Solid solutions of C3A---Na2O in C12A7

This paper reports upon the research into the influence of sodium ions on C₁₂A₇. The actual research work consisted in synthesizing C₁₂A₇, treated with the sodium ions as Na₂CO₃, within the sodium concentration range of up to 25% Na₂O by weight in C₁₂A₇. The resultant combinations have been identified by the X-ray analysis, the infra-red spectroscopy and the quantitative chemical analysis.

The identification procedure together with the analysis of free CaO content in the products of C₁₂A₇ sodium synthesis gave evidence that sodium which is introduced into the researched amount of C₁₂A₇ up to 10% Na₂O by weight, contributes to the formation of the ever increasing phase of the solid solutions of Na₂O in C₃A. The continued increase of the sodium volume ( 15% Na₂O by weight ) makes it resolve gradually into sodium aluminate β -NA and free CaO.