Method for preparing magnesium hydrate through ammonia spray method

A technology of magnesium hydroxide and injection method, applied in the direction of magnesium hydroxide, etc., can solve the problems of not getting rid of the three-step process of normal temperature synthesis, hydrothermal treatment surface modification, poor particle consistency of magnesium hydroxide products, high temperature and pressure, etc. Achieve the effect of saving raw material transportation costs, optimizing macro and micro mixing effects, and reducing pollution

Active Publication Date: 2013-05-15
YINGKOU YINGXIN CHEM TECH CO LTD
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

There are some engineering technical problems in the batch process of ammonia water method: for example, in the production process of ammonia water method, with the continuous addition of ammonia water to the reaction system, water is brought in, and the NH in the reaction system 4 + , Mg 2+ The concentration is constantly changing and the whole system is uneven, which makes the formed magnesium hydroxide product particles poor in crystal form consistency, and the products are mostly mixtures of different crystal forms and particle shapes
[0004] In a word, although the preparation process of magnesium hydroxide reported so far, especially the preparation process of flame retardant magnesium hydroxide, has been continuously improved, it has not got rid of the three-step process of normal temperature synthesis, hydrothermal treatment, and surface modification, and there are still technological processes. Technical disadvantages such as long length, high temperature and pressure, small product yield and high production cost

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  • Method for preparing magnesium hydrate through ammonia spray method
  • Method for preparing magnesium hydrate through ammonia spray method
  • Method for preparing magnesium hydrate through ammonia spray method

Examples

Experimental program
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Effect test

Embodiment 1

[0041] Take 7kg of ammonium sulfate to prepare 30L of aqueous solution, adjust it to 19% (mass percentage concentration) ammonium sulfate aqueous solution, then slowly add light-burned magnesium powder (1 ton / hour), stop adding when the pH value of the solution is 9, and then Ammonia distillation reaction (in the ammonia distillation reactor), the ammonia distillation reaction temperature is 136°C. The reaction solution of the ammonia distillation reaction is filtered to remove Fe 3+ and Al 3+ After the precipitate formed, a clear filtrate of the magnesium salt (magnesium sulfate solution) was obtained.

[0042] The ammonia gas produced by the ammonia distillation reaction is sucked into the absorption tube of the jet reactor through the jet tube of the jet reactor (the flow rate of ammonia gas is 0.09m 3 / h), the magnesium sulfate solution obtained after the above filtration is added to the cylindrical container of the jet reactor, and the temperature in the jet reactor is ...

Embodiment 2

[0044] The difference from Example 1 is: when the ammonia produced by the ammonia distillation reaction is sucked into the injector absorption pipe, its ammonia flow rate is 2m 3 / h, when the magnesium sulfate solution obtained after ammonia distillation reaction, filtration and impurity removal is sprayed to the injector absorption pipe, its flow rate is 300m 3 / h. The magnesium hydroxide product obtained in this process has a purity of 98.8%, good dispersibility and uniform particle shape, and its appearance is hexagonal flakes. The particle size of the obtained magnesium hydroxide product is D 50 2μm, the particle size distribution range is small (concentrated distribution range 0.8-5μm), such as Figure 4 shown.

Embodiment 3

[0046] Ammonia distillation reaction and impurity removal process are the same as embodiment one. The ammonia gas produced by the ammonia distillation reaction is sucked into the absorption pipe of the ejector through the injection pipe of the jet reactor (the flow rate of ammonia gas is 2.5m 3 / h), adjust the magnesium sulfate solution obtained after the above filtration to a temperature of 25°C and add it to the cylindrical container of the jet reactor, and at the same time add a fatty salt surfactant (sodium dodecylbenzenesulfonate, add The amount is 0.5% of the mass of magnesium sulfate solution), the magnesium sulfate solution in the cylindrical container is sprayed into the absorption pipe of the injector through the injection pipe (the flow rate is 300m 3 / h), react with the ammonia gas sucked into the absorption tube of the injector, and stop the reaction when the pH value of the reaction solution is 13, and obtain a milky white suspension mixed with magnesium hydroxid...

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Abstract

The invention discloses a method for preparing magnesium hydrate through ammonia spray method. The method comprises the following steps: by using caustic calcined magnesite and ammonium salt as raw materials, carrying out ammonia stilling reaction to obtain an ammonium and magnesium salt solution, wherein the ammonium and magnesium salt are contacted in a spray type reactor and magnesium hydrate precipitation reaction is performed, aging product mother liquor for a proper time, filtering, returning filtrate containing ammonium salt to an ammonia stilling system, washing and drying filter cake to obtain magnesium hydrate product with uniform particle shape and good dispersion state. The process disclosed by the invention is used for preparing magnesium hydrate through one-step reaction, is simple in operation step, mild in reaction condition, uniform in product particle shape, and the particle shape can be regulated by changing the reaction condition. The ammonium slat is circulated with the ammonia in the reaction process, the production cost is low, the pollution is less, and the scale production is realized, the product can be used as production raw material of high-pure magnesium oxide and inflaming retarding additive of polymer material.

Description

technical field [0001] The invention relates to the technical field of preparing magnesium hydroxide, in particular to a method for preparing magnesium hydroxide by an ammonia injection method. Background technique [0002] Magnesium Hydroxide (Mg(OH) 2 ) is a basic inorganic chemical product. The magnesium hydroxide prepared during the synthesis process is mostly used as a raw material for the production of high-purity magnesium oxide or a flame-retardant additive for polymer materials. In the application of these two aspects, in addition to the requirements on the purity, impurities and content of magnesium hydroxide products, there are usually special requirements on the particle shape, particle size and distribution, and crystal structure of the product. Magnesium oxide products can meet better use requirements. The properties of magnesium hydroxide products are related to the technical method and process of its preparation. [0003] Magnesium hydroxide preparation te...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01F5/20
Inventor 徐胜博
Owner YINGKOU YINGXIN CHEM TECH CO LTD
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