CN111196899A

CN111196899A - Superfine grinding preparation process for nano silicon oxide

Info

Publication number: CN111196899A
Application number: CN201811385064.2A
Authority: CN
Inventors: 王俊甫; 李强; 周雄
Original assignee: King's Ceramic Grinding Technology Co ltd
Current assignee: King's Ceramic Grinding Technology Co ltd
Priority date: 2018-11-20
Filing date: 2018-11-20
Publication date: 2020-05-26

Abstract

The invention discloses a novel process for preparing nanometer silicon oxide superfine powder by using common commercially available silicon micropowder as a raw material and adopting a multistage cascade grinding process. Firstly, carrying out wet ball milling on zirconium silicate-aluminum oxide grinding balls with the particle size of F3.5mm to grind the silicon micropowder until the particle size is less than 2 microns; then zirconium silicate-alumina grinding ball microbeads are adopted to carry out multistage sand grinding cascade superfine grinding in three stages until the grain diameter is less than 100 nanometers: finally, the nanometer-level silicon oxide superfine powder is obtained through spray drying.

Description

Superfine grinding preparation process for nano silicon oxide

Technical Field

The invention relates to a superfine grinding preparation process of a fine ceramic raw material nano silicon oxide.

Background

The silicon oxide has wide application, and plays an important role in the fields of textile industry, refractory materials, grinding materials and the like due to good mechanical strength and wear resistance. When the size of the silicon oxide powder reaches the nanometer level, the silicon oxide powder shows excellent properties of reinforcement, thickening, thixotropy, insulation, extinction, sagging prevention and the like in the material due to the nanometer size effect, so the silicon oxide powder is widely applied to the high polymer industrial fields of rubber, plastics, coatings, adhesives, sealants and the like.

The nano silicon oxide raw material is prepared by using silane or silicon chloride as a raw material and adopting a wet chemistry or soft chemistry method, and has the defects of high cost and small scale. In order to promote the large-scale application of nano-silicon oxide, a new technology for producing nano-silicon oxide superfine powder on a large scale at low cost must be found.

Grinding is a commonly used means of pulverization to reduce the particle size of the powder. The traditional wet ball milling method has low rotating speed and long consumption time, the superfine particle size is limited, the superfine particle size can only reach several microns generally, and submicron powder cannot be obtained. The powder of 1-2 microns can be obtained by performing primary superfine by using a sand mill, but the method has the disadvantages of long time consumption, high energy consumption, high slurry viscosity and low solid content, and can not directly obtain submicron alumina superfine powder.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provides a novel process for preparing nano-silicon oxide superfine powder by using a common commercially available silicon micropowder raw material through a multistage cascade grinding process.

In order to realize the purpose of the invention, the following technical scheme is provided: a nanometer silicon oxide superfine grinding preparation process is characterized by comprising the following steps.

a. Stirring, grinding and coarse grinding: taking zirconium silicate-alumina grinding balls with the diameter of 3.5mm as grinding balls, and grinding the silicon micropowder to silicon oxide with the particle size (D98) of less than 2 microns.

b. The cascade sanding is superfine: the first stage was sand milled with zirconium silicate-alumina grinding balls 1mm in diameter, milling the silica to a particle size (D98) of less than 1 micron; second stage sanding with zirconium silicate-alumina grinding balls of 0.5mm diameter to grind silica to a particle size (D98) of less than 0.3 micron; the third stage was sanded with zirconium silicate-alumina grinding balls 0.2mm in diameter to grind the silica to a particle size (D98) of less than 100 nm. Wherein, ammonia water is added to the second stage and the third stage to adjust the pH value to 9-10, and 0.2 weight percent of ammonium polyacrylate and 0.2 weight percent of polyethylene glycol are added to serve as composite dispersants.

c. In-stage series cycle: each stage comprises 2 or more sand mills filled with zirconium silicate-aluminum oxide grinding balls with the same size, slurry discharged from each sand mill enters a slurry pool, then is pumped into another sand mill filled with zirconium silicate-aluminum oxide with the same size, is circularly ground among the 2 or more sand mills, and is pumped into the slurry pool of the next stage for grinding after the detected particle size (D98) reaches the standard.

d. The slurry discharged from the sand mill must be cooled by water and then enters a slurry pool with water cooling and stirring.

e. And after grinding, spray drying to obtain the superfine nano silicon oxide powder.

The beneficial effects of the invention are as follows.

1. Through the matching of grinding balls with different diameters in the cascade superfine sanding, the particle size of the powder is reduced step by step with the maximum efficiency until the particle size is less than 100 nanometers.

2. In the same level, through the circulation of concatenating of many sand mills, promote the homogeneity of thick liquids in grinding to through the temperature of water-cooling reduction thick liquids at the circulation in-process, avoid the high temperature to the harm of equipment and the rise of thick liquids viscosity, promote the efficiency of grinding.

3. The pH value of the slurry is adjusted in the second stage, and ammonium polyacrylate and polyethylene glycol are added as dispersing agents, so that the viscosity of the superfine silicon oxide powder slurry can be reduced, higher solid content is ensured, the grinding efficiency is improved, and the cost is reduced. Meanwhile, the added ammonium polyacrylate can not add impurity metal ions to the superfine silicon oxide powder.

The method is implemented.

Example 1 was carried out.

Firstly, commercially available silicon micro powder, F3.5mm zirconium silicate-alumina grinding balls and water (weight percentage is 1: 2: 1) are put into a 500L sand mill, the rotation speed is 300rpm, and grinding is carried out for 10-15 hours, so that the particle size of silicon oxide (D98) is less than 2 microns. Then transferring the mixture to a first-stage sanding slurry pool in which two 200L sanding machines are connected in series, adding ammonia water to adjust the pH value to 9-10, adding 0.2 wt% of ammonium polyacrylate and 0.2 wt% of polyethylene glycol serving as dispersing agents, and uniformly stirring. Then pumping the slurry into a grinding ball sand mill provided with F1mm zirconium silicate-alumina grinding balls, rotating at the speed of 300rpm, carrying out sand grinding, cooling by water at the speed of 5L/min, then feeding into a slurry tank of a second sand mill, and after filling, starting to pump into the second sand mill to start grinding. The slurry was ground in two sand mills in a cyclic manner for 2-3 hours to a silica particle size (D98) of less than 1 micron. Then pumped into a second-stage sanding slurry pool formed by connecting two 200L sanding machines in series. The slurry was pumped into a second stage of a ball mill fitted with F0.5mm zirconium silicate-alumina grinding balls and ground in a similar cycle to the first stage in two mills at 300 rpm. After 3-4 hours of circular milling, the particle size of the silica (D98) was less than 0.5 microns. Then pumped into a third-stage sanding slurry tank formed by connecting two 200L sanding machines in series. The slurry was pumped into the third stage of a ball mill fitted with F0.2mm zirconium silicate-alumina grinding balls and ground cyclically in two similar mills at 300 rpm. After 3-4 hours of circular grinding, the particle size of the alumina (D98) is less than 100 nm. Then pumping into a spray drying tower for drying to obtain the nanometer silicon oxide superfine powder.

Example 2 was carried out.

Commercially available fine silica powder, F3.5mm zirconium silicate-alumina grinding balls and water (weight percentage: 0.8: 2: 0.8) were charged into a 500 liter sand mill at 300rpm for 10 to 15 hours to make the silica particle size (D98) less than 2 μm. Then transferring the mixture to a first-stage sanding slurry pool in which two 200L sanding machines are connected in series, adding ammonia water to adjust the pH value to 9-10, adding 0.2 wt% of ammonium polyacrylate and 0.2 wt% of polyethylene glycol serving as dispersing agents, and uniformly stirring. Then pumping the slurry into a grinding ball sand mill provided with F1mm zirconium silicate-alumina grinding balls, rotating at the speed of 300rpm, carrying out sand grinding, cooling by water at the speed of 5L/min, then feeding into a slurry tank of a second sand mill, and after filling, starting to pump into the second sand mill to start grinding. The slurry was ground in two sand mills in a cyclic manner for 2-3 hours to a silica particle size (D98) of less than 1 micron. Then pumped into a second-stage sanding slurry pool formed by connecting two 200L sanding machines in series. The slurry was pumped into a second stage of a ball mill fitted with F0.5mm zirconium silicate-alumina grinding balls and ground in a similar cycle to the first stage in two mills at 300 rpm. After 3-4 hours of circular milling, the particle size of the silica (D98) was less than 0.5 microns. Then pumped into a third-stage sanding slurry tank formed by connecting two 200L sanding machines in series. The slurry was pumped into the third stage of a ball mill fitted with F0.2mm zirconium silicate-alumina grinding balls and ground cyclically in two similar mills at 300 rpm. After 3-4 hours of circular grinding, the particle size of the alumina (D98) is less than 100 nm. Then pumping into a spray drying tower for drying to obtain the nanometer silicon oxide superfine powder.

Claims

1. Stirring, grinding and coarse grinding: and (3) grinding the silicon micropowder to silicon oxide with the particle size (D98) of less than 2 microns by taking zirconium silicate-aluminum oxide grinding balls with the diameter of F3.5mm as grinding balls.

2. The cascade sanding is superfine: the first stage was sanded with F1mm zirconium silicate-alumina grinding balls, grinding silica to a particle size (D98) of less than 1 micron; a second stage of sanding with F0.5mm zirconium silicate-alumina grinding balls to grind the silica to a particle size (D98) of less than 0.3 microns; a third stage of sanding with F0.2mm zirconium silicate-alumina grinding balls to grind the silica to a particle size (D98) of less than 100 nanometers; wherein, ammonia water is added to the second stage and the third stage to adjust the pH value to 9-10, and 0.2 weight percent of ammonium polyacrylate and 0.2 weight percent of polyethylene glycol are added to serve as composite dispersants.

3. In-stage series cycle: each stage comprises 2 or more sand mills filled with zirconium silicate-aluminum oxide grinding balls with the same size, slurry discharged from each sand mill enters a slurry pool, then is pumped into another sand mill filled with zirconium silicate-aluminum oxide with the same size, is circularly ground among the 2 or more sand mills, and is pumped into the slurry pool of the next stage for grinding after the detected particle size (D98) reaches the standard.

4. The slurry discharged from the sand mill must be cooled by water and then enters a slurry pool with water cooling and stirring.

5. And after grinding, spray drying to obtain the superfine nano silicon oxide powder.