A study of the celite part (part VII) -: The systems CaO-Al2O3-Fe2O3 and CaO-Al2O3-Fe2O3-SiO2, whose Al2O3:Fe2O3 molar ratios are 2 or 4

The author performed systematic research on calcium almino-ferrite phase in portland cement by means of optical microscope and powder X-ray diffraction, and presented 7 reports to the Journal. They are Part I, Vol. 45, No. 533, pp. 279-299 (1937), Part II, Vol. 45, No. 534, pp. 361-373 (1937), Part III, Vol. 45, No. 535, pp. 433-446 (1937), Part IV, Vol. 45, No. 537, pp. 614-631 (1937), Part V, Vol. 45, No. 540, pp. 880-896 (1937), Part VI, Vol. 46, No. 541, pp. 12-20 (1938), and Part VII, Vol. 46, No. 542, pp. 66-76 (1938). The ferrite phase in portland cement is known to be crystallized from molten liquid containing CaO, Al2O3, Fe2O3, and SiO2 together with calcium alminate phase. It was concluded, in the last report of the series, that the composition of calcium almino-ferrite was 6.2CaO:2.2Al(2)O(2) :Fe2O3 when Al2O3/Fe2O3 ratio of starting mix exceeded 1.4 in the ternary system CaO-Al2O3-Fe2O3, and that the addition of SiO2 had no effect on the ferrite composition. The calcium alumino-ferrite was called celite, similarly to alite and belite, and it was supposed to be a compound with the composition of 4CaO:Al2O3:Fe2O3. The author found it possible to prepare ferrite phase with any composition in the solid solution series between 2CaO:Fe2O3 and 6.2CaO:2.2Al(2)O(2):Fe2O3, or Cat (AlxFe1-x)(2)O-0 where 0<x<0.7, for the first time. And all text books in cement chemistry show the phase equilibrium diagram as Fig. 1. In addition to the micro-structure observation with optical microscope, crystalo-chemical consideration based on X-ray diffraction determination was applied, and the research out put has contributed not only to ceramic science and but also practical cement technology to a great extent till now, in ceramic held including cements, refractories, and so on. The contribution of the author to ceramics field spread in wide range and extra-ordinal. One of those is the introduction of powder X-ray diffraction technique to ceramic research. It was really hard for him to assemble X-ray apparatus for himself and find his way to analyze experimental results. He started to evacuate the tube in the morning, and the X-ray experiment was continued through night. But, today, it is one of the most popular and important tool for ceramists, we depend strongly on him today and in future. Explanatory article can be seen at Vol. 41, pp. 251-259 (1933), showing illustration of X-ray tube at that time as Fig. 2. And the earliest research report, Vol. 42, pp. 313-322 (1934), is on calcium aluminate, as an out put from fundamental research on castable refractory.