CN104445308A - Method for extracting alumina from fly ash in circulating fluidized bed - Google Patents
Method for extracting alumina from fly ash in circulating fluidized bed Download PDFInfo
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- CN104445308A CN104445308A CN201310420612.1A CN201310420612A CN104445308A CN 104445308 A CN104445308 A CN 104445308A CN 201310420612 A CN201310420612 A CN 201310420612A CN 104445308 A CN104445308 A CN 104445308A
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Abstract
The invention relates to a method for extracting alumina from fly ash in a circulating fluidized bed by using an acid method, which comprises the following steps: 1)using sulfuric acid for leaching the ground fly ash, filtering and separating to obtain high silicon slag; 2)performing a filtrate obtained in the step 1) and cooling to obtain an aluminum sulfate crystal containing impurity; 3)using hydrochloric acid for dissolving the aluminum sulfate crystal obtained in the step 2), introducing hydrogen chloride gas for supersaturating the solution to obtain the aluminium chloride crystal; and 4)performing pyrolysis on the aluminium chloride crystal obtained in the step 3) to obtain high purity alumina and hydrogen chloride gas, wherein the hydrogen chloride gas enables cyclic utilization. According to the invention, aluminium recovery rate in fly ash is high, the recovery rate can reach more than 85%, residue amount accounts for 10% of ash amount after extraction, sulfuric acid and hydrochloric acid enable cyclic utilization without regeneration, and secondary pollution can not generated on environment.
Description
Technical field
The invention belongs to flyash higher value application field, particularly a kind of novel method utilizing acid system to extract aluminum oxide from circulating fluid bed coal ash.
Background technology
In recent years, bring the sharply increase of solid waste coal ash quantity discharged while China's coal electricity industry develops rapidly, by 2007, the annual emissions of China's flyash more than 200,000,000 tons, and was still increasing year by year, and accumulative volume of cargo in storage is more than 2,500,000,000 tons.The flyash of a large amount of discharge had both taken a large amount of soil, and again to soil, water resources and air cause severe contamination.Therefore, the comprehensive utilization of flyash becomes the task of top priority.
At present, multiple fields such as flyash is building work, building are applied, although large usage quantity, its digestion amount is unable to catch up with the growth of quantity discharged far away, and belongs to low value-added, and the extensive style of low technical content utilizes.On the other hand, containing the abundant useful element such as aluminium, silicon, iron in flyash, wherein dioxide-containing silica 40 ~ 60%, alumina content 17 ~ 50%, iron oxide content 2 ~ 15%, extracts these useful matteies from flyash, becomes the focus of flyash higher value application.And current flyash higher value application mainly concentrates on the extraction aspect of aluminum oxide.
Domestic and international treated coal ash is broadly divided into alkaline process and acid system.In the sixties in last century, Poland just utilizes soda-lime sintering process to extract aluminum oxide from flyash, has built up the pilot plant producing 5000 tons of aluminum oxide and 350,000 tons of cement per year.Institute of Metallurgical Technology of Anhui Province of China and Anhui Cement research institute combine in the eighties has declared by limestone sintering, and sodium carbonate stripping extracts aluminum oxide from flyash, and residue for the production of the achievement of cement, and have passed expert statement.Although alkaline process treated coal ash report is a lot, have no industrialized report at present.Its reason is that alkali process is tediously long, and facility investment is large, and energy consumption is high, cost is high, and the level of residue produced is the several times of flyash, a large amount of cement market goods locally difficulties that residue is made, comprehensive benefit is poor, thus hinders the application of alkaline process in total utilization of PCA.
Compared with alkaline process, acidic process flyash has obvious advantage.Acid system, while effectively extracting aluminum oxide, can obtain silicon product, can be made into white carbon black further and sell after process.Acid technological process facility investment is little, and energy consumption is low, and cost is also low, and level of residue is little.But acid technological process also exists some problems: (1) acid-resistant system, particularly high-pressure acid-resistant equipment manufacturing cost is expensive; (2) aluminum salt solution deironing difficulty; (3) from useful component concentration low waste gas, regenerating acid is more difficult; (4) aluminium is trivalent element, LU quality Al
2o
3need a large amount of acid; (5) calcining and decomposing contains the difficulty of the many aluminium salt hydrate of crystal water a lot, and hear rate is large; (6) flyash acid-leaching reaction aluminium leaching yield is low, and time especially with coal-powder boiler flyash, leaching yield is less than 50%.In above-mentioned problems especially problem (2) and (3) more thorny, solve difficulty large, directly affects the industrial application of acid technological process.
Summary of the invention
The technical problem to be solved in the present invention is: for current acid technological process Problems existing, particularly aluminum salt solution deironing difficulty and regenerating acid is more difficult from useful component concentration low waste gas problem, a kind of method utilizing acid system to extract aluminum oxide from flyash is provided, aluminum salt solution does not need deironing, and acid solution does not need regeneration and direct circulation utilizes.
The technical solution used in the present invention is: a kind of method extracting aluminum oxide from circulating fluid bed coal ash, comprises the following steps:
1) flyash coming from circulating fluidized bed is ground to 200 ~ 400 orders, flyash after grinding mixes by the weight ratio of 1:1 ~ 6 with concentration 60% ~ 98% sulfuric acid, be heated to 180 ~ 240 DEG C of reactions 1 ~ 3 hour, reacted the washing of rear filtering separation and obtained high white residue;
2) be cooled to 0 ~ 5 DEG C after filtrate evaporation concentration step 1) obtained, separate out the Tai-Ace S 150 crystal containing impurity;
3) by step 2) the Tai-Ace S 150 crystal that obtains dissolves with concentration 25% ~ 36% hydrochloric acid again, the weight ratio of added Tai-Ace S 150 crystal and hydrochloric acid is 1:0.5 ~ 1, solvent temperature 80 ~ 120 DEG C, and pass into hydrogen chloride gas and make solution supersaturation, separate out aluminum chloride crystal;
4) aluminum chloride crystal step 3) obtained carries out roasting after separating, washing at 1000 ~ 1100 DEG C, obtains high purity aluminium oxide and hydrogen chloride gas, and hydrogen chloride gas returns step 3) recycle.
One during high white residue separating, washing adopts filter separation or subsider to be separated in described step 1).
In described step 1), high white residue separating, washing adopts the washing of one-level, secondary or multi-stage countercurrent or adopts the one in the washing of one-level, secondary or multistage advection.
The high white residue main component obtained in described step 1) is silicon-dioxide, can be used for preparing white carbon black, silica gel or other high silicon product.
Described step 2) in separate out the solution after Tai-Ace S 150 crystal be sulfuric acid, this sulfuric acid returns step 1) recycle.
Separating out the solution after aluminum chloride crystal in described step 3) is hydrochloric acid, directly turns back to recycle in flow process.
One during the washing of aluminum chloride crystal separation adopts filter separation or subsider to be separated in described step 4).
Its chemical composition of flyash handled by the present invention is mainly silicon-dioxide, aluminum oxide, ferric oxide, and content (quality proportion) corresponding to three is respectively 40 ~ 60%, 17 ~ 50%, 2 ~ 15%.The flyash exceeding this scope also can with reference to this method process.
With the method for other treated coal ash, particularly compared with other acid technological process, advantage applies of the present invention exists:
1 adopts circulating fluid bed coal ash to be raw material, and aluminium in flyash, silicon activity are high, and fully can leach in sulphuric acid soln, the leaching yield of aluminium is high, can reach more than 90%;
2 aluminum salt solutions do not need independent deironing, thus solve the problem of acid solution deironing difficulty;
Acid solution used in 3 leaching process does not need regeneration and direct circulation utilizes, and there is not the problem that in other acid technological process, regenerating acid is more difficult from concentration low waste gas;
4 technical process are simple, invest low, and in whole Technology, acid, gas all can realize recycle, can not cause secondary pollution to environment.
Accompanying drawing explanation
Fig. 1 is process flow diagram of the present invention.
Embodiment
Embodiment 1
(1) somewhere circulating fluidized bed aluminous fly-ash (chemical group prejudice table 1) is ground to 200 orders, flyash after grinding mixes by the weight ratio of 1:4 with concentration 85% sulfuric acid, be heated to 200 DEG C of reactions 2 hours, after having reacted, obtain high white residue through filtering separation washing.
(2) be cooled to 3 DEG C after filtrate evaporation concentration step (1) obtained, separate out Tai-Ace S 150, obtain the Tai-Ace S 150 crystal containing impurity after filtering separation, filtrate is sulfuric acid, turns back to recycle in flow process.
(3) Tai-Ace S 150 crystal concentration 31% hydrochloric acid (weight ratio of Tai-Ace S 150 crystal and hydrochloric acid is 1:0.8) step (2) obtained dissolves at 100 DEG C, and pass into hydrogen chloride gas and make solution supersaturation, separate out aluminum chloride, aluminum chloride crystal is obtained after filtering separation washing, filtrate is hydrochloric acid, turns back to recycle in flow process.
(4) the aluminum chloride crystal that step (3) obtains is carried out roasting at 1050 DEG C, obtain high purity aluminium oxide and hydrogen chloride gas, hydrogen chloride gas returns step (3) recycle.Know that in flyash, the rate of recovery of aluminium is about 88% as calculated.
Table 1 somewhere circulating fluidized bed aluminous fly-ash chemical constitution
| Composition | Al 2O 3 | SiO 2 | Fe 2O 3 | CaO | TiO 2 | K 2O | Na 2O | MgO | Burn alkali | Other | Amount to |
| Weight ratio/% | 48.20 | 38.33 | 1.85 | 3.42 | 1.1 | 0.33 | 0.21 | 0.09 | 5.21 | 1.26 | 100.00 |
Embodiment 2
(1) flyash as shown in table 1 for chemical constitution is ground to 300 orders, the flyash after grinding mixes by the weight ratio of 1:6 with concentration 98% sulfuric acid, is heated to 240 DEG C of reactions 3 hours, obtains high white residue after having reacted through filtering separation washing.
(2) be cooled to 5 DEG C after filtrate evaporation concentration step (1) obtained, separate out Tai-Ace S 150, obtain the Tai-Ace S 150 crystal containing impurity after filtering separation, filtrate is sulfuric acid, turns back to recycle in flow process.
(3) Tai-Ace S 150 crystal concentration 36% hydrochloric acid (weight ratio of Tai-Ace S 150 crystal and hydrochloric acid is 1:1) step (2) obtained dissolves at 120 DEG C, and pass into hydrogen chloride gas and make solution supersaturation, separate out aluminum chloride, aluminum chloride crystal is obtained after filtering separation washing, filtrate is hydrochloric acid, turns back to recycle in flow process.
(4) the aluminum chloride crystal that step (3) obtains is carried out roasting at 1100 DEG C, obtain high purity aluminium oxide and hydrogen chloride gas, hydrogen chloride gas returns step (3) recycle.Know that in flyash, the rate of recovery of aluminium is about 90% as calculated.
Embodiment 3
(1) somewhere circulating fluid bed coal ash (chemical group prejudice table 2) is ground to 400 orders, the flyash after grinding mixes by the weight ratio of 1:1 with concentration 60% sulfuric acid, is heated to 180 DEG C of reactions 1 hour, obtains high white residue after having reacted through filtering separation washing.
(2) be cooled to 0 DEG C after filtrate evaporation concentration step (1) obtained, separate out Tai-Ace S 150, obtain the Tai-Ace S 150 crystal containing impurity after filtering separation, filtrate is sulfuric acid, turns back to recycle in flow process.
(3) Tai-Ace S 150 crystal concentration 25% hydrochloric acid (weight ratio of Tai-Ace S 150 crystal and hydrochloric acid is 1:0.5) step (2) obtained dissolves at 80 DEG C, and pass into hydrogen chloride gas and make solution supersaturation, separate out aluminum chloride, aluminum chloride crystal is obtained after filtering separation washing, filtrate is hydrochloric acid, turns back to recycle in flow process.
(4) the aluminum chloride crystal that step (3) obtains is carried out roasting at 1000 DEG C, obtain high purity aluminium oxide and hydrogen chloride gas, hydrogen chloride gas returns step (3) recycle.Know that in flyash, the rate of recovery of aluminium is about 86% as calculated.
Table 2 somewhere circulating fluid bed coal ash chemical constitution
| Composition | Al 2O 3 | SiO 2 | Fe 2O 3 | CaO | TiO 2 | K 2O | Na 2O | MgO | Burn alkali | Other | Amount to |
| Weight ratio/% | 30.6 | 41.9 | 1.6 | 2.4 | 1.15 | 0.2 | 0.37 | 0.6 | 15.9 | 5.28 | 100.00 |
Embodiment 4
(1) flyash as shown in table 2 for chemical constitution is ground to 400 orders, the flyash after grinding mixes by the weight ratio of 1:4 with concentration 90% sulfuric acid, is heated to 200 DEG C of reactions 3 hours, obtains high white residue after having reacted through filtering separation washing.
(2) be cooled to 2 DEG C after filtrate evaporation concentration step (1) obtained, separate out Tai-Ace S 150, obtain the Tai-Ace S 150 crystal containing impurity after filtering separation, filtrate is sulfuric acid, turns back to recycle in flow process.
(3) Tai-Ace S 150 crystal concentration 31% hydrochloric acid (weight ratio of Tai-Ace S 150 crystal and hydrochloric acid is 1:0.8) step (2) obtained dissolves at 120 DEG C, and pass into hydrogen chloride gas and make solution supersaturation, separate out aluminum chloride, aluminum chloride crystal is obtained after filtering separation washing, filtrate is hydrochloric acid, turns back to recycle in flow process.
(4) the aluminum chloride crystal that step (3) obtains is carried out roasting at 1050 DEG C, obtain high purity aluminium oxide and hydrogen chloride gas, hydrogen chloride gas returns step (3) recycle.Know that in flyash, the rate of recovery of aluminium is about 87% as calculated.
Claims (6)
1. from circulating fluid bed coal ash, extract a method for aluminum oxide, it is characterized in that, comprise the following steps:
The flyash coming from circulating fluidized bed is ground to 200 ~ 400 orders, and the flyash after grinding mixes by the weight ratio of 1:1 ~ 6 with concentration 60% ~ 98% sulfuric acid, is heated to 180 ~ 240 DEG C of reactions 1 ~ 3 hour, has reacted the washing of rear filtering separation and has obtained high white residue;
Be cooled to 0 ~ 5 DEG C after filtrate evaporation concentration step 1) obtained, separate out the Tai-Ace S 150 crystal containing impurity;
By step 2) the Tai-Ace S 150 crystal that obtains dissolves with the hydrochloric acid of concentration 25% ~ 36% again, and the weight ratio of Tai-Ace S 150 crystal and hydrochloric acid is 1:0.5 ~ 1, and solvent temperature is 80 ~ 120 DEG C, and passes into hydrogen chloride gas and make solution supersaturation, separates out aluminum chloride crystal;
The aluminum chloride crystal that step 3) obtains carries out roasting after separating, washing at 1000 ~ 1100 DEG C, obtains high purity aluminium oxide and hydrogen chloride gas, and hydrogen chloride gas returns step 3) recycle.
2. a kind of method extracting aluminum oxide from circulating fluid bed coal ash according to claim 1, is characterized in that: in step 1), high white residue separating, washing adopts filter to be separated or subsider separation.
3. a kind of method extracting aluminum oxide from circulating fluid bed coal ash according to claim 1, is characterized in that: in step 1), high white residue separating, washing adopts the washing of one-level, secondary or multi-stage countercurrent or adopts the one in the washing of one-level, secondary or multistage advection.
4. a kind of method extracting aluminum oxide from circulating fluid bed coal ash according to claim 1, is characterized in that: in step 4), the washing of aluminum chloride crystal separation adopts filter to be separated or subsider separation.
5. a kind of method extracting aluminum oxide from circulating fluid bed coal ash according to claim 1, is characterized in that: step 2) in separate out Tai-Ace S 150 crystal after sulphuric acid soln return step 1) recycle.
6., according to a kind of method extracting aluminum oxide from circulating fluid bed coal ash that claim 1 or 5 is stated, it is characterized in that: in step 3), separate out the hydrochloric acid soln after aluminum chloride crystal, directly turn back to recycle in flow process.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106564921A (en) * | 2016-11-03 | 2017-04-19 | 中国神华能源股份有限公司 | Method for acid circulation in process of extracting alumina from fly ash through acid process |
| CN106745131A (en) * | 2017-02-20 | 2017-05-31 | 航天推进技术研究院 | The method that sulfuric acid activated hydrogen chloride crystallizes Joint Production high purity aluminium oxide |
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| US4242313A (en) * | 1980-03-21 | 1980-12-30 | Extraction Research & Development, Inc. | Processes for the recovery of alumina from fly ash and production of cement constituents |
| CN1792802A (en) * | 2005-12-31 | 2006-06-28 | 朔州市人民政府 | Process for extracting aluminium hydroxide from flyash |
| CN1923695A (en) * | 2006-09-15 | 2007-03-07 | 平朔煤炭工业公司 | Method of preparing aluminum oxide from fly ash |
| CN101397146A (en) * | 2007-09-29 | 2009-04-01 | 沈阳铝镁设计研究院 | Method for preparing alumina by using fly ash |
| CN102557091A (en) * | 2011-12-30 | 2012-07-11 | 西安航天科技工业公司 | Method for subsequent treatment of aluminum sulfate generated in technical process of extracting alumina from fly ash |
| CN102849767A (en) * | 2012-04-10 | 2013-01-02 | 沈阳金博新技术产业有限公司 | Method for preparing alumina by using power plant fly ash |
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2013
- 2013-09-16 CN CN201310420612.1A patent/CN104445308A/en active Pending
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4242313A (en) * | 1980-03-21 | 1980-12-30 | Extraction Research & Development, Inc. | Processes for the recovery of alumina from fly ash and production of cement constituents |
| CN1792802A (en) * | 2005-12-31 | 2006-06-28 | 朔州市人民政府 | Process for extracting aluminium hydroxide from flyash |
| CN1923695A (en) * | 2006-09-15 | 2007-03-07 | 平朔煤炭工业公司 | Method of preparing aluminum oxide from fly ash |
| CN101397146A (en) * | 2007-09-29 | 2009-04-01 | 沈阳铝镁设计研究院 | Method for preparing alumina by using fly ash |
| CN102557091A (en) * | 2011-12-30 | 2012-07-11 | 西安航天科技工业公司 | Method for subsequent treatment of aluminum sulfate generated in technical process of extracting alumina from fly ash |
| CN102849767A (en) * | 2012-04-10 | 2013-01-02 | 沈阳金博新技术产业有限公司 | Method for preparing alumina by using power plant fly ash |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106564921A (en) * | 2016-11-03 | 2017-04-19 | 中国神华能源股份有限公司 | Method for acid circulation in process of extracting alumina from fly ash through acid process |
| CN106564921B (en) * | 2016-11-03 | 2018-01-02 | 中国神华能源股份有限公司 | The method that acid recycles in flyash acidity extraction alumina technology |
| CN106745131A (en) * | 2017-02-20 | 2017-05-31 | 航天推进技术研究院 | The method that sulfuric acid activated hydrogen chloride crystallizes Joint Production high purity aluminium oxide |
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Application publication date: 20150325 |