Monocalcium aluminate

Monocalcium aluminate
IUPAC name

Monocalcium aluminate
Properties
Molecular formula CaAl2O4
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Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
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 Ca0.93Al1.94Fe0.11Si0.02O4. 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