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 |
|
|
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℃) |
|
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 ramming mass (refractory taphole mass) is a kind of Refractory used for lining of blast furnace tapping groove. It is mainly used to protect the blast furnace out of the ditch from high-temperature hot metal and slag erosion and erosion, and has excellent high-temperature resistance and wear resistance. The ramming material for the iron discharge ditch is usually composed of corundum, silicon carbide and carbonaceous material, which has the ability of resisting hot metal and molten slag erosion and scouring, reburning line change small, strong resistance to a variety of oxidation characteristics. The construction of the ramming material for the iron ditch is convenient, easy to dismantle and repair, does not produce harmful gas, and is beneficial to environmental protection.
Corundum bricks are mainly used in iron-making blast furnaces and blast furnace hot blast furnaces, refining furnaces outside steel-making furnaces, sliding water heaters, glass melting furnaces and petrochemical industrial furnaces, etc.
The chemical composition of bauxite is mainly Al2O3, SiO2, Fe2O3, TO2, accounting for about 95% of the total composition, and the secondary components are CaO, MgO, K2O, Na20, S, MnO2 organic matter and trace components Ga, Ge, etc.
Insulating high alumina refractory bricks mainly refer to refractory products with an aluminum content of more than 48%. They are also called lightweight high-alumina bricks or heat-insulating high-alumina bricks due to their advantages of low bulk density, light weight, and good heat insulation effect. . It is a kind of thermal insulation refractory brick commonly used in high temperature industrial kilns and thermal equipment.
High alumina brick is mainly used for lining of blast furnace, hot blast furnace, electric furnace roof, reverberatory furnace and rotary kiln. In addition, high alumina brick also widely used as open hearth regenerative lattice brick, pouring system with plug,such as nozzle brick.
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.

