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.
Project |
index |
|||
GWP-35 |
GWP-45 |
GWP-55 |
||
Al2O3≥ |
35 |
45 |
55 |
|
Fe2O3≤ |
1.5 |
1.5 |
1.0 |
|
Refractoriness/CN≥ |
152 |
164 |
168 |
|
Bulk density (g/cm3)(110℃×3h)≥ |
2.00 |
2.10 |
2.20 |
|
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.
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.
Chrome corundum brick refers to corundum refractory products containing Cr2O3. At high temperature, Cr2O3 and Al2O3 form a continuous solid solution, so the high temperature performance of chromium corundum products is better than that of pure corundum products. Chromium corundum products are widely used, and the content of Cr2O3 is mostly in the range of 9% to 15%.
Anti stripping high alumina bricks are referred to as anti-stripping bricks or anti-stripping refractory bricks. Anti-stripping high-alumina bricks are widely used in my country's new dry process kiln, Libore kiln and wet process kiln, including kiln door cover, rising flue, cooling zone, decomposition zone, safety belt, transition zone, coolant rear Walls and side walls and beams with curved ceilings.
Magnesia chrome bricks are refractory products with magnesia (MgO) and chromium trioxide (Cr2O3) as the main components, and periclase and spinel as the main mineral components. The main raw materials for the manufacture of magnesia-chrome bricks are sintered magnesia and chromite.
Magnesia alumina bricks use periclase as the main crystal phase and magnesia-alumina spinel as the matrix. They are better in thermal shock resistance than magnesia bricks. In order to improve the thermal shock resistance of magnesia bricks, alumina or alumina is introduced into the ingredients. Bauxite clinker fine powder to form a magnesia-alumina sharp stone matrix, thereby making magnesia-alumina bricks
The Al2O3 content of clay heat Clay insulating refractory bricks is generally more than 40%, and the Fe2O3 content is less than 2.0-2.5%. The clinker in the ingredients is 65-85%, and the combined clay is 35-15%. The crushed bonded clay and the finely ground clinker are mixed and milled, and then mixed with the granular clinker to make semi-dry mud, high pressure molding, and sintering at about 1400 ℃, with good performance.