The unshaped refractory material used when repairing the lining of thermal equipment by spray construction method is called refractory gunning material. It is made of a refractory set with a certain particle gradation
Refractory gunning material for inner lining maintenance of blast furnace
The unshaped refractory material used when repairing the lining of thermal equipment by spray construction method is called refractory gunning material. It is composed of refractory aggregates with certain particle gradation, chemical binders and additives, and is generally a thermosetting or gas-hardening material. The selection of the main material is based on the maximum temperature fluctuation range that may be reached in the kiln, the properties of the slag, and the material of the lining itself.
The particle size composition and limit particle size of the gunning material and the spraying layer should be determined according to the structure of the gunning machine, the thickness of the gunning layer and different gunning methods. Improper selection of particle size or unreasonable particle gradation have a great influence on the adhesion of gunning material and the density of the gunning layer. Under normal circumstances, the wet and dry spraying particles are too coarse and too many particles will lead to a decrease in the adhesion rate. Generally, the multi-critical particle size of the dry gunning material is larger than that of the wet spray gunning material, and sometimes it can reach 6~7mm or even larger. Fire spray gunning material is divided into wet method (mud method) gunning material, semi-dry method (nozzle mixing type) gunning material and flame method (melting method) gunning material according to the construction method: according to the main material of the gunning material Divided into magnesia, magnesia-calcium, magnesia-chromium, magnesia-carbon, aluminum silicate and alumina-silicon-oxide-carbon gunning materials, etc.: according to the conditions of use, it is divided into gunning materials for converters and gunning for electric furnaces material, gunning material for ladle, gunning material for vacuum degassing furnace (RH, DH), gunning material for tapping ditch and gunning material for blast furnace lining, etc.
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Project |
index |
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GWP-35 |
GWP-45 |
GWP-55 |
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Al2O3≥ |
35 |
45 |
55 |
|
|
Fe2O3≤ |
1.5 |
1.5 |
1.0 |
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|
Refractoriness/CN≥ |
152 |
164 |
168 |
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|
Bulk density (g/cm3)(110℃×3h)≥ |
2.00 |
2.10 |
2.20 |
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|
Normal temperature compressive strength |
110℃×24h after dry |
30 |
35 |
35 |
|
1000℃×3h after burning |
25 |
30 |
30 |
|
|
heat treatment temperature×3h |
45(1200℃) |
50(1400℃) |
55(1500℃) |
|
|
Permanent line rate of change |
1000℃×3h after burning |
±0.5 |
±0.5 |
±0.5 |
|
Experimental temperature×3h |
±1.0(1200℃) |
±1.0(1400℃) |
±1.0(1500℃) |
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Refractory gunning material characteristics are :
simple operation
high adhesion rate
rapid sintering, no dust
low rebound rate
mechanized or automated construction
shortening the construction period
saving labor
and reducing costs
Acid resistant refractory gunning material is used for spraying of blast furnaces, hot blast stoves, hot blast pipes, flue protection layers, working layers, etc.
Converter, electric furnace gunning material has the characteristics of high adhesion rate, good high temperature corrosion resistance, etc.
Refractory wet mud used to block the iron outlet can be divided into two categories: water cannon mud and waterless gun mud. On large and medium -sized blast furnaces on high top pressure and high degree of smelting.
Ceramic wear resistant castable is a special material and is a new type of material developed recently. It not only meets the needs of national defense cutting-edge products and high-tech development, but also meets the requirements of the rapid development of the national economy. Therefore, it is easier for users to accept than other materials, so it develops rapidly.
Silicon carbide used in industry is a synthetic material, commonly known as emery. Silicon carbide is one of the most commonly used non-oxide refractory raw materials in the field of refractories.
The refractoriness of clay bricks is comparable to that of silica bricks, up to 1690~1730℃, but the softening temperature under load is more than 200℃ lower than that of silica bricks. Because in addition to the high refractory mullite crystal, the clay brick also contains nearly half of the low melting point amorphous glass phase.
Silicon carbide castables mainly use 98 silicon carbide as the main raw material, add water reducing agent and micropowder, and use pure calcium aluminate cement as binder to make amorphous refractory materials. Cupola and other high temperature materials to be recorded.
White corundum is made from industrial alumina powder, which is smelted in an arc at a high temperature above 2000 ℃ and then cooled. After crushing and shaping, magnetic separation to remove iron, it is divided into various particle sizes.

