Process for preparing magnesium hydroxide whisker

A technology of magnesium hydroxide and magnesium salt whiskers, applied in magnesium hydroxide, chemical instruments and methods, inorganic chemistry, etc., can solve the problems of difficulty in obtaining fibrous magnesium hydroxide, unstable needle-like crystals, and long time. , to achieve the effect of being beneficial to the application, shortening the production cycle and the method is simple

Inactive Publication Date: 2005-01-05
隗学礼
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The problem of this method is: the problem of this method is: 1. used the high-concentration chlorine compound that corrosivity is big to synthetic reactor equipment; The basic magnesium chloride intermediate must be "cured", which takes a long time (at least 18 hours or more), and the needle-shaped crystals formed are unstable, and it is easy to return to granular crystals, and it is difficult to obtain stable fibrous crystals with a large aspect ratio. magnesium hydroxide

Method used

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  • Process for preparing magnesium hydroxide whisker
  • Process for preparing magnesium hydroxide whisker
  • Process for preparing magnesium hydroxide whisker

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0028] Select crystalline magnesite, which is a special product in Northeast my country, calcinate at 750-1000°C for 1-10 hours, and then pulverize. After analysis, the pulverized matter contains magnesium oxide > 95%. Get 484 grams (12mol) of the magnesium oxide powder, add 8 liters of water, grind it into a slurry (remove sediment and impurities), and put it into a reaction kettle; add 3 liters of sulfuric acid aqueous solution with a concentration of 1mol / L while stirring, and then add alkali Formula magnesium sulfate crystal nucleation promoter 10 grams, make it fully mix uniformly; Heating at 150 ℃, reaction under pressure 0.45Mpa 2 hours; A small amount of samples were taken out and dried in an electric oven. The dry matter was observed by scanning electron microscope, and it was fibrous crystal. The diameter is 0.2-1 μm, the length is 20-100 μm, and the quality is uniform. Its electron microscope photos are as follows: figure 1 . X-ray diffraction analysis, the stru...

Embodiment 2

[0030] Prepare magnesium sulfate aqueous solution: use 863 grams of magnesium sulfate heptahydrate (3.5 mol), add 8 liters of water to dissolve. Add 8 liters of water to 423 grams (10.5 mol) of calcined magnesite powder, and grind it into a slurry (to remove sediment and impurities). Put the two liquid materials prepared by the above method into the reaction kettle, add 15 grams of basic magnesium sulfate crystal nucleus promoter, and stir and mix. Then, it was heated at 150° C. and reacted for 2 hours under a pressure of 0.45 MPa. After cooling, the reaction product was taken out and soaked in water and crushed; then filtered to remove water, some samples were taken and dried in an electric oven, scanned electron microscope observation and X-ray diffraction analysis, the results were the same as in Example 1, it was a single crystal fiber magnesium salt whiskers. Put the dried magnesium salt whiskers of the remaining parts into the reaction kettle, add 9 liters of water, an...

Embodiment 3

[0032] Put the magnesium salt whisker prepared by the method of Example 1 into the reactor, add 8 liters of water, add 1.5 liters of ammonium hydroxide aqueous solution with a concentration of 4mol / L while stirring, and make it fully mixed. Then, the reaction was carried out at 60° C. and a stirring speed of 80 revolutions / minute for 2 hours. After cooling, the reaction product was taken out, soaked in water, stirred and dispersed; filtered, dried to remove water, and dried in an electric oven; 625 grams of white needles were collected, and the calculated conversion rate was 100%. The reaction product was observed by a scanning electron microscope and was a fibrous crystal. The diameter is 0.2-1 μm, the length is 10-60 μm, the quality is uniform, and its electron microscope photo is the same as figure 2 . X-ray diffraction analysis, all magnesium hydroxide, Mg(OH) 2 . (same Figure 3-2 ).

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Abstract

The process of preparing magnesium hydroxide whisker features that the material magnesium salt whisker MgSO4.5Mg(OH)2.3H2O is made to react with the water solution of hydroxide of ammonia, alkali metal or alkali earth metal to obtain magnesium hydroxide whisker. The preparation process uses rich and low cost magnesite resource and prepares magnesium hydroxide whisker from magnesium salt whisker, resulting in short production period, high production efficiency and no serious corrosion of apparatus by chloride. In addition, the preparation process has simple process, low cost and no environmental pollution and is suitable for industrial production.

Description

Technical field: [0001] The present invention relates to the preparation technology of whisker, especially the preparation method of magnesium hydroxide whisker. technical background: [0002] Magnesium hydroxide can be widely used in various fields: such as adding thermoplastic resin to make it flame retardant. However, the commonly used magnesium hydroxide is in the form of powder, and when it is used to achieve flame retardant effect, it will significantly reduce the physical and mechanical properties of the material, make the fluidity and formability of the resin worse, and the forming efficiency and appearance of molded products will be worse. . Analyzing the reason, it is because the magnesium hydroxide crystal particle size is small, the specific surface is large, and the polarity of the crystal surface is large, and the secondary condensation structure containing water is often formed in the crystal, and the residual and adsorbed water in this aggregate Molecules a...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01F5/00C01F5/14C01F5/22
Inventor 隗学礼赵宽放
Owner 隗学礼
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