CN106518035B - A kind of method that modified coal ash high yield prepares high-purity mullite powder - Google Patents
A kind of method that modified coal ash high yield prepares high-purity mullite powder Download PDFInfo
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- CN106518035B CN106518035B CN201611016696.2A CN201611016696A CN106518035B CN 106518035 B CN106518035 B CN 106518035B CN 201611016696 A CN201611016696 A CN 201611016696A CN 106518035 B CN106518035 B CN 106518035B
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- flyash
- powder
- mullite
- aqueous solution
- purity
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- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
- C04B35/01—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics
- C04B35/16—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on silicates other than clay
- C04B35/18—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on silicates other than clay rich in aluminium oxide
- C04B35/185—Mullite 3Al2O3-2SiO2
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- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
- C04B35/622—Forming processes; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
- C04B35/626—Preparing or treating the powders individually or as batches ; preparing or treating macroscopic reinforcing agents for ceramic products, e.g. fibres; mechanical aspects section B
- C04B35/62605—Treating the starting powders individually or as mixtures
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- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
- C04B35/622—Forming processes; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
- C04B35/626—Preparing or treating the powders individually or as batches ; preparing or treating macroscopic reinforcing agents for ceramic products, e.g. fibres; mechanical aspects section B
- C04B35/62605—Treating the starting powders individually or as mixtures
- C04B35/62645—Thermal treatment of powders or mixtures thereof other than sintering
Abstract
The present invention discloses a kind of method that modified coal ash high yield prepares high-purity mullite powder, belongs to technical field of fine ceramics.The present invention comprises the following steps that: (1) adding 2-8% Aluminum sol in flyash powder, by ball milling mixing, realize the coating modification of flyash powder particle surface；(2) modified coal ash is calcined at a certain temperature, so that mullite content reaches 60-70% in flyash, realizes the mullitization (mullitization) of flyash powder；(3) calcined fine coal powder hydro-thermal process in alkaline aqueous solution, and cleaned using acidic aqueous solution, dispel glass phase and other impurities oxide (such as CaO, MgO, Na in flyash2O、K2O、Fe2O3), obtain mullite powder；(4) reverse flotation technology is used, quartzy impurity in mullite powder is dispelled, prepares the high-purity mullite powder that purity is greater than 98%.
Description
Technical field
The present invention relates to coal ash for manufacturing for the method more particularly to Aluminum sol modified coal ash high yield system of high-purity mullite
The method of standby high-purity mullite powder, belongs to fine ceramics field.
Background technique
Flyash is also referred to as flying dust, is fine ash, the primary solids waste of thermal power plant, SiO in flue gas after coal combustion2With
Al2O3Total content is higher than 60%.Early in early 20th century, some developed countries, which just have begun, studies flyash, and very
The resource utilization for paying attention to flyash is widely used to building materials, builds work, traffic, change so total utilization of PCA rate is very high
The fields such as work, agricultural (Z.T. Yao et al. A comprehensive review on the applications of coal fly ash[J]. Earth-Science Reviews, 141 (2015) 105-121), such as Italian flyash benefit
With rate 92%, Belgium 73%, Denmark 90%, and Holland reaches 100% unexpectedly.As China's power industry rapidly develops, thereupon
Be that flyash discharge capacity sharply expands.Flyash discharge capacity in 2000 just reaches 1.5 hundred million tons, 2010 up to 300,000,000 tons, 2015
Up to 600,000,000 tons or more.China's utilization of fly ash rates are lower (< 70%), and a part is applied to building and foundation engineering field, such as water
Mud and concrete admixture, flyash brick or roadbed material, are mostly directly used as back under without any disposition
Filling chock material and grouting material fill some abandoned mines and tunnel.A large amount of landfills and the accumulation of flyash not only break up earth's surface plant
Quilt, and easily cause air, soil and pollution of waterhead.
Mullite is Al2O3-SiO2The binary compound being uniquely stabilized under normal pressure in system is a kind of important
Fine ceramics material.Since mullite self-assembling formation needs the conditions such as high-temperature low-pressure, so natural mullite is very rare, mostly
It is artificial synthesized.Mullite has a series of excellent performance, such as fusing point is high, hardness is high, the coefficient of expansion is low, anti-thermal shock coefficient is high,
Creep resistance is strong, corrosion resistance is strong etc., and it is industrial to be widely used in metallurgy, electric power, chemical industry, ceramics, glass and cement etc..At present not
Carry out stone synthesis mainly using chemical products or natural minerals, the mullite of these raw materials of industry preparation is at high cost, low output, is difficult
Carry out large-scale production；Natural mineral raw, energy consumption is high, and mullite purity obtained is low, and mechanics and thermal property are poor.Flyash
Main chemical compositions are that aluminium oxide and silica by both appropriate adjustments ratio can achieve the component requirements of mullite.
From object phase, flyash is made of mullite, glass microballoon and cristobalite, using mullite crystallization advantage, more
It is easy to fire mullite.Using flyash as raw material, mullite ceramic is prepared, mullite content is higher in resulting product, Neng Gouchong
The shortcomings that its excellent performance is waved in distribution, and compared with first two raw material, has not only overcome them, but also realize flyash scale environmental protection
Disposition and its high value added utilization.
In terms of preparing mullite ceramic using flyash sintering, Lee etc. uses freezing gel injection molding and macromolecule
Two methods of sponge technology, prepare porous mullite ceramics (Lee J H, et al. Porous mullite ceramics derived from coal fly ash using a freeze-gel casting/polymer sponge technique [J]. Journal of Porous Materials, 2013; 20: 219-226), the porosity 61%, compression strength 45
MPa.Lin etc. using aluminous fly-ash as raw material (Li H, et al. Extraction of alumina from coal fly ash by mixed-alkaline hydrothermal method[J]. Hydrometallurgy, 2014; 147- 148: 183-187), after alkali and acid processing, Al in powder2O3Content is 65%, and green compact is sintered after cleaning-drying, in ceramics
Mullite content reaches 88%, surface apparent porosity 1.20%, 2.78 g/cm of density3, 169 MPa of compression strength.Ma etc. is with zirconium
Stone, flyash and aluminium oxide be raw material (Ma B Y, et al. Preparation and sintering properties of zirconia-mullite-corundum composites using fly ash and zircon[J]. Transactions of Nonferrous Metals Society of China, 2010; 20:2331- 2335), 200
MPa pressure forming, calcines 4h at different temperatures, obtains the powder using mullite as principal crystalline phase, and the ceramics of 1600 DEG C of sintering are close
Degree reaches 3.03g/cm3。
For in terms of mullite powder, CN1325432C and CN101643359A are added a certain amount of coal ash for manufacturing in flyash
Bauxite is sintered (1500~1700 DEG C) or calcining (500~800 DEG C) after mixing, respectively obtains mullite ceramic
Or powder.Clearly as containing a large amount of other oxide impurities (such as CaO, TiO in flyash and bauxite2、MgO、K2O、Na2O
Deng), mullite phase purity is lower in corresponding product, and generally below 70%.CN 104671811A and CN 102583411A are using strong
Alkaline solution treatment aluminous fly-ash removes siliceous component in flyash in advance, is then handled using strong acid removal of impurities, reduction Fe, Ca,
Na content, drying roast, Al in obtained mullite product2O3Reach 65%, but still is unable to satisfy common not come
The minimum requirements of alumina content in stone manufacture, i.e., Al in light-burned mullite product2O3Content 68.2%(iron and steel industry professional standard
5267-2005 fused mullite of YB/T, M70 series of products).CN102765944B and CN103848632A are based on flyash
Raw material is wanted, appropriate A1 is added2O3Powder is press-formed after ball milling, and (>=1250 DEG C) of high temperature calcinings reuse hydrofluoric acid wash, obtain
Mullite powder.This preparation process dispels Ca, Mg oxide and glass phase and quartz crystal in flyash using hydrofluoric acid,
It is largely not only at high cost using hydrofluoric acid in industrial production, it is be easy to cause Heavy environmental pollution, and due to CaF2And MgF2Indissoluble
Yu Shui is actually difficult to dispel.
Mullite ceramic performance depends on powder purity, and purity is higher, and the mullite ceramic performance of sintering is more superior.Benefit
It is how high yield prepares high-purity mullite powder with coal ash for manufacturing for the maximum difficult point of mullite.Current purifying process
Partial impurities can only be removed, mullite content is generally below 70% in resulting mullite ceramic.In addition, existing research work is big
Amount addition auxiliary material, leads to the practical efficiency of flyash relatively low (< 60%) and the higher, complex process of cost of material etc.
Problem, therefore coal ash for manufacturing is emphatically to explore the mullite powder production of high yield, high-purity for the research of mullite ceramic
Technology.
Summary of the invention
In view of the deficiencies of the prior art, the purpose of the present invention is to provide a kind of modified coal ash high yield prepare it is high-purity not
Carry out the method for mountain flour body.The content of present invention is made of two parts: mullitization technique and purifying process, in mullitization technique
In, surface coating modification, the heightization that calcination stage Aluminum sol is decomposed thermally to form are carried out to flyash powder particle using Aluminum sol
Learn active nanoWith the highest SiO of content in flyash2Solid phase reaction occurs, generates mullite crystalline phase, significantly
Mullite content (60~70%) in flyash is improved, realizes the mullitization (Mullitization) of flyash；In purifying work
In skill, passes through the hydro-thermal process and pickling of alkaline aqueous solution first, dispel residual glass phase and other metal oxygens in flyash
Compound (such as CaO, MgO, Na2O、K2O、Fe2O3) impurity, mullite powder is obtained, reverse flotation technology is then used, by mullite
It quartzy impurity FLOTATION SEPARATION and is dispelled in powder, to obtain the high-purity mullite powder that purity is greater than 98%.
The object of the present invention is achieved like this, and a kind of modified coal ash high yield prepares the side of high-purity mullite powder
Method, it is characterised in that realized by following processing step:
1) a small amount of Aluminum sol is added in flyash powder, by ball milling mixing, carries out flyash powder particle surface
Coating modification；
2) modified coal ash is calcined at a certain temperature, so that mullite content reaches 60-70% in flyash；
3) calcined fine coal powder hydro-thermal process in alkaline aqueous solution cleans at room temperature in conjunction with acidic aqueous solution, dispels fine coal
Residual glass phase and other oxide impurities in ash, obtain mullite powder after dry；
4) reverse flotation technology is used, quartzy impurity in FLOTATION SEPARATION mullite powder prepares high-purity mullite powder.
The flyash is common coal-burning power plant's flying dust, Al in flyash2O3Content is lower than 38%, and partial size is lower than 120
Mesh.
The Aluminum sol is boehmite (AlOOH) colloid, and colloid concentration 20%, additive amount is fine coal grey matter
The 2-8% of amount.
1000~1200 DEG C of the modified coal ash calcination temperature, 0.5~4 h of calcination time.
The alkaline aqueous solution is NaOH or KOH solution, and solution concentration is 1-5 mol/L；Hydro-thermal process temperature is 120
~150 DEG C, hydrothermal conditions be 1~for 24 hours；Acidic aqueous solution is HCl or HNO3Solution, solution concentration are 0.5~2 mol/
L。
It is flotation agent, concentration of aqueous solution 1.0 × 10 that the reverse flotation technology, which selects dodecyl sodium sulfate,-3 mol/
L, pH value of water solution 11~13.
Compared with existing coal ash for manufacturing is for mullite ceramic technology, the present invention has substantial advance and technological innovation, specifically
It is embodied in:
1) Aluminum sol coating modification is used, Aluminum sol is made uniformly to coat fly ash grain, is expanded in calcination stage by interface
It dissipates, the high chemical activity nanometer that Aluminum sol is decomposed thermally to formWith the SiO on fly ash grain surface2Solid phase occurs for component
Reaction generates mullite crystalline phase, so that mullite content is improved by initial 33% to 60%~70% in flyash, realizes fine coal
The mullitization of ash, and significantly reduce SiO in flyash2Constituent content.
2) aqueous slkali hydro-thermal reaction and acid cleaning process are used, residual glass phase impurity in calcined fine coal powder is dispelled, in conjunction with floating
Selecting technology, quartzy impurity, obtains the high-purity mullite powder of 98% or more purity in FLOTATION SEPARATION mullite powder.
In conclusion the present invention is modified by the Aluminum sol of flyash powder and calcines, significantly improve in flyash not come
Stone content realizes the mullitization of flyash；Using alkaline aqueous solution hydro-thermal process and pickling, and flotation technology is combined, dispelled
Glass phase in mullite powder, oxide impurity and quartzy phase, realize the purifying of mullite powder, obtain high yield, high-purity
The mullite powder of degree.The technology of the present invention has established the energy conservation and environmental protection processing of flyash and its high value added utilization solid
Technical foundation.
Detailed description of the invention
The XRD spectra of the modified coal ash calcining powder of the invention of attached drawing 1.
The XRD spectra of the mullite powder of the invention of attached drawing 2.
The XRD spectra of the high-purity mullite powder of the invention of attached drawing 3.
The SEM pattern of the high-purity mullite powder of the invention of attached drawing 4.
Specific embodiment
Embodiment 1
It takes 50g to cross the flyash of 120 mesh screens, is added the Aluminum sol aqueous solution that 15 g concentration are 20%, 1 h of ball milling mixing,
Fly ash surface modification is carried out, 110 DEG C of dry 2h in drying box after ball milling cross 120 mesh screens, and gained powder is modified fine coal
Ash.Modified coal ash 1100 DEG C of 2 h of calcining in Muffle furnace, then broken using ceramic mortar, being configured to solid content is 20%
ZrO is added in suspension2Mill ball, ball milling 4 hours, distilled water cleaning filtered, is dry, obtained calcined fine coal powder powder.Utilize X
Ray powder diffractometer tests XRD spectra, as shown in Fig. 1, it can be seen that in calcined fine coal powder other than mullite phase, also
Contain glass phase and quartzy phase.Full _ pattern fitting is carried out to XRD spectrum using 6.0 software of Jade, analyzes mullite relative amount,
Account for about the 62% of calcining powder quality.
Embodiment 2
The NaOH aqueous solution that 270ml concentration is 2 mol/L, ultrasonic disperse is added in calcined fine coal powder 30g in Example 1
Afterwards, it is fitted into the hydrothermal reaction kettle that capacity is 500ml, constant temperature 1 hour at 120 DEG C, the HCl for being then 1 mol/L with concentration
Aqueous solution is cleaned, and obtains mullite powder after dry.Powder XRD spectra is tested using X-ray diffractometer, such as 2 institute of attached drawing
Show, it can be seen that glass phase completely eliminates in mullite powder, and powder is by mullite phase and a small amount of quartzy phase composition.It uses
Jade6.0 software carries out Full _ pattern fitting to XRD spectra, analyzes mullite relative amount in powder, accounts for about the 82% of powder quality.
Embodiment 3
100 ml distilled water are added in 10 g of mullite powder in Example 2, mechanical using NaOH adjustment pH value to 11
After stirring 10 min, according to flotation agent concentration 1 × 10-3Flotation agent dodecyl sodium sulfate is added in mol/L, stirs 2 min, floats
6 min of bubble are scraped in choosing, are cleaned product in froth pulp and slot after the completion of flotation, are filtered, is dry, are obtained FLOTATION SEPARATION and are gone out quartz
High-purity mullite powder.Powder XRD spectra is tested using X-ray diffractometer, as shown in Fig. 3, is shown in powder substantially only
Remaining mullite phase.Full _ pattern fitting is carried out to XRD spectrum using 6.0 software of Jade, analyzes mullite relative amount in powder,
Its 98.2%. for accounting for about powder quality is scanned electron microscope morphology observations to high-purity mullite powder, such as 4 institute of attached drawing
Show, mullite grains complete crystal form is clear, in a strip shape and polyhedron, grain size。
Claims (2)
1. a kind of method that modified coal ash high yield prepares high-purity mullite powder, comprises the following steps that:
1) a small amount of Aluminum sol is added in flyash powder, by ball milling mixing, carries out the cladding of flyash powder particle surface
It is modified；The Aluminum sol is boehmite colloid, and colloid concentration 20%, additive amount is the 2 ~ 8% of flyash quality；
2) modified coal ash is calcined at a certain temperature, so that mullite content reaches 60 ~ 70% in flyash；The modification
Flyash calcination temperature is 1000 ~ 1200 DEG C, and calcination time is 0.5 ~ 4 h；
3) calcined fine coal powder hydro-thermal process in alkaline aqueous solution is cleaned at room temperature in conjunction with acidic aqueous solution, is dispelled in flyash
Residual glass phase and other metal oxide impurities obtain mullite powder after dry；The alkaline aqueous solution is NaOH
Or KOH solution, solution concentration are 1 ~ 5 mol/L；Hydro-thermal process temperature is 120 ~ 150 DEG C, and hydrothermal conditions are 1 ~ 24 h；Acid
Property aqueous solution be HCl or HNO3Solution, solution concentration are 0.5 ~ 2 mol/L；
4) reverse flotation technology is used, quartzy impurity in FLOTATION SEPARATION mullite powder prepares high-purity mullite powder；Described
It is flotation agent, concentration of aqueous solution 1.0 × 10 that reverse flotation technology, which selects dodecyl sodium sulfate,-3Mol/L, pH value of water solution 11 ~
13。
2. according to the method described in claim 1, it is characterized by: the flyash is coal-burning power plant's flying dust, in flyash
Al2O3Content is lower than 38%, and partial size is lower than 120 mesh.
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| CN201611016696.2A CN106518035B (en) | 2016-11-18 | 2016-11-18 | A kind of method that modified coal ash high yield prepares high-purity mullite powder |
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| CN109534829A (en) * | 2017-09-21 | 2019-03-29 | 宝山钢铁股份有限公司 | A kind of KR desulfurization agitating paddle castable and preparation method thereof |
| CN108359273A (en) * | 2018-01-29 | 2018-08-03 | 南昌航空大学 | A method of improving marble powder whiteness |
| CN114790108A (en) * | 2022-04-13 | 2022-07-26 | 山西太钢不锈钢股份有限公司 | Closed nano-aperture pore mullite-high silica glass composite material and preparation method thereof |
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