Preparation method of ultra-fine wollastonite with high length-diameter ratio

A high aspect ratio, ultra-fine technology, applied in the direction of silicate, alkaline earth metal silicate, etc., can solve the problems of weakened reinforcement effect, damage of fiber structure, limited product fineness, etc., to improve compatibility, The effect of improving dispersibility and slowing down the tendency of agglomeration

Active Publication Date: 2020-11-17
JIANGXI GUANGYUAN CHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Among them, ultra-fine wollastonite products with high aspect ratio (12-15) can be obtained by jet mill for deep processing, but the product fineness is limited (D50>8μm); ultra-fine wollastonite can be obtained for deep processing by stirring mill products, but most of the fiber structure of wollastonite is destroyed, the aspect ratio (3-5) is small, and the reinforcing effect is weakened

Method used

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  • Preparation method of ultra-fine wollastonite with high length-diameter ratio

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preparation example Construction

[0031] The invention provides a method for preparing ultrafine wollastonite with a high aspect ratio, comprising the following steps:

[0032] (1) Mix the ultrafine wollastonite slurry and the surfactant to obtain the first mixed slurry; the average particle diameter of the ultrafine wollastonite in the ultrafine wollastonite slurry is 0.8 to 1.0 μm, and the long diameter The ratio is 3 to 5;

[0033] (2) mixing water glass, tetraethyl orthosilicate and water to obtain a silicon pre-hydrolyzed solution; hydrolyzing the silicon pre-hydrolyzed solution under acidic conditions to obtain a silicon hydrolyzed solution;

[0034] (3) adding the silicon hydrolyzate and the calcium hydroxide suspension side-by-side to the first mixed slurry for liquid phase deposition reaction to obtain a second mixed slurry;

[0035] (4) After the second mixed slurry is subjected to a hydrothermal reaction, the hydrothermal reaction product is mixed with a coupling agent to obtain the ultrafine wolla...

Embodiment 1

[0053] Select the wollastonite concentrate with a calcium silicate content ≥ 96wt%, and after preliminary dry grinding and iron removal, the ultrafine wollastonite slurry is obtained by wet grinding in a vertical stirring mill. The particle size is 0.9μm, and the aspect ratio is 4;

[0054]Dilute the ultrafine wollastonite slurry to 30wt%, add a surfactant accounting for 1.0wt% of the slurry, surfactant DTAC: F127=6:1 (molar ratio), stir and disperse at a stirring speed of 300rpm for 10min, wait use;

[0055] Prepare 25wt% (as SiO 2 Calculate) silicon pre-hydrolyzed solution, wherein the molar ratio of water glass (modulus 2.6) to ethyl orthosilicate is 1:2, at a temperature of 60°C and a pH value of 4.5 (by adding 1 mol / L acetic acid dropwise) Regulated) under the condition of hydrolysis 30min, obtains silicon hydrolyzate;

[0056] Adopt co-current method, by peristaltic pump, newly synthesized 60wt% calcium hydroxide suspension and silicon hydrolyzate are added dropwise r...

Embodiment 2

[0058] Select wollastonite concentrate with calcium silicate content ≥ 96wt%, and after preliminary dry grinding and iron removal, ultrafine wollastonite slurry is obtained by wet grinding in a vertical stirring mill, and the ultrafine wollastonite slurry is The average particle size is 0.9μm, and the aspect ratio is 4;

[0059] Dilute the ultrafine wollastonite slurry to 30wt%, add surfactants accounting for 1.5wt% of the slurry, surfactant DTAC: F127=6:1 (molar ratio), stir and disperse at a stirring speed of 300rpm for 10min, wait use;

[0060] Prepare 25wt% (as SiO 2 Calculated) silicon pre-hydrolyzate, wherein the molar ratio of water glass (modulus 2.6) to ethyl orthosilicate is 1:3, at a temperature of 60°C and a pH value of 4.5 (by adding 1 mol / L acetic acid dropwise) Regulated) under the condition of hydrolysis 30min, obtains silicon hydrolyzate;

[0061] Adopt co-current method, by peristaltic pump, newly synthesized 60wt% calcium hydroxide suspension and silicon ...

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Abstract

The invention provides a preparation method of ultra-fine wollastonite with a high length-diameter ratio, and relates to the technical field of wollastonite preparation. According to the invention, ultrafine acicular wollastonite is used as a matrix, a mixed silicon source (water glass and tetraethoxysilane) and a calcium source calcium hydroxide turbid liquid are used as reaction raw materials, asurfactant is used as a crystal form inducer, and new calcium silicate is constructed in the one-dimensional direction of the ultrafine acicular wollastonite through a hydrothermal method to increasethe length-diameter ratio of raw wollastonite so as to obtain the superfine wollastonite with high length-diameter ratio, wherein the length-diameter ratio of the superfine wollastonite ranges from 12 to 18, and in combination with treatment with a coupling agent, the superfine wollastonite powder with the high length-diameter ratio can be effectively prevented from being agglomerated, the dispersity of the superfine wollastonite powder with the high length-diameter ratio in downstream application is improved, and the compatibility of the superfine wollastonite powder with matrix resin is improved, so that the comprehensive performance of a product is improved.

Description

technical field [0001] The invention relates to the technical field of wollastonite preparation, in particular to a method for preparing ultrafine wollastonite with a high aspect ratio. Background technique [0002] Wollastonite is a kind of metasilicate mineral that causes metamorphism. It has a unique needle-like structure, good insulation, excellent heat resistance and chemical stability. It is widely used in modified plastics, papermaking, coatings, rubber and ceramics. [0003] At present, there are two main types of wollastonite deep-processing products. One is wollastonite products with high aspect ratio. It mainly uses its unique one-dimensional structure to replace other short fiber mineral raw materials (glass fiber, etc.) as a polymer Reinforced and toughened functional materials, especially in the field of plastics and rubber, can improve the bending strength and impact strength of products, and improve the thermal stability and dimensional stability of products...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B33/24
CPCC01B33/24C01P2004/61C01P2004/62
Inventor 张晓明袁斌李海滨邹检生宋波吴维冰邓鑫
Owner JIANGXI GUANGYUAN CHEM
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