Separation of Cobalt, Samarium, Iron, and Copper in the Leaching Solution of Scrap Magnets

Abstract

With the growing awareness of protecting the urban environment and the increasing demand for strategic materials, recycling of SmCo magnets has become imperative. This paper provides a series of methods regarding the available hydrometallurgical technologies for recycling scrap magnets. This study aimed to recover samarium (Sm), cobalt (Co), copper (Cu), and iron (Fe) from acid leachate of SmCo scrap by using precipitation and ion exchange. IRC748 showed a good adsorption capacity for Fe and Cu. Elution tests were conducted using sulfuric acid at the concentration of 2N as eluents. Precipitation was performed first using a selective chemical precipitation method, and the Sm was first precipitated as a sodium samarium sulfate powder. Then, the samarium-deprived solution was placed in the beaker, and the addition of oxalic acid promoted cobalt oxalate precipitation. Furthermore, the leachate, which is rich in Cu and Fe, was mixed with oxalic acid to obtain the copper oxalate precipitation. This study successfully recovered SmCo magnets through ion exchange and precipitants.