Method for preparing high-concentration silica sol by using superfine silica powder

A technology of silicon dioxide and ultrafine silicon powder, applied in the direction of silicon dioxide and silicon oxide, can solve the problems of unsuitable uniformity, no recycling method, waste, etc., achieve easy operation, avoid hindering sol generation, and be practical strong effect

Active Publication Date: 2010-10-13
SOUTHWEAT UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

There are many types of by-products in the production of organosilicon monomers. After resource reuse such as catalytic cracking and transformation reactions, there are still some unreacted silicon powders. Although the recovered silicon powders (i.e. ultrafi

Method used

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  • Method for preparing high-concentration silica sol by using superfine silica powder

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Embodiment 1

[0030] A method for preparing high-concentration silica sol from ultrafine silica powder, comprising the following steps:

[0031] Add 20g of elemental silicon powder with a particle size of about 1340 mesh and 150ml of deionized water into a three-necked flask, heat to 60°C, and preheat for 20 minutes to activate the silicon powder. Take 8g of water glass and 20ml of 10% ammonia solution, add water to dilute to 50ml, and stir evenly. Place the three-necked flask in a constant temperature water bath at 90°C, quickly add half the volume of the prepared mixed solution, stir the three-necked flask with an electric stirrer, and monitor the pH value change in the three-necked flask with an acidity meter. The pH value in the bottle is 9.7, and the pH value is measured every 10 minutes. The pH value drops rapidly at the beginning, and tends to be stable when the pH value drops to 8.6. At this time, the remaining 1 / 2 volume of the mixed solution is added dropwise. The dropwise additi...

Embodiment 2

[0033]Add 25g of elemental silicon powder with a particle size of about 2000 mesh and 150ml of deionized water into a three-neck flask, heat to 50°C, and preheat for 20 minutes to activate the silicon powder. Weigh 0.32g of sodium hydroxide, add 100ml of deionized water to prepare a sodium hydroxide solution, and stir evenly. Place the three-necked flask in a constant temperature water bath at 90°C, quickly add half the volume of the prepared sodium hydroxide solution, stir the three-necked flask with an electric stirrer, and monitor the pH change in the three-necked flask with a pH meter. At this time, the pH value in the bottle is 10.5, and the pH value is measured every 10 minutes. The pH value drops rapidly at first, and tends to be stable when the pH value drops to 9.1. 10.0, considering that part of the water evaporates as the reaction proceeds, the pH value will increase. In order to avoid the pH value exceeding 10.0, an appropriate amount of deionized water is added at...

Embodiment 3

[0035] Add 20g of elemental silicon powder with a particle size of about 2000 mesh and 150ml of deionized water into a three-neck flask, heat to 50°C, and preheat for 10 minutes to activate the silicon powder. Weigh 0.24g of sodium hydroxide, add 50ml of deionized water to prepare a sodium hydroxide solution, and stir evenly. Place the three-necked flask in a constant temperature water bath at 90°C, quickly add 25ml of the prepared sodium hydroxide solution, stir the three-necked flask with an electric stirrer, and monitor the pH value change in the three-necked flask with a pH meter. The pH value is 9.3, and the pH value is measured once every 10 minutes. At the beginning, the pH value drops rapidly, and tends to be stable when the pH value drops to 8.8. At this time, the remaining 25ml sodium hydroxide solution is added dropwise. Completed within 0.5 hours. Continue to adjust and control the pH between 8.5-10.0. The whole reaction time is 8 hours, and the whole process is ...

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Abstract

The invention relates to a method for preparing high-concentration silica sol by using superfine silica powder, which is characterized by comprising the following steps of: weighing 20-25 parts by mass of silica powder with the purity of 97-99 percent and the granularity of 500-2000 meshes, and adding 100-200 parts by mass of deionized water to heat at 50-60 DEG C for 10-30 minutes; then adding an aqueous sodium hydroxide solution with the mass percent concentration of 0.16-0.96 percent to the mixed liquid of the silica powder and water under stirring at 70-90 DEG C, and controlling a pH value of the reaction liquid at 8.5-10.0 and the time of whole stirring reaction for 6-8 hours; and then carrying out decompression and suction filtration after standing for 8-12 hours so as to prepare the high-concentration silica sol. The high-concentration silica sol with good property is prepared by using the superfine silica powder scrapped in organic silicon monomer production as raw materials, and the invention has simple process and high practicability.

Description

technical field [0001] The invention belongs to waste utilization and a method for preparing silicon compounds, and relates to a method for preparing high-concentration silica sol from superfine silicon powder. It is suitable for preparing high-concentration silica sol by using superfine silicon powder, especially waste silicon powder with a purity of 97%-99% and a particle size of 500-2000 mesh. Background technique [0002] Silica sol (silica sol), also known as colloidal silica (Colloidal Silica), is a white or slightly blue opalescent colloidal solution. Its main component is hydrated silica in colloidal form. The molecular formula can be expressed It is m SiO2 nH2O. The general concentration of silica sol is 25% (based on the weight percentage of silicon dioxide, the same below), and the silica sol with a concentration of more than 30% is called high-concentration silica sol. Silica sol has many excellent properties, such as large specific surface, high adsorption, hi...

Claims

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Application Information

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IPC IPC(8): C01B33/14
Inventor 严云许可萤胡志华
Owner SOUTHWEAT UNIV OF SCI & TECH
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