Aluminate cement is a water-hardening material made primarily of calcium aluminate, with an aluminum oxide content of about 50%, produced by calcining aluminum ore and limestone. Aluminate cement is usually yellow or brown, but can also be gray. The main mineral of aluminate cement is calcium monoaluminate (CaO·Al2O3, abbreviated as CA) and other aluminate minerals, as well as a small amount of dicalcium silicate (2CaO·SiO2), with colors mainly being gray and white.
In amorphous refractory materials, refractory cement is often used as a binder, with aluminate cement being the most commonly used. Aluminate cement is divided into calcium aluminate cement, barium aluminate cement and barium zirconate aluminate cement, etc.
Aluminate cement is a water-hardening material made primarily of calcium aluminate, with an aluminum oxide content of about 50%, produced by calcining aluminum ore and limestone. Aluminate cement is usually yellow or brown, but can also be gray. The main mineral of aluminate cement is calcium monoaluminate (CaO·Al2O3, abbreviated as CA) and other aluminate minerals, as well as a small amount of dicalcium silicate (2CaO·SiO2), with colors mainly being gray and white. As a binder or additive in amorphous refractory materials, the most commonly used is calcium aluminate cement. The chemical composition of this cement mainly contains Al₂O₃ and CaO, with some also containing considerable amounts of Fe₂O₃ and SiO₂. The establishment of cement hydration strength is because the flake-like and needle-like hydration products are interwoven with the colloidal AH, which tightly connects the refractory materials together, forming a strong whole.
According to the provisions of GB201-2000, the code of aluminate cement is CA, and it is divided into four types based on the percentage of Al₂O₃:
CA-50, 50%≤Al₂O₃＜60%, abbreviated as 50 cement, which is the most commonly used refractory cement; CA-60, 60%≤Al₂O₃＜68%, abbreviated as 60 cement; CA-70, 68%≤Al₂O₃＜77%, abbreviated as 70 cement; CA-80, 77%≤Al₂O₃, abbreviated as 80 cement; among them, CA-70 and CA-80 cement are generally referred to as pure calcium aluminate cement.
The designations of CA-50-G6, CA-50-625, and CA-50-A600 all have a meaning, which, in simple terms, means alumina content of around 50% and a three-day strength of approximately 62.5 MPa for aluminate cement. Similarly, G7/725/A700 indicates aluminate cement with a three-day strength of around 72.5 MPa. Aluminate cement has good high-temperature resistance and can maintain a high strength at higher temperatures. Its high-temperature resistance also increases with an increase in the content of dicalcium aluminate (CA2), making it suitable as a binder for various refractory castables.
