Preparation method of pure-phase Li2Si2O5 rodlike crystal

A lithium disilicate, rod-shaped technology, applied in the field of preparation of pure-phase lithium disilicate rod-shaped crystals, can solve the problems of low chemical potential, unfavorable anisotropic growth of target products, non-compliance with stoichiometric ratio, and insufficient reaction kinetics, etc., to achieve Wide range of solid content and hydrothermal filling degree, convenient for industrial application, and good for dispersion effect

Inactive Publication Date: 2019-08-02
XI AN JIAOTONG UNIV
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  • Summary
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AI Technical Summary

Problems solved by technology

In scientific and technological research, there are many methods to prepare lithium disilicate powder, such as solid-state reaction method, calcination method and sol-gel method, etc., but the powder obtained by these methods often contains irregular blocks of Li 2 Si 2 o 5 And the impurity phase Li produced by the reaction 2 SiO 3 and SiO 2 , exhibiting the inherent defect of underpowered reaction
At the same time, due to the influence of the fast diffusion rate of lithium ions, the products formed in the early stage of the reaction are often uncontrolled, and it is easy to form irregular granular substances. Once these substances are formed and remain stable, they will not only affect the purity of the product in the later synthesis process, Moreover, the chemical potential in the later stage of the reaction is too small, which is not conducive to the anisotropic growth of the target product.
[0003] The existing hydrothermal method synthesizes lithium disilicate lath products, but the raw material Si / Li selected for the system must be greater than 1, which does not meet the standard stoichiometric ratio, which not only wastes raw materials, but also affects product purity

Method used

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  • Preparation method of pure-phase Li2Si2O5 rodlike crystal
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  • Preparation method of pure-phase Li2Si2O5 rodlike crystal

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preparation example Construction

[0030] A method for preparing a pure-phase lithium disilicate rod-shaped crystal of the present invention comprises the following steps:

[0031] S1, LiOH·H 2 Add O into distilled water, stir magnetically for 5 to 10 minutes, and rotate at a speed of 800 to 1500 r / min to fully dissolve to obtain a transparent solution;

[0032] S2. Weigh tetraethyl orthosilicate, and add it dropwise to the transparent solution prepared in step S1 within 10 to 15 minutes, so that the Li / Si molar ratio is 1, and continue magnetic stirring after the addition is completed to obtain a uniform mixed solution;

[0033] Among them, the magnetic stirring time is 30-45min, and the rotating speed is 800-1500r / min;

[0034] S3. Pour the mixed solution obtained in step S2 into a polytetrafluoroethylene liner, control the volume filling degree to 60% to 80%, react at 180°C for 24 to 48 hours, and the solid content of raw materials in the reaction solution is 200 to 500g / L , to obtain a white precipitate; ...

Embodiment 1

[0042] S1, LiOH·H 2 O was added to distilled water, magnetically stirred for 5min, and the rotating speed was 800r / min to fully dissolve it to obtain a transparent solution;

[0043] S2. Weigh tetraethyl orthosilicate and add it dropwise to the transparent solution prepared in step S1 within 10 minutes, so that the Li / Si molar ratio is 1. After the addition is completed, control the speed of 800r / min and continue magnetic stirring for 30 minutes to obtain a uniform solution. the mixture;

[0044] S3. Pour the mixed solution obtained in step S2 into a hydrothermal liner, control the volume filling degree to 60%, and react at 180° C. for 24 hours. The solid content of the raw material in the reaction solution is 200 g / L, and a white precipitate is obtained;

[0045] S4, wash with alcohol and distilled water 3 times respectively, remove impurity, obtain filter cake;

[0046] S5. Dry the filter cake obtained in step S4 at 60° C. for 12 hours to remove alcohol and water, and then...

Embodiment 2

[0050] S1, LiOH·H 2 O was added to distilled water, magnetically stirred for 6 minutes, and the rotating speed was 1200r / min to fully dissolve it, and a transparent solution was obtained;

[0051] S2. Weigh tetraethyl orthosilicate and add it dropwise to the transparent solution prepared in step S1 within 12 minutes, so that the Li / Si molar ratio is 1. After the addition is completed, control the speed of 900r / min and continue magnetic stirring for 35 minutes to obtain a uniform solution. the mixture;

[0052] S3. Pour the mixed solution obtained in step S2 into a hydrothermal liner, control the volume filling degree to 75%, and react at 180° C. for 40 hours. The solid content of the raw material in the reaction solution is 400 g / L, and a white precipitate is obtained;

[0053] S4, wash 4 times with alcohol and distilled water respectively, remove impurity, obtain filter cake;

[0054] S5, drying the filter cake obtained in step S4 at 90° C. for 20 h, removing alcohol and mo...

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Abstract

The invention discloses a preparation method of a pure-phase Li2Si2O5 rodlike crystal. After LiOH.H2O is dissolved in distilled water, tetraethyl orthosilicate is dropwise added, the mixture is uniformly mixed, a mixed solution is obtained, the mixed solution is placed in a hydrothermal reaction liner to react to obtain a white precipitate, the white precipitate is subjected to suction filtration,a filter cake is obtained, the filter cake is dried again, white powder is obtained and ground, and the pure-phase Li2Si2O5 rodlike crystal is obtained after heat treatment. The method is simple to operate, low in equipment requirement, wider in parameter range, easy to control and high in yield, the price of raw materials is low, the size of the obtained rodlike crystal is adjustable, the structural strength is high, and the method is suitable for mass commercial promotion.

Description

technical field [0001] The invention belongs to the technical field of inorganic micro-nano powder preparation, and in particular relates to a method for preparing pure-phase lithium disilicate rod-shaped crystals. Background technique [0002] In the ceramic matrix, the anisotropic growth morphology often makes the ceramic material exhibit better mechanical properties, such as lithium disilicate (Li 2 Si 2 o 5 ) adding lithium disilicate rod-shaped crystals to ceramics can significantly improve its strength, and lithium disilicate rod-shaped crystals act as a toughening agent in homogeneous materials. Therefore, the research on the anisotropic growth of lithium disilicate is a focus of current scientific research. In scientific and technological research, there are many methods to prepare lithium disilicate powder, such as solid state reaction method, calcination method and sol-gel method, etc., but the powder obtained by these methods often contains Li 2 Si 2 o 5 And...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C30B7/10C30B29/34C30B29/60
CPCC30B7/10C30B29/34C30B29/60
Inventor 郭生武
Owner XI AN JIAOTONG UNIV
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