Calcium Aluminate Cement

Oxide	Analysis	Formula
CaO	33.39%	1.33
MgO	0.88%	0.05
Al2O3	45.76%	1.00
SiO2	7.69%	0.29
Fe2O3	7.19%	0.10
SO3	5.10%	n/a
Oxide Weight		211.56
Formula Weight		222.93

Notes

Calcium Aluminate Cement (CAC) is a super refractory material. It is made by fusing or sintering alumina and calcia contributing minerals to produce monocalcium aluminate (CaAl2O₄) clinkers that are subsequently powderized. CAC is far superior to Portland cement in its setting properties and its ability to withstand high temperatures and chemical attack. The temperatures that CAC materials can tolerate is astounding to people who normally think in terms of traditional refractory natural materials (e.g. fireclay).

The purest theoretical calcium aluminates would have a 35:65 ratio (molar weight) of CaO:Al₂O₃. The best real world materials have around 30% CaO and 70% Al₂O₃ and very low impurities (like iron, silica, sodium). These products have the best rheological characteristics. Higher percentages of alumina can increase the service temperature (to a staggering 1900C!) but at the expense of strength and workability. One company produces products having alumina percentages from 40-80%.

Advances in particle size distribution and installation technology have made it possible to exceed the capabilities of traditional refractory brick installations. It has also been possible to reduce the CAC percentage in mortar mixes while improving mechanical performance and increasing service temperatures.

Related Information

Links

Materials	Matrix Frit B40-C
Oxides	CaO - Calcium Oxide, Calcia

By Tony Hansen
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