Method for preparing calcium sulfate crystal whiskers

A technology of calcium sulfate whiskers and dilute sulfuric acid, applied in chemical instruments and methods, single crystal growth, crystal growth, etc., can solve problems such as high processing costs, environmental pollution, and technical problems that have not been realized in large-scale applications, and achieve the preparation process Simple, large product length-to-diameter ratio, and beneficial to environmental protection

Inactive Publication Date: 2011-11-02
刘立文
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

White mud contains residual alkali, which is a secondary pollutant, and its discharge will cause environmental pollution
Although Chinese scholars have done a lot of work on the comprehensive utilization of limestone, su

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0018] This embodiment includes the following steps:

[0019] (1) Mix lime mud and water at a weight ratio of 1:3, stir for 8 minutes at a stirring speed of 120 rpm, let stand for 10 hours, filter, and take the filter residue;

[0020] (2) Mix the filter residue obtained in step (1) with distilled water 10 times the weight of the filter residue, place in a stirring container, stir, the stirrer rotates at 45 rpm, and continuously spray dilute sulfuric acid solution. The mass concentration of dilute sulfuric acid is 10%; when the pH of the solution reaches 7, stop stirring and spraying, filter, and take the filtrate;

[0021] (3) Put the filtrate obtained in step (2) in a high-pressure reactor, and add calcium sulfate seeds, the dosage is 1% of the weight of lime mud, the reaction temperature is 80°C, the reaction pressure is 2 Mpa, and the reaction time is 2 hours ;

[0022] (4) After the crystallization is complete, filter off the solution, and dry at room temperature for 2 ...

Embodiment 2

[0025] Except white mud and water are mixed by the weight ratio of 1:7, other are identical with embodiment 1.

Embodiment 3

[0027] Except that the amount of seed crystals is 2% of the lime mud weight, others are the same as in Example 1.

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PUM

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Abstract

The invention relates to a method for preparing calcium sulfate crystal whiskers, which comprises the following steps of: mixing white mud and water according to a weight ratio of 1:(3-10), stirring for 5 to 10 minutes, standing for 8 to 12 hours, and filtering to obtain filter residues; mixing the filter residues and distilled water, stirring in a stirring container, and spraying dilute sulphuric acid solution continuously; when the pH value of the solution is 7, stopping stirring and spraying, and filtering to obtain filter liquor; putting the filter liquor into a high-pressure reaction kettle, adding calcium sulfate seed crystals, and crystallizing; and after crystallizing, filtering and drying to obtain the calcium sulfate crystal whiskers. In the method for preparing the calcium sulfate crystal whiskers, the white mud serving as industrial pollutants is recycled and is low in cost, so environmental protection is facilitated; a preparation process is simple, short in period and easy to control, and large-scale production can be realized; and products are large and uniform in a slenderness ratio, and stable in quality. The method can be used for the modification of rubber, plastics and coatings.

Description

technical field [0001] The invention relates to a preparation method of calcium sulfate whiskers. Background technique [0002] Calcium sulfate whiskers have excellent mechanical properties, good compatibility, excellent smoothness, good regeneration performance, and low toxicity. They are mainly used as friction materials, environmental engineering filter materials, and filling reinforcement for papermaking and composite materials, asphalt Modification, and improve the adhesion, temperature resistance and insulation of coatings and paints. [0003] Calcium sulfate whiskers are divided into three types: anhydrous calcium sulfate whiskers, calcium sulfate hemihydrate whiskers, and calcium sulfate dihydrate whiskers. Among them, anhydrous calcium sulfate whiskers have the highest strength, and dihydrate calcium sulfate whiskers are used at temperatures above 110°C. When the whisker cannot be strengthened, the industrial application prospect is small; the anhydrous and calcium...

Claims

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Application Information

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IPC IPC(8): C30B29/46C30B29/62C30B7/10
Inventor 刘珍如刘立文付桃梅杨志强宁勇鲁纪鸣
Owner 刘立文
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