A method for preparing magnesium hydroxide flame retardant by ammonia method
A technology of magnesium hydroxide and flame retardant, applied in magnesium hydroxide and other directions, can solve the problem of wide particle size distribution, and achieve the effect of narrow particle size distribution, lower production cost and high yield
Inactive Publication Date: 2015-11-18
SHENYANG INSTITUTE OF CHEMICAL TECHNOLOGY
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Problems solved by technology
[0004] Since the preparation of flame-retardant magnesium hydroxide by ammonia gas bubbling is a one-step continuous reaction, there are problems such as wide particle size distribution.
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Embodiment 1
[0025] Take 81.52ml of concentrated sulfuric acid, dilute it with 473ml of water, add 66.67g of lightly burned powder (magnesium oxide content ≥ 90%), and prepare a 3mol / L magnesium sulfate solution. After filtering out the impurities in the solution, pour it into the reactor, adjust the temperature of the water bath to 45° C., and the stirring speed at 1300 r / min. Nitrogen gas (protective gas, to prevent ammonia gas sucking back) was passed into the reactor through the bubbling tube at 100ml / min, and after the recovered liquid discharged gas evenly, it was passed into the reactor through the bubbling tube at 275.67ml / min, and reacted for 4 hours. Stop the ammonia gas, add 3.48g of compound surfactant, and age for 4h. Stop nitrogen, stop stirring, wash and filter several times, and dry at 110°C for 12 hours to obtain a micron-sized narrow distribution magnesium hydroxide flame retardant. The product is in the form of spherical particles, the particle size is concentrated in 7...
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The invention relates to a method for preparing a flame retardant, particularly a method for preparing a magnesium hydroxide flame retardant by an ammonia gas process, which comprises the following steps: preparing a dilute sulfuric acid solution with a certain concentration, and adding a light calcined powder (light calcined magnesium powder) to prepare a magnesium sulfate solution; filtering out impurities in the solution, adding into a reactor, and heating; introducing ammonia gas into the solution by using a bubbler to perform the reaction; after the reaction is finished, adding a compound surfactant, and aging; and washing, carrying out vacuum filtration, and drying to obtain narrow-distribution microsize magnesium hydroxide. By adopting the ammonia gas bubbling process, the method has the advantages of simple process and sufficient reaction, and can control the particle size under low reaction temperature in the aspects of reaction conditions and reaction technique; the product has the advantages of high purity, high yield, narrow particle size distribution, favorable dispersivity and favorable filtering quality; and the method is suitable for large-scale production of the magnesium hydroxide flame retardant.
Description
technical field [0001] The invention relates to a method for preparing the particle size of a flame retardant, in particular to a method for preparing the particle size of a magnesium hydroxide flame retardant by an ammonia method. Background technique [0002] Magnesium hydroxide is a commonly used inorganic flame retardant filler, which is a halogen-free flame retardant and has the advantages of low toxicity, low smoke, low corrosion, and low price. Compared with the commonly used inorganic flame retardant aluminum hydroxide, the thermal decomposition temperature of magnesium hydroxide is about 60 ℃ higher than that of aluminum hydroxide, the heat absorption is about 17% higher, and the smoke suppression ability is also better. Therefore, for high polymers with high processing temperature, magnesium hydroxide is more suitable as a flame retardant than aluminum hydroxide. [0003] At present, there are two main methods for preparing magnesium hydroxide, one is the hydratio...
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IPC IPC(8): C01F5/20C09K21/02
Inventor 梁兵高昌健吕娇
Owner SHENYANG INSTITUTE OF CHEMICAL TECHNOLOGY