CN1970198A - High basicity tundish cover agent and its production method - Google Patents
High basicity tundish cover agent and its production method Download PDFInfo
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- CN1970198A CN1970198A CN 200610119187 CN200610119187A CN1970198A CN 1970198 A CN1970198 A CN 1970198A CN 200610119187 CN200610119187 CN 200610119187 CN 200610119187 A CN200610119187 A CN 200610119187A CN 1970198 A CN1970198 A CN 1970198A
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- coverture
- high basicity
- covering flux
- tundish covering
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Abstract
A high PH value ball type hollow coating agent comprises burnt lime, silica dioxide, and alumind, with the former two taking 40%-70% of the total weight and their rate 2.8:5, alunind taking 15%-40% of the total weight, with pre smelt, high PH value, carbon free material and spraying grain making process, enjoying fine heat preserving capacity, retaining three layer structure, without crustization, with improved capability in avoiding secondary oxidization of steel liquid and impurities adhesion.
Description
Technical field
The present invention relates to metallurgical class, relate to the spherical hollow type tundish covering flux of a kind of high basicity specifically.
Background technology
Tundish covering flux is used for casting process and is covered in tundish molten steel surface, its basic demand be not with molten steel generation bad reaction, avoid polluting molten steel; Do not corrode alkaline tundish cylinder-packing.Its major function is a molten steel insulation, avoids the excessive and cold steel of molten steel surface knot of tundish molten steel temperature drop in casting process; Form liquid slag layer and be covered in molten steel surface, prevent secondary oxidation of steel with secluding air; The field trash that floats in the absorption molten steel, the cleaning molten steel; Prevent that molten steel from returning sulphur etc.
Along with the continuous development of continuous casting technology, the effect of tundish covering flux becomes more and more important, and uses also general day by day.Through metallurgical technicians's years of researches, find to have the secondary oxidation that effectively prevents molten steel through the high basicity tundish covering flux of fritting; The field trash that floats in the absorption molten steel, purify hot metal improves the molten steel cleanliness factor; Prevent that molten steel from returning sulphur; Improve excellent metallurgical functions such as ladle lining life.Therefore, the trend of the oriented high basicity development of tundish covering flux in recent years.
Though present spherical hollow type coverture has good spreadability, heat insulating ability and the feature of environmental protection, obtained each metallargist's of steel mill approval and a large amount of the use, but its basicity usually can only be between 1-2.5 (1＜CaO/SiO
2＜2.5), because basicity is not high, it is all relatively poor that it prevents that molten steel from returning the ability of field trash in sulphur and the absorption molten steel, and easily corrode alkaline tundish cylinder-packing.Facts have proved that basicity is greater than 3 (CaO/SiO
2＞3) tundish covering flux could particularly produce better effect to the production of high-quality cleaning steel to slab quality, and basicity is big more, and its superiority is obvious more.
But there are some problems in present high basicity tundish covering flux, because high basicity tundish covering flux has high fusing point and viscosity and easy-sintering, therefore, under the tundish service condition, the coverture molten slag layer can be lumpd within a certain period of time, produce the crust phenomenon, have influence on carrying out and on-the-spot thermometric, sampling operation that many stoves water steel continuously, this is the topmost problem that high basicity tundish covering flux need solve at present.In addition, another reason that crust produces is owing to exist certain thermograde in the slag, after the slag blanket on molten steel surface all melts, has destroyed the three-decker of original liquid slag layer, sinter layer, solid slag blanket.Prevent that the effective measures that crust from being to guarantee that initial slag has suitable fusing point (1350 ℃～1450 ℃), for this reason, needs to select to have the raw material of suitable fusion temperature.
In addition, also the someone thinks, the burn-off rate of coverture is enough slow, can prevent that crust from appearring in the slag upper strata, can descend but slag absorbs the ability of impurity; The coverture burn-off rate is fast, makes the very fast disappearance of three-decker, forms thick crust on the slag upper strata easily.So tundish covering flux should possess suitable pre-arcing characterisitics.
As seen directly have influence on the result of use of high basicity tundish covering flux for the selection of alkaline covering agent raw material types and proportioning thereof.
Summary of the invention
The objective of the invention is weak point at above-mentioned existing coverture, a kind of high basicity tundish covering flux and production method thereof are provided, by selecting proper raw material, the raw material proportioning that is fit to, again by spray art, produced functions of use such as having good heat insulating ability, spreadability, the feature of environmental protection, had a high basicity coverture of good metallurgical function simultaneously.
Technical scheme of the present invention is as follows:
A kind of high basicity tundish covering flux, this coverture comprises raw material and additive component, it is characterized in that comprising calcium oxide, silica, alundum (Al in this coverture raw material components, wherein to add the percentage that dioxide-containing silica accounts for this coverture gross weight be 40-70%, wherein CaO/SiO to calcium oxide content
2Be 2.8-5, the percentage by weight of alundum (Al is 15-40%, and described coverture face shaping is a hollow spheres.
All the other compositions in the described raw material components can be that oxidation is received, a kind of or wherein combination of at least two kinds of components in magnesia, calcirm-fluoride, boron oxide and the CARBONATE COMPONENT.
Described raw material can be selected a kind of in LF furnace refining slag, aluminium calcium pre-melted slag, the aluminous cement or wherein at least two kinds combination for use.The granularity of described raw material is that 200 order percent of pass are not less than 96%.
The percentage of this coverture gross weight of described content of additive is 1.2%-5%, and its composition can be a kind of in 801 glue, yellow starch gum, the carboxyl methyl cellulose, or at least two kinds combination.
The bulk density of described coverture can be 0.6-1.1g/cm
3, wherein suitable bulk density scope is 0.75-0.95g/cm
3
Described coverture granularity can be ￠ 0.1-1.2mm, and wherein suitable particle size range is ￠ 0.2-0.8mm.
A kind of production method of high basicity tundish covering flux, it is characterized in that this method adopts following steps: at first each component raw material enters blender after the weighing in proportion, stirs; Add water afterwards, form slip, in slurry mixer, stir; To the slip pressurization, in being sprayed onto spray drying tower, spray gun carries out mist projection granulating then; At last the particle cooling that obtains is got final product.
Described spray gun aperture is 1.8-2.2mm.
Advantage of the present invention: adopt fritting, high basicity, carbon-free raw material.Have slagging ability rapidly and uniformly, the ability of come-up field trash in this coverture absorption molten steel is improved a lot, can prevent that molten steel from returning sulphur, molten steel is not polluted in not carburetting.The most steel grades of not only suitable cast are particularly suited for pouring into a mould high-quality steel grade.Adopted atomizing granulating technology, the face shaping that makes this coverture have spherical hollow makes it have good heat insulating ability, can keep three-decker in tundish, makes the molten steel temperature in tundish fluctuation less; Have good spreadability, it can be sprawled on the molten steel face rapidly after adding tundish equably, prevent to open the oxidation of watering the initial stage molten steel: have tangible environment protecting, reduced dust, improved the on-the-spot working environment of cast.Compare with traditional alkaline tundish covering flux, its heat insulation effect, the ability of secondary oxidation of steel and dross inclusion adsorption that prevents all improve a lot, and do not crust, and good environment protecting is arranged.
Description of drawings
Accompanying drawing 1 is a process chart of the present invention.
The specific embodiment
By the following examples feature of the present invention and other correlated characteristic are described in further detail, so that technical staff's of the same trade understanding:
| Embodiment | Coverture composition (percentage by weight %) | Bulk density (g/cm 3) | ||||||||
| CaO | SiO 2 | Al 2O 3 | MgO | CaF 2 | B 2O 3 | Na 2O | Igloss | Additive | ||
| One | 30.55 | 10.18 | 28.56 | 15.13 | 4.10 | 1.51 | 7.47 | (2.5 yellow starch gum) | 0.82 | |
| Two | 32.67 | 9.33 | 25.78 | 16.21 | 3.55 | 1.82 | 7.64 | (3.0 801 glue) | 1.09 | |
| Three | 36.21 | 9.12 | 27.32 | 12.88 | 3.62 | 1.65 | 6.20 | (2.0 yellow starch gum)+1.0 (801 glue) | 0.87 | |
| Four | 38.16 | 12.74 | 26.13 | 14.19 | 3.75 | 1.41 | 1.12 | (2.5 yellow starch gum) | 0.85 | |
| Five | 38.27 | 11.26 | 24.60 | 20.80 | 3.57 | 1.5(CMC) | 0.80 | |||
| Six | 38.45 | 8.56 | 28.32 | 11.14 | 2.11 | 1.32 | 7.60 | (2.5 yellow starch gum) | 0.91 | |
| Seven | 44.18 | 10.52 | 32.9 | 4.66 | 1.00 | 1.00 | 2.74 | (3.0 yellow starch gum) | 0.83 | |
| Eight | 43.24 | 9.40 | 30.46 | 5.82 | 1.52 | 0.50 | 5.56 | (2.5 yellow starch gum)+1.0 (801 glue) | 0.86 | |
| Nine | 46.67 | 9.33 | 27.26 | 2.02 | 2.15 | 0.58 | 2.49 | 8.0 | (2.5 yellow starch gum) | 0.90 |
| Ten | 49.65 | 10.36 | 28.11 | 1.74 | 0.5 | 1.28 | 5.86 | (CMC)+1.0 1.5 (801 glue) | 0.89 | |
| 11 | 48.22 | 13.78 | 25.37 | 6.17 | 2.32 | 2.14 | 2.0(CMC) | 0.92 | ||
| 12 | 53.18 | 11.82 | 23.64 | 2.18 | 0.5 | 6.18 | 2.5(CMC) | 0.89 | ||
| 13 | 55.45 | 11.57 | 20.66 | 3.12 | 0.50 | 5.2 | (CMC)+1.0 2.5 (yellow starch gum) | 0.68 | ||
| 14 | 60.74 | 15.26 | 17.55 | 2.95 | (CMC)+1.0 2.5 (yellow starch gum) | 0.90 | ||||
| 15 | 52.58 | 17.49 | 20.1 | 3.29 | 1.87 | 1.17 | (CMC)+1.0 2.5 (yellow starch gum) | 0.92 | ||
As the raw material of producing high basicity tundish covering flux, at first will satisfy the basic demand of high basicity, simultaneously the generation of crusting when preventing execute-in-place need improve its agglutinating property, this just requires selected raw material must have suitable fusing point, passes through to add Al among the embodiment
2O
3Composition is used for the adjustment of coverture fusing point, the addition of this composition is relevant with basicity, usually basicity is high more, the addition that needs is many more, other are dosed, and magnesia can prevent the erosion of coverture to the tundish cylinder-packing in the composition, oxidation is received and boron oxide can play additional auxiliary effect to the adjustment of fusing point, and calcirm-fluoride can improve the flowability of slag, the booster action that carbonate can play and adjust fusing point, adjust basicity.In addition, raw-material degree of purity also is another important evidence that need consider.
The raw material that degree of purity is not high generally all contain oxides such as FeO, studies show that, because the existence of these oxides, may there be following reaction in the slag steel at the interface between molten steel and the coverture in tundish:
3(FeO)+2[Al]＝3[Fe]+(Al
2O
3) (a)
The generation of above-mentioned reaction can make the field trash in the molten steel increase, and pollutes molten steel, and is totally unfavorable to the production of clean steel.
Belong to CaO-SiO for composition
2-Al
2O
3The tundish covering flux of system, along with the increase of basicity R, the activity coefficient of FeO decreases.Therefore, the basicity that improves tundish covering flux can effectively suppress the carrying out of formula (a) reaction, and is very favourable to the degree of purity that improves molten steel.In addition, when in the steel during [C]＜0.03% because the high as easy as rolling off a log molten steel recarburization that causes of free carbon content in the coverture.Therefore, the raw-material degree of purity of control tundish covering flux could fundamentally satisfy the production requirement of clean steel.Therefore, require Fe in the coverture
2O
3, MnO and the low as far as possible (Fe of free carbon
2O
3＜3%, MnO＜1%, FC＜1%), to prevent that molten steel is produced oxidation or carburetting.
Raw material can be selected a kind of in LF furnace refining slag, aluminium calcium pre-melted slag, the aluminous cement for use among the embodiment, or wherein at least two kinds combination, is standard to satisfy each set of dispense ratio in the selection course.The granularity of described raw material is that 200 order percent of pass are not less than 96%, makes coverture have that slagging is quick, the uniform characteristics of composition.
Additive is selected among the embodiment is a kind of in 801 glue, yellow starch gum, the carboxyl methyl cellulose, or at least two kinds combination, can improve the flowability and the suspension of slurry in the mist projection granulating process effectively, improves the intensity of coverture particle.
The suitable bulk density scope of the foregoing description coverture is 0.75-0.95g/cm
3, make described coverture have good heat insulation effect.The suitable particle size range of coverture is ￠ 0.2-0.8mm, and this scope makes coverture can have suitable bulk density scope (0.75-0.95g/cm
3), if then the dust of coverture is many for granularity＜0.2mm, contaminated environment; If granularity＞0.8mm then can make the coverture bulk density bigger, reduce its heat insulating ability.
The main production equipments that the foregoing description relates in process of production has:
(1) double helix material blender: be used for the mixing of powder, capacity is 2m
3, usage factor 0.6;
(2) octagonal slurry mixer: be used for the mixing of slurry;
(3) mud plunger displacement pump: the slurry in the pipeline is pressurizeed, it is sprayed in the spray drying tower.The pressure of plunger displacement pump generally is controlled at 1.8MPa～2.5Mpa;
(4) spray drying tower: spray drying tower is a columnar drying tower, tower internal diameter 5m, tower height 11m, feed liquid in drying tower, atomize and with the contacting of high-temperature flue gas, reach dry purpose in the mode of reverse-flow drying.Drying tower high-temperature fuel gas inlet temperature is 530 ℃ ± 30 ℃, and outlet temperature is 180 ℃ ± 30 ℃.Particle portion via the spray drying tower ejection is hollow spheres.
The technological process of production as shown in Figure 1, each raw material enters the double helix material mixer after weighing, by blender powder is fully stirred, then adding water makes powder form slip (guaranteeing solid content＞55%), in the octagonal slurry mixer, stir, by the mud plunger displacement pump it is pressurizeed again, slip in being sprayed onto spray drying tower, spray gun is carried out mist projection granulating, wherein the spray gun aperture is 1.8～2.2mm, its granule size of particle of ejection is 0.2～0.8mm, and unit weight is 0.85 ± 0.10g/cm
3The particle that obtains can pack via the cooling of water-cooled bed again, and the pack specification is a 10kg paper bag bag.
The concrete technology of each link in the production is as follows:
Therefore (1) proportioning process: the accuracy of batching directly influences the final physical and chemical performance of product, and it is vital getting accurately that material weighs.Necessary school pound before the weighing, first zero check carries out verification with standard test weight then, can carry out the weighing of material after verification is errorless, should classify by pot weighing successively during weighing.
(2) mixing procedure: the dried mixing of raw material is finished in the twin-screw mixing procedure device, guarantee that enough mixing times make to reach homogeneous between the material as far as possible and distribute, and reduces the composition deviation, to guarantee product quality.Every pot of total inventory 1200kg～1300kg during batch mixing, mixing time 〉=40min.
(3) pulping process: add an amount of cold water and bonding agent in octagon slurry high speed agitator, with elevator siccative mixed in the blender is put into high speed agitator and stir, the time is no less than 20min.
(4) mud plunger displacement pump: should check before producing that whether plunger displacement pump pipeline inner filtration net is damaged, if any breakage, should in time change.The opening plunger pump pumps into the slurry in high speed agitator or the ball mill in the low-speed agitator.Opening plunger pump fuel tank cooling water and plunger displacement pump cooling water.Close the low-speed agitator bleeder valve, open the plunger displacement pump water intaking valve, start plunger displacement pump, pilot plunger pump pressure regulator valve is adjusted to 2.5Mpa with system pressure.
(5) spray drying tower: all should the school rifle before each mist projection granulating, guarantee the slurry atomizing angle at 45 °～55 °, water column is six circular hole centers directly over cat head.Check whether barral of a gun is crooked, and whether the rifle head is crooked, if any crooked, crooked, should carry out alignment, proofreaies and correct, bullet hole aperture size 1.8-2.2MM.When the drying tower inlet temperature reaches 500 ℃ ± 30 ℃, when outlet temperature reaches 180 ℃ ± 30 ℃, open the low-speed agitator outlet valve, the plunger displacement pump bleeder valve enters system by slurry and begins material spray, and opens the cold bed cooling water, starts cold bed.To note plunger displacement pump pressure in the production process, make pressure keep stable.
In the process of mist projection granulating, slip is at first atomized by the nozzle ejection, and in order to prevent the slip precipitation, the convenient simultaneously slurry that stores can be provided with low-speed agitator before the atomizing pressure pump.Droplet by pressure ejection contacts with reflux type with thermal medium, obtains epigranular, moisture is lower, and flowability, particle that spreadability is good.The initial contact phase of drop and thermal current, the drop surface is in saturation state, and drop inside has sufficient liquid medium to add to the surface, and evaporation is carried out with constant speed.When liquid medium is reduced to can not continue to keep saturation state the time, the drop surface just forms dry and smooth shell.Along with the prolongation of time, drying enclosure is constantly thickeied, and pellet moisture slows down gradually to the speed of external diffusion, and evaporation at this moment just enters the decelerating phase.Along with particle temperature is elevated to when approaching the dry gas temperature, the granule interior solids is fully concentrated, thereby makes it to form hollow shape.The time of these two stage experience is very short, and particle only stopped for tens seconds in tower.By keeping the gas access temperature constant and detect the feed speed that gas outlet temperature is regulated slip automatically, the particle that is dried with assurance when going out tower moisture content less than 0.5%.
Claims (11)
1, a kind of high basicity tundish covering flux, this coverture comprises raw material and additive component, it is characterized in that comprising calcium oxide, silica, alundum (Al in this coverture raw material components, in it and calcium oxide content to add the percentage that dioxide-containing silica accounts for this coverture gross weight be 40-70%, wherein CaO/SiO
2Be 2.8-5, the percentage by weight of alundum (Al is 15-40%, and described coverture face shaping is a hollow spheres.
2, a kind of high basicity tundish covering flux according to claim 1 is characterized in that all the other compositions in the described raw material components can be that oxidation is received, a kind of or wherein combination of at least two kinds of components in magnesia, calcirm-fluoride, boron oxide and the CARBONATE COMPONENT.
3, a kind of high basicity tundish covering flux according to claim 1 is characterized in that described raw material can select a kind of in LF furnace refining slag, aluminium calcium pre-melted slag, the aluminous cement or wherein at least two kinds combination for use.
4, a kind of high basicity tundish covering flux according to claim 1, the granularity that it is characterized in that described raw material is that 200 order percent of pass are not less than 96%.
5, a kind of high basicity tundish covering flux according to claim 1, the bulk density that it is characterized in that described coverture is 0.6-1.1g/cm
3
6, a kind of high basicity tundish covering flux according to claim 5, the bulk density that it is characterized in that described coverture is 0.75-0.95g/cm
3
7, a kind of high basicity tundish covering flux according to claim 1 is characterized in that described coverture particle size range is ￠ 0.1-1.2mm.
8, a kind of high basicity tundish covering flux according to claim 7 is characterized in that described coverture particle size range is ￠ 0.2-0.8mm, and satisfies the particle that this particle size range requires and should account for more than 95%.
9, a kind of high basicity tundish covering flux according to claim 1, the percentage that the content that it is characterized in that described additive component accounts for this coverture gross weight is 1.2%-5%, its composition can be a kind of in 801 glue, yellow starch gum, the carboxyl methyl cellulose, or at least two kinds combination.
10, a kind of production method of high basicity tundish covering flux, it is characterized in that this method adopts following steps: at first each component raw material enters blender after the weighing in proportion, stirs; Add water afterwards, form slip, in slurry mixer, stir; To the slip pressurization, in being sprayed onto spray drying tower, spray gun carries out mist projection granulating then; At last the particle cooling that obtains is got final product.
11, a kind of high basicity tundish covering flux according to claim 10 is characterized in that described spray gun aperture is 1.8-2.2mm.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 200610119187 CN1970198A (en) | 2006-12-06 | 2006-12-06 | High basicity tundish cover agent and its production method |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 200610119187 CN1970198A (en) | 2006-12-06 | 2006-12-06 | High basicity tundish cover agent and its production method |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102643950A (en) * | 2011-02-18 | 2012-08-22 | 北大方正集团有限公司 | Method for smelting sulfur containing steel for vehicle and sulfur containing steel |
| CN104831006A (en) * | 2015-03-06 | 2015-08-12 | 江苏嘉耐高温材料有限公司 | Method of recycling refining waste residue for producing molten steel covering agent |
| CN104874755A (en) * | 2015-05-25 | 2015-09-02 | 中南大学 | Tundish covering agent used for chrome-bearing steel and application thereof |
| CN116987841A (en) * | 2023-09-28 | 2023-11-03 | 吕梁建龙实业有限公司 | Tundish covering agent for producing high-quality carbon structural steel and preparation method thereof |
-
2006
- 2006-12-06 CN CN 200610119187 patent/CN1970198A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102643950A (en) * | 2011-02-18 | 2012-08-22 | 北大方正集团有限公司 | Method for smelting sulfur containing steel for vehicle and sulfur containing steel |
| CN104831006A (en) * | 2015-03-06 | 2015-08-12 | 江苏嘉耐高温材料有限公司 | Method of recycling refining waste residue for producing molten steel covering agent |
| CN104874755A (en) * | 2015-05-25 | 2015-09-02 | 中南大学 | Tundish covering agent used for chrome-bearing steel and application thereof |
| CN116987841A (en) * | 2023-09-28 | 2023-11-03 | 吕梁建龙实业有限公司 | Tundish covering agent for producing high-quality carbon structural steel and preparation method thereof |
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