were separated. In the first stage of leaching, with the aim of removing aluminum from the powdered composition, an oxalic acid solution that dissolves more than 99% of aluminum and 96% of lithium, while also precipitating more than 99% of the combination of cobalt, nickel, manganese, and iron metals should be identified as the most optimal option. In the leaching of the second step, aimed at recovering cobalt, the sediment obtained from the first step's leaching with oxalic acid was dissolved in a solution containing sulfuric acid as a base and citric acid as a reducing agent, which was able to dissolve more than 99% of nickel and manganese. A deposit containing 95% cobalt compounds and 3% lithium is introduced as the most optimal option for the second stage of leaching. At this stage, the addition of sodium carbonate resulted in the deposition of lithium carbonate with an efficiency of 85%, leaving a solution that contains aluminum compounds. In the third step of deposition, the solution obtained from the leaching process in the second step, which contained nickel and manganese compounds, was used. By adding ammonium chloride, manganese dioxide was precipitated as a powder with an efficiency of 88%, while the solution contained nickel compounds.
Keywords: Recycling, Lithium-ion Battery, Cathode, Hydrometallurgy, Leaching, Precipitation.
