Refractory cement is also named high temperature cement. It’s special material cement for high temperature refractory monolithic. Mainly include: ① Low-calcium aluminate refractory cement with pure bauxite and limestone as the main raw materials. ② Dolomite high-temperature cement made by adding apatite and iron ore as the main raw material. ③ Use materials that can produce chemical reactions and harden at high temperatures, such as refractory sulfates, borates, and phosphates as high-temperature-resistant cements for cementing materials.
Classification of refractory cement:
1.Aluminate refractory cement
Aluminate refractory cement is usually a kind of refractory cement made by mixing and grinding 4 parts (by mass) of low-calcium aluminate refractory cement clinker and 1 part of high-alumina cement clinker. Compared with low-calcium aluminate refractory cement: higher early strength, similar refractoriness, and same application.
2.Low Calcium Aluminate Refractory Cement
All raw materials made of high-quality aluminum alum and high-quality limestone are mixed in a certain proportion to form raw materials with appropriate ingredients. After sintering, the clinker with low-calcium aluminate as the main component is ground into fine powder. A hydraulic cementitious material with fire resistance, called low calcium aluminate refractory cement.
Low lime aluminate refractory cement is a kind of aluminate cement that is made of high-quality bauxite and limestone in an appropriate proportion, sintered and ground. Its composition is generally: alumina accounts for 70%, calcium oxide accounts for 19% to 23%, silicon dioxide <4%, iron oxide <1.5%. The mineral composition is mainly monocalcium dialuminate, accounting for 60% to 70%, and the refractoriness is above 1650°C. Compared with high alumina cement, the main differences are: high alumina content, low calcium oxide content, low early strength, high refractoriness, etc. It can be formulated with refractory aggregates (such as calcined bauxite, high alumina brick fragments, etc.) with a refractoriness above 1770°C to make refractory concrete or refractory mortar, which can be used as the inner lining of cement rotary kiln and other industrial kilns.
Its uses include: (1) It can be mixed with refractory materials with a refractoriness above 1770°C, such as calcined bauxite, high-alumina brick fragments, etc., to prepare refractory concrete or refractory mortar, which can be used as refractory lining for some high-temperature kilns and Some high-temperature projects that have been eroded by the atmosphere and rain for a long time. (2) It can be formulated with light aggregates to form heat-insulating concrete and heat-resistant concrete. (3) Mix with asbestos to make asbestos cement products with insulation and heat resistance.
3.calcium magnesium aluminate cement
Calcium magnesium aluminate cement is a kind of aluminate cement that is made of high-quality bauxite and dolomite in an appropriate proportion, sintered and ground. The composition of calcium magnesium aluminate cement is generally: alumina accounts for 66% to 74%, calcium oxide accounts for 13% to 18%, and magnesium oxide accounts for 10% to 13%. Silica and iron oxide traces. The mineral composition is calcium aluminate and calcium dialuminate accounting for 45% to 60%, and spinel accounting for 35% to 50%. The refractoriness is above 1650°C.
Compared with low-calcium aluminate cement, calcium magnesium aluminate cement has the following advantages: strong resistance to slag and metal melt chemical erosion; in the case of the same alumina content, due to the existence of spinel, Higher refractoriness; less mixing water, lower porosity after hardening of cement, less calcining shrinkage; less strength loss when heated to 1100°C for dehydration. Calcium magnesium aluminate cement and fused white corundum and other aggregates are used to make concrete, which can be used as the lining of cement rotary kilns and other industrial kilns.
