Abstract: Waste phosphors contains a large amount of rare earth oxides,which has extremely high recycling value.In order to realize the preenrichment of rare earth elements in the waste phosphors,the dispersion and flocculation behaviors of different particulars in the phosphors have been studied.The results showed that interflocculation will occur because the particle size of waste phosphor is too fine.Adding dispersant under alkaline conditions can enhance the dispersion effect of different particles in the phosphors.Under alkaline conditions,cationic polyacrylamide with large molecular weight can be selectively adsorbed on the surface of quartz,increasing the particle size and accelerating its sedimentation rate,so as to realize the separation between different particles.For a certain waste phosphor containing 32.33% rare earth oxides,based on the study of dispersion and flocculation behavior,selective flocculation flotation is used to preenrich rare earth elements.When sodium carbonate,cationic polyacrylamide and dodecylamine are used as dispersants,flocculants and collectors respectively,the grade of rare earth oxide in the concentrate can increase to 43.65% in the flocculation flotation test under the conditions of pH=9,flocculant dosage and collector dosage of 100 and 800 g /t.The grade of rare earth elements were increased observably,which provides a technical basis for the comprehensive recovery and utilization of waste phosphors.

Key words: waste phosphors, preconcentration, dispersion, selective flocculatio, flotation