Removal of nickel from chemical plating waste solution through precipitation and production of microsized nickel hydroxide particles

Chemical plating of nickel is widely used in wafer packaging. However, frequent renewal of plating baths generates a large amount of waste solution. When hazardous Ni2+ ions are removed from waste solutions through chemical precipitation, the complexing agent in the solution hinders nickel removal and reduces the nickel hydroxide [Ni(OH)(2)] precipitate size to approximately 0.5 mu m. This study revealed that the precipitation rate of Ni(OH)(2) can be controlled by the pH, temperature, and agitation. Furthermore, a Ni removal efficiency of more than 98% can be achieved. X-ray diffraction analysis revealed that the recovered particles included amorphous Ni(OH)(2) and alpha-Ni(OH)(2), indicating a high potential for energy conversion in nickel-based secondary batteries. Therefore, the proposed method can be used to sustain a circular economy by creating a Ni waste-toenergy cycle.