Research on recovering rare earth from polishing waste

This thesis mainly discusses how to recover rare earth from polishing waste and ensure the recovery rate of rare earth above 80 %. It puts forward a method to recover rare earth based on analyzing the existing polishing waste composition. The experiment includes two parts, the influences on the recovery rate of rare earth were respectively considered including the raw material pretreatment, acid type, acid concentration, leaching temperature, leaching time and supplement. The optimal leaching experimental conditions are as follows: add supplement B, use 8 mol/L Hydrochloric acid direct leach, the leaching temperature is 92 ℃ and the leaching time is two hours. After impurity removal, extraction, precipitation and calcination, the recovery rate of rare earth is as high as 85.94 %. Then according to the determined conditions for the comprehensive enlarge tests, the results show that the recovery rate can be stabilized above 81 %. According to preliminary estimate, the profit of dealing with a ton of the showed polishing waste is about 2000 RMB.