CN114276153A - High-calcium magnesia-calcium brick and preparation method thereof - Google Patents
High-calcium magnesia-calcium brick and preparation method thereof Download PDFInfo
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- CN114276153A CN114276153A CN202110457905.1A CN202110457905A CN114276153A CN 114276153 A CN114276153 A CN 114276153A CN 202110457905 A CN202110457905 A CN 202110457905A CN 114276153 A CN114276153 A CN 114276153A
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Abstract
The invention belongs to the technical field of refractory materials for stainless steel and other special steel smelting furnaces, and particularly relates to a high-calcium magnesia-calcium brick and a preparation method thereof, wherein the preparation method comprises the following steps: 1-2 parts of natural dolomite with the granularity of 3-1 mm; 1-2 parts of natural dolomite with the granularity of 2-5 mm; 1-2 natural dolomite with the granularity of 200-300 meshes; 45-52 parts of synthetic magnesia-calcium sand with the granularity of 3-1 mm; 35-55 parts of synthetic magnesia-calcium sand with the granularity of 2-5 mm; 60-82 parts of synthetic magnesia-calcium sand with the granularity of 200-300 meshes; 5-18 parts of magnesia with the granularity of 3-1 mm; 1-5 parts of magnesia with the granularity of 2-5 mm; 6-8 parts of magnesia with the granularity of 200-300 meshes; and 2-6 of paraffin. The invention has high thermal shock stability, ideal slag resistance, high temperature strength, hydration resistance and erosion and scouring resistance and long service life.
Description
Technical Field
The invention belongs to the technical field of refractory materials for stainless steel and other special steel smelting furnaces, and particularly relates to a high-calcium magnesia-calcium brick and a preparation method thereof.
Background
The external refining is one of three key technologies of modern metallurgical production and is also an important content of technological progress of the modern steelmaking process. The main functions of the device are desulfurization, deoxidation, removal of harmful gas and nonmetal inclusion, adjustment of components and the like. As the calcium-containing refractory material has the characteristics of adsorbing harmful impurity elements in molten steel and reducing the number of non-metallic inclusions in the molten steel, advanced enterprises at home and abroad try to use the magnesia-calcium refractory material with high calcium content in the process link of external refining, the external refining of a plurality of iron and steel enterprises at home is carried out in a ladle, and most of the refractory materials adopted by the ladle at present are magnesia carbon bricks, alumina-magnesia carbon bricks, magnesia-chrome bricks and the like, so that the use of the high-calcium magnesia-calcium bricks in the external refining is an urgent task of the current efforts.
The Mg-Ca series refractory material is a high-quality alkaline refractory material, has good chemical stability to slag and metal, has high desulfurization rate, plays a role in purifying molten steel, and is particularly suitable for smelting stainless steel, pure steel, low-sulfur steel and ultra-low carbon steel. In addition, China contains abundant magnesium and calcium resources, has high quality grade, and has increasingly greater requirements on stainless steel, clean steel and pure steel along with the development of the steel industry, and the magnesium and calcium refractory material has more and more outstanding superiority.
At present, the content of free calcium oxide of the domestic magnesia-calcium brick for smelting stainless steel and special steel is low, the thermal shock stability is poor, the slag resistance, the high-temperature strength, the hydration resistance and the erosion scouring resistance are not ideal, and the service life is also long.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provides the high-calcium magnesia-calcium brick with high thermal shock stability, ideal slag resistance, high-temperature strength, hydration resistance and erosion and scouring resistance and long service life and the preparation method thereof.
In order to solve the technical problem, the invention is realized as follows:
a high-calcium magnesia-calcium brick comprises the following components in parts by weight:
as a preferable scheme, the high-calcium magnesia-calcium brick further comprises 2-6 parts by weight of aluminum powder.
Further, the high-calcium magnesia-calcium brick further comprises 7-10 parts by weight of graphite.
The preparation method of the high-calcium magnesia-calcium brick can be implemented according to the following steps:
(1) crushing: crushing or grinding large-particle raw materials of natural dolomite, synthetic magnesia-calcium sand and magnesia respectively;
(2) screening: the processed raw materials are magnetically separated and lifted to a screening machine through a bucket elevator, granular materials with the grain sizes of 3-1 mm and 2-5 mm and fine powder materials with the grain sizes of 200-300 meshes are screened in sequence, the screened raw materials meeting the specification enter respective storage bins, and the raw materials not meeting the specification are continuously crushed or ground;
(3) preparing materials: accurately weighing the raw materials in the high-level bin by a batching system according to a certain proportion, feeding the raw materials into a heating type mixing roll by a feeding machine, and simultaneously adding the paraffin which is heated and weighed into the mixing roll;
(4) mixing: in a mixing roll, materials with different components and particle sizes and a proper amount of binding agent are mixed and extruded to achieve uniform distribution and full wetting, and then the materials enter a pug tank in the form of pug;
(5) airing materials: airing the material to 30-40 ℃;
(6) molding: putting the material obtained in the step (5) into a mud material tank again, conveying the material into a feeder, and pressing the material into green bricks by adopting a friction press;
(7) brick stacking: carrying out brick stacking treatment on the green bricks obtained in the step (6);
(8) and (3) firing: pushing the green bricks obtained in the step (7) into a high-temperature tunnel kiln for burning, taking natural gas as fuel, spraying the natural gas into the tunnel kiln through a nozzle arranged in the middle of a kiln body, and fully mixing and burning, wherein the burning temperature in the kiln is 1490-1540 ℃.
(9) Wax dipping: carrying out wax dipping treatment;
(10) packaging: vacuumizing the aluminum foil, and performing thermoplastic packaging.
The invention has high thermal shock stability, ideal slag resistance, high temperature strength, hydration resistance and erosion and scouring resistance and long service life. The invention is an excellent refractory material for smelting clean steel because of the characteristics of high temperature resistance, good slag resistance, structural stripping resistance, molten steel purification and the like. The invention has high calcium content, so the invention has ideal anti-corrosion effect on VOD slag. The invention reacts silicon steel with the aluminum content of 0.23704 percent for 30min at 1650 ℃, and the dealumination rate is as high as more than 98 percent. The high-calcium magnesia-calcium brick has the highest furnace life of 171 times, the average furnace life of 163 times, and the furnace life of 110 times when used on an 80tAOD furnace.
(1) Slag resistance: the slag invaded into the brick reacts with CaO in the brick to generate high melting point C2And S, the viscosity of the slag is improved, so that the slag is prevented from permeating into the deep part of the brick.
(2) Thermal shock resistance: because the high-calcium magnesia-calcium brick contains a lot of free CaO, the high-calcium magnesia-calcium brick can buffer the thermal stress generated by temperature fluctuation, and the thermal shock resistance of the high-calcium magnesia-calcium brick is better than that of a magnesia-chrome brick.
(3) Thermal stability: the high-calcium magnesia-calcium brick of the invention is stable under high-temperature vacuum, has low weight loss speed and low porosity.
(4) High-temperature strength: forced stirring is generally adopted for external refining, the molten steel seriously erodes refractory materials, and the high-calcium magnesium calcium brick has good high-temperature wear resistance.
(5) Purifying molten steel: more free CaO in the high-calcium magnesia-calcium brick is easy to react with P, S and other impurities in molten steel to generate slag, and the high-calcium magnesia-calcium brick has the functions of removing impurities and purifying the molten steel.
Physical and chemical indexes of finished product
Comparative results of slag resistance test
| Brick seed | Amount of erosion |
| High calcium magnesium calciumBrick | 8mm |
| Magnesia-alumina spinel brick | 11mm |
| Magnesia brick | 15mm |
| High-alumina brick | 18mm |
Detailed Description
Example 1
The high-calcium magnesia-calcium brick is characterized by comprising the following components in parts by weight:
the preparation method of the high-calcium magnesia-calcium brick is implemented according to the following steps:
(1) crushing: crushing or grinding large-particle raw materials of natural dolomite, synthetic magnesia-calcium sand and magnesia respectively;
(2) screening: the processed raw materials are magnetically separated and lifted to a screening machine through a bucket elevator, granular materials with the grain sizes of 3-1 mm and 2-5 mm and fine powder materials with the grain sizes of 200-300 meshes are screened in sequence, the screened raw materials meeting the specification enter respective storage bins, and the raw materials not meeting the specification are continuously crushed or ground;
(3) preparing materials: accurately weighing the raw materials in the high-level bin by a batching system according to a certain proportion, feeding the raw materials into a heating type mixing roll by a feeding machine, and simultaneously adding the paraffin which is heated and weighed into the mixing roll;
(4) mixing: in a mixing roll, materials with different components and particle sizes and a proper amount of bonding agent paraffin are mixed and extruded to achieve uniform distribution and full wetting, and then the materials enter a pug tank in the form of pug;
(5) airing materials: airing the materials to 30 ℃;
(6) molding: putting the material obtained in the step (5) into a mud material tank again, conveying the material into a feeder, and pressing the material into green bricks by adopting a friction press;
(7) brick stacking: carrying out brick stacking treatment on the green bricks obtained in the step (6);
(8) and (3) firing: pushing the green bricks obtained in the step (7) into a high-temperature tunnel kiln for burning, taking natural gas as fuel, spraying the natural gas into the tunnel kiln through a nozzle arranged in the middle of a kiln body, and fully mixing and burning, wherein the burning temperature in the kiln is 1540 ℃.
(9) Wax dipping: carrying out wax dipping treatment;
(10) packaging: vacuumizing the aluminum foil, and performing thermoplastic packaging.
Main index of raw material
| IL | SiO2 | AL2O3 | Fe2O3 | CaO | MgO | Body density (g/cm)3) | |
| Dolomite | 46.81 | 0.24 | 0.05 | 0.16 | 29.16 | 23.3 | |
| Synthetic magnesia-calcium sand | 0.11 | 1.18 | 0.36 | 0.44 | 54.95 | 42.96 | 3.31 |
| High grade magnesia | 0.11 | 0.98 | 0.46 | 0.72 | 1.26 | 96.46 | 3.50 |
Example 2
The high-calcium magnesia-calcium brick is characterized by comprising the following components in parts by weight:
the preparation method of the high-calcium magnesia-calcium brick is implemented according to the following steps:
(1) crushing: crushing or grinding large-particle raw materials of natural dolomite, synthetic magnesia-calcium sand and magnesia respectively;
(2) screening: the processed raw materials are magnetically separated and lifted to a screening machine through a bucket elevator, granular materials with the grain sizes of 3-1 mm and 2-5 mm and fine powder materials with the grain sizes of 200-300 meshes are screened in sequence, the screened raw materials meeting the specification enter respective storage bins, and the raw materials not meeting the specification are continuously crushed or ground;
(3) preparing materials: accurately weighing the raw materials in the high-level bin by a batching system according to a certain proportion, feeding the raw materials into a heating type mixing roll by a feeding machine, and simultaneously adding the paraffin which is heated and weighed into the mixing roll;
(4) mixing: in a mixing roll, materials with different components and particle sizes and a proper amount of bonding agent paraffin are mixed and extruded to achieve uniform distribution and full wetting, and then the materials enter a pug tank in the form of pug;
(5) airing materials: airing the materials to 40 ℃;
(6) molding: putting the material obtained in the step (5) into a mud material tank again, conveying the material into a feeder, and pressing the material into green bricks by adopting a friction press;
(7) brick stacking: carrying out brick stacking treatment on the green bricks obtained in the step (6);
(8) and (3) firing: pushing the green bricks obtained in the step (7) into a high-temperature tunnel kiln for burning, taking natural gas as fuel, spraying the natural gas into the tunnel kiln through a nozzle arranged in the middle of a kiln body, and fully mixing and burning, wherein the burning temperature in the kiln is 1620 ℃.
(9) Wax dipping: carrying out wax dipping treatment;
(10) packaging: vacuumizing the aluminum foil, and performing thermoplastic packaging.
Example 3
A high-calcium magnesia-calcium brick comprises the following components in parts by weight:
the preparation method of the high-calcium magnesia-calcium brick is implemented according to the following steps:
(1) crushing: crushing or grinding large-particle raw materials of natural dolomite, synthetic magnesia-calcium sand and magnesia respectively;
(2) screening: the processed raw materials are magnetically separated and lifted to a screening machine through a bucket elevator, granular materials with the grain sizes of 3-1 mm and 2-5 mm and fine powder materials with the grain sizes of 200-300 meshes are screened in sequence, the screened raw materials meeting the specification enter respective storage bins, and the raw materials not meeting the specification are continuously crushed or ground;
(3) preparing materials: accurately weighing the raw materials in the high-level bin by a batching system according to a certain proportion, feeding the raw materials into a heating type mixing roll by a feeding machine, and simultaneously adding the paraffin which is heated and weighed into the mixing roll;
(4) mixing: in a mixing roll, materials with different components and particle sizes and a proper amount of bonding agent paraffin are mixed and extruded to achieve uniform distribution and full wetting, and then the materials enter a pug tank in the form of pug;
(5) airing materials: airing the materials to 35 ℃;
(6) molding: putting the material obtained in the step (5) into a mud material tank again, conveying the material into a feeder, and pressing the material into green bricks by adopting a friction press;
(7) brick stacking: carrying out brick stacking treatment on the green bricks obtained in the step (6);
(8) and (3) firing: pushing the green bricks obtained in the step (7) into a high-temperature tunnel kiln for burning, taking natural gas as fuel, spraying the natural gas into the tunnel kiln through a nozzle arranged in the middle of a kiln body, and fully mixing and burning, wherein the burning temperature in the kiln is 1500 ℃.
(9) Wax dipping: carrying out wax dipping treatment;
(10) packaging: vacuumizing the aluminum foil, and performing thermoplastic packaging.
Example 4
A high-calcium magnesia-calcium brick comprises the following components in parts by weight:
the preparation method of the high-calcium magnesia-calcium brick is implemented according to the following steps:
(1) crushing: crushing or grinding large-particle raw materials of natural dolomite, synthetic magnesia-calcium sand and magnesia respectively;
(2) screening: the processed raw materials are magnetically separated and lifted to a screening machine through a bucket elevator, granular materials with the grain sizes of 3-1 mm and 2-5 mm and fine powder materials with the grain sizes of 200-300 meshes are screened in sequence, the screened raw materials meeting the specification enter respective storage bins, and the raw materials not meeting the specification are continuously crushed or ground;
(3) preparing materials: accurately weighing the raw materials in the high-level bin by a batching system according to a certain proportion, feeding the raw materials into a heating type mixing roll by a feeding machine, and simultaneously adding the paraffin which is heated and weighed into the mixing roll;
(4) mixing: in a mixing roll, materials with different components and particle sizes and a proper amount of bonding agent paraffin are mixed and extruded to achieve uniform distribution and full wetting, and then the materials enter a pug tank in the form of pug;
(5) airing materials: airing the materials to 35 ℃;
(6) molding: putting the material obtained in the step (5) into a mud material tank again, conveying the material into a feeder, and pressing the material into green bricks by adopting a friction press;
(7) brick stacking: carrying out brick stacking treatment on the green bricks obtained in the step (6);
(8) and (3) firing: pushing the green bricks obtained in the step (7) into a high-temperature tunnel kiln for burning, taking natural gas as fuel, spraying the natural gas into the tunnel kiln through a nozzle arranged in the middle of a kiln body, and fully mixing and burning, wherein the burning temperature in the kiln is 1540 ℃.
(9) Wax dipping: carrying out wax dipping treatment;
(10) packaging: vacuumizing the aluminum foil, and performing thermoplastic packaging.
At present, the refractory materials for AOD furnaces are mainly divided into 3 types of magnesia-chrome bricks, magnesia-dolomite bricks (magnesia-calcium bricks) and dolomite bricks. Europe styleCalcined dolomite bricks are generally adopted as continent AOD furnace linings, and MgO-Cr is still adopted in most of Japanese AOD furnaces2O3The bricks may be built by laying MgO-Cr below 10 layers in the eye region2O3The bricks, the front wall, the furnace bottom and other parts use MgO-CaO bricks. In the initial stage of building the Tai-Gai 18tAOD furnace, the furnace lining is made of magnesia-chrome bricks. With the development of magnesium-calcium materials, magnesium-calcium bricks are gradually popularized and used at positions outside a wind eye area. MgO and CaO are NaCl type structures, cubic crystal system and face-centered cubic lattice. Lattice constant a of MgOo0.4211nm, density 3.581g/cm3The melting point is 2800 ℃, the corrosion resistance is excellent, but the thermal stability is poor, the slag is easy to permeate through, and MgO reacts with C at the temperature of more than 1600 ℃, so that the weight loss occurs, which is one of the important reasons for damaging the magnesia carbon brick. CaO lattice constant a。48106nm at 3.5819/cm density3The melting point is 2572 ℃, and the high-temperature-resistant aluminum alloy is also a high-melting-point oxide, has a small thermal expansion coefficient and low high-temperature steam pressure, and has good structural spalling resistance and slag infiltration resistance. At high smelting temperature, the magnesium-carbon material is not suitable, and magnesium-calcium material is necessary.
Under the same conditions, the oxygen partial pressure of the magnesia is lower than that of the magnesia by about 4 orders of magnitude, so that the high-calcium magnesia-calcium brick is more stable than the magnesia refractory material under the high-temperature vacuum condition. The calcium oxide can adsorb non-metallic inclusions such as sulfur, phosphorus, oxygen and the like in the molten steel, and has the effect of purifying the molten steel. The calcium oxide reacts with the slag components to generate a high-temperature mineral phase, so that the viscosity of the slag is improved, and the penetration and erosion to a furnace lining are slowed down. Besides the advantages of calcium oxide over magnesium oxide in ferrous metallurgy, the disadvantage of calcium oxide is that it has poor hydration resistance and is easy to hydrate in air to crack and pulverize brick body. The high-calcium magnesia-calcium brick of the invention has great breakthrough in this respect, and the hydration resistance can reach more than 68 days (under the same condition) from the original 18 days (the storage in the air till the complete damage).
It should be understood that the detailed description of the present invention is only for illustrating the present invention and is not limited by the technical solutions described in the embodiments of the present invention, and those skilled in the art should understand that the present invention can be modified or substituted equally to achieve the same technical effects; as long as the use requirements are met, the method is within the protection scope of the invention.
Claims (2)
1. The high-calcium magnesia-calcium brick is characterized by comprising the following components in parts by weight:
2. the method for preparing the high-calcium magnesia-calcium brick according to claim 1, wherein: the method comprises the following steps:
(1) crushing: crushing or grinding large-particle raw materials of natural dolomite, synthetic magnesia-calcium sand and magnesia respectively;
(2) screening: the processed raw materials are magnetically separated and lifted to a screening machine through a bucket elevator, granular materials with the grain sizes of 3-1 mm and 2-5 mm and fine powder materials with the grain sizes of 200-300 meshes are screened in sequence, the screened raw materials meeting the specification enter respective storage bins, and the raw materials not meeting the specification are continuously crushed or ground;
(3) preparing materials: accurately weighing the raw materials in the high-level bin by a batching system according to a certain proportion, feeding the raw materials into a heating type mixing roll by a feeding machine, and simultaneously adding the paraffin which is heated and weighed into the mixing roll;
(4) mixing: in a mixing roll, materials with different components and particle sizes and a proper amount of binding agent are mixed and extruded to achieve uniform distribution and full wetting, and then the materials enter a pug tank in the form of pug;
(5) airing materials: airing the material to 30-40 ℃;
(6) molding: putting the material obtained in the step (5) into a mud material tank again, conveying the material into a feeder, and pressing the material into green bricks by adopting a friction press;
(7) brick stacking: carrying out brick stacking treatment on the green bricks obtained in the step (6);
(8) and (3) firing: pushing the green bricks obtained in the step (7) into a high-temperature tunnel kiln for burning, taking natural gas as fuel, spraying the natural gas into the tunnel kiln through a nozzle arranged in the middle of a kiln body, and fully mixing and burning, wherein the burning temperature in the kiln is 1490-1540 ℃.
(9) Wax dipping: carrying out wax dipping treatment;
(10) packaging: vacuumizing the aluminum foil, and performing thermoplastic packaging.
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| CN115448701A (en) * | 2022-08-19 | 2022-12-09 | 山西太钢不锈钢股份有限公司 | Magnesium-calcium refractory material for AOD smelting nickel-based alloy and preparation method thereof |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115448701A (en) * | 2022-08-19 | 2022-12-09 | 山西太钢不锈钢股份有限公司 | Magnesium-calcium refractory material for AOD smelting nickel-based alloy and preparation method thereof |
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