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Preparation method of silicon dioxide

A technology of silicon dioxide and precipitated silicon dioxide, applied in the direction of silicon dioxide, silicon oxide, etc., can solve the problems of increasing the complexity of the process, hidden dangers of safety, increasing the manufacturing cost, and the effect is not ideal.

Active Publication Date: 2011-09-28
FUJIAN YUANXIANG CHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0008] However, this method needs to use organic reagents such as ethanol and n-butanol in the production process, which increases the complexity of the process and potential safety hazards, and also increases the manufacturing cost.
And its method is still based on the traditional method of adding sodium silicate solution and acid to sodium silicate dilute solution at the same time, and the silica prepared by it is used for the preparation of high-temperature vulcanized silicone rubber, and its effect is not ideal enough

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0044] Step 1. Add 383ml of water, 15ml of sodium silicate (M=3.60, concentration 25%) solution and 10g of sodium hexametaphosphate into a 1000ml glass flask equipped with stirring, heat the material temperature to 90°C on a water bath, and the pH of the solution=10.5 ±0.1;

[0045] Step 2.174ml of sodium silicate solution (M=3.60, concentration 25%) was added to the above material in 25 minutes, and concentrated sulfuric acid (98%) was added at the same time to keep the pH of the reaction material=10.5±0.1;

[0046] Step 2.2111ml of sodium silicate solution was added to the above material in 25 minutes, and concentrated sulfuric acid (98%) was added simultaneously to keep the pH of the reaction material=10.5±0.1;

[0047] Step 2.3185ml of sodium silicate solution was added to the above-mentioned material in 40 minutes, and concentrated sulfuric acid (98%) was added simultaneously to keep the pH of the reaction material=10.5±0.1;

[0048] Step 3. stop adding sodium silicate s...

Embodiment 2

[0057] Repeat Example 1, only change the "Cetyltrimethylammonium Chloride" in Step 4 of Example 1 into fatty alcohol polyoxyethylene ether.

[0058] The suspension was vacuum filtered using a Buchner funnel and washed with 3000 ml of water. The filter cake was dried in an oven at 105°C until the moisture content was lower than or equal to 5.0%, and a white powdery precipitated silica was obtained which was crushed by hand.

[0059] Filtration time is 20 minutes and washing time is 75 minutes.

[0060] The conductivity of the product precipitated silica aqueous suspension is 180 μs / cm.

[0061] The particle size of the product precipitated silica (ultrasonic treatment for 2 minutes, measured by a laser particle size analyzer) is 14 μm.

[0062] White precipitated silica is mixed with silicone rubber raw rubber, and after secondary vulcanization, it is visually inspected for yellowing, and there is no yellowing. The film has no white spots, that is, the dispersibility is good...

Embodiment 3

[0064] Repeat Example 1, only adjust pH=10.5±0.1 in each step of Example 1 to pH=9.0±0.1.

[0065] The suspension was vacuum filtered using a Buchner funnel and washed with 3000 ml of water. The filter cake was dried in an oven at 105°C until the moisture content was lower than or equal to 5.0%, and a white powdery precipitated silica product was obtained which was crushed by hand.

[0066] Filtration time is 15 minutes and washing time is 65 minutes.

[0067] The conductivity of the product precipitated silica aqueous suspension is 160 μs / cm.

[0068] The particle size of the product precipitated silica (ultrasonic treatment for 2 minutes, measured by a laser particle size analyzer) is 13 μm.

[0069] White precipitated silica is mixed with silicone rubber raw rubber, and after secondary vulcanization, it is visually inspected for yellowing, and there is no yellowing. The film has no white spots, that is, the dispersibility is good.

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PUM

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Abstract

The invention discloses a preparation method of silicon dioxide, which sequentially comprises the following steps of: 1, preparing a sodium silicate solution A; 2, sectionally adding a sodium silicate solution B with sodium silicate mass concentration of 22-26 percent in a reaction kettle containing the sodium silicate solution A at a variable speed, controlling and regulating the addition speed of concentrated sulfuric acid at each section so as to keep pH of a reaction medium constant; 3, stopping adding the sodium silicate solution B, continuously adding the concentrated sulfuric acid, regulating the pH of the material obtained from the steps 2 to be 3.0-4.0, and preparing a sediment silicon dioxide suspension; 4, adding an organic surfactant in the suspension obtained in the step 3, ageing; and 5, filtering, washing, drying, post-treating and crushing to prepare the silicon dioxide product. According to the invention, the defect of poor dispersity of silicon dioxide in high-temperature vulcanized silicon rubber is overcome, yellowing performance of the silicon dioxide is improved, filtering and washing efficiencies are increased, washing time is shortened and washing water is saved.

Description

technical field [0001] The invention relates to a method for preparing silicon dioxide, in particular to a method for preparing silicon dioxide by a precipitation method. Background technique [0002] Silicone rubber is a specialty rubber that achieves an excellent compromise of mechanical and chemical properties (eg electrical properties, chemical resistance, high temperature stability, physiological inertness) required for many fields of industrial application. [0003] The mechanical strength of pure silicone rubber is very low, and the tensile strength of the vulcanized rubber is only about 0.35MPa. When the reinforcing filler is mixed, the tensile strength of the vulcanized rubber can be increased from 0.35MPa to 14MPa, and the reinforcement rate is as high as 40 times. Higher than other rubber can achieve the reinforcement rate (1.4 to 10 times). It can be seen that the use of fillers has decisive significance for the final performance of silicone rubber. [0004] At...

Claims

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Application Information

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IPC IPC(8): C01B33/12
Inventor 朱延辰
Owner FUJIAN YUANXIANG CHEM
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