This project focus on the study and analysis of the permanent magnet components from waste electrical appliances (air-conditioner compressors), and the developments solvent extraction and purification technology for light rare earths and heavy rare earths contained in rare earth permanent magnets. The dismantling, demagnetization and smashing pre-treatment of the rare earth permanent magnets contained in waste electrical appliances have been completed, and the oxidation roasting to form insoluble iron oxide. After immersing in hydrochloric acid and acid-dissolving, the heavy rare earths and light rare earths are separated by solvent extraction. The heavy rare earth stripping solution and the light rare earth raffinate were precipitated and calcined with oxalic acid, respectively, and successfully recovered as heavy rare earth oxides and light rare earth oxides. The permanent magnet is heated at 400°C for 30 minutes and then demagnetized to 100 mesh. The composition test results show that the selected air- conditioning compressor motor rotor is a neodymium ironboron rare earth permanent magnet. It is recovered by iron oxidation and hydrochloric acid impregnation technology. After the iron oxide is roasted at 800℃, it is dissolved in acid with a hydrochloric acid solid-liquid ratio of 1:4 ~ 1:20 at 90℃. The pH is adjusted to 3.5 by sodium hydroxide solution. Keep the temperature at 50°C and heat for 30 minutes to make the ferric hydroxide in the residual acid solution gel and precipitate and filter to remove the miscellaneous metals. The pH value of the filtrate is adjusted to 4, and the heavy rare earth is 3 times the molar dose of P507, which is a 1:1 oil-water phase volume ratio solvent extraction and separation of heavy rare earths and light rare earths. The heavy rare earth stripping solution and the light rare earth raffinate are respectively added with anhydrous oxalic acid in a solid-to-liquid ratio of 1:100, and the temperature of the precipitation liquid is controlled at 40°C, and the precipitate is calcined at 850°C to obtain the products of heavy rare earth oxides and light rare earth oxides. Things. The total rare earth recovery rate is 91.5%, the purity of heavy rare earths is 96.9%, and the purity of light rare earths is 94.8%.

waste electrical equipment, rare earth recovery, light rare earth, heavy rare earth