Refractory ramming material is an unshaped refractory material that is constructed by manual mechanical ramming hardened by heating. The ramming material is composed of graded refractory aggregates, powders, binders, admixtures, mixed with water other liquids. Classified by material, there are high-interest-rate clay, magnesia, dolomite, zirconium zirconium silicon carbide carbon carbon refractory ramming materials.
Ramming materials can be prepared various refractory aggregates powders according to the needs of use. At the same time, the appropriate bonding agent is selected according to the refractory aggregate material use requirements. Some ramming materials do need bonding agent but add a small amount of flux to promote their sintering. Sodium silicate, ethyl silicate silica gel are commonly used as binding agents in acid ramming materials. Alkaline ramming materials use aqueous solutions of magnesium chlorides salts, as well as phosphates their polymers as binders, often use organic substances temporary binders that contain higher carbon form carbon bonds at high temperatures. Glauber's salt is often used as a binder for chromium ramming materials. High-aluminum corundum ramming materials often use phosphoric acid aluminum phosphate, chloride, salt other inorganic substances as binders. When phosphoric acid is used as the binding agent, the phosphoric acid reacts with the activated alumina in the ramming material during the storage process to form water-insoluble aluminum orthophosphate precipitates harden, which loses plasticity is difficult to construct. Therefore, to extend the shelf life of ramming materials, add appropriate preservatives to prevent delay the occurrence of coagulation hardening, oxalic acid is usually used as a preservative. Carbonaceous ramming materials mainly use binders that form carbon bonds. Asphalt tar resin is used as the binder to form carbon bonds, which can prevent molten metal wetting, improve corrosion resistance thermal shock resistance. It can also play a role in preventing hydration of dolomite.
Ramming materials are usually mainly used in the parts that are in direct contact with the melt. The refractory materials are required to have good volume stability, compactness corrosion resistance, so high-temperature firing electric melting materials are generally used. The particle size of the ramming material is related to the application location construction method, the general critical particle size is 8mm. The normal temperature strength of most ramming materials before sintering is low, some medium temperature strengths are high, a good combination can only be obtained after sintering coking of the carbon-containing compounds in the binder when heated. The fire resistance melt erosion resistance of the ramming material can be obtained through the selection of high-quality raw materials, adjustment of a reasonable ratio careful construction. In addition to the high stability corrosion resistance of the ramming material at high temperatures, its service life depends to a large extent on the baking before use the sintering quality during use. If the heating surface is sintered as a whole, without cracks separated the bottom layer, the service life can be improved.
The construction quality of refractory ramming material is very important, its quality is closely related to the use effect. The ramming material is usually rammed with an air hammer a ramming machine. The thickness of the ramming material is about 50-150mm. The refractory ramming material can be constructed at room temperature, such as the use of thermal organic materials that can form carbon bonds. As a binding agent, most of them use hot stirring to mix the mixture evenly construct it immediately. After molding, different heating methods are adopted to promote hardening sintering according to the hardening characteristics of the mixture. For ramming materials containing inorganic chemical binders, they can be demolded baked after they have hardened to a considerable strength. Materials containing thermoplastic carbon binders can be demolded after they have cooled to considerable strength, used after demolding It should be heated quickly before carbonization. The binder material that hardens at room temperature is often sintered with a mold after tamping. The sintering of the refractory ramming material furnace lining can be carried out in advance before use, can be completed by heat treatment with a suitable thermal system during use. The baking heating system of the ramming material varies according to the material. The main purpose of the ramming material is to build the lining of the smelting furnace that is in direct contact with the melt, such as the blast furnace tapping trough, the bottom of the steelmaking furnace, the lining of the induction furnace, the top of the electric furnace, the blanking part of the rotary kiln. In addition to the furnace lining, large prefabricated components can also be manufactured.
The carbon ramming material silicon carbide ramming material developed by our company have good normal temperature construction performance thermal conductivity. WH-03 is suitable for filling ramming the gap between carbon bricks cooling stave; WH-04 is suitable for filling ramming the leveling layer above the center line of the water-cooled tube at the bottom of the large blast furnace above the bottom sealing plate; WH-05 is suitable for Filling ramming between the cooling walls of the blast furnace hearth; WH-06 is suitable for filling ramming between the cooling walls above the blast furnace hearth.