Monocalcium aluminate

Monocalcium aluminate
IUPAC name Monocalcium aluminate
Properties
Molecular formula	CaAl2O4
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Infobox references

Monocalcium aluminate (CaAl₂O₄) is one of the series of calcium aluminates^[1]. It does not occur in nature, but is important in the composition of calcium aluminate cements.

Properties

Monocalcium aluminate is formed when the appropriate proportions of calcium carbonate and aluminium oxide are heated together until the mixture melts. It melts incongruently at 1390°C. The crystal is monoclinic and pseudohexagonal, and has density 2945 kg.m^-3. In calcium aluminate cements, it exists as a solid solution in which the amount of minor elements depends upon the bulk composition of the cement. A typical composition^[2] is Ca_0.93Al_1.94Fe_0.11Si_0.02O₄. It reacts rapidly with water, forming the metastable hydrate CaO.Al₂O₃.10H₂O, or a mixture of 2CaO.Al₂O₃.8H₂O, 3CaO.Al₂O₃.6H₂O and Al(OH)₃ gel. These reactions form the first stage of strength development in calcium aluminate cements.

References

1. ^ H F W Taylor, Cement Chemistry, Academic Press, 1990, ISBN 0-12-683900-X, p 35
2. ^ P. C. Hewlett (Ed)Lea's Chemistry of Cement and Concrete: 4th Ed, Arnold, 1998, ISBN 0-340-56589-6, p715