A process using a thermal reduction for producing the battery grade lithium hydroxide from wasted black powder generated by cathode active materials manufacturing

Recent lithium consumption is doubled in a decade due to the Li-ion battery (LIB) demand for electric vehicles, the energy storage system, etc. The LIBs market capacity is expected to be in strong demand due to the political drive by many nations. Wasted black powders (WBP) are generated from the manufacturing of the cathode active material and spent LIBs. The recycling market capacity is also expected to expand rapidly. This study is to propose a thermal reduction technique for recovering Li selectively. The WBP, containing 7.4 % Li, 62.1 % Ni, 4.5 % Co, and 0.3 % Al, was reduced in a vertical tube furnace using a 10 % H2 gas as a reducing agent at 750 ºC for 1 h, and 94.3 % of Li was recovered from a water leaching, while other metal values, including Ni and Co remained in the residue. A leach solution was treated in a series of crystallisations, filtering, and washing. An intermediate product was produced and re-dissolved in hot water at 80 ºC for 0.5 h to minimise Li2CO3 content into a solution. A final solution was crystallised repeatedly to produce the final product. A 99.5 % of LiOH·H2O was characterised and passed the impurity specification by the manufacturer as a marketable product. The proposed process is relatively simple to utilise to scale up for bulk production, and it can also be contributed to the battery recycling industry as the spent LIBs are expected to overabundance within the near future. A brief cost evaluation confirms the process feasibility, particularly, for the company that produces cathode active material (CAM) and generates WBP in their own supply chain.