Who can tell me the properties and classification of insulating refractories?
The refractory materials refers to the refractory material of high porosity, low volume density, low thermal conductivity of the insulating material. Also called lightweight refractories. It includes insulating refractory products, refractory fiber and refractory fiber products.The characteristics of insulating refractory material is of high porosity, generally 40% to 85%; the volume density is low, generally less than 1.5g/cm3; the thermal conductivity is low, generally less than 1.0W (M - K). It is used as the insulation material of industrial furnace, furnace can reduce heat loss, save energy, and reduce thermal insulation equipment weight. The mechanical strength of refractory material, abrasion resistance and slag resistance is poor, should not be used for load-bearing structure of furnace slag, furnace, and direct contact with the molten metal and other parts.
It is the chemical method. The chemical reaction in the brick making process to produce gas and method for obtaining a porous brick. Usually use chemical reactions such as carbonate and acid, metal powder with acid, caustic and aluminum. Chemical reactions can be used must be relatively slow and can control or mechanical disturbance will disappear bubble in an injection mold. If the reaction is too fast, adding inhibitors such as hydrogen peroxide and manganese dioxide. The fine powder material slurry mixed with reactant bubbles to obtain stable foam slurry injection model, after drying the firing. This method of making pure oxide insulating refractory products, its porosity can reach 55% ~ 75%.
Bubble method. This method is the foam agent in a frothing machine mixing with water and prepared uniform fine foam, the foam added in common mud mixing into the foam slurry injection model, together with the drying, demoulding, at 1320 DEG C to 1380 DEG C (high alumina insulating refractory brick for burning) after processing, the plastic products.
Burn out addition method. This method is sawdust or combustible additives into mud. Sublimation mixing and extrusion method, semi dry or slurry casting moulding, drying and sintering. Combustible or sublimation additives in the firing process of burned, leaving the empty hole, become insulating refractory products.
Insulation materials can be classified according to service temperature, production process and application fields.
