CN101624198A - Method for preparing basic magnesium chloride and magnesium oxide by pyrolyzing bischofite - Google Patents
Method for preparing basic magnesium chloride and magnesium oxide by pyrolyzing bischofite Download PDFInfo
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- CN101624198A CN101624198A CN200910056036A CN200910056036A CN101624198A CN 101624198 A CN101624198 A CN 101624198A CN 200910056036 A CN200910056036 A CN 200910056036A CN 200910056036 A CN200910056036 A CN 200910056036A CN 101624198 A CN101624198 A CN 101624198A
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- magnesium chloride
- bischofite
- basic magnesium
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Abstract
The invention relates to a method for preparing basic magnesium chloride and magnesium oxide by pyrolyzing bischofite. The method is characterized by adopting section calcining, recovering HCl in a section manner, particularly pressurizing and spraying the hot solution of refined bischofite under the temperature of 130 to 150 DEG C to a reaction kettle, carrying out primary calcining under the 250 to 300 DEG C after removing parts of crystal water with the calcining time of 1 to 3 hours, and obtaining the product of basic magnesium chloride (MgOHCl); absorbing the tail gas with water to obtain hydrochloric acid; the washing the calcining product which contains little amount of undecomposed magnesium chloride hydrate to obtain the basic magnesium chloride (MgOHCl); carrying out secondary calcining on the obtained MgOHCl under a temperature of 450 to 500 DEG C with the calcining time for 1 to 3 hours to obtain MgO, and cooling and recovering the produced HCl to obtain hydrochloric acid. The method has the advantages of low calcining temperature, little equipment corrosion, little energy consumption, high HCl recovery rate, simple technique, high product purity and low cost.
Description
[technical field]
The present invention relates to the magnesium compound technical field, specifically, is a kind ofly to prepare basic magnesium chloride and method of magnesium oxide with the bischofite pyrolysis.
[background technology]
Secondly magnesium oxide is a kind of important inorganic chemical product, and purposes is very extensive, is mainly used in the preparation refractory materials, also is used for paper pulp, carries uranium, material of construction, animal food section, fertilizer, rubber, plastics and tackiness agent etc.Magnesium oxide mainly contains three and originates greatly: magniferous ore (magnesite and rhombspar etc.), bittern, seawater.The magnesium oxide series product comprise light magnesium oxide, activated magnesia, heavy-calcined magnesia, electrician's level magnesium oxide, silicon steel level magnesium oxide, pharmaceutical magnesium oxide, high-purity magnesium oxide etc.
Basic magnesium chloride (Mg
x(OH)
yCl
zMH
2O, 2x-y-z=0,0≤m≤6) be a kind of good fire retardant and weighting agent, also be the presoma of preparation one dimension magnesium oxide and magnesium hydroxide; But MgOHCl and HCl direct reaction generate Magnesium Chloride Anhydrous.Prepare at present method that basic magnesium chloride takes has at 400 ℃ of calcining bischofites and with methods such as magnesium chloride and calcium hydroxide or ammoniacal liquor synthesize down.
Preparation magnesium oxide mainly contains following method at present:
One, solid ore deposit calcination method
(1) magnesite calcination method---China's magnesite reserves are big, and this method technology is simple, and cost is low, but the magnesium oxide purity that obtains is low, generally is lower than 95%, is difficult to reach 99%, and can produce a large amount of carbonic acid gas, contaminate environment;
(2) carborization is that solid ore deposits such as magnesite are sintered into powder, feeds carbonic acid gas and water, and heating generates Magnesium hydrogen carbonate, and calcination obtains magnesium oxide then; This method cost is low, but technical process is long, and facility investment is big, and the magnesium oxide purity that obtains is low;
Two, bittern or bischofite direct pyrolysis method
Direct pyrolysis method is that this method technical process is simple, need not consume any auxiliary material with directly heating in air (or hot gas flow) of hydrated magnesium chloride, and production cost is low, easily realizes the high-valued and industrialization of magnesium; Current methods is mainly spray method and boiling oven process:
(1) spray pyrolysis
Bittern is directly sprayed into pyrolysis oven, get thick magnesium oxide after the calcining, repeatedly the muriate that does not decompose is fully removed in washing, and the complete aquation of thick magnesium oxide generates Mg (OH)
2, be fired to light magnesium oxide, heavily burn again highly-purity magnesite, purity reaches more than 99%; This technical process is simple, and pyrolysis time is short, and production cost is low, but the rate of recovery is lower, and hydrogen chloride tail gas corrodibility is strong, and to the equipment requirements height, the absorption of dust catching, HCl and concentrated difficulty are big, and environment is polluted;
(2) fluidizing furnace pyrolysis method
Raw material is dewatered through fluidizing furnace, pyrolysis and roasting, product overflows into the narrow-necked earthen jar that gathers materials automatically by discharge nozzle and stores, and the heat radiation of fluidizing furnace body of heater is bigger, adopt suitable heat-insulation and heat-preservation measure, could reduce heat radiation, improves the net heat utilization ratio of stove;
Three, the precipitator method
The precipitator method are to add precipitation agent in the solution of bittern or bischofite, and as lime, soda ash, ammoniacal liquor etc., the precipitation that obtains gets the magnesia product after calcining:
(1) bittern soda ash method---with bittern or other magnesium chloride solution and yellow soda ash generation MgCO under 50 ℃
33H
2O is with sedimentation and filtration, washing, the dry Stan-Mag Magnesium Carbonate that gets; Stan-Mag Magnesium Carbonate is added water, and logical steam boils and can pyrolysis become magnesium basic carbonate; Magnesium basic carbonate after filtration, drying, pulverizing, classification get Magnesium Carbonate Light 41-45; Magnesium Carbonate Light 41-45 can get light magnesium oxide through pulverizing, classification, packing again 700～900 ℃ of down calcinings, and bittern is with hydrogen peroxide or clorox pre-treatment, remove impurity such as de-iron, manganese, can improve the quality of products, bittern is the raw material that a kind of economy is easy to get, but soda ash cost height;
(2) bittern carborization---bittern and refining milk of lime in and still in generate Mg (OH)
2, with Mg (OH)
2The sedimentation and filtration washing is delivered to carbonating tower after adding the water adjustment, with lime-kiln gas it is carried out carbonization and gets magnesium bicarbonate solution, and the open steam pyrolysis gets magnesium oxide behind the filtering and impurity removing;
(3) bittern ammonium carbonate method---with bittern is raw material, utilize the carbon ammonium or the carbonated aqueous ammonia of small nitrogenous fertilizer plant to replace soda ash to produce light magnesium oxide, bittern carries out replacement(metathesis)reaction with the carbon ammonium and generates the magnesiumcarbonate precipitation after pre-treatment, after the washing of precipitate, drying and calcining gets light magnesium oxide, filtering in the mother liquor of magnesiumcarbonate has a spot of sodium-chlor and a large amount of ammonium chloride, separablely after filtering goes out sodium-chlor, and the cooling post crystallization reclaims ammonium chloride;
(4) lime method---raw material is cheap, and cost is low, if byproduct is fully used, cost can also reduce, but this method Production Flow Chart is long, and poor, the energy consumption height, high to the active requirement of lime of magnesium hydroxide strainability is suitable for handling lower concentration bittern in the production process;
(5) ammonia process---ultimate principle is identical with lime method, selects for use ammoniacal liquor as precipitation agent, and this method advantage is the Mg (OH) that generates
2Degree of crystallinity height, settling velocity be fast, be easy to filter and washing, and impurity controls easily, helps improving the quality of products; But yield is on the low side, the recovery utilization rate of ammonia and environmental issue are outstanding is the key issue of this method, wherein can be with the NH of by-product in the production process
4Cl, resynthesis ammonium carnallitite, deamination obtain anhydrous chlorides of rase magnesium eletrolysis system magnesium.
[summary of the invention]
The objective of the invention is to overcome the deficiencies in the prior art, provide a kind of and prepare basic magnesium chloride and method of magnesium oxide with the bischofite pyrolysis.
The objective of the invention is to be achieved through the following technical solutions:
A kind ofly prepare basic magnesium chloride and method of magnesium oxide with the bischofite pyrolysis, concrete steps are:
(1) hot solution of bischofite under 130～150 ℃ after will making with extra care sprays to reactor through pressurization, the solid hydrate that partial crystallization water is taken off in acquisition carries out the calcining first time under 250～300 ℃, calcination time is 1～3 hour, obtain product basic magnesium chloride Mg OHCl, tail gas absorbs through water and obtains hydrochloric acid, concentration of hydrochloric acid is 28～32%, and reaction equation is:
MgCl
2·nH
2O →MgOHCl+HCl+H
2O
Described calcining temperature is preferably 280 ℃, and calcination time is 2 hours;
(2) contain a small amount of undecomposed magnesium chloride hydrate in the calcinate, use the solvent wash product, obtain basic magnesium chloride Mg OHCl, basic magnesium chloride Mg OHCl purity is greater than 96%;
Described solvent is selected from methyl alcohol or ethanol, is preferably methyl alcohol;
(3), under 450～500 ℃, carry out the calcining second time, calcination time 1～3 hour with the basic magnesium chloride Mg OHCl that obtains in step (1) or (2), obtain MgO, MgO purity is greater than 99%, and the HCl of generation reclaims through cooling and obtains hydrochloric acid, concentration of hydrochloric acid is 28～32%, and reaction equation is:
MgOHCl→MgO+HCl
Described calcining temperature is preferably 480 ℃, and calcination time is 2 hours.
Compared with prior art, positively effect of the present invention is:
The present invention divides once spray to add the calcining of two steps, obtain different target products respectively, once spray purpose and be to take off partial crystallization water, the tail gas that calcining for the first time produces is HCl and mixture of steam, strong to equipment corrosion, but calcining temperature of the present invention is low, can slow down the corrosion of equipment greatly, water content is low in the gaseous product, can improve the rate of recovery of hydrochloric acid; The tail gas that calcining for the second time produces is water content less than 1% HCl, and is little to equipment corrosion, will reclaim after the HCl condensation again; Take stepwise process to reclaim HCl, improved the rate of recovery of HCl, reduced the corrosion to equipment, the bischofite among the present invention after refining can directly be calcined and obtain purity greater than 99% MgO, need not generate Mg (OH) through aquation
2Process, shortened technical process, it is low that the present invention simultaneously has calcining temperature, energy consumption is little, technical process is simple, the product purity height, raw material is simple, low cost and other advantages makes its heavy industrialization become possibility.
[description of drawings]
Fig. 1 process flow sheet of the present invention.
[embodiment]
The present invention below is provided a kind of embodiment for preparing basic magnesium chloride and method of magnesium oxide with the bischofite pyrolysis.
Embodiment 1
Bischofite hot solution pressurization after refining is sprayed to reactor, obtain solid hydrate, calcining temperature is 250 ℃ for the first time, calcination time 3 hours, calcining is used the methanol wash product after finishing, it is 96% MgOHCl that filtering drying gets purity, the bischofite rate of decomposition is 96%, and the tail gas of generation is through absorbing concentrated concentration greater than 28% hydrochloric acid, methanol loop utilization; To send in the secondary clacining stove without the product of washing simultaneously, be warming up to 450 ℃, calcined 3 hours, obtain purity and be 99.5% magnesium oxide, the HCl that calcining for the second time produces reclaims after condensation and obtains concentration greater than 28% hydrochloric acid, and residual gas reaches emission standard emptying discharge.
Embodiment 2
With embodiment 1 operational condition, calcining temperature is 280 ℃ for the first time, calcination time 2 hours, and the bischofite rate of decomposition is 96.5%, and the MgOHCl purity after methanol wash is 97%, and concentration of hydrochloric acid is greater than 28%; For the second time calcining temperature is 480 ℃, and calcination time 2 hours obtains purity and be 99.2% magnesium oxide, and concentration of hydrochloric acid is greater than 28%.
Embodiment 3
With embodiment 1 operational condition, calcining temperature is 300 ℃ for the first time, calcination time 1.5 hours, and the bischofite rate of decomposition is 96.2%, and the MgOHCl purity after methanol wash is 96.5%, and concentration of hydrochloric acid is greater than 28%; For the second time calcining temperature is 500 ℃, and calcination time 2 hours obtains purity and be 99.6% magnesium oxide, and concentration of hydrochloric acid is greater than 28%.
The above only is a preferred implementation of the present invention; should be pointed out that for those skilled in the art, without departing from the inventive concept of the premise; can also make some improvements and modifications, these improvements and modifications also should be considered within the scope of protection of the present invention.
Claims (9)
1. one kind prepares basic magnesium chloride and method of magnesium oxide with the bischofite pyrolysis, it is characterized in that concrete steps are:
(1) hot solution of bischofite under 130～150 ℃ after will making with extra care sprays to reactor through pressurization, acquisition is carried out the calcining first time after taking off the solid hydrate of partial crystallization water under 250～300 ℃, calcination time is 1～3 hour, obtain product basic magnesium chloride Mg OHCl, tail gas absorbs through water and obtains hydrochloric acid, and reaction equation is:
MgCl
2·nH
2O→MgOHCl+HCl+H
2O
(2) contain a small amount of undecomposed magnesium chloride hydrate in the calcinate, use the solvent wash product, obtain basic magnesium chloride Mg OHCl;
(3) with the basic magnesium chloride Mg OHCl that obtains in step (1) or (2), under 450～500 ℃, carry out the calcining second time, calcination time 1～3 hour obtains MgO, and the HCl of generation reclaims through cooling and obtains hydrochloric acid, and reaction equation is:
MgOHClMgO+HCl。
2. as claimed in claim 1ly a kind ofly prepare basic magnesium chloride and method of magnesium oxide with the bischofite pyrolysis, it is characterized in that in described step (1), described calcining temperature is 280 ℃, calcination time is 2 hours.
3. as claimed in claim 1ly a kind ofly prepare basic magnesium chloride and method of magnesium oxide, it is characterized in that in described step (1), described concentration of hydrochloric acid is 28～32% with the bischofite pyrolysis.
4. as claimed in claim 1ly a kind ofly prepare basic magnesium chloride and method of magnesium oxide, it is characterized in that in described step (2), described basic magnesium chloride Mg OHCl purity is greater than 96% with the bischofite pyrolysis.
5. as claimed in claim 1ly a kind ofly prepare basic magnesium chloride and method of magnesium oxide, it is characterized in that in described step (2), described solvent is selected from methyl alcohol or ethanol with the bischofite pyrolysis.
6. as claimed in claim 5ly a kind ofly prepare basic magnesium chloride and method of magnesium oxide, it is characterized in that described solvent is a methyl alcohol with the bischofite pyrolysis.
7. as claimed in claim 1ly a kind ofly prepare basic magnesium chloride and method of magnesium oxide, it is characterized in that in described step (3), described MgO purity is greater than 99% with the bischofite pyrolysis.
8. as claimed in claim 1ly a kind ofly prepare basic magnesium chloride and method of magnesium oxide, it is characterized in that in described step (3), described concentration of hydrochloric acid is 28～32% with the bischofite pyrolysis.
9. as claimed in claim 1ly a kind ofly prepare basic magnesium chloride and method of magnesium oxide with the bischofite pyrolysis, it is characterized in that in described step (3), described calcining temperature is 480 ℃, calcination time is 2 hours.
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Cited By (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106395865A (en) * | 2016-08-29 | 2017-02-15 | 中国科学院青海盐湖研究所 | Preparation method of basic magnesium chloride |
| CN107033454A (en) * | 2017-04-13 | 2017-08-11 | 郭峰 | A kind of method of nano antimony tin oxide/calcining basic magnesium chloride/nanometer zinc aluminate composite flame-proof MODIFIED PP/PS alloys |
| CN109437263A (en) * | 2018-12-25 | 2019-03-08 | 王晓明 | A kind of recovery method for magnesite wheel waste material |
| CN110015671A (en) * | 2019-04-12 | 2019-07-16 | 常州工学院 | A kind of preparation method of high purity magnesium oxide |
| CN111348844A (en) * | 2020-03-12 | 2020-06-30 | 辽宁科大中驰镁建材科技有限公司 | System and process for preparing light-burned magnesia powder by using low-grade high-calcium magnesite |
| CN112624162A (en) * | 2021-01-13 | 2021-04-09 | 中国科学院上海应用物理研究所 | Method for preparing industrial-grade magnesium oxide by taking bischofite as raw material |
| CN112850760A (en) * | 2021-02-26 | 2021-05-28 | 山东昌邑海能化学有限责任公司 | Method for producing high-purity magnesium oxide from high-concentration seawater |
| CN113184884A (en) * | 2021-06-18 | 2021-07-30 | 马鞍山市安工大工业技术研究院有限公司 | Method for recovering high-purity magnesium hydroxide by taking ethyl maltol waste residue as raw material |
| CN113213511A (en) * | 2021-06-21 | 2021-08-06 | 马鞍山市安工大工业技术研究院有限公司 | Method for recovering high-purity magnesium oxide by taking ethyl maltol waste residue as raw material |
| CN114180603A (en) * | 2020-12-11 | 2022-03-15 | 安徽金禾实业股份有限公司 | Method for producing active magnesium oxide from waste residues of spices |
| CN114408951A (en) * | 2021-12-06 | 2022-04-29 | 南京工业大学 | Method for preparing industrial-grade magnesium oxide and hydrochloric acid by using glass magnesium board solid waste |
-
2009
- 2009-08-07 CN CN200910056036A patent/CN101624198A/en active Pending
Cited By (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106395865A (en) * | 2016-08-29 | 2017-02-15 | 中国科学院青海盐湖研究所 | Preparation method of basic magnesium chloride |
| CN107033454A (en) * | 2017-04-13 | 2017-08-11 | 郭峰 | A kind of method of nano antimony tin oxide/calcining basic magnesium chloride/nanometer zinc aluminate composite flame-proof MODIFIED PP/PS alloys |
| CN109437263A (en) * | 2018-12-25 | 2019-03-08 | 王晓明 | A kind of recovery method for magnesite wheel waste material |
| CN110015671A (en) * | 2019-04-12 | 2019-07-16 | 常州工学院 | A kind of preparation method of high purity magnesium oxide |
| CN111348844A (en) * | 2020-03-12 | 2020-06-30 | 辽宁科大中驰镁建材科技有限公司 | System and process for preparing light-burned magnesia powder by using low-grade high-calcium magnesite |
| CN114180603A (en) * | 2020-12-11 | 2022-03-15 | 安徽金禾实业股份有限公司 | Method for producing active magnesium oxide from waste residues of spices |
| CN112624162A (en) * | 2021-01-13 | 2021-04-09 | 中国科学院上海应用物理研究所 | Method for preparing industrial-grade magnesium oxide by taking bischofite as raw material |
| CN112850760A (en) * | 2021-02-26 | 2021-05-28 | 山东昌邑海能化学有限责任公司 | Method for producing high-purity magnesium oxide from high-concentration seawater |
| CN113184884A (en) * | 2021-06-18 | 2021-07-30 | 马鞍山市安工大工业技术研究院有限公司 | Method for recovering high-purity magnesium hydroxide by taking ethyl maltol waste residue as raw material |
| CN113213511A (en) * | 2021-06-21 | 2021-08-06 | 马鞍山市安工大工业技术研究院有限公司 | Method for recovering high-purity magnesium oxide by taking ethyl maltol waste residue as raw material |
| CN114408951A (en) * | 2021-12-06 | 2022-04-29 | 南京工业大学 | Method for preparing industrial-grade magnesium oxide and hydrochloric acid by using glass magnesium board solid waste |
| CN114408951B (en) * | 2021-12-06 | 2023-12-26 | 南京工业大学 | Method for preparing industrial grade magnesium oxide and hydrochloric acid by utilizing solid waste of glass magnesium board |
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