CN103936448B - Method for inhibiting desolvation of zirconia metering nozzle stabilizing agent - Google Patents
Method for inhibiting desolvation of zirconia metering nozzle stabilizing agent Download PDFInfo
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- CN103936448B CN103936448B CN201410152594.8A CN201410152594A CN103936448B CN 103936448 B CN103936448 B CN 103936448B CN 201410152594 A CN201410152594 A CN 201410152594A CN 103936448 B CN103936448 B CN 103936448B
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- stabilized zirconia
- gel
- zro
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- partial stabilized
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Abstract
The invention discloses a method for inhibiting the desolvation of a zirconia metering nozzle stabilizing agent. The method comprises the following steps: preparing a ZrO2-Al2O3-MgO composite powder by a gel-sol method; controlling the proportion and granularity of the ZrO2-Al2O3-MgO composite powder, mixing magnesium oxide stabilized zirconia particles and the ZrO2-Al2O3-MgO composite powder in a certain ratio, jointly grinding for 24-28 hours, mixing the jointly-grinded powder, the magnesium oxide stabilized zirconia particles and a proper amount of binding agent, isostatically pressing for molding, drying for 24 hours at 105+/-5 DEG C, and calcining at 1,700-1,720 DEG C to prepare a composite inner layer of the modified zirconia composite metering nozzle, wherein the service life of the composite inner layer can be 33 hours. Residual sample microscopic structure analysis indicates that the number of desolvation of the stabilizing agent is extremely small, and the zirconia particles hardly have phase-change cracking.
Description
Technical field
The present invention relates to preparation controls the device material modification of molten steel flow a kind of technique about casting tundish in ferrous metallurgical industry continuously, specifically a kind of inhibited oxidation zirconia metering nozzle stablizer desolventizing method.
Background technology
Metering nozzle refers to the functional device that a kind of high-temperature structural ceramics being arranged on continuous casting tundish bottom makes.Its Main Function is that Metal in Tundish static pressure remains unchanged substantially, and molten steel flows into crystallizer by metering nozzle, and crystallizer is by large discharge water-cooled, and liberated heat when taking away solidification of molten steel, makes molten steel solidification become base.Due to the thermal Finite that crystallizer water-cooled is taken away, thus, the molten steel quantity flowing into crystallizer in the unit time must be within limits.The aperture of metering nozzle is larger, and the unit time flows into crystallizer molten steel quantity the more, selects suitable aperture to make tundish water nozzle, is metering nozzle.The major cause that metering nozzle lost efficacy is because the heat in MOLTEN STEEL FLOW process and the stablizer in zirconium white react, cause stablizer precipitation, and then cause zirconium white unstability, particle is made an exception, intensity significantly reduces, scour resistance decline cause expanding, the molten steel solidification liberated heat of inflow crystallizer is greater than heat that crystallizer water coolant can take away and exit use.
Composite metering nozzle refer to the mouth of a river by two portions unlike material compound, inlay and make.General outside is the lower material of price, and internal layer and steel contacts position are the material that price is higher.Compared with all-in-one-piece metering nozzle, the major cause of composite metering nozzle is to not affect the prerequisite decline lower production cost in work-ing life.
The profile variation of composite metering nozzle is little.Pore size is determined by applying unit.The key improving work-ing life is the improvement of inlaying internal layer material.
The monoblock type metering nozzle produced both at home and abroad mostly at present is zircon stone; Composite metering nozzle outer material mostly is High-Alumina, and composite inner layer is zirconium oxide, and its zirconic content (wt%) is generally about 95%, and actual service life is 10 hours.Work-ing life, short major cause was Zirconia-stabilized dose of precipitation, other elements in stablizer and steel, slag with form low melting point eutectic, eutectic runs off, zirconium white unstability, particle is made an exception, intensity significantly reduces, and scour resistance decline causes expanding, thus causes composite metering nozzle composite inner layer short for work-ing life.
In current tundish refractory materials ton steel contracted land price, tundish paint accounts for the largest percentage, and accounts for about 50%.And along with the digestion of imported technology and the raising of raw material quality, current tundish paint develops into by the silica heat-insulating plate being 6-8 hour original work-ing life the wet method coating that work-ing life is 16-20 hour work-ing life, and then develop into the dry-type vibration material that the work-ing lifes adopted at present are more than 30-40 hour more, namely tundish is except metering nozzle, all the other materials'use life-spans all reach more than 30-40 hour, and work-ing life is the bottleneck that the metering nozzle of 10 hours has become restriction whole tundish work-ing life.
In order to reduce tundish ton steel production cost, position is used to add a kind of device at sizing nozzle of tundish---sizing nozzle of tundish quick-changing mechanism.After first metering nozzle uses 6-8 hour, slide by force with hydraulic efficiency plant and push second mouth of a river; So go down, to maintain whole tundish non-stop run more than 30 hours.
The problem that sizing nozzle of tundish quick-changing mechanism brings is complex manufacturing, device structure and complicated operation, increases containing chromium trade waste quantity, and production cost increases.In the overall contracted land price of tundish ton steel, only sizing nozzle of tundish quick-changing mechanism just accounts for about 1/3rd of overall contracted land price.Therefore, produce long lifetime composite metering nozzle, composite metering nozzle is synchronous for work-ing life with tundish, is reduce production cost, solves the key that sizing nozzle of tundish quick-changing mechanism brings problems.
Summary of the invention
The object of the invention is to, provide a kind of inhibited oxidation zirconia metering nozzle stablizer precipitation novel method, adopt the zirconium oxide metering nozzle internal layer that the method is obtained, work-ing life can reach more than 30 hours.
In order to realize above-mentioned task, the present invention takes following technical solution:
A kind of suppression semi-stability Zirconia-stabilized dose of precipitation technique, is characterized in that, carry out according to the following step:
1) ZrO
2-Al
2o
3prepared by-MgO composite powder
Get ZrOCl by weight percentage
2.8H
2o prepares mother liquor, mother liquid concentration 0.5-2.0Mol/L, adds the dispersion agent of material gross weight 1.2%, NH
4(OH) positive titration, is stirred to PH=7 ~ 10, obtained first gel.
Get AlCl by weight percentage
36H
2o prepares mother liquor, mother liquid concentration 0.5-2.0Mol/L, adds the dispersion agent of material gross weight 1.2%, NH
4(OH) positive titration, is stirred to PH=8 ~ 9, obtained second gel.
Get MgCl by weight percentage
26H
2o prepares mother liquor, mother liquid concentration 0.5-1.0Mol/L, adds the dispersion agent of material gross weight 1.2%, NH
4(OH) positive titration, is stirred to PH=7 ~ 9, obtained 3rd gel.
Be converted to ZrO by weight percentage
2: Al
2o
3: MgO=(30-50): (40-60): (10-20) gets the first gel, the second gel and the 3rd gel mix and blend, obtained mixed gel.
Mixed gel ageing 9h ~ 16h ,-0.095MPa vacuum suction filter, deionized water wash can't detect Cl to Silver Nitrate
-till;
Then under 500 DEG C of conditions, react 1h, temperature rises to 700 DEG C, and reaction 5h comes unstuck, and react rear ball milling 10h, obtains mean particle size at the ZrO of 1 μm
2-Al
2o
3-MgO composite powder;
2) magnesia partial stabilized zirconia particle and magnesia partial stabilized zirconia granule fines is got according to mass ratio 50:50, wherein, magnesia partial stabilized zirconia average particle size is 0-1mm, and magnesia partial stabilized zirconia powder particle size consists of median size 2-3 μm, D
50=1.8-2.7 μm, D
90=4-5 μm.
ZrO is got according to the total mass 2% ~ 6% of magnesia partial stabilized zirconia particle and magnesia partial stabilized zirconia granule fines
2-Al
2o
3-MgO composite powder, by ZrO
2-Al
2o
3-MgO composite powder and magnesia partial stabilized zirconia fine powder grind 24h ~ 48h altogether, ensure ZrO
2-Al
2o
3-MgO composite powder being uniformly distributed in magnesia partial stabilized zirconia fine powder, then magnesia partial stabilized zirconia particle is added and appropriate bonding agent is mixed with blank, isostatic pressing, dry 24h under 105 ± 5 DEG C of conditions, sinter at 1700 DEG C ~ 1720 DEG C temperature, obtained modified zirconia matter composite metering nozzle composite inner layer.
Adopt the modified zirconia matter composite metering nozzle composite inner layer that method of the present invention is obtained, alumina content is 1-3%, and content of magnesia is that 0.3-0.8%(disregards content of magnesia in magnesia partial stabilized zirconia), volume density is 5.10-5.30g/cm
3, cold conditions compressive strength>=800Mpa.Result on trial through applicant shows, work-ing life can reach more than 30 hours.
Accompanying drawing explanation
Fig. 1 is preparation technology's schema of composite metering nozzle of the present invention.
Below in conjunction with drawings and Examples, the present invention is described in further detail.
Embodiment
2003, applicant (Xi'an University of Architecture and Technology) assume responsibility for industry in Shaanxi province brainstorm project " exploitation of baddeleyite corundum eutectoid fine crystallization pyroceramic " (item number 2003K07-G9), and Xi'an City, Shanxi Province industry brainstorm project " zirconium white compound disperse corundum phase Special high-temperature pottery (numbering GG200347) " born; Within 2010, assume responsibility for Jinan Quan Cheng scholar's construction project " research of ZrO2/Al2O3 composite diphase material and the application in continuous casting functional material ", applicant obtains Jinan " spring city scholar " honorary title; 2013, previous research work basis assume responsibility for state natural sciences fund general project " zirconia metering nozzle stablizer precipitation breakage of particles mechanism and life-span improve research " (item number 51372193); According to born project research zirconium oxide metering nozzle Wear mechanism and raising achievement in research in work-ing life, devise and suppress semi-stability Zirconia-stabilized dose of New technology for desolventizing hot.
Stabilizer magnesium oxide in semi-stability zirconium white because its activity is high according to the main process of achievement in research zirconium oxide metering nozzle damage, in use first react with the composition in molten steel or slag and form eutectic and run off, after stabilized magnesium hydroxide agent precipitation in zirconium white, zirconium white undergoes phase transition, crack, zirconia particles breaks, macrobead division becomes many small-particles, zirconia metering nozzle intensity significantly declines, the performance of flushing of anti-molten steel and slag declines, small-particle washes away loss, causes that metering nozzle is expanding to roll off the production line.
Applicant once studied the ZrO adding sol-gel method and prepare in zirconium oxide metering nozzle
2-Al
2o
3composite powder, metering nozzle intensity, work-ing life increase substantially.Dominant mechanism is ZrO
2-Al
2o
3zrO in composite powder
2the script composition of metering nozzle, the ZrO introduced in composite powder
2active high, be conducive to sintering.Under same firing temperature the volume density of product and intensity high.Al in composite powder
2o
3must strictly control to introduce quantity, in sintering process, Al
2o
3the stablizer MgO gone out with precipitation in part semi-stability zirconium white reacts, form magnesium-aluminium spinel, magnesium-aluminium spinel fusing point is high, erosion-resisting characteristics good, integument is formed around zirconia particles, stablizer in zirconia particles and molten steel and slag-metal reaction can be stoped, organized the further precipitation of stablizer.After the stabilizer magnesium oxide that aluminum oxide in composite powder and part precipitation go out is reacted and formed magnesium-aluminium spinel integument, residue zirconium white forms columnar structure, and product strength is improved further.But the stabilizer magnesium oxide that the aluminum oxide that must strictly control in composite powder and part precipitation go out is reacted and formed magnesium-aluminium spinel, experiment proves that the massfraction of composite powder introducing aluminum oxide is 1.5-2.0%, best results.
Magnesium-aluminium spinel integument should be formed around zirconia particles to solve, stabilizer magnesium oxide and molten steel, slag-metal reaction precipitation in zirconia particles is stoped to run off, in controlled oxidization zirconium particle, in stabilizer magnesium oxide precipitation and composite powder, aluminum oxide forms the quantity of magnesium-aluminium spinel again, have employed at ZrO
2-Al
2o
3small amounts magnesium is introduced, by adding a small amount of ZrO in composite powder
2-Al
2o
3-MgO composite powder suppresses the precipitation of stablizer, improves the work-ing life of metering nozzle further.Optimized by technical recipe, the actual use of sample, respond well.The mouth of a river uses more than 30h substantially without expanding phenomenon.
Below in an example, the preparation method of gel is:
Get ZrOCl by weight percentage
2.8H
2o prepares mother liquor, mother liquid concentration 0.5-2.0Mol/L, adds the dispersion agent of material gross weight 1.2%, NH
4(OH) positive titration, is stirred to PH=7 ~ 10, obtained first gel;
Get AlCl by weight percentage
36H
2o prepares mother liquor, mother liquid concentration 0.5-2.0Mol/L, adds the dispersion agent of material gross weight 1.2%, NH
4(OH) positive titration, is stirred to PH=8 ~ 9, obtained second gel;
Get MgCl by weight percentage
26H
2o prepares mother liquor, mother liquid concentration 0.5-1.0Mol/L, adds the dispersion agent of material gross weight 1.2%, NH
4(OH) positive titration, is stirred to PH=7 ~ 9, obtained 3rd gel.
Use the technical requirements of raw material:
1) granularity of magnesia partial stabilized zirconia particle is: 0-1mm, i.e. 1mm screen underflow.
2) size composition of magnesia partial stabilized zirconia granule fines is: median size 2-3 μm, D
50=1.8-2.7 μm, D
90=4-5 μm.
3) bonding agent: concentration is the cellulose solution of 2%.
It is below the embodiment that contriver provides.
Embodiment 1:
Step one, produces ZrO by weight percentage
2: Al
2o
3: first gel of MgO=50:40:10, the second gel and the 3rd gel mix and blend, obtained mixed gel.Mixed gel ageing 15h ,-0.095MPa vacuum suction filter, deionized water wash can't detect Cl to Silver Nitrate
-till; Then under 500 DEG C of conditions, react 1h, temperature rises to 700 DEG C, and reaction 5h comes unstuck, and react rear ball milling 10h, obtains mean particle size at the ZrO of 1.24 μm
2-Al
2o
3-MgO composite powder;
Step 2, gets magnesia partial stabilized zirconia particle and each 5kg of magnesia partial stabilized zirconia fine powder, additional ZrO according to mass ratio 50:50
2-Al
2o
3-MgO composite powder 0.45kg.By magnesia partial stabilized zirconia fine powder and ZrO
2-Al
2o
3the mixing of-MgO composite powder grinds 36h altogether, ensures ZrO
2-Al
2o
3-MgO composite powder being uniformly distributed in magnesia partial stabilized zirconia fine powder, then adds the cellulose solution bonding agent 0.5kg that magnesia partial stabilized zirconia particle and concentration are 2%, the obtained blank of mixing.
Step 3, obtained blank loads mould, and in 230MPa cold isostatic compaction, dry 24h under 105 ± 5 DEG C of conditions, sinters at 1700 DEG C of temperature, and obtained modified zirconia matter composite metering nozzle composite inner layer, its work-ing life can reach 33h.Few by rear residual sample microstructure analysis display stablizer precipitation quantity, zirconia particles breaks without phase transformation substantially.
Embodiment 2:
The present embodiment and embodiment 1 difference are: the ZrO in step one
2-Al
2o
3the ZrO of-MgO composite powder
2: Al
2o
3: MgO=40:45:15, even if ZrO
2-Al
2o
3al in-MgO composite powder
2o
3/ MgO ratio forms closer to the theory of magnesium-aluminium spinel; Additional ZrO in step 2
2-Al
2o
3-MgO composite powder is 4.0%, namely ensures that the introduction volume of aluminum oxide is constant.Obtained modified zirconia matter composite metering nozzle composite inner layer, its work-ing life can reach 37h.
Embodiment 3:
The present embodiment and embodiment 1 difference are: the sintering temperature in step 3 is adjusted to 1720 DEG C, and obtained modified zirconia matter composite metering nozzle composite inner layer, its work-ing life can reach 34h.
Claims (3)
1. an inhibited oxidation zirconia metering nozzle stablizer desolventizing method, is characterized in that, carries out according to the following step:
1) ZrO
2-Al
2o
3prepared by-MgO composite powder
Get ZrOCl by weight percentage
28H
2o prepares mother liquor, mother liquid concentration 0.5-2.0mol/L, adds the dispersion agent of material gross weight 1.2%, NH
4(OH) positive titration, is stirred to pH=7 ~ 10, obtained first gel;
Get AlCl by weight percentage
36H
2o prepares mother liquor, mother liquid concentration 0.5-2.0mol/L, adds the dispersion agent of material gross weight 1.2%, NH
4(OH) positive titration, is stirred to pH=8 ~ 9, obtained second gel;
Get MgCl by weight percentage
26H
2o prepares mother liquor, mother liquid concentration 0.5-1.0mol/L, adds the dispersion agent of material gross weight 1.2%, NH
4(OH) positive titration, is stirred to pH=7 ~ 9, obtained 3rd gel;
Be converted to ZrO by weight percentage
2: Al
2o
3: MgO=(30-50): (40-60): (10-20) gets the first gel, the second gel and the 3rd gel mix and blend, obtained mixed gel;
By mixed gel ageing 9h ~ 16h ,-0.095MPa vacuum suction filter, deionized water wash can't detect Cl to Silver Nitrate
-till;
Then under 500 DEG C of conditions, react 1h, temperature rises to 700 DEG C, and reaction 5h comes unstuck, and react rear ball milling 10h, obtains mean particle size at the ZrO of 1 μm
2-Al
2o
3-MgO composite powder;
2) magnesia partial stabilized zirconia particle and magnesia partial stabilized zirconia granule fines is got according to mass ratio 50:50, wherein, magnesia partial stabilized zirconia grain graininess is 0-1mm, and magnesia partial stabilized zirconia powder particle size consists of median size 2-3 μm, D
50=1.8-2.7 μm, D
90=4-5 μm;
ZrO is got according to magnesia partial stabilized zirconia particle and magnesia partial stabilized zirconia granule fines total mass 2-6%
2-Al
2o
3-MgO composite powder, by ZrO
2-Al
2o
3-MgO composite powder and magnesia partial stabilized zirconia fine powder grind 24h ~ 48h altogether, ensure ZrO
2-Al
2o
3-MgO composite powder being uniformly distributed in magnesia partial stabilized zirconia fine powder, then magnesia partial stabilized zirconia particle is added and appropriate bonding agent is mixed with blank, isostatic pressing, dry 24h under 105 ± 5 DEG C of conditions, sinter at 1700 DEG C ~ 1720 DEG C temperature, obtained modified zirconia matter composite metering nozzle composite inner layer.
2. the method for claim 1, is characterized in that, the consumption of described bonding agent is 5% of magnesia partial stabilized zirconia particle and magnesia partial stabilized zirconia granule fines total mass.
3. method as claimed in claim 2, is characterized in that, described bonding agent to be concentration be 2% cellulose solution.
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| CN106278308B (en) * | 2016-08-02 | 2018-11-09 | 西安建筑科技大学 | A method of addition magnesium-rich spinel micro mist prepares zirconium oxide metering nozzle |
| CN110655399B (en) * | 2019-09-06 | 2022-01-11 | 钟祥市中原电子有限责任公司 | Breathable ceramic head for molten steel hydrogen determination probe and preparation method thereof |
| CN110903086A (en) * | 2019-12-10 | 2020-03-24 | 中钢集团洛阳耐火材料研究院有限公司 | High-performance magnesium-stabilized zirconia raw material |
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| CN102557690A (en) * | 2012-01-06 | 2012-07-11 | 西安建筑科技大学 | Preparation method for corundum baddeleyite eutectoid composite nonswirl nozzle inner layer |
| CN102584301A (en) * | 2012-03-09 | 2012-07-18 | 西安建筑科技大学 | Method for preparing zirconium oxide metering nozzle |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102557690A (en) * | 2012-01-06 | 2012-07-11 | 西安建筑科技大学 | Preparation method for corundum baddeleyite eutectoid composite nonswirl nozzle inner layer |
| CN102584301A (en) * | 2012-03-09 | 2012-07-18 | 西安建筑科技大学 | Method for preparing zirconium oxide metering nozzle |
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