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Preparation method of calcium sulfate hemihydrate crystal whiskers high in length diameter ratio

A technology of calcium sulfate hemihydrate and calcium sulfate whiskers, applied in chemical instruments and methods, single crystal growth, crystal growth, etc., can solve problems such as uneven morphology, small long diameter, and coexistence of agglomerates, and achieve product The effect of regular shape, large aspect ratio and easy process control

Inactive Publication Date: 2012-09-19
KUNMING UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0005] In order to overcome the existing problems in the preparation of calcium sulfate whiskers such as small length-to-diameter ratio, uneven appearance and coexistence of agglomerates, the present invention provides a calcium sulfate hemihydrate crystal with regular appearance and high length-to-diameter ratio. A new method for whiskers; this method uses co-precipitation-activation-hydrothermal technology to realize the directional growth of calcium sulfate whiskers. The products produced by this method have regular morphology, uniform particle size, good dispersion, high purity, and high added value

Method used

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  • Preparation method of calcium sulfate hemihydrate crystal whiskers high in length diameter ratio
  • Preparation method of calcium sulfate hemihydrate crystal whiskers high in length diameter ratio

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Embodiment 1

[0020] Embodiment 1: the preparation method of this high aspect ratio calcium sulfate hemihydrate whisker ， Specific steps are as follows:

[0021] Prepared with 1.5 mol / L Ca(NO 3 ) 2 A solution of 30 mL and 1.5 mol / L (NH 4 ) 2 SO 4 60 mL of the solution of (NH 4 ) 2 SO 4 The solution was added (8 mL / min) Ca(NO 3 ) 2 solution, maintaining Ca(NO 3 ) 2 : (NH 4 ) 2 SO 4 The molar ratio was 1:2 to obtain a white precipitate, which was filtered and washed until the pH was neutral to obtain a primary precursor; the primary precursor was activated at 150°C for 1 hour to obtain a hydrothermal precursor; the hydrothermal precursor was formulated into 12 The suspension slurry with % solid content was placed in a hydrothermal reaction kettle, and 10 wt% ferric nitrate as a precursor was added. After sealing, the temperature was raised (10 ℃ / min) to 80 ℃, and the reaction was performed at a constant temperature under the condition of stirring (120 rpm / min). After cooling f...

Embodiment 2

[0022] Embodiment 2: the preparation method of this high aspect ratio calcium sulfate hemihydrate whisker ， Specific steps are as follows:

[0023] Formulated with saturated Ca(OH) 2 and 0.2 mol / L H 2 SO 4 60 ml of the solution of H 2 SO 4 The solution was added dropwise (1 mL / min) to saturated Ca(OH) 2 solution, maintaining Ca(OH) 2 : H 2 SO 4 The molar ratio is 1:0.5 to obtain a white precipitate, which is filtered and washed until the pH is neutral to obtain a primary precursor; the primary precursor is activated at 40°C for 6 hours to obtain a hydrothermal precursor; the hydrothermal precursor is made into 1 The suspension slurry with % solid content is placed in a hydrothermal reaction kettle, and 0.1wt% ferric chloride is added as a precursor. After sealing, the temperature is raised (10 ℃ / min) to 180 ℃, and the temperature is kept constant under stirring (120 rpm / min). After reacting for 2 h, cooling, filtering, and washing until the pH was neutral, the hydrot...

Embodiment 3

[0024] Embodiment 3: the preparation method of this high aspect ratio calcium sulfate hemihydrate whisker ， Specific steps are as follows:

[0025] Prepared with 0.8 mol / L CaCl 2 and 0.8 mol / L Na 2 SO 4 60 ml of the solution of Na 2 SO 4 The solution was added (10 mL / min) with CaCl 2 solution, maintaining CaCl 2 : Na 2 SO 4 The molar ratio is 1:1 to obtain a white precipitate, which is filtered and washed until the pH is neutral to obtain a primary precursor; the primary precursor is activated at 110°C for 3 hours to obtain a hydrothermal precursor; the hydrothermal precursor is made into 3 The suspended slurry with a solid content of % is placed in a hydrothermal reaction kettle, and 4.6 wt% ferric sulfate is added as a precursor. After sealing, the temperature is raised (10°C / min) to 130°C, and the temperature is reacted under the condition of stirring (120 rpm) After cooling for 4 h, filtering, and washing until the pH was neutral, the hydrothermal product was obta...

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Abstract

The invention discloses a preparation method of calcium sulfate hemihydrate crystal whiskers high in length diameter ratio. The method includes firstly subjecting soluble inorganic calcium salt and inorganic sulfate to coprecipitation at the temperature of 10-90 DEG C, activating for 1-6 hours at the temperature of 40-150 DEG C to obtain a precursor after filtering and washing, adding the precursor into a hydrothermal medium with crystal form control agent for hydrothermal treatment for 2-10 hours at the temperature of 80-180 DEG C, washing, filtering and drying hydrothermal products, and then obtaining calcium sulfate hemihydrate crystal whiskers in the diameter of 0.1-4 micrometers, the length of 20-3000 micrometers and the length diameter ratio of 50-1000, uniform in shape and identical in size. The preparation method is simple, mild in conditions and low in cost of materials which are easy to obtain, and is easy to industrially popularize. The main content of the calcium sulfate hemihydrate crystal whiskers prepared by the preparation method is larger than 98%, and the calcium sulfate hemihydrate crystal whiskers are uniform in shape and diameter and high in additional value and can be expectedly used as high-performance reinforcing materials for the industries of ceramics, plastics, rubber and paper making and the like.

Description

technical field [0001] The invention relates to a hydrothermal synthesis preparation method of calcium sulfate hemihydrate whiskers with high aspect ratio, and belongs to the technical field of inorganic chemical industry. Background technique [0002] Compared with other whiskers, calcium sulfate whiskers have the advantages of non-toxicity, environmental protection, and low price. Its price is the lowest among all whiskers (10~20 yuan / kg), and its application range is very wide. As a reinforcing agent for plastics, rubber, polyurethane and other materials, calcium sulfate whiskers can significantly improve the flexural modulus, tensile strength, dimensional stability and thermal distortion temperature of the products, and the reinforced products can be widely used in mechanical and electronic devices. Components, improve related performance. Calcium sulfate whiskers have a small loose density, a large specific surface area, and are non-toxic to the human body. They can be...

Claims

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Application Information

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IPC IPC(8): C30B29/62C30B29/46C30B7/10
Inventor 李沪萍罗康碧李春梅向兰夏家群苏毅赵榆林
Owner KUNMING UNIV OF SCI & TECH
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