Introduction of refractory cement properties and chemical composition

Refractory cement often refers to cement with calcium aluminate as the main component. Refractory cement is an amorphous binder, especially a basic binder for casting refractories. Its chemical composition is mainly Al2O3 and CaO, and some also contain considerable Fe2O3 and SiO2. The mineral composition has the following five minerals: aluminum aluminate-calcium CaO· Al2O3 (CA), calcium aluminate CaO · 2Al2O3 (CA2), lauric acid 12CaO · 7Al2O3 (C12A7) three compounds and inclusions Calcium feldspar 2CaO · Al2O3 · SiO2 (C2AS), iron tetraaluminate 4CaO & middot; Al2O3 & middot; Fe2O3 (C4AF). They are generally classified into three categories based on their chemical mineral composition.

The nature of refractory cement depends primarily on its mineral composition. The main mineral composition of refractory cements, calcium permanganate (CA), has a high hydraulic activity. Although it is not very fast but hardens hard (hardening time is less than one day), it is the main source of high alumina cement strength, especially early strength. Calcium dialium aluminate (CA2) has a slower hydration hardening, lower early strength and higher late strength. Decacalcium laurate (C12A7) has the characteristics of rapid hydration and rapid condensation, but its strength is not high. In ordinary high-aluminum cement containing inclusions (calcium feldspar C2AS, tetracalcium tetracalcium C4AF), C4AS plays a role in hardening the cement as early as possible, while in high-grade high-aluminum cement, C12A7 acts as a hardening agent. As for C2AS, there is basically no hydration, and its strength cannot be displayed.