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Method for preparing magnesium hydroxide, magnesium oxide and gypsum from dolomite lime denitration and desulfurization of flue gas

A technology of magnesium hydroxide and magnesium oxide, applied in magnesium hydroxide, chemical instruments and methods, magnesium oxide and other directions, can solve problems such as separation of calcium and magnesium from dolomitic lime, and achieve the effect of reducing costs

Active Publication Date: 2014-02-12
彭振超 +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0009] The present invention uses cheap NH 4 Cl solution also ingeniously solves the separation problem of calcium and magnesium in dolomitic lime

Method used

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  • Method for preparing magnesium hydroxide, magnesium oxide and gypsum from dolomite lime denitration and desulfurization of flue gas

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Embodiment 1

[0058] Embodiment 1: The present invention denitrates and desulfurizes and produces magnesium hydroxide, magnesium oxide, the method for building gypsum comprising the following steps:

[0059] ① Digestion and refining step: Digest dolomite lime containing 5% sand and dolomite raw blocks and water into a digestion reactor in a weight ratio of 1:6 while stirring to make dolomite milk, so that MgO CaO (dolomite lime) Form Mg(OH) with water 2 ·Ca(OH) 2 water mixture. Remove impurities such as sand grains and dolomite raw blocks in the ashes by filtering and sieving to obtain refined ashes with a concentration of 10-20%;

[0060] ②Calcium-magnesium separation ammonia distillation step: inject refined dolomite lime milk into the calcium-magnesium separation ammonia distillation reactor, add a sufficient amount of 10% NH 4 Cl solution, close the feeding port, start the agitator, feed steam to directly heat for calcium and magnesium separation reaction, start the fan at the air di...

Embodiment 2

[0066] Embodiment 2: the present invention denitrates and desulfurizes and produces magnesium hydroxide, magnesium oxide, the method for building gypsum comprising the following steps:

[0067] ① Digestion and refining step: Digest dolomite lime containing 10% impurities such as sand and dolomite raw blocks and water in a digestion reactor in a weight ratio of 1:8 while stirring and digesting into dolomite milk to make MgO CaO (dolomite lime) Form Mg(OH) with water 2 ·Ca(OH) 2 water mixture. Remove impurities such as sand grains and dolomite raw blocks in the ashes by filtering and sieving to obtain refined ashes with a concentration of 10-20%;

[0068] ②Calcium-magnesium separation ammonia distillation step: inject refined dolomite lime milk into the calcium-magnesium separation ammonia distillation reactor, add a sufficient amount of 8% NH 4 Cl solution, close the feeding port, start the agitator, pass in steam to indirect heating for calcium and magnesium separation reac...

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Abstract

The invention relates to a method for simultaneously preparing magnesium hydroxide, magnesium oxide and gypsum from dolomite lime denitration and desulfurization of flue gas, and belongs to the technical field of flue gas pollution control. The problems of separation of dolomite lime calcium-magnesium separation are ingeniously solved by a low-cost solution of NH4Cl. Ammonia gas (NH3) obtained by ammonia distillation in a calcium-magnesium separation process is heated for denitration. Mg(OH)2 precipitates formed in the calcium-magnesium separation process are used for the desulfurization of the flue gas. A solution of CaCl2 subjected to solid-liquid separation after calcium-magnesium separation is used for precipitating a solution of MgSO4 generated by desulfurization to produce byproducts CaSO4.1 / 2H2O building gypsum and a solution of MgCl2. Residual Mg(OH)2 is dried or calcinated to form a finished product Mg(OH)2 or MgO. According to the method, the denitration and desulfurization cost is greatly lowered; in addition, a novel production process for magnesium hydroxide and magnesium oxide products are created, and waste is comprehensively utilized.

Description

technical field [0001] The invention relates to a process for flue gas desulfurization and denitrification and preparation of magnesium hydroxide, magnesium oxide and gypsum, especially in the removal of SO in flue gas, especially coal-fired flue gas, using dolomite as raw material. x , NO x A process for simultaneously preparing magnesium hydroxide, magnesium oxide and gypsum. Background technique [0002] SO x , NO x It is one of the main substances that cause air pollution and is very harmful to the environment, ecology, economic development and human health. Flue gas desulfurization and denitrification have become global technical issues, and my country will also 2 , SO 3 , NO, NO 2 Listed as the main regulations to control air pollutants, whether there are desulfurization and denitrification means, whether there is desulfurization and denitrification equipment, and whether desulfurization and denitrification can meet the emission targets have become important cons...

Claims

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Application Information

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IPC IPC(8): B01D53/75B01D53/60C01F11/46C01F5/08C01F5/14
CPCY02A50/20
Inventor 彭振超韩默先
Owner 彭振超
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