CN102491382B - Method for preparing anhydrous magnesium chloride by utilizing ammonium camallite - Google Patents
Method for preparing anhydrous magnesium chloride by utilizing ammonium camallite Download PDFInfo
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- CN102491382B CN102491382B CN 201110393810 CN201110393810A CN102491382B CN 102491382 B CN102491382 B CN 102491382B CN 201110393810 CN201110393810 CN 201110393810 CN 201110393810 A CN201110393810 A CN 201110393810A CN 102491382 B CN102491382 B CN 102491382B
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- chloride anhydrous
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- ammonium carnallite
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Abstract
The invention relates to a method for preparing anhydrous magnesium chloride by utilizing ammonium camallite, which comprises the following steps: (1) heating the ammonium camallite at a certain temperature to prepare lower-water ammonium camallite, and (2) placing a covering on the lower-water ammonium camallite obtained in the step (1), and performing heating and reaction to prepare the anhydrous magnesium chloride. The method for preparing the anhydrous magnesium chloride by utilizing the ammonium camallite can shorten production process of the anhydrous magnesium chloride, improve production efficiency and reduce production cost and input cost for environmental protection.
Description
Technical field
The invention belongs to the preparing technical field of inorganic materials, specifically, relate to a kind of method for preparing Magnesium Chloride Anhydrous, adopt the Magnesium Chloride Anhydrous of present method preparation solution production MAGNESIUM METAL of can directly powering to use.
Background technology
The key link that adopts generating metal magnesium by electrolyzing magnesium chloride is the preparation Magnesium Chloride Anhydrous.The method for preparing Magnesium Chloride Anhydrous has:
(1) low water ammonium carnallite ammonia process prepares Magnesium Chloride Anhydrous.Yuichi Suzukaw specific operation process and principle to the method in patent US3798314 is described: will hang down first water ammonium carnallite (MgCl
2NH
4ClnH
2O, n=0.5-4) carry out preliminary hydro-extraction at 110 ℃-160 ℃, the product of preliminary hydro-extraction generates ammino ammonium carnallite MgCl at 200 ℃-400 ℃ with the ammonia contact reacts
2NH
4ClnNH
3(n=0.2-3).The ammino ammonium carnallite is calcined for some time at 712 ℃-900 ℃ just obtain Magnesium Chloride Anhydrous.The advantage of the method is that technique is simpler, and the Magnesium Chloride Anhydrous that makes can be directly used in electrolysis refining magnesium.Shortcoming is the large usage quantity of ammonia, and energy consumption is higher.
(2) the standby Magnesium Chloride Anhydrous of gas-solid reaction legal system.The Zhou Ningbo of Central South University described the method in 2005 in detail in Ph D dissertation " ammonium carnallite prepares Magnesium Chloride Anhydrous novel process and fundamental research ": with the low water ammonium carnallite (MgCl of raw material
2NH
4ClnH
2O, n=0.5-1.0) with after ammonium chloride mixes according to mass ratio at 1: 4 at 410 ℃ of thermal dehydrations, generate product ammino ammonium carnallite.The ammino ammonium carnallite is obtained Magnesium Chloride Anhydrous 700 ℃ of calcinings, and wherein magnesian massfraction is less than 0.1%.The advantage of the method is that processing unit is simple, and energy consumption is low, and the Magnesium Chloride Anhydrous purity that makes is high.Shortcoming is that the consumption of ammonium chloride is large, and ammonium chloride reclaims difficulty and easy blocking pipe in process of production.
(3) the bischofite gas-solid reaction prepares Magnesium Chloride Anhydrous.Zhou Ningbo is at document " the bischofite gas-solid reaction prepares Magnesium Chloride Anhydrous " (Zhou Ningbo, Xiao Hua, Chen Baizhen.The bischofite gas-solid reaction prepares Magnesium Chloride Anhydrous [J]. chemical research and application, 2010,22 (10): describe the method 1290-1294) in detail: with Bischofite in Salt lake (MgCl
26H
2O) 135 ℃ of dehydration 2h become low water of hydration chloromagnesite (MgCl under nitrogen protection
2NH
2O, n=1.6).Low water of hydration chloromagnesite mixes according to mass ratio with solid ammonium chloride at 1: 6.5, makes under the high temperature that the dividing potential drop of ammonia reaches more than the 49.6KPa in the reaction system, dewaters at 440 ℃ and calcines and became Magnesium Chloride Anhydrous in 12 minutes with 710 ℃ in 18 minutes.Magnesian massfraction meets the requirement that electrolytic magnesium is produced less than 0.15% in the Magnesium Chloride Anhydrous that makes.The advantage of the method is simple to operation, and solid ammonium chloride can recycling use.Shortcoming is that the consumption of ammonium chloride is excessive, so that production cost is high, ammonium chloride reclaims difficulty and easy blocking pipe in process of production.
(4) the magnesium oxide chlorination prepares Magnesium Chloride Anhydrous method (IG Farben method), it be agglomerate with magnesium oxide and reductive agent charcoal in the electrically heated shaft furnace with chlorine reaction (about 800 ℃) with preparation melting Magnesium Chloride Anhydrous, its shortcoming is that production efficiency is low, chlorine utilization is low and vent gas treatment has high input, and has chlorinated hydrocarbons in the exhaust.Patent US4269816 proposes a kind of shaft type stove chlorination method, it is to adopt carbon monoxide to make reductive agent directly to make the melting Magnesium Chloride Anhydrous from block magnesite under high temperature, chlorine effect, its advantage is to have saved the operation that magnesite makes magnesian calcination process and magnesium oxide and charcoal mixing briquetting piece, but require very pure magnesite raw material, and it exist still that production efficiency is low, chlorine utilization is low and vent gas treatment has high input and exhaust in have the shortcoming of chlorinated hydrocarbons.
(5) the standby Magnesium Chloride Anhydrous melt of melting chlorination Dehydration.A kind of method is that the employing chlorizating agent is the method for chlorine, discloses a kind of method of producing the melting Magnesium Chloride Anhydrous such as patent US3953574, and its utilizes contains MgO and H
2O is respectively 5% spraying drying MgCl
2Powder and solid carbon reductive agent and chlorine react under 800 ℃.Realize that this process is to finish in the square furnace of two series connection, the MgCl that finally obtains
2Fused solution contains and is lower than 0.5% MgO, but chlorine utilization is low.The US4981674 patent is with spray-dired MgCl
2Powder, magnesite or magnesium oxide add 750-850 ℃ MgCl
2In the fused solution, gaseous reactant chlorine and carbon monoxide are by melting MgCl
2Gas distributor in the pond enters the magnesium oxide reaction in fused solution formation tiny bubble and the pond, content of magnesia is reduced to below 0.1%, but still exists the gaseous reactant utilization ratio not high.Another kind method is that the employing chlorizating agent is the method for hydrogen chloride gas, has described the electrolytic solution (25%MgCl that hydrated magnesium chloride is added magnesium chloride containing such as Japanese Patent 32-9052
2) in, at 750 ℃ of lower injection anhydrous hydrogen chloride gas, make the Magnesium Chloride Anhydrous melt simultaneously, but the electrolysis of magnesium chloride liquid electrolysis graphite that consumption rate is more that makes, produce MAGNESIUM METAL per ton and will consume 13-15Kg graphite, the content of the large expression of graphite consumption MgO is high.The patent CN1146757A of Canada Noranda Metallurgy Inc. discloses a kind of method that directly contains Magnesium Chloride Anhydrous fused solution or electrolytic solution from the production of hydrated magnesium chloride feed, it is that hydrated magnesium chloride is fed from the magnesium eletrolysis pond in the stove that contains molten electrolyte to produce fused solution, furnace temperature remains on 450-650 ℃, simultaneously anhydrous hydrogen chloride gas is injected fused solution, and stir fused solution to disperse injecting gas, magnesium oxide is suspended state in the maintenance fused solution, make magnesium chloride dehydration and react with magnesium oxide, obtain the fused solution of enrichment Magnesium Chloride Anhydrous, the content of magnesia in the fused solution is not more than 0.2% (magnesium chloride in 100%).Utilize gas chlorination agent (HCl or Cl
2) in fused solution preparation contain the Magnesium Chloride Anhydrous melt and mainly have following point: a) gas chlorination agent utilization ratio is not high, because gas is difficult for realizing Uniform Dispersion in fused solution, and the chloridating gas concentration that needs to keep enough in whole fused solution just can make magnesium oxide be converted into magnesium chloride, and gas chlorination agent utilization ratio was very low when especially content of magnesia was low in the fused solution; B) when dehydration the moisture hydrogen chloride gas that obtains recycle the dehumidification system that needs a complexity, and this system cost and running cost are all very high.
The advanced strict sealing in magnesium eletrolysis pond, such as Norsk Hydro single-stage pond (US4308116) and the multistage pond of Alcan (US4560449), can prevent that like this moisture from immersing, this hermetic electrolyte pond advantage is relatively low (the about 10kWh/Kg-Mg of power consumption, the Dow electrolyzer is about 15kWh/Kg-Mg), graphite electrode consumption very low (generally need not change), do not produce that mud, purity of chlorine gas feeding are high (discharges Cl greater than 95%, Dow electrolyzer
2Less than 30%), but its requires to contain MgO content very low (magnesium chloride in 100%, magnesium oxide preferably are not more than 0.1%) in the electrolytic solution of Magnesium Chloride Anhydrous.As seen, the key link that reduces the electrolytic magnesium production cost be exactly with relatively simple technique realize economical, prepare the very low Magnesium Chloride Anhydrous of MgO content efficiently.
Summary of the invention
The present invention is directed to the deficiency that prior art exists, proposed a kind of method of utilizing ammonium carnallite to prepare Magnesium Chloride Anhydrous.Can under relatively simple processing condition, prepare Magnesium Chloride Anhydrous by described method, under some optimum condition, can prepare MgO content less than 0.1% Magnesium Chloride Anhydrous.
To achieve these goals, the present invention is achieved through the following technical solutions:
A kind of method of utilizing ammonium carnallite to prepare Magnesium Chloride Anhydrous may further comprise the steps:
(1) ammonium carnallite is heated to prepare low water ammonium carnallite;
(2) place coverture above low water ammonium carnallite, heat, reaction makes Magnesium Chloride Anhydrous.
Crystal water is 0～3 in the low water ammonium carnallite of step of the present invention (1) product, is low water ammonium carnallite.Step (1) preferably with ammonium carnallite 90 ℃～200 ℃ heating at least 1 hour to prepare low water ammonium carnallite; Further preferred 1～6 hour heat-up time.Other type of heating that can make the ammonium carnallite dehydration form low water ammonium carnallite all can be used for the present invention.
The present invention preferably is covered in solid powder on the low water ammonium carnallite that step (1) obtains and heats.Other modes that can make low water ammonium carnallite be in relative sealed environment that those skilled in the art can be known all can be used for implementing the present invention, for example will hang down the water ammonium carnallite directly is positioned in crucible or other sealed vessel, or after solid powder is covered in low water ammonium carnallite top, be positioned in the sealed vessel again.Solid powder does not participate in reaction, can reuse, and is conducive to reduce cost.Commercially available various solid powders all can be used for implementing the present invention, and the particle diameter of solid powder does not have particular restriction yet.Solid powder preferential oxidation aluminium of the present invention and/or quartz sand; The preferred 0.1 μ m～20mm of its particle diameter, further preferred 10 μ m～12mm.
The described type of heating of step (2) at first 200 ℃～550 ℃ lower reacting by heating 0.5～5 hour, then 600 ℃～850 ℃ reacting by heating 0.2～3 hour; Preferably at first 300～450 ℃ of lower reactions 0.5～2 hour, under 650 ℃～780 ℃ temperature, carried out 0.2～1 hour again.
The mass ratio preferred 1: 2～5 of low water ammonium carnallite of the present invention and solid powder, further preferred 1: 2.4.This mass ratio means optimum condition, and solid powder consumption in the present invention guarantees to be covered on the low water ammonium carnallite and gets final product.
The present invention can with in the step (2) in fire door or temperature lower again synthetic ammonium chloride be recycled to step (1) and reuse.
The raw material (for example, ammonium carnallite, quartz sand, aluminum oxide etc.) that adopts in the inventive method all is not specifically limited, and they all can adopt the common product that is purchased.Described raw material preferably is in powder type, and the particle diameter of described powder is not particularly limited.
The principle of the invention is as follows: low water ammonium carnallite at high temperature decomposites ammonia and hydrogen chloride gas, wherein ammonia can replace the crystal water in the low water ammonium carnallite, hydrogen chloride gas to a great extent the inhibited reaction thing hydrolysis and the magnesium oxide that is hydrolyzed generation can be converted into magnesium chloride.The effusion that the envrionment conditions that relatively seals under the high temperature has been slowed down ammonia and hydrogen chloride gas; so that dehydration reaction can fully be carried out; coverture has also cut off contacting of ambient atmosphere and product Magnesium Chloride Anhydrous; protected the Magnesium Chloride Anhydrous of easy hydrolysis, so that the product Magnesium Chloride Anhydrous has higher purity.Hydrogenchloride and ammonia be synthesis of solid ammonium chloride again to fire door or temperature lower, turn back in the step (1) with recycle, and when using solid powder, solid covers powder and does not participate in reaction, naturally separate with lower floor product Magnesium Chloride Anhydrous behind the end of processing, recyclable, thus reduce production costs, enhance productivity.
Compare with the prior art scheme, the present invention has following beneficial effect:
(1) directly prepares Magnesium Chloride Anhydrous with ammonium carnallite, compared with prior art, need not to add in addition a large amount of ammonium chloride, and the recovery of a small amount of ammonium chloride is also relatively easy, has reduced cost.(2) mass percent that magnesium oxide accounts for Magnesium Chloride Anhydrous in the Magnesium Chloride Anhydrous that makes satisfies advanced magnesium eletrolysis pond requirement less than 0.1%; (3) simple to requiring as the solid powder that covers: the granularity of solid powder is in 0.1 μ m～20mm scope, and mulch is not participated in reaction process, can recycle; (4) technique is simple, does not need special equipment and atmosphere protection, easy operation control.
In addition, the present invention can shorten the Production Flow Chart of producing Magnesium Chloride Anhydrous, enhance productivity, reduces production costs, and reduces the environmental protection input cost.
Description of drawings
Accompanying drawing 1 is for utilizing the Magnesium Chloride Anhydrous XRD figure spectrum of ammonium carnallite preparation in the embodiment of the invention one.
Below the present invention is described in more detail.But following example only is simple and easy example of the present invention, does not represent or limit the scope of the present invention, and interest field of the present invention is as the criterion with claims.
Embodiment
In the present invention, Magnesium Chloride Anhydrous meter based on 100%, magnesian content is less than 0.5% (that is, for the technique of common electrical solution production MAGNESIUM METAL in the acceptable electrolyte melt upper limit of contained magnesian content), preferably less than 0.1%.Therefore, the Magnesium Chloride Anhydrous prepared according to the methods of the invention solution production MAGNESIUM METAL of can directly powering is used.
In addition, in the present invention, unless otherwise noted, the described content that contains the magnesium oxide (MgO) in the Magnesium Chloride Anhydrous refers to the magnesian weight percentage in 100% Magnesium Chloride Anhydrous.
For the present invention is described better, be convenient to understand technical scheme of the present invention, typical but non-limiting embodiment of the present invention is as follows:
Raw material involved in the present invention is commercially available product, comprising:
Ammonium carnallite (self-control): be mixed with analytical pure Magnesium dichloride hexahydrate and analytical pure ammonium chloride;
Low water ammonium carnallite (self-control): with above-mentioned ammonium carnallite thermal dehydration preparation;
Aluminum oxide (analytical pure): Chemical Reagent Co., Ltd., Sinopharm Group, purity 〉=99.4%;
Quartz sand (analytical pure): Chemical Reagent Co., Ltd., Sinopharm Group, purity 〉=99.8%;
Magnesium dichloride hexahydrate (analytical pure): Xilong Chemical Co., Ltd, purity 〉=98%;
Ammonium chloride (analytical pure): Xilong Chemical Co., Ltd, purity 〉=99.5%.
Embodiment 1
Ammonium carnallite 160 ℃ of dehydrations 2.5 hours, is obtained low water ammonium carnallite (MgCl
2NH
4ClnH
2O, n=2).With the low Hydrated Ammonium carnallitite (MgCl of 5g
2NH
4ClnH
2O, n=2) grind in the crucible of the rear 30ml of adding.Then, the 12g aluminum oxide is covered on the low water ammonium carnallite material, crucible is added after the upper cover first 400 ℃ of lower insulations 1.5 hours, 700 ℃ of lower insulations 0.5 hour, so just obtained the obvious aluminum oxide of layering and Magnesium Chloride Anhydrous again.In this embodiment, take the feeding quantity of low water ammonium carnallite as 1.00 weight parts, the feeding quantity of aluminum oxide is 2.40 weight parts.
According to above-mentioned measuring method the Magnesium Chloride Anhydrous that obtains is characterized.Its result is as follows:
Sample composition is carried out the XRD material phase analysis, and composition is anhydrous MgCl
2, as shown in Figure 1.
Magnesium ion in the sample and chlorion are carried out titration, and the result is Cl
-: Mg
2+=1.98: 1, be 99.86% of sample total mass through the weight that calculates Magnesium Chloride Anhydrous; Water-soluble postprecipitation thing in the sample is carried out titration, and recording magnesian weight is 0.12% of Magnesium Chloride Anhydrous.
Moisture content in the sample is measured, recorded that moisture content is 0.23% in the sample.
Embodiment 2
Ammonium carnallite 160 ℃ of dehydrations 3 hours, is obtained low water ammonium carnallite (MgCl
2NH
4ClnH
2O, n=1.48).With the low Hydrated Ammonium carnallitite (MgCl of 5g
2NH
4ClnH
2O, n=1.48) grind in the crucible of the rear 30ml of adding.Then, 12g quartz sand is covered on the low water ammonium carnallite material, crucible is added after the upper cover first 400 ℃ of lower insulations 1.5 hours, 700 ℃ of lower insulations 0.5 hour, so just obtained layering obvious upper strata quartz sand and lower floor's Magnesium Chloride Anhydrous again.In this embodiment, take the feeding quantity of low water ammonium carnallite as 1.00 weight parts, the feeding quantity of quartz sand is 2.40 weight parts.
According to above-mentioned measuring method the Magnesium Chloride Anhydrous that obtains is characterized.Its result is as follows:
Sample composition is carried out the XRD material phase analysis, and composition is anhydrous MgCl
2
Magnesium ion in the sample and chlorion are carried out titration, and the result is Cl
-: Mg
2+=2.00: 1, be 99.94% of sample total mass through the weight that calculates Magnesium Chloride Anhydrous; Water-soluble postprecipitation thing in the sample is carried out titration, and recording magnesian weight is 0.03% of Magnesium Chloride Anhydrous.
Moisture content in the sample is measured, recorded that moisture content is 0.17% in the sample.
Embodiment 3
Ammonium carnallite 160 ℃ of dehydrations 3 hours, is obtained low water ammonium carnallite (MgCl
2NH
4ClnH
2O, n=1.69).With the low Hydrated Ammonium carnallitite (MgCl of 5g
2NH
4ClnH
2O, n=1.69) grind in the crucible of the rear 30ml of adding.Then, 12g quartz sand is covered on the low water ammonium carnallite material, crucible added after the upper cover crucible added after the upper cover first 400 ℃ of lower insulations 1.5 hours, 700 ℃ of lower insulations 0.5 hour, so just obtained layering obvious upper strata quartz sand and lower floor's Magnesium Chloride Anhydrous again.In this embodiment, take the feeding quantity of low water ammonium carnallite as 1.00 weight parts, the feeding quantity of quartz sand is 2.40 weight parts.
According to above-mentioned measuring method the Magnesium Chloride Anhydrous that obtains is characterized.Its result is as follows:
Sample composition is carried out the XRD material phase analysis, and composition is anhydrous MgCl
2
Magnesium ion in the sample and chlorion are carried out titration, and the result is Cl
-: Mg
2+=1.99: 1, be 99.88% of sample total mass through the weight that calculates Magnesium Chloride Anhydrous; Water-soluble postprecipitation thing in the sample is carried out titration, and recording magnesian weight is 0.04% of Magnesium Chloride Anhydrous.
Moisture content in the sample is measured, recorded that moisture content is 0.15% in the sample.
Embodiment 4
Ammonium carnallite 160 ℃ of dehydrations 3 hours, is obtained low water ammonium carnallite (MgCl
2NH
4ClnH
2O, n=1.62).With the low Hydrated Ammonium carnallitite (MgCl of 5g
2NH
4ClnH
2O, n=1.62) grind in the crucible of the rear 30ml of adding.Then, 12g quartz sand is covered on the low water ammonium carnallite material, crucible is added after the upper cover first 400 ℃ of lower insulations 1.5 hours, 700 ℃ of lower insulations 0.5 hour, so just obtained layering obvious upper strata quartz sand and lower floor's Magnesium Chloride Anhydrous again.In this embodiment, take the feeding quantity of low water ammonium carnallite as 1.00 weight parts, the feeding quantity of quartz sand is 2.40 weight parts.
According to above-mentioned measuring method the Magnesium Chloride Anhydrous that obtains is characterized.Its result is as follows:
Sample composition is carried out the XRD material phase analysis, and composition is anhydrous MgCl
2
Magnesium ion in the sample and chlorion are carried out titration, and the result is Cl
-: Mg
2+=1.98: 1, be 99.84% of sample total mass through the weight that calculates Magnesium Chloride Anhydrous; Water-soluble postprecipitation thing in the sample is carried out titration, and recording magnesian weight is 0.06% of Magnesium Chloride Anhydrous.
Moisture content in the sample is measured, recorded that moisture content is 0.32% in the sample.
Embodiment 5
Ammonium carnallite 160 ℃ of dehydrations 3.5 hours, is obtained low water ammonium carnallite (MgCl
2NH
4ClnH
2O, n=1.13).With the low Hydrated Ammonium carnallitite (MgCl of 5g
2NH
4ClnH
2O, n=1.13) grind in the crucible of the rear 30ml of adding.Then, 12g quartz sand is covered on the low water ammonium carnallite material, crucible is added after the upper cover first 400 ℃ of lower insulations 1.5 hours, again 700 ℃ of lower insulations 0.5 hour, so just obtained the Magnesium Chloride Anhydrous of layering obvious upper strata quartz sand and lower floor.In this embodiment, take the feeding quantity of low water ammonium carnallite as 1.00 weight parts, the feeding quantity of quartz sand is 2.40 weight parts.
According to above-mentioned measuring method the Magnesium Chloride Anhydrous that obtains is characterized.Its result is as follows:
Sample composition is carried out the XRD material phase analysis, and composition is anhydrous MgCl
2
Magnesium ion in the sample and chlorion are carried out titration, and the result is Cl
-: Mg
2+=2.00: 1, be 99.94% of sample total mass through the weight that calculates Magnesium Chloride Anhydrous; Water-soluble postprecipitation thing in the sample is carried out titration, and recording magnesian weight is 0.02% of Magnesium Chloride Anhydrous.
Moisture content in the sample is measured, recorded that moisture content is 0.20% in the sample.
Embodiment 6
Ammonium carnallite 160 ℃ of dehydrations 3.5 hours, is obtained low water ammonium carnallite (MgCl
2NH
4ClnH
2O, n=1.13).With the low Hydrated Ammonium carnallitite (MgCl of 5g
2NH
4ClnH
2O, n=1.13) grind in the crucible of the rear 30ml of adding.Then, 12g quartz sand is covered on the low water ammonium carnallite material, crucible is added after the upper cover 350 ℃ of lower insulations 1.5 hours, 700 ℃ of lower insulations 0.5 hour, so just obtained layering obvious upper strata quartz sand and lower floor's Magnesium Chloride Anhydrous again.In this embodiment, take the feeding quantity of low water ammonium carnallite as 1.00 weight parts, the feeding quantity of quartz sand is 2.40 weight parts.
According to above-mentioned measuring method the Magnesium Chloride Anhydrous that obtains is characterized.Its result is as follows:
Sample composition is carried out the XRD material phase analysis, and composition is anhydrous MgCl
2
Magnesium ion in the sample and chlorion are carried out titration, and the result is Cl
-: Mg
2+=1.99: 1, be 99.90% of sample total mass through the weight that calculates Magnesium Chloride Anhydrous; Water-soluble postprecipitation thing in the sample is carried out titration, and recording magnesian weight is 0.03% of Magnesium Chloride Anhydrous.
Moisture content in the sample is measured, recorded that moisture content is 0.17% in the sample.
Embodiment 7
Ammonium carnallite 90 ℃ of dehydrations 6 hours, is obtained low water ammonium carnallite (MgCl
2NH
4ClnH
2O, n=3).With the low Hydrated Ammonium carnallitite (MgCl of 5g
2NH
4ClnH
2O, n=3) grind in the crucible of the rear 30ml of adding.Then, 10g quartz sand is covered on the low water ammonium carnallite material, crucible is added after the upper cover 200 ℃ of lower insulations 5 hours, 850 ℃ of lower insulations 0.2 hour, so just obtained layering obvious upper strata quartz sand and lower floor's Magnesium Chloride Anhydrous again.In this embodiment, take the feeding quantity of low water ammonium carnallite as 1.00 weight parts, the feeding quantity of quartz sand is 2.00 weight parts.
According to above-mentioned measuring method the Magnesium Chloride Anhydrous that obtains is characterized.Its result is as follows:
Sample composition is carried out the XRD material phase analysis, and composition is anhydrous MgCl
2
Magnesium ion in the sample and chlorion are carried out titration, and the result is Cl
-: Mg
2+=1.97: 1, be 99.86% of sample total mass through the weight that calculates Magnesium Chloride Anhydrous; Water-soluble postprecipitation thing in the sample is carried out titration, and recording magnesian weight is 0.04% of Magnesium Chloride Anhydrous.
Moisture content in the sample is measured, recorded that moisture content is 0.13% in the sample.
Embodiment 8
Ammonium carnallite 200 ℃ of dehydrations 4 hours, is obtained low water ammonium carnallite (MgCl
2NH
4ClnH
2O, n=0).With the low Hydrated Ammonium carnallitite (MgCl of 5g
2NH
4ClnH
2O, n=0) 25g quartz sand is covered on the low water ammonium carnallite material after grinding, 550 ℃ of lower insulations 0.5 hour 600 ℃ of lower insulations 3 hours, have so just obtained layering obvious upper strata quartz sand and lower floor's Magnesium Chloride Anhydrous again.In this embodiment, take the feeding quantity of low water ammonium carnallite as 1.00 weight parts, the feeding quantity of quartz sand is 5.00 weight parts.
According to above-mentioned measuring method the Magnesium Chloride Anhydrous that obtains is characterized.Its result is as follows:
Sample composition is carried out the XRD material phase analysis, and composition is anhydrous MgCl
2
Magnesium ion in the sample and chlorion are carried out titration, and the result is Cl
-: Mg
2+=1.99: 1, be 99.96% of sample total mass through the weight that calculates Magnesium Chloride Anhydrous; Water-soluble postprecipitation thing in the sample is carried out titration, and recording magnesian weight is 0.015% of Magnesium Chloride Anhydrous.
Moisture content in the sample is measured, recorded that moisture content is 0.2% in the sample.
Embodiment 9
Ammonium carnallite 180 ℃ of dehydrations 1 hour, is obtained low water ammonium carnallite (MgCl
2NH
4ClnH
2O, n=2.12).With the low Hydrated Ammonium carnallitite (MgCl of 5g
2NH
4ClnH
2O, n=2.12) grind in the crucible of the rear 30ml of adding.Then, crucible is added after the upper cover 450 ℃ of lower insulations 0.5 hour, 650 ℃ of lower insulations 1 hour, so just obtained Magnesium Chloride Anhydrous again.
According to above-mentioned measuring method the Magnesium Chloride Anhydrous that obtains is characterized.Its result is as follows:
Sample composition is carried out the XRD material phase analysis, and composition is anhydrous MgCl
2
Magnesium ion in the sample and chlorion are carried out titration, and the result is Cl
-: Mg
2+=2.00: 1, be 99.88% of sample total mass through the weight that calculates Magnesium Chloride Anhydrous; Water-soluble postprecipitation thing in the sample is carried out titration, and recording magnesian weight is 0.02% of Magnesium Chloride Anhydrous.
Moisture content in the sample is measured, recorded that moisture content is 0.22% in the sample.
Embodiment 10
Ammonium carnallite 120 ℃ of dehydrations 5 hours, is obtained low water ammonium carnallite (MgCl
2NH
4ClnH
2O, n=1.04).With the low Hydrated Ammonium carnallitite (MgCl of 5g
2NH
4ClnH
2O, n=1.04) grind in the crucible of the rear 30ml of adding.Then, 12g quartz sand is covered on the low water ammonium carnallite material, crucible is added after the upper cover 300 ℃ of lower insulations 2 hours, 780 ℃ of lower insulations 0.2 hour, so just obtained layering obvious upper strata quartz sand and lower floor's Magnesium Chloride Anhydrous again.In this embodiment, take the feeding quantity of low water ammonium carnallite as 1.00 weight parts, the feeding quantity of quartz sand is 2.40 weight parts.
According to above-mentioned measuring method the Magnesium Chloride Anhydrous that obtains is characterized.Its result is as follows:
Sample composition is carried out the XRD material phase analysis, and composition is anhydrous MgCl
2
Magnesium ion in the sample and chlorion are carried out titration, and the result is Cl
-: Mg
2+=1.99: 1, be 99.82% of sample total mass through the weight that calculates Magnesium Chloride Anhydrous; Water-soluble postprecipitation thing in the sample is carried out titration, and recording magnesian weight is 0.03% of Magnesium Chloride Anhydrous.
Moisture content in the sample is measured, recorded that moisture content is 0.23% in the sample.
To being described as follows of experimental result: the present invention is in the characterization of Magnesium Chloride Anhydrous, moisture determination is carried out in moisture tester, before carrying out moisture measurement, need in samples weighing and the adding tester, because the characteristic that Magnesium Chloride Anhydrous very easily absorbs water, in whole test process, Magnesium Chloride Anhydrous can absorb the water in the portion of air, Magnesium Chloride Anhydrous, magnesium oxide is to measure in the different time with diverse ways with water, therefore the three's of experimental result demonstration percentage composition sum is greater than 100%, belong to normal experimental error, but still can satisfy product requirement.
The embodiment of the invention is according to following method the Magnesium Chloride Anhydrous of preparation to be tested:
1. titration measuring chlorine magnesium ion ratio is to determine the content of Magnesium Chloride Anhydrous in sample: the content to the magnesium ion in the molten salt system and chlorion is measured, and measuring method is seen GB/T 15428-95 " Ca in the industrial circulating cooling water
2+And Mg
2+Mensuration-EDTA volumetry " and GB/T 15453-95 " mensuration-silver nitrate titration method of chlorion in the industrial circulating cooling water ".With 1: 100 sulfuric acid (analytical pure, the purity 95.98% of product sample with preparation; Producer: Beijing North fine chemicals limited liability company) measure after the solution dissolving wherein magnesium ion and the content of chlorion.Come thus to determine the content of Magnesium Chloride Anhydrous in the sample.
2. titration measuring sample aqueous solution throw out is to determine the content of magnesium oxide in Magnesium Chloride Anhydrous: the Magnesium Chloride Anhydrous sample that obtains is soluble in water, the aqueous solution is filtered three times repeatedly at least until till filtrate clarifies especially with the quantitative paper (Hangzhou Special Paper Industry Co., Ltd.) of four Ф 90mm.Filter paper is washed the magnesium ion that adheres to above with flush away repeatedly with deionized water, the filter paper that contains magnesium oxide particle after washing is put into beaker, add 1: 100 sulfuric acid (analytical pure, the purity 95.98% of excessive preparation; Producer: Beijing North fine chemicals limited liability company), on electric furnace with the beaker heated and boiled and leave standstill to make in five minutes and react completely.Solution in the beaker is carried out the EDTA titration with the content of definite magnesium ion, thereby obtain magnesian content in the Magnesium Chloride Anhydrous.
Above precondition according to magnesian content in the volumetry calculating Magnesium Chloride Anhydrous is can not have MgOHCl in the melt.MgOHCl is converted into MgO fully in the time of 500 ℃ time is 30 minutes, and the time that transforms when temperature is higher can shorten.Judge that thus MgOHCl can all be converted into MgO under the condition of this patent embodiment, namely sedimentary composition only has magnesium oxide to exist.[Data Source is seen document: Kashani-Nejad, S., K.Ng, et al. (2005). " MgOHCl kinetics of thermal decomposition (MgOHCl thermaldecomposition kinetics.) " metallurgical and material communique (Metallurgical and MaterialsTransactions B) 2005].
3. the mensuration of moisture content in the sample.The sample that obtains with this art breading is because be incubated the long period under comparatively high temps, should not contain free water or crystal water in the sample, even there is water also to generate magnesium oxide with the anhydrous chlorides of rase reactive magnesium under so high temperature, the moisture that experiment measures all is the moisture of absorption of sample in the mensuration process and in normal temperature preservation process.The mensuration of moisture adopts karl Fischer titration measuring moisture, and instrument adopts the KF-1B type moisture content tester [concrete grammar referring to: " " preparation of basic magnesium chloride and the research of physicochemical property thereof " " " salt lake science and technology data (1980) "] of instrucment and meter plant of Shanghai Chemical Research Inst
In addition, use X-ray diffractometer (model: X ' Pert PRO MPD; Producer: Philips) adopt X-ray diffraction (XRD) to determine the existence of Magnesium Chloride Anhydrous.
Result by above embodiment can see, in the prepared Magnesium Chloride Anhydrous of the method for utilizing ammonium carnallite to prepare Magnesium Chloride Anhydrous according to the present invention, objectionable impurities magnesium oxide can be controlled to as 0.5% of the upper limit of industrial application with respect to the content of Magnesium Chloride Anhydrous.In addition, through after optimizing, the content of objectionable impurities magnesium oxide with respect to Magnesium Chloride Anhydrous can be controlled to below 0.1%, reach the requirement of the advanced electrolytic magnesium technique in the world to raw material.
Applicant's statement, the present invention illustrates preparation process of the present invention by above-described embodiment, but the present invention is not limited to above-mentioned preparation process, does not mean that namely the present invention must rely on above-mentioned preparation process and could implement.The person of ordinary skill in the field should understand, any improvement in the present invention to the interpolation of the equivalence replacement of the selected raw material of the present invention and ancillary component, the selection of concrete mode etc., all drops within protection scope of the present invention and the open scope.
Claims (8)
1. method of utilizing ammonium carnallite to prepare Magnesium Chloride Anhydrous may further comprise the steps:
(1) ammonium carnallite is heated to prepare low water ammonium carnallite;
(2) place coverture above low water ammonium carnallite, heat, reaction makes Magnesium Chloride Anhydrous;
Described coverture is solid powder, and described solid powder is aluminum oxide and/or quartz sand;
The mass ratio of described low water ammonium carnallite and solid powder is 1:2～5;
The described type of heating of step (2) at first 200 ℃～550 ℃ lower reacting by heating 0.5～5 hour, then 600 ℃～850 ℃ reacting by heating 0.2～3 hour.
2. the method for claim 1 is characterized in that, crystal water is 0～3 in the low water ammonium carnallite of the product of described step (1).
3. method as claimed in claim 1 or 2 is characterized in that, described step (1) with ammonium carnallite 90 ℃～200 ℃ heating at least 1 hour to prepare low water ammonium carnallite.
4. method as claimed in claim 3 is characterized in that, described step (1) is 1～6 hour with ammonium carnallite 90 ℃～200 ℃ heat-up times.
5. method as claimed in claim 4 is characterized in that, described solid powder particle diameter is 0.1 μ m～20mm.
6. method as claimed in claim 5 is characterized in that, described solid powder particle diameter is 10 μ m～12mm.
7. the method for claim 1 is characterized in that, the described type of heating of step (2), carried out 0.2～1 hour under 650 ℃～780 ℃ temperature 300～450 ℃ of lower reactions 0.5～2 hour at first again.
8. the method for claim 1 is characterized in that, the mass ratio of described low water ammonium carnallite and solid powder is 1:2.4.
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3282642A (en) * | 1963-11-04 | 1966-11-01 | Dow Chemical Co | Preparation of anhydrous magnesium chloride from hydrous ammonium carnallite |
| US5514359A (en) * | 1993-04-06 | 1996-05-07 | Alcan International Limited | Process for making anhydrous magnesium chloride |
| CN1689973A (en) * | 2004-04-29 | 2005-11-02 | 中南大学 | Preparation method of high-purity anhydrous magnesium chloride |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3282642A (en) * | 1963-11-04 | 1966-11-01 | Dow Chemical Co | Preparation of anhydrous magnesium chloride from hydrous ammonium carnallite |
| US5514359A (en) * | 1993-04-06 | 1996-05-07 | Alcan International Limited | Process for making anhydrous magnesium chloride |
| CN1689973A (en) * | 2004-04-29 | 2005-11-02 | 中南大学 | Preparation method of high-purity anhydrous magnesium chloride |
Non-Patent Citations (1)
| Title |
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| 周宁波 等.铵光卤石热脱水及热分解动力学.《中南大学学报（自然科学版）》.2008,第39卷(第2期),311-316. * |
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