Method for preparing high-purity magnesium oxide by pyrolysis of magnesium chloride

A technology of magnesium oxide and magnesium chloride, applied in magnesium oxide and other directions, can solve the problems of high energy consumption of pyrolysis, complicated control of pyrolysis process, etc., and achieve the effects of short decomposition time, simple process, and increased concentration and temperature.

Inactive Publication Date: 2011-04-27
QINGHAI INST OF SALT LAKES OF CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0030] The method is simple in process, does not require other raw materials in the production process, and has high product quality, but the control of the pyrolysis process is relatively complicated, and the energy consumption of pyrolysis is relatively high.

Method used

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Experimental program
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Effect test

Embodiment 1

[0047] Embodiment 1 A method for preparing high-purity magnesium oxide by pyrolysis of magnesium chloride comprises the following steps:

[0048] (1) After dissolving the salt lake bischofite with water, then use barium chloride and boron adsorption special effect resin to remove B 2 o 3 and SO 2- 4 , to obtain a magnesium chloride solution with a mass concentration of 29-32%, wherein 15-20 g of barium chloride is consumed per kg of bischofite.

[0049](2) After the magnesium chloride solution obtained in step (1) is concentrated to a mass concentration of 38-41% and the solution temperature is 80-90°C in a pre-concentration container, it is sprayed into the pyrolysis reaction with a flow rate of 55L / h through a pressure nozzle In the device, under the nozzle pressure of 0.3MPa, it is in contact with the gas at a temperature of 1200-1500°C; it is decomposed under the conditions of a decomposition temperature of 500°C, a pressure of -60Pa, and a decomposition time of 1-5s to...

Embodiment 2

[0053] Embodiment 2 A method for preparing high-purity magnesium oxide by pyrolysis of magnesium chloride comprises the following steps:

[0054] (1) After dissolving the old brine in water, remove B with barium chloride and boron adsorption special effect resin respectively 2 o 3 and SO 2- 4 , to obtain a magnesium chloride solution with a mass concentration of 29-32%, wherein 15-20 g of barium chloride is consumed per kg of old brine.

[0055] (2) After the magnesium chloride solution obtained in step (1) is concentrated to a mass concentration of 38-41% and the solution temperature is 80-90°C in a pre-concentration container, it is sprayed into the pyrolysis reaction with a flow rate of 55L / h through a centrifugal nozzle In the device, under the nozzle pressure of 0.5MPa, it is in contact with the gas at a temperature of 1200-1500°C; it is decomposed under the conditions of a decomposition temperature of 500°C, a pressure of -80Pa, and a decomposition time of 1-5s to obt...

Embodiment 3

[0059] Embodiment 3 A method for preparing high-purity magnesium oxide by pyrolysis of magnesium chloride comprises the following steps:

[0060] (1) After dissolving the salt lake bischofite with water, then use barium chloride and boron adsorption special effect resin to remove B 2 o 3 and SO 2- 4 , to obtain a magnesium chloride solution with a mass concentration of 29-32%, wherein 15-20 g of barium chloride is consumed per kg of bischofite.

[0061] (2) After the magnesium chloride solution obtained in step (1) is concentrated to a mass concentration of 38-41% and the solution temperature is 80-90°C in a pre-concentration container, it is sprayed into the pyrolysis reaction at a flow rate of 61L / h through a pressure nozzle In the device, under the action of the nozzle pressure of 0.5MPa, it is in contact with the gas with a temperature of 1200-1500°C; it is decomposed under the conditions of a decomposition temperature of 550°C, a pressure of -35Pa, and a decomposition ...

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Abstract

The invention relates to a method for preparing high-purity magnesium oxide by pyrolysis of magnesium chloride. The method comprises the following steps of: (1) dissolving salt lake bischofite or old brine, and then removing B2O3 and SO2<-4>, so as to obtain a magnesium chloride solution with the mass concentration of 29-32%; (2) preconcentrating the magnesium chloride solution, spraying the preconcentrated magnesium chloride solution into a pyrolysis reactor by virtue of a nozzle, decomposing under the conditions that the decomposition temperature is 500-650 DEG C, the pressure is -80 to -20Pa and the decomposition time is 1-5 seconds to obtain themolysis products of magnesium oxide and themolysis tail gas; and (3) sintering the pyrolysis product magnesium oxide sequentially subjected to hydration purifying, washing and filtering to obtain high-purity magnesium oxide with the MgO content of more than 99.0%. The invention has the advantages of simple process, low cost, high raw material decomposition rate, short decomposition time, high thermal efficiency and high thermal utilization ratio.

Description

technical field [0001] The invention relates to a method for preparing high-purity magnesium oxide in the technical field of inorganic chemical industry, in particular to a method for preparing high-purity magnesium oxide by pyrolyzing magnesium chloride using salt lake bischofite (brine) as raw material. Background technique [0002] Magnesium oxide is mainly used as a raw material for the preparation of ceramics, enamel, refractory crucibles and refractory bricks, and is also used as a filler for polishing agents, adhesives, coatings and paper, as an accelerator and activator for neoprene and fluorine rubber; and After mixing magnesium chloride and other solutions, it can be made into magnesium oxide water. In medicine, it is used as an antacid and laxative, for gastric and duodenal ulcer disease with hyperacidity; in the chemical industry, it is used as a catalyst and a raw material for the manufacture of magnesium salts. [0003] MgO≥99.0% is called high-purity magnesia...

Claims

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Application Information

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IPC IPC(8): C01F5/06
Inventor 火焱都永生韩继龙王世栋李明珍孙庆国周园
Owner QINGHAI INST OF SALT LAKES OF CHINESE ACAD OF SCI
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