Unshaped refractory materials that are constructed by ramming (manual or mechanical) and hardened by heating above normal temperature. It is composed of refractory aggregates, powders, binders, and admixtures with a certain grade, and is mixed with water or other liquids. According to the material classification, there are high-alumina, clay, magnesia, dolomite, zirconium, and zirconium silicon carbide carbon refractory ramming materials.
Composition Ramming materials can be prepared from refractory aggregates and powders of various materials according to the needs of use. At the same time, suitable binders are selected according to the material of refractory aggregates and the requirements of use. Some ramming materials do not use binders but only add a small amount of flux to promote their sintering. Sodium silicate, ethyl silicate and silica gel are commonly used as binders in acidic ramming materials. Alkaline ramming materials use aqueous solutions of magnesium chloride and sulfate, as well as phosphates and their polymers as binders. Organic matter with a high carbon content that forms carbon bonds at high temperatures and temporary binders are also often used. Chromium ramming materials often use Glauber's salt as a binder. High-aluminum and corundum ramming materials often use phosphoric acid and inorganic substances such as aluminum phosphates, oxides, and sulfates as binders. When phosphoric acid is used as a binder, during storage, phosphoric acid reacts with the active alumina in the ramming material to form water-insoluble aluminum orthophosphate precipitation, which solidifies and hardens, loses plasticity and is difficult to construct. Therefore, to extend the shelf life of the ramming material, an appropriate preservative must be added to prevent or delay the occurrence of solidification and hardening. Oxalic acid is usually used as a preservative. Carbonaceous ramming materials mainly use binders that form carbon bonds. Using asphalt tar or resin as a binder to form a carbon bond can prevent molten metal from wetting, improve corrosion resistance and thermal shock resistance, and can also prevent dolomite from hydrating in dolomite ramming materials.
Performance Ramming materials are usually used in the parts that are in direct contact with the melt. The refractory materials must have good volume stability, density and corrosion resistance. Therefore, high-temperature sintering or electric melting raw materials are generally selected. The maximum particle size of the ramming materials is related to the use part and the construction method. The general critical particle size is 8mm. Most ramming materials have low room temperature strength before sintering, and some have low medium temperature strength. Only when they are sintered or the carbon-containing compounds in the binder are coked during heating can they obtain good bonding. The refractory properties and resistance to erosion by melts of ramming materials can be obtained by selecting high-quality raw materials, adjusting reasonable proportions and careful construction. In addition to having high stability and corrosion resistance at high temperatures, the service life of ramming materials depends to a large extent on the baking before use or the sintering quality during the first use. If the heating surface is sintered as a whole, without cracks and not separated from the bottom layer, the service life can be improved.
Products Description
Application The construction quality of refractory ramming materials is very important, and its quality is closely related to the use effect. Ramming materials are usually rammed by air hammer or ramming machine. The thickness of the material added at one ramming is about 50~150mm. Refractory ramming materials can be constructed at room temperature. If thermoplastic organic materials that can form carbon bonds are used as binders, most of them use hot stirring methods to stir the mixture evenly and then immediately construct it. After molding, different heating methods are adopted according to the hardening characteristics of the mixture to promote hardening or sintering. For ramming materials containing inorganic chemical binders, they can be demolded and baked after self-hardening to a considerable strength. Materials containing thermoplastic carbon binders can be demolded after cooling to a considerable strength. After demolding, they should be quickly heated to carbonize before use. Materials that do not contain binders that harden at room temperature are often sintered with molds after tamping. The sintering of refractory ramming material linings can be carried out in advance before use, or it can be completed by heat treatment with a suitable thermal system when used for the first time. The baking and heating system of ramming materials varies according to different materials. The main purpose of ramming mass is to build the lining of smelting furnaces that are in direct contact with the molten material, such as the iron ditch of blast furnace, the bottom of steelmaking furnace, the lining of induction furnace, the top of electric furnace and the blanking part of rotary kiln. In addition to being used to form the overall lining, it can also be used to manufacture large prefabricated components.
|
name |
Corundum |
Aluminum Magnesium |
Magnesium Aluminum |
|||
|
Brand |
|
|
|
|
|
|
|
chemical composition AL2O3％≥ |
80 |
85 |
70 |
40 |
30 |
|
|
MgO%≥ |
/ |
/ |
8 |
50 |
/60 |
|
|
Refractoriness ℃≥ |
1790 |
1790 |
1790 |
1790 |
1790 |
|
|
Operating temperature ℃≥ |
1790 |
1790 |
1790 |
1790 |
1790 |
|
|
Bulk density g/cm3≥ |
2.75 |
2.6 |
2.6 |
2.7 |
2.75 |
|
Hot Tags: refractory ramming mass, China refractory ramming mass manufacturers, suppliers, factory, Self-flowing Castable, Self-flowing Castables, Silicon Carbide Ramming Mass, Refractory Ramming Mass, Refractory Repair Material, Hot Blast Furnace Refractory Spray Coating