Effect of alkaline fusion pre-treat on extraction rate of rare from waste rare earth fluorescent powder

The method of combining high-temperature alkaline fusion and acid leaching was used to pre-treat waste rare earth fluorescent powder according to its characters to investigate the effect of alkaline fusion temperature, sodium hydroxide dosage and alkaline fusion time on rare earth extraction rate and aluminum deprivation rate, and to analyze the phase structure and surface morphology during the process of alkaline fusion. The results show that alkaline fusion can be achieved at temperature of 1 050 & for 2 h when the mass of the ratio of sodium hydroxide to waste rare earth fluorescent is 25:1 with the leaching rate of the total rare earth more than 98 %, and aluminum deprivation rate being 98 %. The phase and morphology analysis of the alkaline fusion indicates that the structure of waste crystal structure is destroyed effectively, rare earth is in form of rare earth oxide, and alkaline fusion product becomes amorphous cotton-like.