With the increasing use of refractory castables, there are indeed certain methods and skills on how to choose the material of the castable or what index of castable to choose. This is mainly because the working conditions of different types are of different refractory castables.
Working Conditions of Different Types of Refractory Castables in Different Atmospheres
Refractory castables are divided into neutral, acidic, and alkaline. There is also the difference between heavy and light. Heavy refractory castables are generally used in the working layer, while lightweight castables are used in the thermal insulation layer for heat preservation.
If it is a neutral high-aluminum refractory castable, the index of the castable used is determined according to the temperature and erosion of the furnace lining. If the temperature is below 1200°C, use clay castables. If the temperature exceeds 1250°C, high-aluminum castables should be used. If the use temperature exceeds 1350℃, the corundum refractory castable is used. If it is extremely corrosive, chromium corundum castable should be used. If the wear is severe, wear-resistant refractory castables are used. The storage time of neutral materials is 6 months, so we must pay attention to the separate storage of raw materials and binders.
If it is a castable used in an acidic atmosphere, an acidic castable should be used. Acidic castables are combined with two binders, one is water glass combination and the other is phosphoric acid combination. If it is an acidic atmosphere with a temperature not exceeding 1250°C, the acidic castable combined with water glass can be used. If the temperature is too high, choose acid-resistant castable combined with phosphoric acid.
If it is a castable used in an alkaline atmosphere, magnesia refractory castable should be used. In the case of erosion and wear resistance, use magnesia-aluminum refractory castable or magnesia-chromium castable. If the temperature is too high, magnesia castables with high specific gravity or high content magnesia castables can be used. However, the preservation of magnesia castables must be paid attention to and cannot be stored in the open air. Because magnesia castables can’t come into contact with water, otherwise they will pulverize.
Refractory Castable for Insulation Layer
If it is a castable for the insulation layer, it also depends on the temperature. If the temperature is low, general lightweight thermal insulation castables can be used. If the temperature is too high, use lightweight high-aluminum or alumina hollow sphere lightweight castables as the insulation layer. The storage of lightweight castables must also be paid attention to, and it should not be placed with materials that are too corrosive, otherwise, it will cause damage to the lightweight castables.
If the furnace shell requires low temperature, it is necessary to use double-layer insulation to solve it, that is, first ceramic fiber and then light insulation castable, or directly use ceramic fiber block to solve it. However, if there is a weight requirement in the insulation area, use a specific gravity of 0.6-0.8 as the insulation layer. If the flue is directly used in the thermal insulation castable of the working layer, a lightweight castable with a specific gravity of 1.3-1.5 is used as the lining. If it is an acidic atmosphere, it is necessary to choose to use a light acid-resistant castable as the lining.
Lightweight mullite thermal insulation castable for thermal insulation layer
Due to the development trend of high efficiency, energy-saving, and environmental protection of various industrial kilns, there are higher requirements on the configuration of refractory materials for the insulation layer of industrial kilns. The Rongsheng unshaped refractory material manufacturer produces high-quality lightweight mullite castables suitable for this working condition, and has achieved good results. Next, let’s understand some of the characteristics of lightweight mullite castables.
Features of lightweight mullite castable
- It can be used for the working lining or thermal insulation lining of various flame furnaces and other industrial kilns, which can realize heat preservation and energy saving.
- High strength and small unit weight. It can be used on the roof, wall, door, and other parts of the industrial kiln. Compared with ordinary low-cement castables, the structural weight is reduced by more than 30%, which eliminates hidden dangers such as structural brick breakage and collapse.
- Using high-quality porous mullite as aggregate, combined with a variety of micro-powders and dispersants, the thermal conductivity is low and the heat preservation effect is good. Compared with ordinary castables, it can reduce the heat loss of the kiln by 25%-35% and save fuel by about 10%.
- Simple construction. It can be cast as a whole on-site, or cast into any shape preforms, and then combined and installed.
Application of lightweight mullite castable in a regenerative heating furnace. The high-quality lightweight mullite castable produced by Rongsheng refractory manufacturer is used on the working lining of the regenerative chamber of a regenerative walking beam reheating furnace in a steel plant, with an amount of 180t. Due to the construction in winter, the corresponding technical regulations have been formulated, and the construction performance of the castable is excellent. No damages such as peeling, cracking, etc. have been found in the construction body so far. The strength and heat insulation performance is affirmed by users.
In short, no matter what kind of refractory castable is selected, the castable must be selected according to the use situation, lining atmosphere, and temperature. To learn more about the use conditions and characteristics of refractory castables, please continue to pay attention to our website. If you need to buy a variety of high-quality refractory castable products, please do not hesitate, you can contact us by email, or leave a message on our website page below. We will provide you with refractory castable products that best suit your production needs according to your specific needs. Contact us to learn more about manufacturers, prices, models, pictures, origins, brands, and other information!Leave your requirements about the refractories you need. We will reply you within 24 hours. :