Preparation method for cerium base polishing powder used for optical glass and liquid crystal display glass

Abstract

The invention discloses a preparation method for cerium base polishing powder used for optical glass and liquid crystal display glass. During precursor preparation, a raw material can be purified through physical and chemical methods, i.e., firstly, the raw material lanthanum cerium salt is dissolved and filtered to remove impurity particles, including dust and the like, in the raw material; then,a pH value during the precursor preparation is controlled to be 5.5-7.5, so that rare earth lanthanum cerium precipitates, other metal elements, including calcium, magnesium, zinc, ferrum, plumbum and the like, do not precipitate, washing and filtering are carried out to remove precipitates, and finally, the prepared polishing powder can be used for the refined polishing of the optical glass andthe liquid crystal display glass. By use of the preparation method, when the polishing powder precursor is prepared, composite precipitant consisting of phosphate, villiaumite and carbonate is added,the morphology of the particle of the prepared polishing powder precursor is an even aggregate, a particle size is moderate, particle size distribution is narrow, and a quantity of large particles issmall. The polishing powder has a high cutting rate and long service life, the grinded glass is almost free from scratches, and a surface degree of 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 ...

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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

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