Preparation method of magnesium hydrate

A technology of magnesium hydroxide and hydroxide, applied in the direction of magnesium hydroxide, etc., can solve the problems of high production cost, large aggregation tendency, wide distribution, etc., and achieve the effect of low production cost and simple equipment

Inactive Publication Date: 2013-01-02
HEBEI UNIV OF TECH
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  • Abstract
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  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The chemical precipitation method prepared by magnesium hydroxide mainly includes ammonia precipitation magnesium, sodium hydroxide precipitation magnesium and lime water precipitation magnesium. Among them, the magnesium hydroxide product of ammonia magnesium precipitation has high purity, but the grain size is too large. Large, too wide distribution, with certain limitations
Although the magnesium hydroxide product of magnesium hydroxide precipitation by sodium hydroxide method has a small particle size, the production cost is high, and the grains are prone to agglomeration
The magnesium hydroxide product of the lime water method for magnesium precipitation has a small particle size, but has a large tendency to agglomerate and is extremely difficult to filter. It is only suitable for industries that do not require high purity. Therefore, it is necessary to develop a new chemical precipitation method

Method used

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  • Preparation method of magnesium hydrate
  • Preparation method of magnesium hydrate
  • Preparation method of magnesium hydrate

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0041] The first step, the configuration of raw material magnesium salt solution

[0042] The magnesium chloride from the salt mine is mixed with the raw material magnesium salt solution that the molar concentration is 1mol / L;

[0043] The second step is to mix alkali magnesium precipitation

[0044] Take ammonia water with a concentration of 25% by weight and sodium hydroxide from bipolar membrane electrolysis in a ratio of 4:1 by mass to prepare a mixed alkali solution. Drop into the magnesium salt solution prepared in the first step at a rate of 0.1mL / min. When the pH value of the reaction solution system is 10, stop adding the above-mentioned mixed alkali solution dropwise, continue the reaction for half an hour, end the reaction, and generate hydrogen oxide Magnesium precipitation;

[0045] The third step, filter

[0046] The precipitation of the magnesium hydroxide generated in the second step is filtered, and the filtrate obtained by filtering is then processed in th...

Embodiment 2

[0062] The first step, the configuration of raw material magnesium salt solution

[0063] The magnesium chloride separated from the salt mine is mixed with a raw material magnesium salt solution whose molar concentration is 1.5mol / L;

[0064] The second step is to mix alkali magnesium precipitation

[0065] Take ammonia water with a concentration of 25% by weight and potassium hydroxide from bipolar membrane electrolysis in a ratio of 6:1 by mass to prepare a mixed alkali solution. Drop into the magnesium salt solution prepared in the first step at a rate of 0.1mL / min. When the pH value of the reaction solution system is 10, stop adding the above-mentioned mixed alkali solution dropwise, continue the reaction for half an hour, end the reaction, and generate hydrogen oxide Magnesium precipitation;

[0066] The third step, filter

[0067] The precipitation of the magnesium hydroxide generated in the second step is filtered, and the filtrate obtained by filtering is then proce...

Embodiment 3

[0083] The first step, the configuration of raw material magnesium salt solution

[0084] The magnesium sulfate separated from the sea and lake salt is prepared into a raw material magnesium salt solution whose molar concentration is 2mol / L;

[0085] The second step is to mix alkali magnesium precipitation

[0086] Take ammonia water with a concentration of 25% by weight and calcium hydroxide from bipolar membrane electrolysis in a ratio of 9:1 by mass to prepare a mixed alkali solution. Drop into the magnesium salt solution prepared in the first step at a rate of 0.1mL / min. When the pH value of the reaction solution system is 11, stop adding the above-mentioned mixed alkali solution dropwise, continue the reaction for half an hour, end the reaction, and generate hydrogen oxide Magnesium precipitation;

[0087] The third step, filter

[0088] The precipitation of the magnesium hydroxide generated in the second step is filtered, and the filtrate obtained by filtering is then...

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Abstract

The invention provides a preparation method of magnesium hydrate, and relates to the technical field of magnesium hydrate. The preparation method comprises the following steps of: preparing a raw material magnesium salt solution by magnesium chloride or magnesium sulfate separated out of salt mine or sea salt, adding a mixed aqueous alkali precipitator prepared by the ammonia water, the alkali metal hydroxide or the alkaline-earth metal hydroxide to generate precipitate of magnesium hydrate, filtering, washing, thermally modifying water, aging in a cooling way, filtering, washing and drying to obtain a magnesium hydrate product of which the grain size is 0.5-5.0mu m and the purity is larger than 97%, and treating and recovering the filter liquor in the process to obtain ammonia water, preparing the mixed aqueous alkali to be recycled by the recycled ammonia water, the alkali metal hydroxide or the alkaline-earth metal hydroxide according to the proportion by the mass percent such as (4-9): 1, so that the mixed bases can be recycled, therefore, various defects of the existing chemical precipitation method can be overcome, and the high-purity and low-granularity magnesium hydrate product can be prepared at low production cost.

Description

technical field [0001] The technical scheme of the present invention relates to magnesium hydroxide, specifically a kind of preparation method of magnesium hydroxide. Background technique [0002] Magnesium hydroxide is considered as a green and safe material due to its advantages of strong adsorption, high decomposition temperature, non-corrosiveness, high activity, and non-toxicity, and has been widely used in ceramics, environmental protection, medicine and other fields. Since the publication of magnesium hydroxide as a flame retardant, the research on magnesium hydroxide has become increasingly prosperous. The thermal decomposition temperature of magnesium hydroxide is 340°C, and no toxic and harmful gases are released during the decomposition process. It has a better smoke suppression effect than other inorganic flame retardants such as aluminum hydroxide and antimony oxide. [0003] Generally, the amount of flame retardant added is usually above 40% to achieve a good ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01F5/20
Inventor 李洪王军杨超鹏
Owner HEBEI UNIV OF TECH
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