Preparation method of cerium-based polishing powder for optical glass and liquid crystal display glass

Abstract

The invention discloses a preparation method of a cerium-based polishing powder precursor for optical glass and liquid crystal display glass. In the preparation of the precursor, the invention purifies the raw material through physical and chemical methods, that is, firstly, the raw material lanthanum cerium salt is passed through Dissolve and filter to remove dust and other impurity particles in the raw materials; then by controlling the pH value of the precursor preparation between 5.5-7.5, the rare earth lanthanum and cerium are precipitated, while other metal elements such as calcium, magnesium, zinc, iron, Lead and the like do not form precipitates, which can be removed by washing and filtering, and the finally prepared polishing powder can be used for fine polishing of optical glass and liquid crystal display glass. The present invention also adds a composite precipitant composed of phosphate, fluoride, and carbonate during the preparation of the polishing powder precursor, and the particle morphology of the prepared polishing powder precursor is a uniform aggregate with moderate particle size and narrow particle size distribution. , the number of large particles is small. The polishing powder has a high cutting rate and a long service life. After grinding, there is basically no scratch on the glass and the surface finish is good.

Description

Technical field: [0001] The invention relates to a preparation method of polishing powder, in particular to a preparation method of cerium-based polishing powder for optical glass and liquid crystal display glass. Background technique: [0002] Rare earth cerium-based polishing powder is currently the mainstream glass polishing powder, and rare earth polishing powder can be roughly divided into four categories in terms of technological process. [0003] The first category, wet fluorination. Rare earth carbonate containing cerium (generally lanthanum cerium carbonate, low neodymium carbonate or cerium carbonate) is mixed with hydrogen fluoride for fluorination, then suction filtered or dried, and finally airflow classification to prepare polishing powder with different particle sizes. [0004] The second type, dry fluorination method. The cerium-containing rare earth carbonate (generally lanthanum cerium carbonate, low neodymium carbonate or cerium carbonate) is soft-fired ...

AI Technical Summary

Problems solved by technology

[0007] At present, the disadvantage of the first three processes is that the ionic impurities and particle impurities brought in by the rare earth carbonate during the feeding process cannot be effectively removed, and the glass is easy to be scratched after polishing. Therefore, most of these polishing powders are used for rough polishing of glass or low-end applications.

In addition, the quality is greatly fluctuated by the quality of lanthanum carbonate, the particle size distribution is wide, and the quality stability is poor.

The rare earth polishing powder prepared by the fourth type of process is pure oxide polishing powder, with low cutting rate and narrow application range

The precursor particle size distribution is wide, the hardness range is large, and the degree of spheroidization is not high, and the particles are angular, which is not conducive to the particle shape and large particle control in the subsequent process; although there are grinding and classification processes in the subsequent process, it can only It is impossible to absolutely remove large particles from the microscopic view by reducing its particle size macroscopically. Large particles will always remain with a certain probability, and their hardness range and particle shape cannot be changed, resulting in many scratches on the product and surface The finish and surface roughness are not good, which affects its scope of use

Images