CN1536102A

CN1536102A - Method for synthesizing magnesium salt whiskers

Info

Publication number: CN1536102A
Application number: CNA031114067A
Authority: CN
Inventors: 高绪国; 邹积兴; 王汝军; 丛卫军; 刘庆忠; 胡艳; 薛慧娟
Original assignee: DALIAN WHISKERS MATERIAL Co Ltd
Current assignee: DALIAN WHISKERS MATERIAL Co Ltd
Priority date: 2003-04-10
Filing date: 2003-04-10
Publication date: 2004-10-13

Abstract

The present invention relates to a method for synthesizing magnesium salt whiskers. It uses magnesium sulfate and magnesium hydroxide as reaction raw material, and makes them directly implement synthesis in the reactor still according to the mole concentration of 1:5, and adopts the processes of cooling, filtering, water-washing and drying so as to can obtain the invented product. Its reaction temp. can be controlled at 150-170 deg.C, reaction pressure is 0.6-0.8 Mpa, and reaction time is 2-5 hr. The obtained magnesium salt whiskers are made into the form of needle, its diameter can be up to 1.0 micron, its length is 30-100 microns, and its yield rate can be up to 95%.

Description

Synthesis method of magnesium salt whisker

Technical Field

The invention relates to a magnesium salt whisker compound, in particular to magnesium salt whisker MgSO₄·5Mg(OH)₂·3H₂A method for synthesizing O (M-HOS).

Technical Field

The magnesium salt whisker M-HOS is a novel inorganic reinforced fiber material. Mainly has the reinforcing function when being compounded with plastic; the flame retardant has obvious flame retarding and smoke inhibiting effects when used as a flame retardant. It can also be used for tackifying coating, making flame-retardant paper, light building material and filtering material.

The magnesium salt whisker is prepared by MgSO₄Adding NaOH into raw materials, controlling process conditions, and crystallizing magnesium salt whiskers, wherein the reaction formula is as follows:

the method has the main defects that a large amount of by-product sodium sulfate is directly discharged to generate a large amount of liquid pollution, and the recovery treatment energy dissipation is large, thereby bringing difficulty to large-scale industrial production.

Disclosure of Invention

The invention aims to provide a method for synthesizing magnesium salt whiskers which is relatively energy-saving and has little pollution.

The technical scheme of the invention is as follows:

magnesium sulfate and magnesium hydroxide are used as reaction raw materials, are directly synthesized in a reaction kettle according to the molar concentration of 1: 5, and then are cooled, filtered, washed and dried; wherein: the reaction temperature is controlled within the range of 150-170 ℃, the reaction pressure is 0.6-0.8 Mpa, and the reaction time is 2-5 hours;

preparing reaction raw materials into aqueous solutions respectively, and then feeding the aqueous solutions into a reaction kettle through a nuclear reactor; the nuclear reactor is a cylindrical container filled with agate balls, is provided with a material inlet and a material outlet and is driven to rotate by a motor; the rotating speed of the motor can be 500-800 r/min.

The invention has the following advantages:

1. compared with the synthesis method which has the advantages of direct discharge, generation of a large amount of liquid pollution and large energy dissipation of recovery treatment in the prior art, the key technology of the method is specifically embodied in that magnesium hydroxide and magnesium sulfate are used as reaction raw materials for direct synthesis in a reaction kettle, the whole process has no pollution except the defects of washing and filtering, the defect of large energy consumption of recovery treatment is avoided, and the method is a relatively clean and effective process; greatly facilitates large-scale industrial production.

2. The method can adopt a mixed nucleation reactor to control the crystallization size, and controls the particle size of the crystal whisker by controlling the conditions of material concentration, nucleation mode (mixing), crystallization temperature, crystallization time and the like; the microscopic morphology of the magnesium salt whisker of the product is needle-shaped, and the diameter can reach 1.0 mu m.

3. The yield of the product reaches 95 percent by adopting the method.

Drawings

FIG. 1 is a schematic process flow diagram of one embodiment of the present invention.

FIG. 2 is a scanning electron micrograph of an embodiment of the present invention.

FIG. 3 is a schematic diagram of a hybrid nuclear reactor according to an embodiment of the present invention.

Detailed Description

Example 1

Adding 2.6g of magnesium hydroxide, 2.1g of magnesium sulfate hexahydrate and 100ml of water into a 200ml stainless steel high-pressure reaction kettle, heating by adopting an oil bath (constant temperature at 170 ℃) and magnetic stirring, reacting for 2 hours at 170 ℃ and 0.8Mpa, naturally cooling, precipitating white crystals, filtering by using a Buchner funnel, washing by using clean water twice, drying at 100 ℃ in an oven to obtain 4g of needle-shaped magnesium salt whiskers with the diameter of 30-300 mu m and the length of 30-200 mu m, wherein a scanning electron microscope photo is shown in figure 2; the product is obtained after crushing, and the yield is 95%.

The reaction formula of the magnesium hydroxide and the magnesium sulfate is as follows:

。

example 2

Dissolving 2.6g of magnesium hydroxide in 50ml of water to obtain a solution A, dissolving 2.1g of magnesium sulfate hexahydrate in 50ml of water to obtain asolution B, slowly passing the solution A and the solution B through a nuclear reactor at constant speed respectively, adding a milky solution which is discharged from an outlet of the nuclear reactor into a 200ml stainless steel high-pressure reaction kettle, heating by adopting an oil bath and stirring by magnetic force, reacting for 2 hours at 170 ℃ and 0.8Mpa to grow crystal nuclei, cooling, separating out white crystals, filtering, washing twice with water, and drying to obtain 4g of needle-like magnesium salt whiskers with the diameter of 1-10 microns and the length of 30-300 microns. The yield thereof was found to be 95%.

Wherein: the process flow is shown in figure 1; the reaction raw materials enter a reaction kettle through a nuclear reactor; as shown in fig. 3, the structure of the nucleation reactor is a cylindrical container 1 (diameter is 100mm, height is 100mm) filled with agate balls 2 (diameter is 20mm), the cylindrical container is connected with a motor 3 through a belt 4, the cylindrical container is driven by the motor 3 to rotate, the rotation speed can be 500-800 revolutions, in this embodiment, under the high-speed rotation of the nucleation reactor at 800 revolutions per minute, reaction raw materials are added from a feeding hole arranged above, and the reaction raw materials pass through the moving agate balls 2 in the nucleation reactor, and enter the reaction kettle after coming out.

Example 3

The difference from the embodiment 2 is that: the same results were obtained using the same amount of magnesium sulfate pentahydrate.

Example 4

Reacting at 150 deg.C and 0.6MPa for 3hr as described in example 2; the magnesium salt whisker has a diameter of 1-100 μm and a length of 30-100 μm. The yield thereof was found to be 90%.

Example 5

The reaction wascarried out at 130 ℃ and 0.4MPa for 5hr as described in example 2 to obtain magnesium salt crystals with a diameter of 1 to 100 μm in a yield of 93%. This example demonstrates that magnesium salt whisker products cannot be obtained at reaction temperatures below 150 ℃.

Claims

1. A method for synthesizing magnesium salt whiskers is characterized by comprising the following steps: magnesium sulfate and magnesium hydroxide are used as reaction raw materials, are directly synthesized in a reaction kettle according to the molar concentration of 1: 5, and then are cooled, filtered, washed and dried; wherein: the reaction temperature is controlled within the range of 150-170 ℃, the reaction pressure is 0.6-0.8 Mpa, and the reaction time is 2-5 hours.

2. The method of synthesis of claim 1, wherein: the reaction raw materials are respectively prepared into aqueous solution and then enter a reaction kettle through a nuclear reactor.

3. The method of synthesis of claim 2, wherein: the structure of the nucleation reactor is a cylindrical container filled with agate balls, is provided with a material inlet and a material outlet, and is driven to rotate by a motor.

4. A method of synthesis as claimed in claim 3, characterised in that: the rotating speed of the motor can be 500-800 r/min.