CN104445313A - Method for extracting aluminum oxide from fly ash by acid-base combination - Google Patents
Method for extracting aluminum oxide from fly ash by acid-base combination Download PDFInfo
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- CN104445313A CN104445313A CN201410602100.1A CN201410602100A CN104445313A CN 104445313 A CN104445313 A CN 104445313A CN 201410602100 A CN201410602100 A CN 201410602100A CN 104445313 A CN104445313 A CN 104445313A
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- flyash
- sulfuric acid
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01F—COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM, CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THE RARE-EARTH METALS
- C01F7/00—Compounds of aluminium
- C01F7/02—Aluminium oxide; Aluminium hydroxide; Aluminates
Abstract
The invention discloses a method for extracting aluminum oxide from fly ash by acid-base combination. After uniformly mixing and curing the fly ash and a proper amount of concentrated sulfuric acid, performing high-temperature rapid reduction roasting desulfurization by using carbon residue in the fly ash and a proper amount of supplementary reducing agent, realizing regeneration and recycling of sulfuric acid by making acid from sulfur-containing flue gas, and producing alumina from reduced roasted product by an alkaline leaching method. The method of the invention integrates the advantages of the fly ash acid method and the alkaline method for extracting the alumina, and effectively avoids the disadvantages of the fly ash acid method and the alkaline method. The high-energy-consumption evaporative crystallization aluminum salt and aluminum salt crystallization water decomposition process in the conventional acid method process are avoided, so that a large amount of energy consumption is saved; compared with the conventional alkaline process, the method does not need a sintering process with high energy consumption, has low slag quantity and can be reused as a silicon raw material, has little waste output, and realizes real reduction green clean production; the alumina product has good quality, high recovery rate, low energy consumption, small equipment corrosion and easy realization of large-scale industrialization.
Description
Technical field
The invention belongs to the comprehensive utilization of flyash, specifically relate to a kind of method extracting aluminum oxide from flyash, especially adopt soda acid process integration to extract aluminum oxide.
Background technology
Along with the fast development of modernization industry, scarcity of resources becomes one of pendulum main social problems in face of people increasingly.Produce the raw material mainly bauxite of aluminum oxide, traditional smelting process is that alkaline process produces aluminum oxide, and the silicon oxide in ore is the main harmful element during alkaline process is produced, and requires (the Al in ore of alumina silica ratio A/S in bauxite
2o
3with SiO
2mass values) be greater than 3.Alkaline process is divided into Bayer process, sintering process and integrated process, and wherein Bayer process is suitable for process containing Al
2o
3high, SiO
2low rich ore, general requirement Al
2o
3> 65%, A/S > 7, the aluminum oxide of more than 90% is produced by Bayer process in the world; It is the raw material of 3 ~ 5 that sintering process is applicable to process A/S; It is the raw material of 5 ~ 7 that integrated process is applicable to process A/S.But along with the increase of aluminium consumption, ore extraction amount increases, bauxite resource reduces year by year, ore aluminium grade constantly declines, cost of winning improves constantly, from the non-traditional alumina raw material of the low aluminium of some high silicon, extract aluminum oxide come into one's own, from flyash, particularly extract aluminum oxide not only can expand alumina source, the environmental problem that flyash stores up generation can be solved simultaneously.
China is coal production and consumption big country, coal production and consumption have reached about 3,700,000,000 tons all, wherein over half for thermal power generation, combustion processes produces a large amount of flyash, the flyash of output is used for cement building material raw materials for production except small part and obtains except part utilization, major part is stored up, and not only take a large amount of land resources, and environmental pollution is serious.China's flyash is rich in aluminium, aluminum oxide average content 27%, and the alumina content of East China, North China's flyash is generally more than 30%, and in the flyash of some areas, aluminium content is especially up to 40-60%, is a kind of very important potential bauxite making & breaking.Different according to the composition of flyash, can be used for the products such as production of silica white, aluminum oxide, powdered iron ore, gallium, germanium, form new industry chain of circular economy, wherein most important product is aluminum oxide.
Because the alumina silica ratio in flyash is very low, and cannot beneficiation enrichment, the process for making alumina of conventional process bauxite is difficult to transplanting and carrys out treated coal ash, need research and development to be applicable to the Technology of flyash bauxite resource feature, the flyash of research and development both at home and abroad at present extracts aluminum oxide method and is roughly divided into alkaline process and the large class of acid system two.
Alkaline process comprises direct sintering and pre-desiliconizing-sintering process etc.Direct sintering is similar to Bauxite Sintering method and produces alumina technology, comprise sintering, the master operation such as grog divides from efflorescence, leaching, carbon, calcination, the method of flyash and Wingdale combination producing aluminum oxide and cement is utilized disclosed in CN 1644506A, flyash is mixed dry sintering after ore grinding by a certain percentage with limestone powder, then extract aluminum oxide with alkali stripping grog, leached mud is for the production of cement.Due to the siliceous height of flyash, direct sintering needs to allocate large quantities of lime stone flour into, and flyash and limestone powder quality proportioning reach 30:70.Because direct sintering adds lime or limestone powder in a large number, a large amount of calcium silicate slag can be produced during leaching, often produce 1 ton of aluminum oxide and will produce calcium silicate slag about 8-10 ton, if periphery does not have enough building materials market digestion capability, will certainly cause new, heap is high-volume larger and be alkaline waste discharge, form more unmanageable solid waste environmental problem, the inventory simultaneously due to high temperature sintering is large, causes sintering energy consumption high.
Carry out the process of alkali leaching pre-desiliconizing to flyash and can reduce sinter doses, thus reduce sintering energy consumption and reduce the leaching quantity of slag, the siliceous solution that pre-desiliconizing obtains simultaneously can produce the high level such as white carbon black, wollastonite silicon product.A kind of method extracting silicon-dioxide, aluminum oxide and gallium oxide from aluminous fly-ash disclosed in CN101284668A, aluminous fly-ash and sodium hydroxide solution are carried out pressure leaching in autoclave, make the stripping of part silicon, siliceous leach liquor is for the production of white carbon black, sinter after flyash after pre-desiliconizing mixes with limestone powder, sodium carbonate solution, then leach aluminium.In order to improve the silicon decreasing ratio of pre-desiliconizing further, a kind of method utilizing flyash to produce silicon-dioxide and aluminum oxide disclosed in CN100491247C, before leaching pre-desiliconizing with sodium hydroxide solution, preroasting is carried out to flyash, or soak with sulfuric acid or sodium hydroxide solution, so that the stripping improving silicon in flyash is active, thus improves the pre-decreasing ratio of silicon.Adopt pre-desiliconizing technology can improve the alumina silica ratio of flyash, reduce sintering amount, thus reduce alumina producing energy consumption, and the silicon products such as by-product white carbon black, wollastonite, but for large-scale total utilization of PCA, the market sale that huge white carbon black, wollastonite product face and competitive pressure very large.
Acid system mainly comprises sulfuric acid process and hydrochloric acid method, normally by certain density sulfuric acid or hydrochloric acid and flyash in heating condition agitation leach, gained solution adds alkali reaction and generates aluminum hydroxide precipitation, filters to obtain aluminium hydroxide.Due to the poor activity of aluminum oxide in flyash, the alumina extraction ratio of general acidleach is lower, needs to adopt the enhancements such as calcination activation, Leaching by strong acid curing.A kind of method extracting aluminum oxide from flyash disclosed in CN1792802A, its technological process to be ground to 200 ~ 400 object flyash, first calcination activation 1 ~ 1.5h at 300 ~ 760 DEG C, then at 160 ~ 300 DEG C with the sulfuric acid leaching of 60 ~ 98% concentration, the slurry filtration leached is to be separated spent acid, and spent acid returns and leaches circulation, then from filter residue, leaches aluminium with water, then through condensing crystal, drying and dehydrating, calcination, γ-Al is obtained
2o
3adopt the method, the leaching rate of recovery of aluminium can reach 85%, but the method complex process, not only needs preroasting to activate, and leaching is carried out under the condition of high temperature concentrated acid, energy consumption is high, a large amount of acid carries out inefficient cycle in system, and the material of leaching, filtration, material transfer equipment is difficult to resolve certainly, operational difficulty.A kind of method being produced aluminum oxide by flyash disclosed in CN1923695A, first by flyash fine grinding and in 200-760 DEG C of calcination activation, again with appropriate vitriol oil mix evenly after burn till at 200-400 DEG C, then aluminum oxide is extracted in water logging, can obtain higher aluminium leaching yield equally.CN100413981C discloses a kind of method of acidity extraction aluminium from high silicon aluminum-containing mineral raw material, carries out roasting after being mixed by flyash with the vitriol oil, then produces aluminum oxide through water logging, condensing crystal, calcining.CN101811711A discloses a kind of Leaching in Hydrochloric Acid that adopts by the method extracting aluminum oxide in flyash, its process at 140-160 DEG C, leaches aluminium by after flyash and mixed in hydrochloric acid, then solid-liquid separation, condensing crystal, aluminum chloride calcining obtain active just aluminum oxide, by first aluminum oxide through Bayer process process for producing aluminum oxide.In order to directly obtain qualified aluminum oxide, a kind of flyash acid system disclosed in CN103803617A is produced in the method for aluminum oxide, the pre-deferrization of magnetic separation has been carried out to flyash, and resin absorption removal of impurities is adopted to the leach liquor that Leaching in Hydrochloric Acid obtains, thus separate out purer aluminum chloride crystals when crystallization, aluminum chloride crystals calcining directly obtains qualified alumina product, thus shortens alumina producing flow process.Acidic process aluminum oxide is not owing to needing to add slag former, and the level of residue extracted after aluminum oxide is few, meets the requirement of minimizing comprehensive utilization Industrial Solid Waste, and can obtain higher alumina recovery rate.But because the leach liquor of acidic process output needs condensing crystal, and it is higher containing crystal water to obtain aluminium intermediate product, and follow-up dehydration energy is high, causes the total energy consumption of acid oxidation aluminium high.Simultaneously due to the leaching poor selectivity of acidic process, the a large amount of strippings of impurity such as iron, calcium, magnesium, titanium, the aluminium purity salt of condensing crystal output is not high, the further Bayer process process of follow-up need, although adopt the flyash pre-deferrization of former grey magnetic separation and pickling liquor chemical purification to improve product purity, cost is high.
Except above-mentioned alkaline process, acid system, also have ammonium sulfate roasting method, fluoridize auxiliary agent lixiviation process etc.Disclosed in CN102344155A, utilize coal ash for manufacturing for the method for aluminum oxide, roasting after mixing with flyash with ammonium sulfate, burn till material through water logging, ammonia neutralization precipitation aluminium hydroxide, after heavy aluminium, liquid condensing crystal ammonium sulfate returns firing cycles use, achieves the circulation of ammonia.Although compared with acid system, leach selectivity and be improved, obtain qualified alumina product still needs to increase deep purifying operation, and the environmental issue of production process ammonia has to be solved.
Summary of the invention
The object of the invention is the deficiency in order to overcome in existing flyash extraction aluminum oxide technology, a kind of method adopting using acid and alkali combination method to extract aluminum oxide from flyash is provided, object is by soda acid process integration, solve aluminium salt condensing crystal and the problem that pyrolysis energy consumption is high, alumina product purity is low in flyash acidic process technique, avoid the defects such as flyash alkaline process process sinter doses is large, energy consumption is high, the leaching quantity of slag is large simultaneously.
For achieving the above object, the method for a kind of soda acid combined extracting aluminum oxide from flyash of the present invention comprises the steps:
(1) sulfuric acid slaking: carry out slaking after being mixed by a certain percentage with the vitriol oil by flyash, obtains sulfuric acid slaking material;
(2) reducing roasting: sulfuric acid slaking material above-mentioned steps (1) obtained carries out reducing roasting at a certain temperature together with appropriate supplementary reductive agent, obtain calcining and sulfur-containing smoke gas, the rear relieving haperacidity of sulfur-containing smoke gas collection returns step (1) and recycles;
(3) calcining alkali leaching: the solution of calcining above-mentioned steps (2) obtained containing sodium hydroxide carries out alkali leaching, has leached rear solid-liquor separation and has obtained sodium aluminate solution and Silicon-rich slag.
(4) aluminum oxide is prepared: sodium aluminate solution above-mentioned steps (3) obtained is through to plant point or carbon divides and prepares aluminium hydroxide, then solid-liquid separation obtains aluminium hydroxide and mother liquor, mother liquor returns step (3) and recycles, and aluminium hydroxide produces aluminum oxide through calcining.
The method of a kind of soda acid combined extracting aluminum oxide from flyash of the present invention, is characterized in that in its step (1) in sulfuric acid slaking, and sulphuric acid is 1-2.5 times of described flyash quality, preferred 1.1-1.5 times, concentration >=85% of sulfuric acid.
The method of a kind of soda acid combined extracting aluminum oxide from flyash of the present invention, is characterized in that sulfuric acid slaking in its step (1), its curing temperature 100-500 DEG C, preferred 150-350 DEG C, curing time 1-48h, preferred 2-8h.
The method of a kind of soda acid combined extracting aluminum oxide from flyash of the present invention, the supplementary reductive agent that it is characterized in that in its step (2) is one or more the mixture in the low value carbonaceous fuels such as coal dust, colliery powder, coal gas, Sweet natural gas, sulphur or refinery coke, and the amount of allocating into of supplementing reductive agent regulates according to the alumina content in flyash and the carbon left in flyash.
The method of a kind of soda acid combined extracting aluminum oxide from flyash of the present invention, it is characterized in that the supplementary reductive agent in its step (2) is coal dust, allocating into than the 0-30% for described sulfuric acid slaking material quality of coal dust, allocates into and regulates than according to the alumina content in flyash and the carbon left in flyash.
The method of a kind of soda acid combined extracting aluminum oxide from flyash of the present invention, is characterized in that reducing roasting temperature 500-900 DEG C, preferred 650-800 DEG C in its step (2), reducing roasting time 0.1-60min, preferred 0.1-15min.
The method of a kind of soda acid combined extracting aluminum oxide from flyash of the present invention, it is characterized in that the reducing roasting described in its step (2) is fast fluidization roasting, stoving oven is the one in cyclic fluid roaster, gaseous pollutant control or fluidised form flash roaster.
The method of a kind of soda acid combined extracting aluminum oxide from flyash of the present invention, is characterized in that the alkali leaching described in its step (3) is the one in the leaching of normal pressure alkali, alkaline pressure of oxygen leaching or Bayer Process digestion.
The method of a kind of soda acid combined extracting aluminum oxide from flyash of the present invention, it is characterized in that the alkali leaching described in its step (3), its alkali leaching condition is: leaching temperature 80-250 DEG C, alkali concn 30-220g/L, extraction time 20-80min, ingredients molecular ratio α
k0.8-2.0, lime-crushed stone pile 0-15%.
The method of a kind of soda acid combined extracting aluminum oxide from flyash of the present invention, it is characterized in that described in its step (4) prepare aluminum oxide when adopt carbon divide prepare aluminum oxide time, mother liquor is through causticization process Posterior circle.
The method of a kind of soda acid combined extracting aluminum oxide from flyash of the present invention, it is characterized in that the mother liquor described in its step (4), when containing gallium in mother liquor, regular extraction section mother liquor adopts carbonization precipitation, ion-exchange or solvent extration to reclaim gallium.
The method of a kind of soda acid combined extracting aluminum oxide from flyash of the present invention, described sulfation slaking, utilize the pyroreaction of the vitriol oil active, react with the dominant phase mullite of flyash, generate Tai-Ace S 150 thing phase, react as shown in the formula (1), thus destroy flyash Minerals structure, aluminium mineral and silicon mine are dissociated.
(3Al
2O
3·2SiO
2)+9H
2SO
4＝3Al
2(SO
4)
3+2SiO
2+9H
2O (1)
The method of a kind of soda acid combined extracting aluminum oxide from flyash of the present invention, described reducing roasting, that flyash sulfuric acid slaking material is directly carried out reducing roasting with reductive agent, the condensing crystal Tai-Ace S 150 and the crystalline sulfuric acid aluminium that avoid highly energy-consuming in acidic process flyash dewater and Roasting Decomposition operation, simultaneously, because adopting quick medium temperature roast, in calcining, the leaching activity of aluminum oxide is high, and the reaction of coal reduction roasting is such as formula (2).In reducing roasting process, the carbon residue that can make full use of in flyash makees reductive agent, when carbon residue is not enough, can supplement reductive agent in right amount.
Al
2(SO
4)
3+3/2C＝Al
2O
3+3SO
2(g)+3/2CO
2(g)(2)
The method of a kind of soda acid combined extracting aluminum oxide from flyash of the present invention, described calcining alkali leaching, because in the calcining that described reducing roasting obtains, alumina leaching activity is good, can leach under lesser temps and basicity condition, ensureing, under higher aluminium leaching yield prerequisite, the stripping of silicon can be suppressed.Calcining alkali leaching reaction is as shown in the formula (3).
Al
2O
3+3H
2O+2NaOH＝2NaAl(OH)
4(3)
The method of a kind of soda acid combined extracting aluminum oxide from flyash of the present invention, vitriol oil pyroreaction is utilized to enhance the decomposition of dominant phase mullite in flyash, different from traditional acid system, directly do not carry out the leaching of Tai-Ace S 150, but the desulfurization utilizing reductive agent to realize sulfuric acid slaking material is decomposed, and ensureing the activity of aluminum oxide, the flue gas that desulfurization produces realizes the regeneration of main agents sulfuric acid by relieving haperacidity.In the calcining of desulfurization simultaneously, aluminum oxide has activity, can realize low-temperature low-alkali Bayer Process digestion, carry out the preparation of conventional alumina product.
Solve in traditional acid system treated coal ash and leach poor selectivity, a difficult problem for solution purification difficulty, without the need to highly energy-consuming processes such as the condensing crystal Tai-Ace S 150 in traditional sulfuric acid process, Tai-Ace S 150 dehydrations.Compared with traditional alkaline process treated coal ash technique, avoid the sintering circuit of highly energy-consuming, without the need to adding the slag former such as limestone powder, lime, leaching the quantity of slag and significantly reducing.
Accompanying drawing explanation
Accompanying drawing is the principle flow chart of method of the present invention.
Embodiment
Below in conjunction with accompanying drawing the present invention made and further illustrating.
Mixed by a certain percentage with sulfuric acid by flyash, sulphuric acid is 1-2.5 times of described flyash quality, preferred 1.1-1.5 times, concentration >=85% of sulfuric acid, curing temperature 100-500 DEG C, curing time 1-48h.
Sulfuric acid slaking material is carried out reducing roasting together with reductive agent, reductive agent coal dust allocate into than the 0-30% for described sulfuric acid slaking material quality, reducing roasting maturing temperature 500-900 DEG C, roasting time 0.1-60min.The sulfur-containing smoke gas of reducing roasting output collects extracting sulfuric acid, realizes the recycling utilization of sulfuric acid.
The solution of reduced calcine containing sodium hydroxide is leached, alkali leaching temperature 80-250 DEG C, alkali concn 30-220g/L, extraction time 20-80min, ingredients molecular ratio α
k0.8-2.0, lime-crushed stone pile 0-15%.After alkali leaching solid-liquid separation on ore pulp, the sodium aluminate solution that obtains is through to plant point or carbon divides and prepares aluminium hydroxide, and seed precipitation solution or carbon mother liquid causticization process Posterior circle use.The stripping slag of low-temperature low-alkali Bayer process can directly as the siliceous raw material of building product.
Be further described method of the present invention with nonlimiting examples below, to contribute to understanding content of the present invention and advantage thereof, and not as limiting the scope of the present invention, protection scope of the present invention is determined by claims.
The present invention is suitable for the flyash of different chemical composition.Following table is that the present invention tests adopted flyash main component.
| Main component | Al 2O 3 | CaO | Fe 2O 3 | K 2O | MgO | Na 2O | SiO 2 |
| Content (%) | 48.15 | 3.9 | 1.79 | 0.36 | 0.24 | 0.11 | 32.64 |
Embodiment 1
Mixed with sulfuric acid by flyash, sulphuric acid is 1.5 times of described flyash quality, and the sulfuric acid concentration of use is 90%, after mixing, and curing temperature 200 DEG C, obtains sulfuric acid slaking material under curing time 8h condition.Sulfuric acid slaking material mixes than 8% by coal, carries out fast restore roasting, roasting time 5min temperature 750 DEG C.
Carry out alkali leaching to reduced calcine, leaching condition is: leaching temperature 100 DEG C, alkali concn 50g/L, ingredients molecular ratio α
k0.9, time 60min, lime-crushed stone pile 0%.Now, the actual solubility rate 83% of aluminium, carry out kind point to dissolution fluid, obtain aluminum hydroxide product, prepare metallurgical-grade aluminum oxide product after calcining, seed precipitation solution returns calcining stripping.
Embodiment 2
Mixed with sulfuric acid by flyash, sulphuric acid is 2.2 times of described flyash quality, and the sulfuric acid concentration of use is 93%, after mixing, and curing temperature 320 DEG C, obtains sulfuric acid slaking material under curing time 8h condition.Sulfuric acid slaking material mixes with coal dust than 15% by coal, carries out fast restore roasting, roasting time 10min temperature 800 DEG C.
Carry out alkali leaching to reduced calcine, leaching condition is: leaching temperature 90 DEG C, alkali concn 70g/L, ingredients molecular ratio α
k1.2, time 40min, lime-crushed stone pile 2%.Now, the actual solubility rate of aluminium, 92%, carries out kind point to dissolution fluid, obtains aluminum hydroxide product, prepare metallurgical-grade aluminum oxide product after calcining, and seed precipitation solution returns to the batching new ore deposit of stripping.
Embodiment 3
Mixed with sulfuric acid by flyash, sulphuric acid is 1.8 times of described flyash quality, and the sulfuric acid concentration of use is 93%, after mixing, and curing temperature 380 DEG C, obtains sulfuric acid slaking material under curing time 4h condition.Sulfuric acid slaking material passes into coal gas in fluidized roaster, carries out fast restore roasting, roasting time 1min temperature 750 DEG C.
Carry out alkali leaching to reduced calcine, leaching condition is: leaching temperature 150 DEG C, alkali concn 50g/L, ingredients molecular ratio α
k0.9, time 60min, lime-crushed stone pile 0%.Now, the actual solubility rate of aluminium, 85%, carries out kind point to dissolution fluid, obtains aluminum hydroxide product, prepare metallurgical-grade aluminum oxide product after calcining, and seed precipitation solution returns to the batching new ore deposit of stripping.
Embodiment 4
Mixed with sulfuric acid by flyash, sulphuric acid is 2.0 times of described flyash quality, and the sulfuric acid concentration of use is 93%, after mixing, and curing temperature 250 DEG C, obtains sulfuric acid slaking material under curing time 24h condition.Sulfuric acid slaking material passes into Sweet natural gas in fluidized roaster, carries out fast restore roasting, roasting time 2min temperature 850 DEG C.
Carry out alkali leaching to reduced calcine, leaching condition is: leaching temperature 120 DEG C, alkali concn 160g/L, ingredients molecular ratio α
k1.8, time 30min, lime-crushed stone pile 8%.Now, the actual solubility rate of aluminium, 90%, carries out kind point to dissolution fluid, obtains aluminum hydroxide product, prepare metallurgical-grade aluminum oxide product after calcining, and seed precipitation solution returns to the batching new ore deposit of stripping.
Embodiment 5
Mixed with sulfuric acid by flyash, sulphuric acid is 1.2 times of described flyash quality, and the sulfuric acid concentration of use is 90%, after mixing, and curing temperature 400 DEG C, obtains sulfuric acid slaking material under curing time 2h condition.Sulfuric acid slaking material mixes than 12% by coal, carries out fast restore roasting, roasting time 15min temperature 600 DEG C.
Carry out alkali leaching to reduced calcine, leaching condition is: leaching temperature 100 DEG C, alkali concn 200g/L, ingredients molecular ratio α
k1.9, time 60min, lime-crushed stone pile 3%.Now, the actual solubility rate of aluminium, 77%, carries out kind point to dissolution fluid, obtains aluminum hydroxide product, prepare metallurgical-grade aluminum oxide product after calcining, and seed precipitation solution returns to the batching new ore deposit of stripping.
Embodiment 6
Mixed with sulfuric acid by flyash, sulphuric acid is 1.5 times of described flyash quality, and the sulfuric acid concentration of use is 90%, after mixing, and curing temperature 200 DEG C, obtains sulfuric acid slaking material under curing time 8h condition.Sulfuric acid slaking material mixes than 8% by coal, carries out reducing roasting, roasting time 0.1min temperature 900 DEG C.
Carry out alkali leaching to reduced calcine, leaching condition is: leaching temperature 100 DEG C, alkali concn 50g/L, ingredients molecular ratio α
k0.9, time 60min, lime-crushed stone pile 0%.Now, the actual solubility rate 84% of aluminium, carry out kind point to dissolution fluid, obtain aluminum hydroxide product, prepare metallurgical-grade aluminum oxide product after calcining, seed precipitation solution returns calcining stripping.
Embodiment 7
Mixed with sulfuric acid by flyash, sulphuric acid is 1.8 times of described flyash quality, and the sulfuric acid concentration of use is 90%, after mixing, and curing temperature 200 DEG C, obtains sulfuric acid slaking material under curing time 8h condition.Sulfuric acid slaking material mixes than 8% by coal, carries out fast restore roasting, roasting time 60min temperature 550 DEG C.
Carry out alkali leaching to reduced calcine, leaching condition is: leaching temperature 100 DEG C, alkali concn 50g/L, ingredients molecular ratio α
k0.9, time 60min, lime-crushed stone pile 0%.Now, the actual solubility rate 90% of aluminium, carry out kind point to dissolution fluid, obtain aluminum hydroxide product, prepare metallurgical-grade aluminum oxide product after calcining, seed precipitation solution returns calcining stripping.
Embodiment 8
Mixed with sulfuric acid by flyash, sulphuric acid is 1.8 times of described flyash quality, and the sulfuric acid concentration of use is 93%, after mixing, and curing temperature 230 DEG C, obtains sulfuric acid slaking material under curing time 12h condition.Sulfuric acid slaking material mixes than 12% by coal, carries out fast restore roasting, roasting time 7min temperature 650 DEG C.
Carry out alkali leaching to reduced calcine, leaching condition is: leaching temperature 90 DEG C, alkali concn 50g/L, ingredients molecular ratio α
k1.4, time 120min, lime-crushed stone pile 0%.Now, the actual solubility rate of aluminium, 92%, carries out carbon to dissolution fluid and divides, obtain aluminum hydroxide product, prepare metallurgical-grade aluminum oxide product after calcining, carbon mother liquid secondary carbonization precipitation enrichment gallium, gallium deposition rate 85%.
Embodiment 9
Mixed with sulfuric acid by flyash, sulphuric acid is 1.8 times of described flyash quality, and the sulfuric acid concentration of use is 93%, after mixing, and curing temperature 320 DEG C, obtains sulfuric acid slaking material under curing time 4h condition.Sulfuric acid slaking material mixes than 15% by coal, carries out fast restore roasting, roasting time 10min temperature 700 DEG C.
Carry out alkali leaching to reduced calcine, leaching condition is: leaching temperature 95 DEG C, alkali concn 100g/L, ingredients molecular ratio α
k1.0, time 80min, lime-crushed stone pile 1%.Now, the actual solubility rate of aluminium, 93%, carries out kind point to dissolution fluid, obtains aluminum hydroxide product, prepare metallurgical-grade aluminum oxide product after calcining..Seed precipitation solution adopts acylamide-oxime resin absorption gallium, gallium adsorption rate 85%.
Claims (10)
1. the method for soda acid combined extracting aluminum oxide from flyash, is characterized in that, comprise the following steps:
(1) sulfuric acid slaking: carry out slaking after being mixed by a certain percentage with sulfuric acid by flyash, obtains sulfuric acid slaking material;
(2) reducing roasting: sulfuric acid slaking material above-mentioned steps (1) obtained carries out reducing roasting at a certain temperature together with appropriate supplementary reductive agent, obtain calcining and sulfur-containing smoke gas, the rear relieving haperacidity of sulfur-containing smoke gas collection returns step (1) and recycles;
(3) calcining alkali leaching: the solution of calcining above-mentioned steps (2) obtained containing sodium hydroxide carries out alkali leaching, has leached rear solid-liquor separation and has obtained sodium aluminate solution and Silicon-rich slag;
(4) aluminum oxide is prepared: sodium aluminate solution above-mentioned steps (3) obtained is through to plant point or carbon divides and prepares aluminium hydroxide, then solid-liquid separation obtains aluminium hydroxide and mother liquor, mother liquor returns step (3) and recycles, and aluminium hydroxide produces aluminum oxide through calcining.
2. method according to claim 1, is characterized in that, in its step (1), sulphuric acid is 1-2.5 times of described flyash quality, preferred 1.1-1.5 times, concentration >=85% of sulfuric acid.
3. method according to claim 1, is characterized in that, curing temperature 100-500 DEG C, preferred 150-350 DEG C, curing time 1-48h, preferred 2-8h in its step (1).
4. method according to claim 1, it is characterized in that, supplementary reductive agent in its step (2) is one or more the mixture in the low value carbonaceous fuels such as coal dust, colliery powder, coal gas, Sweet natural gas, sulphur or refinery coke, and the amount of allocating into of supplementing reductive agent regulates according to the alumina content in flyash and the carbon left in flyash.
5. method according to claim 4, it is characterized in that, supplementary reductive agent in its step (2) is coal dust, allocating into than the 0-30% for described sulfuric acid slaking material quality of coal dust, allocates into and regulates than according to the alumina content in flyash and the carbon left in flyash.
6. method according to claim 1, is characterized in that, reducing roasting temperature 500-900 DEG C, preferred 650-800 DEG C in its step (2), reducing roasting time 0.1-60min, preferred 0.1-15min.
7. method according to claim 1, is characterized in that, the reducing roasting described in its step (2) is fast fluidization roasting, and stoving oven is the one in cyclic fluid roaster, gaseous pollutant control or fluidised form flash roaster.
8. method according to claim 1, is characterized in that, the alkali leaching described in its step (3) is the one in the leaching of normal pressure alkali, alkaline pressure of oxygen leaching or Bayer Process digestion.
9. method according to claim 1, is characterized in that, the alkali leaching described in its step (3), its alkali leaching condition is: leaching temperature 80-250 DEG C, alkali concn 30-220g/L, extraction time 20-80min, ingredients molecular ratio α
k0.8-2.0, lime-crushed stone pile 0-15%.
10. method according to claim 1, is characterized in that, when containing gallium in the mother liquor described in its step (4), regular extraction section mother liquor adopts carbonization precipitation, ion-exchange or solvent extration to reclaim gallium.
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|---|---|---|---|
| CN201410602100.1A CN104445313B (en) | 2014-10-30 | 2014-10-30 | Method for extracting aluminum oxide from fly ash by acid-base combination |
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| CN104787790A (en) * | 2015-04-17 | 2015-07-22 | 北京矿冶研究总院 | Method for extracting aluminum oxide and silicon oxide from coal-based solid waste |
| CN104803403A (en) * | 2015-04-17 | 2015-07-29 | 北京矿冶研究总院 | Acid-alkali combined process for extracting alumina from coal-based solid waste through pre-desilication |
| CN106477609A (en) * | 2016-10-12 | 2017-03-08 | 北京矿冶研究总院 | Method for producing alumina by coal ash sulfuric acid curing |
| CN106477606A (en) * | 2016-10-12 | 2017-03-08 | 北京矿冶研究总院 | Method for extracting aluminum oxide from fly ash based on sulfuric acid curing |
| CN106517279A (en) * | 2016-10-12 | 2017-03-22 | 北京矿冶研究总院 | Method for extracting aluminum oxide by reducing and decomposing fly ash ammonium sulfate roasting clinker |
| CN107935005A (en) * | 2016-10-12 | 2018-04-20 | 北京矿冶研究总院 | Method for pretreating fly ash carbonate solution and extracting alumina |
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| CN109835930A (en) * | 2019-02-19 | 2019-06-04 | 昆明理工大学 | A kind of production method of aluminium oxide |
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| CN113292088A (en) * | 2021-05-19 | 2021-08-24 | 神华准能资源综合开发有限公司 | Method for producing low-magnesium and low-calcium alumina from crystalline aluminum chloride |
| CN115196659A (en) * | 2022-07-21 | 2022-10-18 | 四川顺应动力电池材料有限公司 | Environment-friendly low-consumption system for circularly preparing alumina by leaching acid and alkali from coal-based solid waste nitric acid and preparation method of industrial-grade alumina |
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| CN104803403A (en) * | 2015-04-17 | 2015-07-29 | 北京矿冶研究总院 | Acid-alkali combined process for extracting alumina from coal-based solid waste through pre-desilication |
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| CN110983057A (en) * | 2019-12-04 | 2020-04-10 | 北京科技大学 | Soot treatment method capable of realizing UPOPs synthesis retardation and low-temperature decomposition |
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| CN115196659A (en) * | 2022-07-21 | 2022-10-18 | 四川顺应动力电池材料有限公司 | Environment-friendly low-consumption system for circularly preparing alumina by leaching acid and alkali from coal-based solid waste nitric acid and preparation method of industrial-grade alumina |
| CN115196659B (en) * | 2022-07-21 | 2023-12-05 | 四川顺应动力电池材料有限公司 | Environment-friendly low-consumption system for circularly preparing alumina by leaching acid and alkali from coal solid waste nitric acid and preparation method of industrial grade alumina |
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