CN1660520A - Covering agent for pouring basket in high alkalinity - Google Patents
Covering agent for pouring basket in high alkalinity Download PDFInfo
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- CN1660520A CN1660520A CN 200410016591 CN200410016591A CN1660520A CN 1660520 A CN1660520 A CN 1660520A CN 200410016591 CN200410016591 CN 200410016591 CN 200410016591 A CN200410016591 A CN 200410016591A CN 1660520 A CN1660520 A CN 1660520A
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- molten steel
- tundish
- covering agent
- alkalinity
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Abstract
A high-basicity covering agent for the tundish to decrease O2 and S from molten steel, and prevent secondary oxidizing is proportionally prepared from the calcium aluminate prepared from calcium carbonate and bauxite, magnesium sand, adhesive chosen from dextrin, wheat flour and water glass, additive chosen from phosphate, lignosulfonate, citric acid glycerine, etc, calcium carbonate and quartz sand.
Description
Technical Field
The invention relates to an auxiliary material for continuous casting of steel making, in particular to a tundish covering agent.
Background
The tundish for storing and delivering molten steel is a transition reactor in metallurgical process, which is used for distributing the molten steel delivered from a ladle to a crystallizer, stabilizing the pouring speed and reducing the impact momentum of the pouring flow in the crystallizer, and is an ideal place for removing the inclusion in the molten steel.
The tundish covering agent is a granular or powder type artificially synthesized auxiliary material added on the liquid level of tundish steel and has the functions of: (1) the heat insulation and preservation are realized, and the temperature drop of molten steel in the steel casting process is reduced; (2) air is isolated, and secondary oxidation of the molten steel is prevented; (3) absorbing non-metallic inclusion floating on the molten steel surface.
The tundish covering agent commonly used at present comprises three types of acid slag, neutral slag and alkaline slag, the specific types and components are shown in the following table 1, and the alkalinity R is defined as: r is CaO/SiO2。
TABLE 1
| Kind of slag | Chemical composition of slag | Alkalinity of | Prepare for Note that | ||||||
| CaO | Al2O3 | SiO2 | MgO | Auxiliary agent | Fever reduction | Others | |||
| Acid slag | 0.6 | 0.5 | 26.9 | 0.5 | 5.72 | 64.86 | 0.92 | 0.02 | |
| Neutral slag | 23.82 | 21.06 | 29.15 | 4.75 | 4.06 | 13.70 | 3.46 | 0.82 | |
| 38.20 | 4.86 | 25.66 | 10.94 | 2.54 | 12.70 | 5.10 | 1.49 | ||
| 36.32 | 5.95 | 27.85 | 15.38 | 2.67 | 8.88 | 2.95 | 1.30 | ||
| Alkaline slag | 27.71 | 19.28 | 12.93 | 17.96 | 6.16 | 11.65 | 4.31 | 2.14 | Calcium carbonate Quality of food |
| 4.15 | 0.59 | 1.80 | 86.94 | 0.98 | 4.63 | 0.91 | 2.30 | Magnesium alloy Quality of food | |
Wherein:
acid residue, represented by carbonized rice hull, containing SiO as main ingredient275-90% of the total amount, and the alkalinity R is less than 0.5.
Advantages: the heat insulation performance is good;
the disadvantages are that: for protection and absorption of Al2O3The capacity of the alloy is not ideal enough, and molten steel is easy to carburete or absorb hydrogen.
Neutral slag with CaO and SiO as main components2And Al2O3The alkalinity R is about 0.9-1.5, which is the most used at present.
Advantages: liquid slag is easy to form on the surface of the steel water, and the capability of absorbing Al2O3 is strong;
the disadvantages are that: the heat preservation effect is not good.
Advantages: has certain capability of absorbing Al2O 3;
the disadvantages are that: air isolation, the effect of preventing molten steel secondary oxidation is relatively poor.
The alkalinity of the covering agent (CaO/SiO) of the tundish at present2) Typically less than 3.0. For example, U.S. Pat. Nos. 6174347B1 and 6179895B1 are high alkalinity tundish covering agents, but they are produced in Ladle metallurgical furnaces (Ladle metallurgical Fur)nice) is taken as a main raw material, and the content of impurity elements such as S in the material is relatively high, so that the material is not suitable for producing steel grade with requirements on S.
Disclosure of Invention
The invention aims to provide a high-alkalinity tundish covering agent, which emphasizes the metallurgical function while meeting the conventional functions of insulating heat, preventing secondary oxidation of molten steel, absorbing non-metallic inclusions floating on the molten steel surface and the like, namely reducing the increase range of T [ O]in molten steel, further desulfurizing the molten steel in a tundish, reducing the corrosion degree of the covering agent to refractory materials and improving the cleanliness of the molten steel.
The research shows that: with SiO in the covering agent2The content of the covering agent is reduced, the alkalinity of the covering agent is increased, and T [ O]in the molten steel]Reduced because of aluminum deoxidized molten steel and SiO-containing molten steel2The following reactions must occur when the covering agents are contacted:
when SiO in the covering agent2When the content is decreased, the rate of the forward reaction of the reaction equation (1) is decreased, so that the reaction proceeds from Al2O3The oxygen carried into molten steel by the product is reduced correspondingly, T [ O]in molten steel]The SiO content in the covering agent is correspondingly reduced, thereby reducing2The content of the intermediate coating agent is increased, the alkalinity of the intermediate coating agent is increased, and SiO can be slowed down2Reacts with dissolved aluminum in steel to generate Si and Al2O3The speed of (2) is reduced, Si and T [ O]in molten steel are reduced]The degree of corrosion of the covering agent to refractory materials is reduced, and the cleanliness of molten steel is improved.
In addition, when CaO exists in the slag layer of the covering agent, the CaO reacts with [ S]in the molten steel to remove sulfur in the molten steel, and the specific reaction equation is as follows:
therefore, the content of CaO in the tundish covering agent is increased, the alkalinity of the covering agent is improved, molten steel in the tundish can be further desulfurized, the effect of secondary refining is achieved, and the purity of the molten steel is improved.
In a word, the high-alkalinity tundish covering agent (1) can slow down the reaction of the covering agent and Al in molten steel and reduce the content of T [ O]in the molten steel; (2) the molten steel can be further desulfurized in the tundish; finally, the aim of improving the purity of the molten steel is achieved.
The present invention uses calcium aluminate as main raw material, and adds partial other auxiliary materials, and adopts a certain processing procedure to produce high-alkalinity tundish covering agent using calcium aluminate as basic component, and said tundish covering agent can be made into two forms of solid granular form and hollow spherical form.
The high-alkalinity tundish covering agent comprises the following components in percentage by mass:
70-90% of calcium aluminate;
0.1-20% of magnesia;
0.1-10% of a binder;
0.1-5% of an additive.
The high-alkalinity tundish covering agent also comprises one or more of calcium carbonate and quartz sand, 0-25% of calcium carbonate and 0-5% of quartz sand.
The calcium aluminate is prepared by high-temperature smelting of 55-70% of calcium carbonate and 30-45% of bauxite.
The binder is dextrin, flour or water glass; the ingredients are bonded together and give them a certain strength.
The additive is phosphate, lignosulfonate, citric acid, glycerol, a naphthalene water reducer, a water-soluble resin water reducer or ethylene glycol; the phosphate, the lignosulfonate, the naphthalene water reducer and the water-soluble resin water reducer can obviously reduce the water consumption for blending the ingredients under the condition of keeping the flow property of the ingredients basically unchanged, but the substances do not chemically react with the ingredients to generate new compounds and only play a role in surface physical chemistry; citric acid, glycerin and glycol can delay the setting and hardening time of the ingredients.
The invention has the advantages of
The invention takes calcium aluminate as main raw material and alkalinity(CaO/SiO2Not less than 6.0), can effectively reduce the total oxygen in the molten steel of the tundish, can further remove the sulfur in the molten steel in the tundish, improves the cleanliness of the molten steel in the tundish, effectively prevents the secondary oxidation of the molten steel in the tundish, further improves the quality of a casting blank, and has good heat preservation performance.
Drawings
FIGS. 1a and 1b show the effect of tundish covering agents with different basicities on Total Oxygen (TO) in molten steel.
FIGS. 2a and 2b show the effect of different basicity tundish covering agents on sulfur (S) in molten steel.
FIGS. 3a and 3b show the effect of different alkalinity tundish covering agents on the observation field area occupied by inclusions in steel samples.
FIG. 4 shows the results of a 300T converter production test in which tundish covering agents of different basicities affect secondary oxidation of molten steel in a tundish.
FIGS. 5a and 5b show the results of the heat retaining property of the tundish covering agent in the 300T converter production test.
Detailed Description
See table 2 for examples of high basicity tundish covering agents of the present invention and comparative examples.
TABLE 2
| Examples | Ingredients (mass percent) | Alkalinity of | Effects of use | |||||||||
| Calcium aluminate | Calcium carbonate | Magnesite clinker | Quartz sand | Binder | Additive agent | Erosion of furnace lining | ||||||
| 1 | 87.1 | 3.9 | 0.1 | 1.9 | 6.0 | 1.0 | 8.51 | Not severe | ||||
| 2 | 89.9 | 0.3 | 2.2 | 4.5 | 1.7 | 1.4 | 6.00 | Not severe | ||||
| 3 | 71.2 | 24.1 | 0.8 | 3.0 | 0.1 | 0.8 | 10.71 | Not severe | ||||
| 4 | 72.3 | 3.6 | 14.2 | 0.7 | 9.1 | 0.1 | 12.10 | Not severe | ||||
| 5 | 73.5 | 21.3 | 2.8 | 0.9 | 0.3 | 1.2 | 11.18 | Not severe | ||||
| 6 | 75.5 | 7.2 | 11.0 | 1.1 | 3.0 | 2.2 | 16.48 | Not severe | ||||
| 7 | 77.2 | 16.2 | 1.5 | 4.2 | 0.4 | 0.5 | 8.17 | Not severe | ||||
| 8 | 79.3 | 12.3 | 3.1 | 0.2 | 3.5 | 1.6 | 7.05 | Not severe | ||||
| 9 | 80.1 | 9.7 | 3.6 | 1.4 | 1.1 | 4.1 | 12.74 | Not severe | ||||
| 10 | 82.3 | 2.5 | 10.2 | 2.1 | 2.7 | 0.2 | 10.47 | Not severe | ||||
| 11 | 76.6 | 11.9 | 7.7 | 0.0 | 0.8 | 3.0 | 9.87 | Not severe | ||||
| 12 | 81.0 | 4.0 | 9.3 | 3.2 | 2.1 | 0.4 | 8.69 | Not severe | ||||
| CaO | Al2O3 | MgO | SiO2 | Others | Alkalinity of | Erosion of furnace lining | ||||||
| Comparative example 1 | 38.2 | 4.86 | 10.94 | 25.66 | 20.34 | 1.49 | Is more serious | |||||
| Comparative example 2 | 35.22 | 4.93 | 0.72 | 37.05 | 22.08 | 0.95 | Severe severity of disease | |||||
| Comparative example 3 | 36.32 | 5.95 | 15.38 | 27.85 | 14.5 | 1.30 | Severe severity of disease | |||||
Wherein the binder is dextrin or flour; the additive is calcium lignosulphonate and sodium phosphate.
FIGS. 1a and 1b show the effect of tundish covering agents with different basicities on Total Oxygen (TO) in molten steel, wherein FIG. 1a shows the test results of a 100Kg non-vacuum induction furnace and FIG. 1b shows the test results of a 300T converter, and it can be seen from the results that the covering agent of the present invention can effectively reduce Total Oxygen (TO) in molten steel in a tundish.
FIGS. 2a and 2b show the effect of tundish covering agents with different basicities on sulfur (S) in molten steel, wherein FIG. 2a shows the test result of a 100Kg non-vacuum induction furnace and FIG. 2b shows the test result of a 300T converter, and it can be seen from the figure that the covering agent of the present invention can prevent the resulfurization of molten steel and has a certain desulfurization effect.
FIGS. 3a and 3b show the effect of tundish covering agents with different alkalinity on the observation field area occupied by inclusions in a steel sample, wherein FIG. 3a shows the test result of a 100Kg non-vacuum induction furnace, and FIG. 3b showsthe test result of a 300T converter production.
FIG. 4 shows the results of a 300T converter production test in which tundish covering agents of different basicities affect secondary oxidation of molten steel in a tundish, and it can be seen from the results that the covering agent of the present invention can effectively prevent secondary oxidation of molten steel in a tundish.
FIGS. 5a and 5b show the results of the tests on the heat insulating property of the tundish covering agent in the production test of a 300T converter, wherein FIG. 5a shows the first test and FIG. 5b shows the second test, and it can be seen that the covering agent of the present invention has good heat insulating property.
The use tests of the high-basicity tundish covering agent of the present invention (examples 1 to 12) and the conventional low-basicity tundish covering agent (comparative examples 1, 2 and 3) were carried out. The covering agent is used under the same conditions respectively, does not erode a furnace lining, has small pollution degree to molten steel, and has the functions of obviously desulfurizing and inhibiting the resulfurization of the molten steel.
In conclusion, the covering agent can effectively reduce the total oxygen in the molten steel of the tundish, can further remove the sulfur in the molten steel in the tundish, improves the cleanliness of the molten steel in the tundish, effectively prevents the molten steel in the tundish from being secondarily oxidized, further improves the quality of a casting blank, and has good heat insulation performance.
Claims (5)
1. The high-alkalinity tundish covering agent comprises the following components in percentage by mass:
70-90% of calcium aluminate;
0.1-20% of magnesia;
0.1-10% of a binder;
0.1-5% of an additive.
2. The high-alkalinity tundish covering agent according to claim 1, further comprising one or more of calcium carbonate and quartz sand, wherein the calcium carbonate is 0-25% and the quartz sand is 0-5%.
3. The high basicity tundish covering agent according to claim 1, wherein said calcium aluminate comprises: 55-70% of calcium carbonate and 30-45% of bauxite.
4. The high alkalinity tundish covering flux as claimed in claim 1, wherein the binder is dextrin, flour or water glass.
5. The high-alkalinity tundish covering flux according to claim 1, wherein the additive is phosphate, lignosulfonate, citric acid, glycerol, a naphthalene water reducing agent, a water-soluble resin water reducing agent or ethylene glycol.
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| Application Number | Priority Date | Filing Date | Title |
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| CNB2004100165918A CN1308101C (en) | 2004-02-26 | 2004-02-26 | Covering agent for pouring basket in high alkalinity |
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|---|---|---|---|
| CNB2004100165918A CN1308101C (en) | 2004-02-26 | 2004-02-26 | Covering agent for pouring basket in high alkalinity |
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| CN1660520A true CN1660520A (en) | 2005-08-31 |
| CN1308101C CN1308101C (en) | 2007-04-04 |
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Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100371105C (en) * | 2006-08-25 | 2008-02-27 | 重庆大学 | Molten steel covering agent and its preparation method |
| CN101618442B (en) * | 2008-07-04 | 2011-08-17 | 上海梅山钢铁股份有限公司 | Reductive covering agent for continuous casting tundish |
| CN101486587B (en) * | 2009-01-04 | 2012-03-21 | 攀钢集团研究院有限公司 | Double-layer tundish covering agent |
| CN102581240A (en) * | 2011-01-11 | 2012-07-18 | 宝山钢铁股份有限公司 | Tundish covering flux |
| CN102744381A (en) * | 2012-07-25 | 2012-10-24 | 洛阳市科丰冶金新材料（集团）有限公司 | High-alkalinity tundish covering agent |
| CN104001884A (en) * | 2013-02-26 | 2014-08-27 | 宝山钢铁股份有限公司 | High-alkalinity tundish covering agent |
| CN106011383A (en) * | 2016-07-06 | 2016-10-12 | 登封市少林刚玉有限公司 | Processing method of steel-making hollow covering agent with ultra-light weight and low volume density |
| CN106336231A (en) * | 2016-08-29 | 2017-01-18 | 武汉科技大学 | Fireproof working lining used for steel refining and preparing method thereof |
| CN110102725A (en) * | 2019-05-16 | 2019-08-09 | 鞍山市和丰耐火材料有限公司 | A kind of magnesia tundish hollow particle coverture of height being not crusted and its production method |
Families Citing this family (1)
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| TWI403589B (en) * | 2009-04-10 | 2013-08-01 | China Steel Corp | Granular humectant liquid steel and its manufacturing method |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6179895B1 (en) * | 1996-12-11 | 2001-01-30 | Performix Technologies, Ltd. | Basic tundish flux composition for steelmaking processes |
| CN1238134C (en) * | 2002-05-31 | 2006-01-25 | 宝山钢铁股份有限公司 | Tundish covering agent for pure steel, and its making method |
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2004
- 2004-02-26 CN CNB2004100165918A patent/CN1308101C/en not_active Expired - Fee Related
Cited By (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100371105C (en) * | 2006-08-25 | 2008-02-27 | 重庆大学 | Molten steel covering agent and its preparation method |
| CN101618442B (en) * | 2008-07-04 | 2011-08-17 | 上海梅山钢铁股份有限公司 | Reductive covering agent for continuous casting tundish |
| CN101486587B (en) * | 2009-01-04 | 2012-03-21 | 攀钢集团研究院有限公司 | Double-layer tundish covering agent |
| CN102581240A (en) * | 2011-01-11 | 2012-07-18 | 宝山钢铁股份有限公司 | Tundish covering flux |
| CN102581240B (en) * | 2011-01-11 | 2014-04-30 | 宝山钢铁股份有限公司 | Tundish covering flux |
| CN102744381A (en) * | 2012-07-25 | 2012-10-24 | 洛阳市科丰冶金新材料（集团）有限公司 | High-alkalinity tundish covering agent |
| CN104001884A (en) * | 2013-02-26 | 2014-08-27 | 宝山钢铁股份有限公司 | High-alkalinity tundish covering agent |
| CN104001884B (en) * | 2013-02-26 | 2016-06-29 | 宝山钢铁股份有限公司 | Covering agent for pouring basket in high alkalinity |
| CN106011383A (en) * | 2016-07-06 | 2016-10-12 | 登封市少林刚玉有限公司 | Processing method of steel-making hollow covering agent with ultra-light weight and low volume density |
| CN106336231A (en) * | 2016-08-29 | 2017-01-18 | 武汉科技大学 | Fireproof working lining used for steel refining and preparing method thereof |
| CN106336231B (en) * | 2016-08-29 | 2019-02-12 | 武汉科技大学 | A kind of steel refining whole fire resisting working lining and preparation method thereof |
| CN110102725A (en) * | 2019-05-16 | 2019-08-09 | 鞍山市和丰耐火材料有限公司 | A kind of magnesia tundish hollow particle coverture of height being not crusted and its production method |
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| CN1308101C (en) | 2007-04-04 |
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