Production method of polishing powder for liquid crystal display device

Abstract

The invention relates to a method for producing polishing powder used for a liquid crystal display device. The method comprises the following steps: at the room temperature, 30 to 40 percent of fluorosilicic acid is added into rare earth chloride solution with REO of between 80 and 100 gram / litre and CeO2 / REO of more than or equal to 70 percent under the stirring; after five minutes, an additive A is added into the mixture, is heated to the temperature of between 70 and 80 DEG C, is kept at the temperature and is added with mixed precipitant solution till the reaction ends; the PH value of the mixture is 7; the mixture is stirred for 10 minutes, is kept stand for 3 to 5 hours and supernatant fluid of the mixture is removed through siphonage; under the stirring, cold water is added to nearly fill a groove fully; before the stirring is stopped, flocculant solution is added till appearing the flocculating effect; the mixture is kept stand, is deposited and the supernatant fluid of the mixture is removed through siphonage for three times; the mixture is washed, is heated up to 98 DEG C, is kept at the temperature for 10 minutes and is discharged to a stainless steel sieve with 120 meshes; the mixture is subjected to solid-liquid separation, vacuum extraction and filtering and dewatering by a centrifuge; a filter cake is transferred to a quartz material sagger; the charging thickness is less than or equal to 9 centimeters; the filter cake is transported to a muffle tunnel kiln at the temperature of 900 DEG C, is subjected to dehydration in a preheating section and decomposition and transformation at certain degree, is roasted for 3 to 4 hours at high temperature of 900 DEG C, is cooled to the temperature of less than 400 DEG C in a cooling section and comes out from the kiln; a roasted material is cooled to the room temperature and is subjected to stage treatment; and a quality part is the product.

Description

Technical field: [0001] The invention relates to a production method of polishing powder, in particular to a production method of liquid crystal display polishing powder. Background technique: [0002] Compared with other rare earth polishing powders, LCD polishing powder has the most notable features: the powder particle size is small and the distribution is narrow, and the general requirement is that the central particle size D 50 =0.8~1.2um, maximum particle size D 100 ≤5um, such particle size and its distribution determine its high-precision polishing quality. Therefore, this kind of polishing powder is not only used for LCD polishing, but also suitable for other high-demand optical equipment polishing. [0003] For the production of this kind of rare earth polishing powder with small particle size and narrow distribution, at present, the popular method at home and abroad is: use rare earth carbonate as raw material, fluoride it to a certain extent after mixing and gri...

AI Technical Summary

Problems solved by technology

This popular production method, due to the existence of ultra-fine grinding links, inevitably has several shortcomings: 1. The original crystal shape of the product is destroyed, lacking rich edges and corners, which affects the polishing ability; 2. Due to a certain degree of Over-grinding and under-grinding, the particle size distribution of the product is wide, not only because of over-grinding produces more fine particles that affect the polishing efficiency, but also because of under-grinding produces a small amount of larger particles that cannot be removed by classification, which affects the polishing quality; 3. During the ultra-fine grinding process , the particles are subjected to forces such as collision, extrusion, friction, shearing, etc., which may cause cracks and reduce the service life of the product; As far as the fluidized bed jet mill is concerned, the 400-type fluidized bed jet mill with an installed capacity of about 100KW can only obtain about 30 kg of LCD polishing powder per hour