CN102275964A - Method for extracting high-purity superfine aluminum oxide from coal ash - Google Patents
Method for extracting high-purity superfine aluminum oxide from coal ash Download PDFInfo
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- CN102275964A CN102275964A CN2011102086840A CN201110208684A CN102275964A CN 102275964 A CN102275964 A CN 102275964A CN 2011102086840 A CN2011102086840 A CN 2011102086840A CN 201110208684 A CN201110208684 A CN 201110208684A CN 102275964 A CN102275964 A CN 102275964A
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Abstract
The invention relates to a method for extracting high-purity superfine aluminum oxide from coal ash. The method comprises the following steps of: adding ammonium sulfate into the coal ash, and calcining to obtain a sintered material; dissolving the sintered material out of water, and cooling and crystallizing to form aluminum salt; adding the aluminum salt and a dispersing agent into ammonia water, and precipitating to ensure aluminum ions in the aluminum salt are precipitated to obtain aluminum hydroxide; and washing an aluminum hydroxide precipitate by using ethanol, drying and calcining at high temperature to obtain aluminum oxide powder of different crystalline forms. The method for extracting the high-purity superfine aluminum oxide from the coal ash is low in cost and small in investment, and the purity and extraction rate of the obtained aluminum oxide are high.
Description
Technical field
The present invention relates to a kind of method of from flyash, extracting high purity aluminium oxide, relate in particular to a kind of method of from flyash, extracting high-purity ultra-fine alumina.
Background technology
Flyash is the main solid waste that the coal-burning power plant discharges, and its important oxide components is silicon oxide and aluminum oxide, and wherein the composition of aluminum oxide is about 30%, and some geographic content is up to 50%.The present range of application of the aluminum oxide of high pure and ultra-fine is more and more wider, and demand is also increasing, China is because the restriction of bauxite self property, the aluminum oxide cost is higher, can't satisfy the demand of domestic and international market, therefore extracting high-purity ultra-fine alumina from flyash becomes the focus that people pay close attention to gradually.
(1) extract method of alumina from flyash, the research report from present has following several method:
The soda-lime method: the soda-lime method need be at sintering under the very high temperature (1200～1300 ℃), and power consumption is high; The lime large percentage that adds in the test produces a large amount of waste residues; Because contain a large amount of active silicas in the flyash, sila matter very easily enters in the dissolution fluid under alkaline condition, need to add related process and be removed; Such complex process, power consumption is high, and produces a large amount of waste residues.
(2) the direct stripping of acid/alkali is sent out: this method needs the acid/alkali of high density, and the requirement harshness to equipment is easy to generate secondary pollution, and the extraction yield of aluminum oxide is very low; Because the existence of these negative factors makes to be restricted from the industry of flyash extraction aluminum oxide.The relevant aluminium manufacturer of China carried out trial production in this respect, but because there are serious problems in technology and benefit, finally can only stop production.
Summary of the invention
The present invention is directed to the existing high-purity ultra-fine alumina that from flyash, extracts and have above-mentioned deficiency, a kind of method of extracting high-purity ultra-fine alumina from flyash is provided.
The technical scheme that the present invention solves the problems of the technologies described above is as follows: a kind of method of extracting high-purity ultra-fine alumina from flyash may further comprise the steps:
Step 1: ammonium sulfate joined to calcine in the flyash obtain sintered material;
Step 2: after the direct water stripping of sintered material, decrease temperature crystalline forms aluminium salt again;
Step 3: will aluminium salt and dispersion agent add in the ammoniacal liquor and precipitate, wherein aluminum ion precipitation is separated out is obtained aluminium hydroxide;
Step 4: use ethanol to aluminum hydroxide precipitation wash, after drying and the high-temperature calcination, thereby obtain the alumina powder jointed of different crystal forms.
On the basis of technique scheme, the present invention can also do following improvement.
Further, described step 1 places retort furnace with mixture then with the aluminum oxide that contains in ammonium sulfate and the flyash mixed by weight 3～10, calcines 60min～120min under 300 ℃～450 ℃.
In flyash, add ammonium sulfate and participate in calcination reaction, ammonium sulfate can react under lower temperature with the aluminum oxide in the flyash, therefore can reduce the incinerating temperature, reduce energy consumption, activating fly ash effectively, also the compound fine grinding can be improved the extraction yield of aluminum oxide so that solid state reaction is more abundant when calcining.The waste residue that produces of this technology is less in addition, and how based on silicon, can be used as sorbing material and utilizes this waste residue.The reaction that takes place in the incinerating process is as follows:
(NH
4)
2SO
4(s)→NH
4HSO
4(l)+NH
3(s)
Al
2O
3(s)+4NH
4HSO
4(l)→2NH
4Al(SO
4)
2(s)+2NH
3(s)+3H
2O(g)
4(NH
4)
2SO
4(s)+Al
2O
3(s)→2NH
4Al(SO
4)
2(s)+6NH
3(s)+3H
2O(g)
Further, be 1～8 to mix water and sintered material by mass ratio in the described step 2, and obtain dissolution fluid in 95 ℃ of following strippings, the solubility rate of aluminum oxide in the filtrate (solubility rate is the quality of aluminum oxide in the quality * 100%/flyash of aluminum oxide in the filtrate) can reach more than 75% like this, place 5 ℃～10 ℃ cold water to place the time that is greater than or equal to 5h described dissolution fluid, can be so that 99% exsiccated ammonium alum crystallization.
The direct water stripping of sintered material, decrease temperature crystalline.Water can because the cost of water is lower, can reduce reducing production costs with the whole strippings of exsiccated ammonium alum when high temperature.Exsiccated ammonium alum solubleness when low temperature is low-down, reduces temperature and can quicken the crystallization of exsiccated ammonium alum.
Further, be dispersion agent with the polyoxyethylene glycol in the described step 3, the dispersion agent that in the ammoniacal liquor of 0.5mol/L, adds 1% volume～3% volume, be that 1/3～1/4 ratio adds aluminium salt in ammoniacal liquor in the ratio of the ammonia mole number in aluminium salt and the ammoniacal liquor then, and at rotating speed is 900 r/min～1000r/min, and temperature precipitates under 50 ℃～60 ℃ condition.
Crystalline aluminium salt is equipped with certain dispersion agent adds in the ammoniacal liquor and precipitate, aluminum ion precipitation is wherein separated out, wherein the dispersion agent of Jia Ruing can stop the agglomeration between the aluminum hydroxide particles, makes the granularity of the aluminum oxide that obtains at last can reach nanometer scale; The precipitin reaction formula is: Al
3++ OH
-→ Al (OH)
3↓
Further, under 1250 ℃ dried aluminium hydroxide is calcined in the described step 4, it is single to obtain crystalline form, the α-Al of good dispersity
2O
3, its particle diameter is 40nm～70nm.
Aluminum hydroxide precipitation is washed, after drying and the high-temperature calcination, can obtain the alumina powder jointed of different crystal forms with ethanol, and reaction formula is as follows: 2Al (OH)
3→ α-Al
2O
3+ 3H
2O
The invention has the beneficial effects as follows: the present invention extracts high-purity ultra-fine alumina from flyash method cost is low, investment is little, the aluminum oxide purity that obtains can reach more than 99.9%, the extraction yield of aluminum oxide (quality of the aluminum oxide of converting in quality * 100%/aluminium salt of extraction yield for the aluminum oxide that obtains at last) can reach more than 99%, wherein the dispersion agent polyoxyethylene glycol of Jia Ruing can stop the agglomeration between the aluminum hydroxide particles, make the granularity of the aluminum oxide that obtains at last can reach nanometer scale, the mean particle size of aluminum oxide is between 40～70nm.
Embodiment
Below principle of the present invention and feature are described, institute gives an actual example and only is used to explain the present invention, is not to be used to limit scope of the present invention.
Embodiment 1
1, the low temperature calcination process:
With the aluminum oxide that contains in ammonium sulfate and the flyash mixed by weight 3, then mixed powder is placed retort furnace, at 300 ℃ of fully calcined 90min.
2, the stripping of aluminium salt, crystallisation process:
Is 1 to mix water and sintered material by mass ratio, be warming up to 95 ℃ of stripping 30min, the dissolution fluid that can obtain after the filtration remaining waste residue and contain aluminium, the solubility rate of aluminum oxide can reach 85% in the filtrate at this moment, places cold water (10 ℃) to place 5h the filtrate after the stripping.
3, precipitation process:
With PEG-400 (polyoxyethylene glycol) is dispersion agent, the dispersion agent that in the ammoniacal liquor of 0.5mol/L, adds 1% volume, be that 1/3 ratio adds aluminium salt in ammoniacal liquor in the ratio of ammonia mole number in aluminium salt and the ammoniacal liquor then, and be 900r/min that temperature precipitates under 50 ℃ condition at rotating speed.Filter cake after the filtration will be used absolute ethanol washing thorough washing 3 times, makes ethanol molecule replace the water molecules between the aluminium hydroxide.
4, heat treatment process:
Obtain white powder after earlier aluminum hydroxide precipitation being placed the dry 3h of vacuum dehydrating at lower temperature case.Place retort furnace at 1250 ℃ of insulation 1h then, the particle diameter of the aluminum oxide that obtains is 68nm, and purity is 99.94%, and extraction yield is 99.3%.
Embodiment 2
Step of preparation process is identical with embodiment 1, different calcining temperature differences must be low temperature calcination the time, present embodiment changes the calcining temperature in the step 1 into 350 ℃, the solubility rate of aluminum oxide is 75% in the filtrate that obtains, the particle diameter of the aluminum oxide that obtains is 64nm, purity is 99.96%, and extraction yield is 99.4%.
Embodiment 3
Step of preparation process is identical with embodiment 1, different calcining temperature differences must be low temperature calcination the time, present embodiment changes the calcining temperature in the step 1 into 450 ℃, the solubility rate of aluminum oxide is 79% in the filtrate that obtains, the particle diameter of the aluminum oxide that obtains is 58nm, purity is 99.93%, and extraction yield is 99.5%.
Embodiment 4
Step of preparation process is identical with embodiment 1, the different alumina weights that contain in ammonium sulfate and the flyash must be low temperature calcination the time than different, present embodiment changes the weight ratio in the step 1 into 5, the solubility rate of aluminum oxide is 82% in the filtrate that obtains, the particle diameter of the aluminum oxide that obtains is 45nm, purity is 99.95%, and extraction yield is 99.7%.
Embodiment 5
Step of preparation process is identical with embodiment 1, the different alumina weights that contain in ammonium sulfate and the flyash must be low temperature calcination the time than different, present embodiment changes the weight ratio in the step 1 into 10, the solubility rate of aluminum oxide is 84% in the filtrate that obtains, the particle diameter of the aluminum oxide that obtains is 63nm, purity is 99.92%, and extraction yield is 99.6%.
Embodiment 6
Step of preparation process is identical with embodiment 1, different must be that water is different with the mass ratio of sintered material in the stripping, crystallisation process of aluminium salt, present embodiment changes the mass ratio in the step 2 into 4, the solubility rate of aluminum oxide is 89% in the filtrate that obtains, the particle diameter of the aluminum oxide that obtains is 43nm, purity is 99.97%, and extraction yield is 99.8%.
Embodiment 7
Step of preparation process is identical with embodiment 1, different must be that water is different with the mass ratio of sintered material in the stripping, crystallisation process of aluminium salt, present embodiment changes the mass ratio in the step 2 into 8, the solubility rate of aluminum oxide is 85% in the filtrate that obtains, the particle diameter of the aluminum oxide that obtains is 58nm, purity is 99.94%, and extraction yield is 99.6%.
Embodiment 8
Step of preparation process is identical with embodiment 1, different must be (the volume ratio difference of polyoxyethylene glycol of PEG-400 in the precipitation process, present embodiment changes the volume ratio in the step 3 into 2%, the solubility rate of aluminum oxide is 75% in the filtrate that obtains, the particle diameter of the aluminum oxide that obtains is 50nm, purity is 99.98%, and extraction yield is 99.2%.
Embodiment 9
Step of preparation process is identical with embodiment 1, different must be (the volume ratio difference of polyoxyethylene glycol of PEG-400 in the precipitation process, present embodiment changes the volume ratio in the step 3 into 3%, the solubility rate of aluminum oxide is 86% in the filtrate that obtains, the particle diameter of the aluminum oxide that obtains is 48nm, purity is 99.95%, and extraction yield is 99.3%.
The above only is preferred embodiment of the present invention, and is in order to restriction the present invention, within the spirit and principles in the present invention not all, any modification of being done, is equal to replacement, improvement etc., all should be included within protection scope of the present invention.
Claims (5)
1. a method of extracting high-purity ultra-fine alumina from flyash is characterized in that, said method comprising the steps of:
Step 1: ammonium sulfate joined to calcine in the flyash obtain sintered material;
Step 2: after the direct water stripping of sintered material, decrease temperature crystalline forms aluminium salt again;
Step 3: will aluminium salt and dispersion agent add in the ammoniacal liquor and precipitate, wherein aluminum ion precipitation is separated out is obtained aluminium hydroxide;
Step 4: use ethanol to aluminum hydroxide precipitation wash, after drying and the high-temperature calcination, thereby obtain the alumina powder jointed of different crystal forms.
2. the method for from flyash, extracting high-purity ultra-fine alumina according to claim 1, it is characterized in that, described step 1 is with the aluminum oxide that contains in ammonium sulfate and the flyash mixed by weight 3～10, then mixture is placed retort furnace, calcine 60min～120min down in 300 ℃～450 ℃.
3. the method for from flyash, extracting high-purity ultra-fine alumina according to claim 1, it is characterized in that, be 1～8 to mix water and sintered material by mass ratio in the described step 2, and obtain dissolution fluid in 95 ℃ of following strippings, place 5 ℃～10 ℃ cold water to place the time that is greater than or equal to 5h described dissolution fluid.
4. the method for from flyash, extracting high-purity ultra-fine alumina according to claim 1, it is characterized in that, be dispersion agent with the polyoxyethylene glycol in the described step 3, the dispersion agent that in the ammoniacal liquor of 0.5mol/L, adds 1% volume～3% volume, be that 1/3～1/4 ratio adds aluminium salt in ammoniacal liquor in the ratio of the ammonia mole number in aluminium salt and the ammoniacal liquor then, and at rotating speed is 900 r/min～1000r/min, and temperature precipitates under 50 ℃～60 ℃ condition.
5. the method for extracting high-purity ultra-fine alumina from flyash according to claim 1 is characterized in that under 1250 ℃ dried aluminium hydroxide is calcined in the described step 4, it is single to obtain crystalline form, the α-Al of good dispersity
2O
3, its particle diameter is 40nm～70nm.
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103214014A (en) * | 2013-04-22 | 2013-07-24 | 河北科技大学 | Reaction device and method for producing aluminum oxide |
| CN106495193A (en) * | 2016-10-31 | 2017-03-15 | 航天推进技术研究院 | Based on the method that ethanol auxiliary agent extracts aluminum oxide in flyash using ammonium sulfate method |
| CN107697975A (en) * | 2017-11-17 | 2018-02-16 | 齐鲁工业大学 | A kind of high-efficiency defluorinating adsorbent green wood preparation method for material |
| CN108975410A (en) * | 2018-08-27 | 2018-12-11 | 合肥学院 | One kind extracting high-purity AlFeO from flyash3The method of powder |
| CN109592971A (en) * | 2017-09-30 | 2019-04-09 | 天津大学 | A kind of fused alumina zirconia abrasive material and preparation method thereof |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20010051121A1 (en) * | 2000-02-04 | 2001-12-13 | Barnett Robert J. | Process for treating alumina-bearing ores to recover metal values therefrom |
| CN101117228A (en) * | 2007-07-12 | 2008-02-06 | 中国铝业股份有限公司 | Method for extracting aluminium oxide from coal ash |
| CN102120593A (en) * | 2010-01-08 | 2011-07-13 | 北京世纪地和科技有限公司 | Method for extracting aluminum oxide from pulverized flue ash |
-
2011
- 2011-07-25 CN CN2011102086840A patent/CN102275964A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20010051121A1 (en) * | 2000-02-04 | 2001-12-13 | Barnett Robert J. | Process for treating alumina-bearing ores to recover metal values therefrom |
| CN101117228A (en) * | 2007-07-12 | 2008-02-06 | 中国铝业股份有限公司 | Method for extracting aluminium oxide from coal ash |
| CN102120593A (en) * | 2010-01-08 | 2011-07-13 | 北京世纪地和科技有限公司 | Method for extracting aluminum oxide from pulverized flue ash |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103214014A (en) * | 2013-04-22 | 2013-07-24 | 河北科技大学 | Reaction device and method for producing aluminum oxide |
| CN103214014B (en) * | 2013-04-22 | 2015-12-09 | 河北科技大学 | A kind of reaction unit and method thereof of producing aluminum oxide |
| CN106495193A (en) * | 2016-10-31 | 2017-03-15 | 航天推进技术研究院 | Based on the method that ethanol auxiliary agent extracts aluminum oxide in flyash using ammonium sulfate method |
| CN109592971A (en) * | 2017-09-30 | 2019-04-09 | 天津大学 | A kind of fused alumina zirconia abrasive material and preparation method thereof |
| CN107697975A (en) * | 2017-11-17 | 2018-02-16 | 齐鲁工业大学 | A kind of high-efficiency defluorinating adsorbent green wood preparation method for material |
| CN108975410A (en) * | 2018-08-27 | 2018-12-11 | 合肥学院 | One kind extracting high-purity AlFeO from flyash3The method of powder |
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Application publication date: 20111214 |