CN102502735B - Method for producing alumina by using pulverized fuel ash - Google Patents
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- CN102502735B CN102502735B CN201110342628.6A CN201110342628A CN102502735B CN 102502735 B CN102502735 B CN 102502735B CN 201110342628 A CN201110342628 A CN 201110342628A CN 102502735 B CN102502735 B CN 102502735B
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Abstract
The invention relates to a method for preparing alumina by using pulverized fuel ash. The method comprises the following steps of: (1) preparing raw meal; (2) baking clinker; (3) recovering ammonia gas; (4) dissolving the clinker out; (5) separating and washing high-silicon residues; (6) preparing alumina with an obtained aluminum sulfate solution; and (7) evaporating an ammonia sulfate solution. The method has the advantages and effects that: no aid is added, so that alumina in pulverized fuel ash can be extracted effectively, and the extraction ratio of alumina can be over 85 percent. In the process flow of the method, circulation of ammonia sulfate is realized, so that alumina can be extracted from pulverized fuel ash in batches by circulating; no waste gas or waste liquid is discharged in an entire process; and a major component in residues left by extraction of alumina from pulverized fuel ash is carbon dioxide which is easy to utilize. A reaction system is a weakly acid system, equipment is easy to handle, and industrialization is facilitated.
Description
Technical field
The present invention relates to a kind of method of utilizing industrial solid castoff to produce aluminum oxide, relate in particular to a kind of method of coal ash for manufacturing for aluminum oxide of utilizing.
Background technology
Flyash is the solid waste that coal-burning power plant discharges.China's flyash annual emissions in 2010 is up to 3.5 hundred million tons, and total volume of cargo in storage of China's flyash has more than 50 hundred million tons.A large amount of soils are are not only occupied in the discharge of a large amount of flyash, and serious environment pollution, have formed the dual destruction to ecosystem environment.Therefore the comprehensive utilization of carrying out flyash has Great significance and long-range strategic importance.Equally, China is a country that bauxite resource is not rich in, and by the rate of growth of current aluminum oxide output and bauxite recovery rate, even if consider prospective reserves, the time limit of the bauxite of China is also difficult to reach 30 years.So the method that solves this crisis of resource has two kinds: the one, rationally utilize existing bauxite resource; The 2nd, actively look for and utilize other to contain bauxite resource.And aluminum oxide is one of main component of flyash, its massfraction is generally 10% ~ 40%, reaches as high as 58%.So, carry out and from flyash, extract the pollution that the research work of aluminum oxide can solve flyash, turn waste into wealth.
At present, from flyash, extract aluminum oxide research comparative maturity have limestone sintering method and a soda-lime sintering process, both are commonly referred to as alkaline process for this.In December, 2004, Inner Mongolia Autonomous Region Science and Technology Department held " flyash extracts aluminum and coproducing cement industrialization technology " project appraisal of scientific and technological achievements meeting of Liao Mengxi new and high technology Group Co.,Ltd research and development, employing be exactly improved soda-lime sintering process.But in alkaline process extract powder coal ash also there are some problems in aluminum oxide, it is mainly the calcium silicate slag that 1. sintering process produces, can only be used as cement raw material, the aluminum oxide that every production is 1 ton will produce the calcium silicate slag that is several times as much as flyash, and cement has its corresponding radius of selling, do not have large-scale Cement industry support will cause secondary pollution if local; 2. sintering process has only been extracted the aluminum oxide in flyash, and the utility value of its silicon-dioxide is low.3. the facility investment of sintering process treated coal ash is large, and energy consumption is high, and cost is high.
Because the alumina silica ratio of flyash is very low, be generally all less than 1, so adopt acidic process flyash more reasonable in principle.Acid or acidic cpd react the aluminium salt generating with the aluminum oxide in flyash, aluminium salt enters solution after dissolving, and silicon does not react with acid or acidic cpd, completely in solid phase slag.Acidic process flyash can overcome the deficiency of sintering process, can not produce the solid waste more than raw material powder coal ash, and extract after aluminum oxide, silicon-dioxide meeting enrichment, in slag, its content can reach 80 ~ 90%(by alumina extraction ratio 85%), be so more conducive to its utilization.It is feasible that acid system (comprising sulfuric acid process and salt acid system) treated coal ash is produced aluminum oxide in principle, but because acid has severe corrosive, the etching problem of equipment and pipeline restricts its large-scale application.
Adopt ammonium sulfate sintering process treated coal ash to extract aluminum oxide and become the direction of vast researcher research, adopting ammonium sulfate is that circulatory mediator does not add extra increment material, silicon-dioxide meeting enrichment in slag the same as acid system, but without strong corrosive material, be easy to industrialization promotion in whole technological process.
Summary of the invention
The invention provides a kind of method of coal ash for manufacturing for aluminum oxide of utilizing for solving the problems of the technologies described above, do not add any auxiliary agent, in flyash, alumina extraction ratio is high, and ammonium sulfate cycle efficiency is high.
A kind of method of coal ash for manufacturing for aluminum oxide of utilizing of the present invention for achieving the above object, it comprises the steps: the preparation of (1) raw material: flyash and ammonium sulfate are mixed and made into raw material, and wherein the weight ratio of the aluminum oxide in ammonium sulfate and flyash is 4.5～8:1; (2) grog burns till: raw material are heated to 350 ~ 700 ℃, and firing time is controlled at 0.5 ~ 5h, makes grog and the ammonia of sulfur acid aluminium, and ammonia is for the preparation of ammoniacal liquor or pass into Tai-Ace S 150 decomposition process; (3) Ammonia recovery: the ammonia and the grog that adopt water or washing lotion to absorb the generation of grog sintering process burn till the CO that decomposition produces with alum liquor of generation
2, form ammonium salt; (4) grog stripping: grog hot water stripping, dissolution time 0.1 ~ 2h, aluminium enters solution with the form of Tai-Ace S 150, and silicon is stayed and in residue, is formed high white residue; (5) high white residue separating, washing: the slurries after stripping carry out solid-liquid separation and countercurrent washing, and solution is alum liquor, washing rear slag is high white residue; (6) alum liquor obtaining is prepared aluminum oxide; (7) ammoniumsulphate soln evaporation: separate the ammoniumsulphate soln obtaining and evaporate, obtain being applicable to ammoniumsulphate soln or the ammonia sulfate crystal of batching.
The described alum liquor obtaining is prepared aluminum oxide: the ammonium salt that adds Ammonia recovery operation to obtain to alum liquor, obtains aluminium hydroxide, ironic hydroxide, ammoniumsulphate soln and CO
2gas, solid is the thick aluminium hydroxide that foreign matter content is many; Thick aluminium hydroxide carries out the processing of low temperature Bayer process with circulation alkali solution, removes wherein iron, calcium impurities, obtains aluminum oxide and high scum.
The described alum liquor obtaining is prepared aluminum oxide: add the ammonium salt that Ammonia recovery operation obtains to regulate pH value fractional precipitation ironic hydroxide and aluminium hydroxide to alum liquor, pH value is 1.5 ~ 3.5 precipitation ironic hydroxides, isolate after high scum, continue to add ammonium salt to obtain aluminium hydroxide, ammoniumsulphate soln and CO in solution
2gas, aluminium hydroxide roasting at 900 ~ 1300 ℃ obtains finished product aluminum oxide.
The described alum liquor obtaining is prepared aluminum oxide: alum liquor is by multi-stage counter current extraction deironing, and the ammonium salt that the alum liquor after deironing adds Ammonia recovery operation to obtain, obtains aluminium hydroxide, ammoniumsulphate soln and CO
2gas, aluminium hydroxide roasting at 900 ~ 1300 ℃ obtains finished product aluminum oxide.
The described alum liquor obtaining is prepared aluminum oxide: alum liquor is by ion exchange resin deironing, and the ammonium salt that the alum liquor after deironing adds Ammonia recovery operation to obtain, obtains aluminium hydroxide, ammoniumsulphate soln and CO
2gas, aluminium hydroxide roasting at 900 ~ 1300 ℃ obtains finished product aluminum oxide.
Described raw material preparation is the one adopting in dry method batch mixing or material by wet type mixing; The main component of described high white residue is silicon-dioxide, for the preparation of the silicon series product such as white carbon black or high silicon filler.
It is the full bayer process flow process of producing aluminum oxide that described employing Bayer process is processed thick aluminium hydroxide, comprises raw pulp allotment, low temperature stripping, red mud separating, washing, decomposing sodium aluminate solution, aluminium hydroxide separating, washing and Aluminium hydroxide roasting operation.
The extraction agent that described alum liquor extraction deironing adopts is the one in lipid acid, primary amine or tertiary amine;
The anionite-exchange resin that described ion exchange resin deironing adopts or the one of Zeo-karb;
Described high scum or ironic hydroxide can be used as iron-smelting raw material.
Advantageous effect of the present invention: the present invention does not add any auxiliary agent, effectively aluminum oxide in extract powder coal ash, the extraction yield of aluminum oxide can reach more than 85%.In technical process of the present invention, realize ammonium sulfate circulation, aluminum oxide in extract powder coal ash that can be many batches of by circulation, whole process does not have the discharge of waste gas, waste liquid, and the residue main component that flyash extracts after aluminum oxide is silicon-dioxide, is easy to utilize.Reaction system of the present invention is weak acid system, and equipment easily solves, and is beneficial to industrialization.
Accompanying drawing explanation
Fig. 1 ~ Fig. 4 is process flow sheet of the present invention.
Embodiment
embodiment 1
Raw material powder coal ash consists of: Al
2o
3: 41%, SiO
2: 48%, Fe
2o
3: 3.3%, CaO:3.3%, TiO
2: 1.3%, MgO:0.2%.Raw material powder coal ash composition also can adopt other moiety, and this can not be used for limiting protection scope of the present invention.
Get the flyash of the above-mentioned composition of 1000g, flyash is obtained to raw material with ammoniumsulphate soln mixing wet-milling, wherein the weight ratio of the aluminum oxide in ammonium sulfate and flyash is 5:1; Raw material are heated to 450 ℃, and insulation 1h, makes grog, and water absorbs the ammonia, the CO that discharge
2decompose with alum liquor the CO producing
2make ammonium salt, decompose for Tai-Ace S 150; Grog is stripping 0.5h in hot water, and aluminium enters solution with the form of Tai-Ace S 150, and silicon is stayed and in residue, formed high white residue; Stripping rear slurry is through solid-liquid separation and countercurrent washing, and liquid is alum liquor, and solid is high white residue; To the ammonium salt that adds Ammonia recovery to obtain in alum liquor, make aluminium, iron precipitation in solution become rough aluminium hydroxide, liquid is ammoniumsulphate soln, gas is CO
2; Rough aluminum hydroxide slurry separating, washing obtains rough aluminium hydroxide solid and ammoniumsulphate soln; Ammoniumsulphate soln returns to raw material preparation after evaporation, recycles; Roughly carry out the processing of low temperature Bayer process with circulation alkali solution, remove the wherein impurity such as iron, calcium, obtain aluminum oxide and high scum.It is the full bayer process flow process of producing aluminum oxide that Bayer process is processed thick aluminium hydroxide, comprises raw pulp allotment, low temperature stripping, red mud separating, washing, decomposing sodium aluminate solution, aluminium hydroxide separating, washing and Aluminium hydroxide roasting operation.
embodiment 2
The raw material powder coal ash of getting composition in 1000g embodiment 1, obtains raw material by raw material powder coal ash and ammonium sulfate circulation fluid material by wet type mixing, and wherein the weight ratio of the aluminum oxide in ammonium sulfate and flyash is 6:1; Raw material are heated to 500 ℃, and insulation 3h, makes grog, and water absorbs the ammonia, the CO that discharge
2decompose with alum liquor the CO producing
2make ammonium salt, decompose for Tai-Ace S 150; Grog is stripping 1h in hot water, and aluminium enters solution with the form of Tai-Ace S 150, and silicon is stayed and in residue, formed high white residue; Stripping rear slurry is through solid-liquid separation and countercurrent washing, and liquid is alum liquor, and solid is high white residue; To the ammonium salt that adds Ammonia recovery to obtain in alum liquor, regulate pH value to 2.5 precipitation ironic hydroxide, to isolate after high scum, continuation adds ammonium salt to obtain aluminium hydroxide, ammoniumsulphate soln and CO in alum liquor
2, ammoniumsulphate soln returns to raw material preparation after evaporation, recycles; Aluminium hydroxide roasting at 1150 ℃ obtains finished product aluminum oxide.
embodiment 3
The raw material powder coal ash of getting composition in 1000g embodiment 1, obtains raw material by raw material powder coal ash and ammonium sulfate circulation fluid material by wet type mixing, and wherein the weight ratio of the aluminum oxide in ammonium sulfate and flyash is 7:1; Raw material are heated to 350 ℃, and insulation 5h, makes grog, absorbs the ammonia, the CO that discharge by washing lotion
2decompose with alum liquor the CO producing
2make ammonium salt, decompose for Tai-Ace S 150; Grog is stripping 2h in hot water, and aluminium enters solution with the form of Tai-Ace S 150, and silicon is stayed and in residue, formed high white residue; Stripping rear slurry is through solid-liquid separation and countercurrent washing, and liquid is alum liquor, and solid is high white residue; Alum liquor adopts lipid acid extraction deironing by multi-stage countercurrent, and the ammonium salt that the alum liquor after deironing adds Ammonia recovery operation to obtain, obtains aluminium hydroxide, ammoniumsulphate soln and CO
2, ammoniumsulphate soln returns to raw material preparation after evaporation, recycles; Aluminium hydroxide roasting at 1200 ℃ obtains finished product aluminum oxide.
embodiment 4
In embodiment 3, alum liquor extraction iron removal employing primary amine is extraction agent, and other is identical with embodiment 4.
embodiment 5
In embodiment 3, alum liquor extraction iron removal employing tertiary amine is extraction agent, and aluminium hydroxide roasting at 900 ℃ obtains finished product aluminum oxide, and other is identical with embodiment 4.
embodiment 6
The raw material powder coal ash of getting composition in 1000g embodiment 1, obtains raw material by raw material powder coal ash and ammonium sulfate circulation fluid material by wet type mixing, and wherein the weight ratio of the aluminum oxide in ammonium sulfate and flyash is 8:1; Raw material are heated to 700 ℃, and insulation 0.5h, makes grog, and water absorbs the ammonia, the CO that discharge
2decompose with Tai-Ace S 150 the CO producing
2make ammonium salt, decompose for Tai-Ace S 150; Grog is stripping 0.1h in hot water, and aluminium enters solution with the form of Tai-Ace S 150, and silicon is stayed and in residue, formed high white residue; Stripping rear slurry is through solid-liquid separation and countercurrent washing, and liquid is alum liquor, and solid is high white residue; Alum liquor is by Zeo-karb deironing, and the ammonium salt that the alum liquor after deironing adds Ammonia recovery operation to obtain, obtains aluminium hydroxide, ammoniumsulphate soln and CO
2, ammoniumsulphate soln returns to raw material preparation after evaporation, recycles; Aluminium hydroxide roasting at 1200 ℃ obtains finished product aluminum oxide.
embodiment 7
In embodiment 6, absorb by high white residue washing lotion the ammonia, the CO that discharge
2decompose with alum liquor the CO producing
2make ammonium salt; Alum liquor adopts anionite-exchange resin deironing, and other is identical with embodiment 6.
embodiment 8
The weight ratio of the aluminum oxide in ammonium sulfate and flyash in embodiment 2 is 4.5:1; To the ammonium salt that adds Ammonia recovery to obtain in alum liquor, regulate pH value to 1.5 precipitation ironic hydroxide, aluminium hydroxide roasting at 1300 ℃ obtains finished product aluminum oxide, the other the same as in Example 2.
embodiment 9
In embodiment 2 to the ammonium salt that adds Ammonia recovery to obtain in alum liquor, regulate pH value to 3.5 precipitation ironic hydroxide, the other the same as in Example 2.
Claims (2)
1. utilize flyash to produce the method for aluminum oxide, it is characterized in that comprising the steps:
(1) raw material preparation: flyash and ammonium sulfate are mixed and made into raw material, and wherein the weight ratio of the aluminum oxide in ammonium sulfate and flyash is 4.5～8:1;
(2) grog burns till: raw material are heated to 500 ~ 700 ℃, and firing time is controlled at 0.5 ~ 5h, makes grog and the ammonia of sulfur acid aluminium, and ammonia is for the preparation of ammoniacal liquor or pass into Tai-Ace S 150 decomposition process;
(3) Ammonia recovery: the ammonia and the grog that adopt water to absorb the generation of grog sintering process burn till the CO that decomposition produces with alum liquor of generation
2, form ammonium salt;
(4) grog stripping: grog hot water stripping, dissolution time 0.1 ~ 2h, aluminium enters solution with the form of Tai-Ace S 150, and silicon is stayed and in residue, is formed high white residue;
(5) high white residue separating, washing: the slurries after stripping carry out solid-liquid separation and countercurrent washing, and solution is alum liquor, washing rear slag is high white residue;
(6) alum liquor obtaining is prepared aluminum oxide: the ammonium salt that adds Ammonia recovery operation to obtain to alum liquor, obtains aluminium hydroxide, ironic hydroxide, ammoniumsulphate soln and CO
2gas, solid is the thick aluminium hydroxide that foreign matter content is many; Thick aluminium hydroxide carries out the processing of low temperature Bayer process with circulation alkali solution, removes wherein iron, calcium impurities, obtains aluminum oxide and high scum;
(7) ammoniumsulphate soln evaporation: separate the ammoniumsulphate soln obtaining and evaporate, obtain being applicable to ammoniumsulphate soln or the ammonia sulfate crystal of batching;
Described raw material preparation is the one adopting in dry method batch mixing or material by wet type mixing; The main component of described high white residue is silicon-dioxide, for the preparation of white carbon black or high silicon filler;
Adopting Bayer process to process thick aluminium hydroxide is the full bayer process flow process of producing aluminum oxide, comprises raw pulp allotment, low temperature stripping, red mud separating, washing, decomposing sodium aluminate solution, aluminium hydroxide separating, washing and Aluminium hydroxide roasting operation.
2. the method for utilizing flyash to produce aluminum oxide according to claim 1, is characterized in that described high scum or ironic hydroxide are as iron-smelting raw material.
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| CN102358623A (en) * | 2011-09-24 | 2012-02-22 | 沈阳铝镁设计研究院有限公司 | Method for producing aluminum oxide by treating fly ash through ammonia process |
| CN103848447B (en) * | 2012-11-28 | 2015-09-30 | 沈阳铝镁设计研究院有限公司 | A kind of flyash raw material pelletizing preparation method |
| CN103936048B (en) * | 2013-01-18 | 2015-10-14 | 新疆大学 | A kind of recoverying and utilizing method of flyash acidity extraction aluminum oxide technology sewage |
| CN104098116A (en) * | 2013-04-12 | 2014-10-15 | 沈阳铝镁设计研究院有限公司 | Roasting clinker dissolve-out method in fly ash and ammonium sulfate mixed roasting technology |
| CN104030329B (en) * | 2013-07-04 | 2016-02-10 | 沈阳工业大学 | A kind of method containing bauxite resource comprehensive utilization |
| CN103342376B (en) * | 2013-07-11 | 2015-07-01 | 中北大学 | Process for extracting valuable metal from coal gangues |
| CN104609451B (en) * | 2015-01-30 | 2017-01-25 | 魏子贺 | Process for preparing aluminum oxide by virtue of dry-sintering method |
| CN105753026B (en) * | 2016-04-11 | 2018-05-04 | 北京世纪地和控股有限公司 | A kind of method for recycling aluminium oxide from flyash with sulfuric acid |
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| CN1285510C (en) * | 2004-10-27 | 2006-11-22 | 上海大学 | Prepn process of nano aluminium hydroxide |
| CN1868884A (en) * | 2006-06-02 | 2006-11-29 | 李禹� | Method of extracting aluminium oxide from fly ash and simultaneously producing white carbon black |
| CN101734698A (en) * | 2009-09-08 | 2010-06-16 | 东北大学 | Method for preparing aluminum oxide from aluminiferous material |
| CN102020303A (en) * | 2010-12-23 | 2011-04-20 | 南京航空航天大学 | Method for producing ultra-high purity aluminium sulfate from fly ash |
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| CN1285510C (en) * | 2004-10-27 | 2006-11-22 | 上海大学 | Prepn process of nano aluminium hydroxide |
| CN1868884A (en) * | 2006-06-02 | 2006-11-29 | 李禹� | Method of extracting aluminium oxide from fly ash and simultaneously producing white carbon black |
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