Superfine and spheroidizing rare-earth polish and preparing process thereof

Abstract

The invention provides ultrafine spheroidized rare earth polishing powder and a process for making the same. The process comprises the following steps that: one of or the mixture of ammonia water, ammonium bicarbonate and ammonium carbonate is used as precipitant; ammonium salt and fluoride ions are added into precipitated slurry to adjust the ionic strength in mother liquid, so as to increase the surface electrical property of solid particles in the slurry; after high temperature aging, the ultrafine rare earth polishing powder with good dispersity and high spheroidization degree can be obtained by filtering the slurry, drying, burning, ball-milling and sieving filter cakes. The average particle size of the obtained polishing powder is between 0.02 mu m and 2.0 mu m, wherein the specific surface area BET is more than 0 and less than 10 m<2> / g, and the powder is in a well-dispersed spherical shape. The powder is used for polishing optical glass, crystal, display screens, etc., strong in cutting force, few in scratch and long in service time.

Description

technical field [0001] The invention relates to an ultrafine, spheroidized rare earth polishing powder and a preparation process thereof, and belongs to the technical field of chemical preparation of rare earth powder materials. Background technique [0002] Rare earth polishing powder is mainly used for polishing glass, crystal and other products. Rare earth polishing powder is mainly cerium-based oxide powder. According to the content of cerium oxide, it can be divided into high cerium polishing powder, medium cerium polishing powder and low cerium polishing powder. At present, there are many low-grade polishing powders produced in China, and there is still some gap in the production of higher-grade rare earth polishing powders compared with foreign countries, and it is still necessary to rely on imported polishing powders for the polishing of devices with high requirements. Many countries produce high-performance polishing powder, but it still cannot meet the growing dome...

AI Technical Summary

Problems solved by technology

U.S. Patent 5543216 discloses a preparation method for synthesizing cerium oxide particles. The method adjusts the pH value of the reactant to 8-9, and raises the temperature to 100-200°C under pressure. The particle size obtained is between 0.03-5um. This method is more complicated, the equipment is expensive, the particle size distribution is wide, and the polishing effect is not good

[0005] Chinese patent CN1821314 discloses a preparation method of ultrafine cerium oxide, which uses a salt solution containing cerium ions, and after adding a surfactant, the solution is first contacted with an alkaline substance to control the pH value of the reaction suspension to form a precipitate Then the suspension is converted with oxalic acid to control the pH value at the end of the reaction. Finally, the precipitate is filtered, washed, dried, and burned at 600-1000°C. The obtained ultra-fine cerium oxide can be used for polishing, but this method The preparation steps are also relatively complicated, and the particle size distribution of the prepared product is also relatively wide between 10nm and 30um, and the specific surface area reaches 50m 2 / g, it has poor reusability as a polishing powder

[0006] The preparation steps in the method disclosed in Chinese patent 200510132522.8 are also relatively complicated, and the particle size distribution of the prepared product is also relatively wide, between 10nm and 30um, and the specific surface area reaches 50m 2 / g, when it is used as polishing powder, the reusability is poor

[0007] At present, the average particle size of polishing powder is between 0.02-2.0um, 02 / g, 0<dispersion degree σ<1.5, good spheroidization, high cutting force, and good reusability The preparation method of polishing powder has not been reported

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