This technology utilizes water-soluble polymers (e.g., PEI) to selectively form complexes with valuable metals, followed by sequential diafiltration and nanofiltration to separate and concentrate these metals from impurity ions.
Wastewater generated from processes such as secondary battery cathode manufacturing contains high concentrations of impurity metal ions like sodium and lithium, which limits the separation efficiency of valuable metals like nickel and cobalt when using conventional solvent extraction, adsorption, or nanofiltration techniques. Furthermore, high ion concentrations lead to increased osmotic pressure, making stable operation of membrane processes difficult.
This technology consists of a five-stage process: macromolecularizing valuable metals into polymer-ion complexes, filtering out impurity ions via ultrafiltration, dissociating the complexes by adding acid, recovering the valuable metals through diafiltration, and finally concentrating them to high levels using nanofiltration. It can be applied to cathode manufacturing wastewater treatment, wet recycling of spent batteries, and metal resource recovery from plating and smelting waste, enabling the high-purity recovery of discarded nickel and cobalt while reducing raw material procurement costs.
US2024-0170752A1
