The mineral constitutions of zircon-dolomite refractories formed by the firing at 1500°C have been studied quantitatively by X-ray diffraction analysis. The materials consisted of zircon and zirconia in the range of 10-20mol% dolomite, and of calcium zirconate, periclase, tricalcium silicate, dicalcium silicate and merwinite in the range of 70-90mol% dolomite. In the other range of dolomite content, materials usable as refractories were not expected to be obtained because in the range of 30-70mol% dolomite, softening or melting occurred, and in the range of more than 90mol% dolomite, slaking occurred due to the free lime.
By considering systematically the order of all reactions that may occur, a method of calculation of mineral constitutions covering the ranges of 10-20mol% and 70-90mol% dolomite has been introduced. It was confirmed that the method gave very good agreement between experimental and calculated values in the former range, and considerably good in the latter range. It may be emphasized that this method of calculation is very useful not only for the fundamental study but also for the industrial application of the system.