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High-Quality Magnesia and Magnesia-Chrome Materials Based on the Fired Magnesia Materials Imported from Korea and China
Copyright © IFAC Automation in the Steel Industry, Kyongju, Korea, 1997
HIGH - QUALITY MAGNESIA AND MAGNESIA - CHROME MATERIALS BASED ON THE FIRED MAGNESIA MATERIALS IMPORTED FROM KOREA AND CHINA.
Professor Wladyslaw Bieda M. Se. Boguslaw Bieda
Polish Academy ofScience ul.Slawkowska 17 PL-31-916 Krakow, Poland Dept. of Management Academy of Mining and Metallurgy ul. Gramatyka 10 PL-30-067 Krakow, Poland
AbstractThis paper describes the production of the high-quality magnesia and magnesiachrome materials based on the fired magnesia materials imported from Korea and China. Practical experiments pennitted to develop oryginally technology of the production of the: three, four and five components refractory materials.We illustrate this technology with detailed characteristics gived in Table I and Table 2. Copyright © 19981FAC
°-
I. INTRODUCTION
five components refractory materials: MgO - Ca Si 02 - Fe2 03 - AI2 03 . Magnesia chrome bricks contained two kinds of fired magnesia and chrome ore which in technology processing enables us to get refractory materials. The chemical composition of these bricks contained from 44.0 to 68.6 % ofMgO, from 1.0 to 3 % of Si 02 and from 16 to 24.6 % ofCr2 03 . The low porosity ( 15.4 - 18.9 %), high cold crusing strenght (44.0 - 62.2 MPa) and the high refractoriness under load ( T0.6
Refractory materials industry in East Europa used small quantities of magnesia materials from Korea and China to produce the magnesia and magnesia chrome materials. Only refractory materials industry in Poland used big quantities of fired magnesia materials from Far East which are composed of high contents of Si 02 at the cost of Mg 0 . Refractory Materials Factory in Poland is based on fired magnesia materials imported from Korea and China.
1660 - 1700 oc) prefered these bricks to vacuum degasing plant ( DH ) , ladle refractory lining in VOD I VAD processing, oxygen - blow converters refractory lining and in furnace lining in copper industry.
2. DESCRIPTION OF TECHNOLOGY Practical experiments with magnesia refractory materials pennitted allowed to bring in practice the oryginally technology in order to manufacture the refractory materials for modern steelrnaking and irorunaking processing ( like oxygen converters, tubs, etc.).
But in steel ladleselectric furnaces and oxygen blow converters is used unfired magnesia - carbon bricks. The chemical composition of these bricks contained from 89.0 to 94.0 % ofMg 0, from 1.8 t to 4.5 % of Si 02 and from 7.0 to 9.0 % of carbon.
This paper descibes a general approach to the producing of : three components refractory materials: MgO - Ca Si 02, four components refractory materials: MgO - Ca Si 02 - Fe2 03 ,
°-
These materials are characterized by high compactness, low bulk density (2 .70-2.80 g/cm'), low porosity ( 8.0-12.0%) and high cold crushing (25.035 .0 Kpa). Magnesia - carbon materiais have positive influence on the live of steel ladles because in large
°49
These elements gived the resistance to chemical agents of metallurgical process in high temperatures.
quantItIes of ladle heats have been not observed overgrowth of slag in the ladles. Laboratory and industial test of magnesia - chrome and magnesia carbon bricks have been prooved the high quality of these materials due to the optimal content of Si0 2 (from 2.0 to 3.0 and 4.0%). Crystallographic structure, mineralogical composition and texture have been investigated by microscopy.
The detailed characteristics of the magnesia - chrome bricks are listed in Table I . In refractory materials industry in Poland are producted many kinds of these materials.
Table I. Magnesia - chrome bricks. Measure Unit
Properties
Chemical Composi-tion
44.6 24.6 2.9 13.3 0.9 13.4 3.17 19 30
34.3 33 .8 3.3 17.5 1.0 9.9 3.20 17.7 35
1700
1700
1660
1660
MCV MCT
MPa
68.6 15.6 1.5 7.9 0.9 5.5 3.10 18.8 38
54.8 22.1 1.0 14.5 0.8 7.6 3.25 16.2 55
54.2 22.1 1.0 13.5 0.9 8.2 3.25 16.4 62
TO.6
°C
1660
1700
1700
700°C 1100°C 20-40
W /m . oC W /m . oC
20-1000
kJ/k!:i. oC
Cr20~
SiO? Fe203 CaO Ah 0 3
Specific Head (Average)
57.6 22.2 1.3 10.9 0.9 6.7 3.31 16.7 53
MXTO MXT6 0 75.3 60.8 17.5 9.5 1.6 1.2 13.0 8.3 0.6 0.8 4.2 6.2 3.12 3.12 17.9 16.4 44 50
MCI0 MC9 MgO
Bulk Densi!}: AEEarent Porosi!}: Cold Crushing Strength Refractoriness Unter Load Thermal Conductivity
Product
% % % % % % g/cm
3
%
1700
MX40 CM30
3.7 3.7 3.7 3.7 2.8 2.8 2.8 2.8 kJ/kg. oC 1.008 1.088 1.088 1.088 1.172
1.172
1.172
1.172
refractory quality but simultanously limits in magnesia plastics the wettability of the magnesia part under influence of slag chemical action in high temperatures.
On the contrary Table 2 gives the parameters of the unfired magnesia - carbon bricks. These unfrred materials produced on the base the high quality flake graphite which has not only high
Table 2. Unfrred magnesia - carbon brikcs Measure unit
Properties
Chemical composition Carbon contents Residual carbon Bulk densi!}: AEparent Eorosi!}: Cold crushing strength
MgO SiO? CaO
% % % % % glcm3 % MPa
Product MWK51
MWK6
MWK8
MWK81
91 2.0 1.8 5.5 4.0 2.85 14 28
92 2.5 2.0 7.0 4.0 2.70 12 25
94 1.4 1.9 8.0 5.5 2.75 10 30
94 1.0 2.0 9.0 7.0 2.80 8 35
50
MWKlOl S 90 4.0 2.0 11 9 2.70 5 30
In this way slag chemical aggressive action have been considerably reduced, what perfectly prolongs refractory lining worktime. The microscopic image the frred refractory materials microstructure in the reflected light shows the perfect cristals and compact texture of the magnesia plastics with the growths of the chrome cristals in the spinel phase part.
3. CONCLUSION The microscopic investigation have been proved the high physical and chemical as well as thermo mechanical properties of those refractory materials described above .
51
HIGH - QUALITY MAGNESIA AND MAGNESIA - CHROME MATERIALS BASED ON THE FIRED MAGNESIA MATERIALS IMPORTED FROM KOREA AND CHINA.
Professor Wladyslaw Bieda M. Se. Boguslaw Bieda
Polish Academy ofScience ul.Slawkowska 17 PL-31-916 Krakow, Poland Dept. of Management Academy of Mining and Metallurgy ul. Gramatyka 10 PL-30-067 Krakow, Poland
AbstractThis paper describes the production of the high-quality magnesia and magnesiachrome materials based on the fired magnesia materials imported from Korea and China. Practical experiments pennitted to develop oryginally technology of the production of the: three, four and five components refractory materials.We illustrate this technology with detailed characteristics gived in Table I and Table 2. Copyright © 19981FAC
°-
I. INTRODUCTION
five components refractory materials: MgO - Ca Si 02 - Fe2 03 - AI2 03 . Magnesia chrome bricks contained two kinds of fired magnesia and chrome ore which in technology processing enables us to get refractory materials. The chemical composition of these bricks contained from 44.0 to 68.6 % ofMgO, from 1.0 to 3 % of Si 02 and from 16 to 24.6 % ofCr2 03 . The low porosity ( 15.4 - 18.9 %), high cold crusing strenght (44.0 - 62.2 MPa) and the high refractoriness under load ( T0.6
Refractory materials industry in East Europa used small quantities of magnesia materials from Korea and China to produce the magnesia and magnesia chrome materials. Only refractory materials industry in Poland used big quantities of fired magnesia materials from Far East which are composed of high contents of Si 02 at the cost of Mg 0 . Refractory Materials Factory in Poland is based on fired magnesia materials imported from Korea and China.
1660 - 1700 oc) prefered these bricks to vacuum degasing plant ( DH ) , ladle refractory lining in VOD I VAD processing, oxygen - blow converters refractory lining and in furnace lining in copper industry.
2. DESCRIPTION OF TECHNOLOGY Practical experiments with magnesia refractory materials pennitted allowed to bring in practice the oryginally technology in order to manufacture the refractory materials for modern steelrnaking and irorunaking processing ( like oxygen converters, tubs, etc.).
But in steel ladleselectric furnaces and oxygen blow converters is used unfired magnesia - carbon bricks. The chemical composition of these bricks contained from 89.0 to 94.0 % ofMg 0, from 1.8 t to 4.5 % of Si 02 and from 7.0 to 9.0 % of carbon.
This paper descibes a general approach to the producing of : three components refractory materials: MgO - Ca Si 02, four components refractory materials: MgO - Ca Si 02 - Fe2 03 ,
°-
These materials are characterized by high compactness, low bulk density (2 .70-2.80 g/cm'), low porosity ( 8.0-12.0%) and high cold crushing (25.035 .0 Kpa). Magnesia - carbon materiais have positive influence on the live of steel ladles because in large
°49
These elements gived the resistance to chemical agents of metallurgical process in high temperatures.
quantItIes of ladle heats have been not observed overgrowth of slag in the ladles. Laboratory and industial test of magnesia - chrome and magnesia carbon bricks have been prooved the high quality of these materials due to the optimal content of Si0 2 (from 2.0 to 3.0 and 4.0%). Crystallographic structure, mineralogical composition and texture have been investigated by microscopy.
The detailed characteristics of the magnesia - chrome bricks are listed in Table I . In refractory materials industry in Poland are producted many kinds of these materials.
Table I. Magnesia - chrome bricks. Measure Unit
Properties
Chemical Composi-tion
44.6 24.6 2.9 13.3 0.9 13.4 3.17 19 30
34.3 33 .8 3.3 17.5 1.0 9.9 3.20 17.7 35
1700
1700
1660
1660
MCV MCT
MPa
68.6 15.6 1.5 7.9 0.9 5.5 3.10 18.8 38
54.8 22.1 1.0 14.5 0.8 7.6 3.25 16.2 55
54.2 22.1 1.0 13.5 0.9 8.2 3.25 16.4 62
TO.6
°C
1660
1700
1700
700°C 1100°C 20-40
W /m . oC W /m . oC
20-1000
kJ/k!:i. oC
Cr20~
SiO? Fe203 CaO Ah 0 3
Specific Head (Average)
57.6 22.2 1.3 10.9 0.9 6.7 3.31 16.7 53
MXTO MXT6 0 75.3 60.8 17.5 9.5 1.6 1.2 13.0 8.3 0.6 0.8 4.2 6.2 3.12 3.12 17.9 16.4 44 50
MCI0 MC9 MgO
Bulk Densi!}: AEEarent Porosi!}: Cold Crushing Strength Refractoriness Unter Load Thermal Conductivity
Product
% % % % % % g/cm
3
%
1700
MX40 CM30
3.7 3.7 3.7 3.7 2.8 2.8 2.8 2.8 kJ/kg. oC 1.008 1.088 1.088 1.088 1.172
1.172
1.172
1.172
refractory quality but simultanously limits in magnesia plastics the wettability of the magnesia part under influence of slag chemical action in high temperatures.
On the contrary Table 2 gives the parameters of the unfired magnesia - carbon bricks. These unfrred materials produced on the base the high quality flake graphite which has not only high
Table 2. Unfrred magnesia - carbon brikcs Measure unit
Properties
Chemical composition Carbon contents Residual carbon Bulk densi!}: AEparent Eorosi!}: Cold crushing strength
MgO SiO? CaO
% % % % % glcm3 % MPa
Product MWK51
MWK6
MWK8
MWK81
91 2.0 1.8 5.5 4.0 2.85 14 28
92 2.5 2.0 7.0 4.0 2.70 12 25
94 1.4 1.9 8.0 5.5 2.75 10 30
94 1.0 2.0 9.0 7.0 2.80 8 35
50
MWKlOl S 90 4.0 2.0 11 9 2.70 5 30
In this way slag chemical aggressive action have been considerably reduced, what perfectly prolongs refractory lining worktime. The microscopic image the frred refractory materials microstructure in the reflected light shows the perfect cristals and compact texture of the magnesia plastics with the growths of the chrome cristals in the spinel phase part.
3. CONCLUSION The microscopic investigation have been proved the high physical and chemical as well as thermo mechanical properties of those refractory materials described above .
51