Tundish Coating Materials is made of high quality magnesia, olivine as the main raw materials, adding plasticizer and explosion-proof agent.
Tundish Coating Application:
There are two kinds of binders suitable for the preparation of magnesia calcia coating mixture, one is silicate series(different modulus of sodium silicate), the other is polyphosphate(different polymerization sodium phosphate), the second is most often used. The functions of organic fiber in coating mixture are: avoiding cracking during drying or rupture during roasting, reducing thermal conductivity of coating mixture. Additive used for tundish coating mixture is usually plasticizer, which includes plastic clay, bentonite, silica micro powder, slaked lime and so on. The additives not only has adding plasticity function, but also play the role of sintering agent.
Tundish Coating Features:
The construction performance, anti – burst performance, anti – erosion performance, anti – sintering performance and heat preservation performance are good. It doesn’t contain sulfur and phosphorus, which do not pollute molten steel.
The raw material of magnesia calcia tundish coating mixture is composed of dolomite or sintered magnesite calcia, sintered or fused magnesite, binder, additives(dispersant, plasticizer, sintering agent) and organic fibers. Dolomite is compound salt which is consisted of CaCO3 and MgO3, its theoretical CaO content is 30.4%, MgO content is 21.9%. Calcined dolomite contains 58% CaO and 42% MgO. But dolomite clinker is easy to be hydrated, it is difficult to be used for preparing coating mixture, so usually adopts dolomite sand and sintered( fused) magnesite or anti-hydration magnesia calcia sand and sintered magnesite for the making of tundish coating mixture. The interior of the tundish is lined with refractory materials that can withstand the high temperatures of molten steel. These materials are typically alumina-based or magnesia-based bricks or castables that provide thermal insulation and protect the tundish shell from heat damage.
