Liquid amonia pressurized precipitation and hydrothermal modification process for preparing magnesium hydroxide fire retardant

A magnesium hydroxide and hydrothermal modification technology, applied in the direction of magnesium hydroxide, etc., can solve the problems of low ammonia utilization rate, large amount of waste water, and harsh working environment, so as to increase ammonia concentration, reduce water consumption, and have no environmental pollution Effect

Inactive Publication Date: 2006-03-01
TSINGHUA UNIV
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  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] In order to overcome the shortcomings of the current ammonia water method, such as low ammonia utilization rate, large amount of waste water, and harsh working environment, the present invention proposes a new process of liquid ammonia pressurized precipitation-hydrothermal modification to prepare magnesium hydroxide flame retardant

Method used

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  • Liquid amonia pressurized precipitation and hydrothermal modification process for preparing magnesium hydroxide fire retardant
  • Liquid amonia pressurized precipitation and hydrothermal modification process for preparing magnesium hydroxide fire retardant
  • Liquid amonia pressurized precipitation and hydrothermal modification process for preparing magnesium hydroxide fire retardant

Examples

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Embodiment 1

[0030]Prepare 40 liters of 10% (w / v) magnesium chloride solution and add it to a closed reactor, and feed (0.7 mol / min) liquid ammonia at a constant speed under the condition of stirring (150 rpm) at 15°C for 1 hour. Enter air to maintain the reactor pressure at 0.05 MPa, and continue the reaction for 3 hours. After the reaction, the gas phase is discharged into the ammonia recovery device. After the slurry is filtered and washed, a slurry with a solid content of 5% is made under stirring (150 rpm) and added to the hydrothermal reactor, and then 0.1% polyacrylic acid is added. , stirred at 250°C (150 rpm) for 6 hours, then cooled, filtered, washed, dried (105°C, 4 hours), and pulverized to obtain particles with an average primary particle size of 2.0 μm and an average aggregated particle size of 3.0 μm. Specific surface area 5m 2 / g, hexagonal flaky magnesium hydroxide particles with a purity of 99.5%. Put the normal-temperature synthetic filtrate and 5.2 kg of quicklime int...

Embodiment 2

[0032] Prepare 40 liters of 40% (w / v) magnesium chloride solution and add it to a closed reactor, and feed (2.8 mol / min) liquid ammonia at a constant speed under the condition of stirring (150 rpm) at 90 ° C for 1 hour. Air was added to maintain the reactor pressure at 0.5 MPa, and the reaction was continued for 1 hour. After the reaction, the gas phase is discharged into the ammonia recovery device. After the slurry is filtered and washed, a slurry with a solid content of 30% is made under stirring (150 rpm) and added to the hydrothermal reactor, and then 0.01% hexadecimal Sodium phosphate, stirred at 100°C (150 rpm) for 1 hour, then cooled, filtered, washed, dried (105°C, 4 hours), and crushed to obtain particles with an average primary particle size of 0.5 μm and an average aggregated particle size of 4.0 μm, specific surface area 30m 2 / g, hexagonal flaky magnesium hydroxide particles with a purity of 98.0%. Put the normal-temperature synthetic filtrate and 21.5 kg of qu...

Embodiment 3

[0034] Prepare 40 liters of 20% (w / v) magnesium chloride solution and add it to a closed reactor, and feed (1.5 mol / min) liquid ammonia at a constant speed under the condition of stirring (150 rpm) at 40°C for 1 hour. Air was added to maintain the reactor pressure at 0.2 MPa, and the reaction was continued for 3 hours. After the reaction, the gaseous phase is discharged into the ammonia recovery unit. After the slurry is filtered and washed, a slurry with a solid content of 15% is made under stirring (150 rpm) and added to the hydrothermal reactor, and then 0.05% ethanol is added. Stir at 180°C (150 rpm) for 4 hours, then cool, filter, wash, dry (105°C, 4 hours), and pulverize to obtain particles with an average primary particle size of 1.0 μm and an average aggregated particle size of 2.0 μm. Surface area 15m 2 / g, hexagonal flaky magnesium hydroxide particles with a purity of 98.5%. Put the normal-temperature synthetic filtrate and 10.8 kg of quicklime into a closed ammoni...

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Abstract

The present invention belongs to the field of inorganic chemical technology, and proposes one kind of liquid ammonia pressurized precipitation and hydrothermal modification process for preparing magnesium hydroxide fire retardant. Through the first precipitation reaction of magnesium chloride material with liquid ammonia as precipitant at 15-90 deg.c and sealed and pressurized conditions to synthesize magnesium hydroxide, and the subsequent modification of the normal temperature synthesized magnesium hydroxide at 100-250 deg.c in the presence of dispersant of 0.01-0.1 % for 1-6 hr, magnesium hydroxide fire retardant is prepared, which has primary granularity of 0.3-2.0 micron, average coagulation particle size of 1.0-4.0 micron, specific surface area of 5-30 sq m/g, and magnesium hydroxide content over 98 %. The magnesium hydroxide fire retardant may be used in rubber, plastic, building material, etc.

Description

technical field [0001] This patent relates to a new process for preparing magnesium hydroxide flame retardant, which belongs to the technical field of inorganic chemical industry. Background technique [0002] my country is a country with large sea and lake salt resources, mainly distributed in Qinghai, Inner Mongolia, Xinjiang, Tibet, Shanxi and other provinces and coastal areas (such as Tianjin, Dalian, Shandong, etc.). Magnesium in sea and lake salt is the resource second only to sodium in reserves. For a long time, limited by technical and economic conditions, the utilization of sea and lake salt resources has mainly focused on salt production or potassium extraction, and insufficient attention has been paid to the comprehensive utilization of by-product magnesium salt. At present, only a very small part of magnesium salt is used to produce primary products such as magnesium chloride hexahydrate (100-300 yuan / ton) and magnesium sulfate heptahydrate (500-600 yuan / ton), w...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C09K21/02C01F5/20
Inventor 向兰张英才吴庆流魏飞
Owner TSINGHUA UNIV
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