New method of measuring the reaction heat and Formation of mullite.
Applying the principle of the thermal conduction, the writer devised an apparatus of measuring the reaction heat by which the reaction velocity between Al₂O₃ and SiO₂ is studied. Mullite is formed from the mixture of Al₂O₃ and SiO₂ powder at above 750°C and this activation energy is about 40 Kcal/mol.

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[in Japanese]

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[in Japanese]

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[in Japanese]

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Several kinds of orucibles obtained from the market and special markers were tested for the corrosion on the synthetic phlogopite melt.
High aluminous grog crucibles were attacked easily by the melt. The melt penetrated through pores of the wall and reacted with the soft bond and the perifery of the grog particles. A loose layer of spinel octahedrons was formed along the wall of crucible as the reacion product. The corundum orystals grew larger, when they contacted with the melt. These crucibles could not be used for a slow cooling experiment.
Roseki (Agalmatolite) crucible was attacked from the surface. Spinel crystals produced were scattered in the melt. Small amount of forsterite needles and hexagonal skeleton crystals were formed, too. The latter were estimated to be cordierite crystals from their optical properties.
Sintered corundum crucible stood to a heavy duty. It was attacked gradually from the surface. A reaction layer of spinel crystals and glass was formed along the wall. Many round pores were found in the layer.
“Magnite” crucibles were prepared specially by KUROSAKI YOGYO K.K. from calcined dunite and magnesite. It was composed of forsterite crysttals and a small amount of periclase, small particles of iron conpound, glassy matter and many pores. The melt penetrated through the wall and reacted with the matrix. The olivine crystals were not affected.
Among the above mentioned crucibles, only the sintered corundum crucible can be used for a slow cooling experiment.
Artificial graphite crucibles were used conveniently for the non-wetting property for the melt. But the carbon made the atmosphere to be reducing and accelerated the evaporation loss of the components of the melt The solidified mass was colored light gray. Electro-plated chromium lining prevented the reduction somewhat
Hard porcelain crucible was attacked largely, The solidified mass became very hard and diffioult to split off mica crystals.

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[in Japanese]

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The authors reported the physical properties of special high aluminous cement prepared by heating raw mixture of alunite-limestone, alunite-calcium, carbonategypsum at 1000°C in the electric furnaoe. That cement is very interesting in chemical Composition and it's setting time is shorter than normal portland Cement, it's color is cream or faint pink.

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