The reaction processes of hydrazine intercalation in dickite and kaolinite were examined under various reaction temperatures and concentrations of hydrazine. The intercalated clay samples were ground in hydrazine solutions of the minimum concentrations to retain the previous extent of intercalation. The grinding characteristics were compared with those of non-intercalated materials. The extent of intercalation was evaluated from the ratio of the two peak intensities (I_10.41Å/I_7.16Å+I_10.41Å) in X-ray diffraction.
The results obtained are summarized as follows.
1) The dickite and the kaolinite showed maximum intercalation, so far tested, reaching 90% in the aqueous solution of 15.6mol concentration of hydrazine at 25°C after 24 hrs. The kaolinite exhibited greater rate of intercalation and somewhat larger difficulty for the removal of intercalated hydrazine molecules than the dickite, suggesting that the rate of intercalation depends primarily on stacking disorder rather than grain size.
2) The efficiency of wet-mill-grinding for intercalated dickite was 4-5 times larger than that of non-intercalated sample, whereas no notable effect of the intercalation on grinding efficiency was detected with the kaolinite.
3) The observation of particle shapes of the intercalated ground materials revealed no distinct predominant delamination. However, the density of negative charge of intercalated dickite diminished much more drastically as grinding proceeds than the nonintercalated sample, which might indicate predominant creation of basal planes having no or fewer negative charges.

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Various chromium compounds were added into zircon up to 5 wt% in order to investigate their effects on sintering and dissociation of zircon after firing at 1500°C and 1600°C.
Corrosive resistances of fired products containing their chromium compounds for pouring pit refractories was studied.
Na₂Cr₂O₇⋅2H₂O, Fe₂O₃⋅4CrO₃⋅H₂O, Fe₂O₃-Cr₂O₃ solid solution, Fe₂O₃ and Cr₂O₃ equimolecular mixture and Masinloc chromite promoted sintering of zircon. MgO⋅Cr₂O₃, (CrO₃+MgO) aq., CaO⋅Cr₂O₃, (CrO₃+1/2 CaO) aq., FeO⋅Cr₂O₃, Fe₂O₃-3Cr₂O₃ solid solution, ferrochrome oxide and {CrO₃+Fe(OH)₃} aq. promoted slightly it. But Cr₂O₃, amorphous Cr₂O₃, CrO₃, CrPO₄⋅2H₂O, ferrochrome and {CrO₃+Cr(OH)₃} aq. did not to promote sintering of zircon.
Among the chromium compounds which promoted sintering of zircon, Na₂Cr₂O₇⋅2H₂O promoted dissociation of zircon, and CaO⋅Cr₂O₃, (CrO₃+1/2 CaO) aq. and Masinloc chromite did slightly. The others did not.
Concerning the corrosive resistance of their fired products, Cr₂O₃, CrO₃, MgO⋅Cr₂O₃, (CrO₃+MgO) aq., CaO⋅Cr₂O₃ and (CrO₃+1/2 CaO) aq. improved it, but Fe₂O₃-Cr₂O₃ solid solution and Masinloc chromite increased penetration of slag.
Conclusively, zircon brick added a little amount of both Cr₂O₃ and (CrO₃+MgO) aq. or (CrO₃+CaO) aq. had lower apparent porosity and better corrosive resistance.

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Thermal properties and thermal fracture on the typical two kinds of clays of the roofing tile bodies i. e. chloritic “Awaji” roofing tile clay body and kaolinitic “Akashi” roofing tile clay body were studied at temperatures of 300° to 700°C.
Thermal properties observed were as follows: exo- and endothermal phenomena on heating, heating weight loss, thermal expansion, bulk density, specific heat, thermal diffusivity, thermal conductivity, modulus of rupture and elasticity, and heat transfer coefficient. They were characteristic of dehydration of the clay minerals and quartz transformation.
Assuming that a roofing tile body was a infinite slab of 1.6cm thickness, maximum safe heating or cooling rate “φ_max” on the uniform heating or cooling and temperature difference causing fracture “ΔT_f” were calculated from the following equations.
φ_max(heating)=6σ_f(1-ν)k/Eαγ_m²
φ_max(cooling)=φ_max(heating)/2
ΔT_f=3.25λσ_f(1-ν)/Eαγ_mh
φ_max values gave the safe firing schedules. φ_max and ΔT_f values showed that care must be taken in a firing of clay bodies between 500° and 600°C, especially around 560°C.

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A study was made on the compositions and amounts of gases desorbed from BeO powders in the temperature range between 200° and 1100°C and the adsorption isotherms of water at 25°C on the powders which had been pretreated at 600°, 800° and 1000°C. The BeO powders were obtained by calcination of sulfate. These measurements showed that the BeO powders were changed in the surface structure or surface state as the calcination temperature was raised and the following conclusions were obtained from the present study.
1) The BeO powders, calcined at lower temperature, adsorb or absorb SO and SO₂ and are disordered in their surface structure. The structure are sensitive to the pretreatments.
2) The amounts of gases desorbed from S₉₀₀ BeO and S₁₂₀₀ BeO in the temperature range between 800° and 1000°C are much more than those between 600° and 800°C. The amounts of SO and SO₂ desorbed from S₉₀₀ BeO and those of CO and CO₂ desorbed from S₁₂₀₀ BeO increase from 800°C, reach maximum at about 900°C and then decrease with increasing outgassing temperature.
3) The surface structures are more ordered with the calcination temperature to about 1000°C but above this temperature they become again disordered, particularly at 1200°C.
4) The monolayer capacities of physisorbed water are not affected by the calcination temperature.

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Several observations of the corrosion of chrome-magnesite and magnesite-chrome refractories by sodium carbonate vapor at 1200°C are described. One of the cause of the corrosion was that chrome ore being the main constituent mineral of these refractories was subjected to attack of sodium carbonate vapor. It was found that, at the early stage of the corrosion process, the grains of chrome ore decomposed into periclase and some compound to be expressed by following formula;
Na_2x (Si_1-x, X_x) O₂-Na_y(Si_1-y, Y_y)O₂ s. s.
(2/5≤x≤1/2, 1/2≤y≤1, X: Mg²⁺, Fe²⁺, Y: Al³⁺, Cr³⁺, Fe³⁺)
The compound was considered to have the derivative structure of cristobalite as well as carnegieite. As the supply of sodium carbonate vapor was continued, the compound changed into periclase and Na₂CrO₄.

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To survey the author's method for calculating the packed volume of multi-component particle-size systems, the various equations for particle-size grading model for refractory batches were discussed and new model were derived.
Employing the author's calculating method, the volumes of bodies packed by moulding method with stick penetration of magnesia clinker mixes, and the volume of bodies packed by press moulding of magnesia clinker mixes, were calculated.
From the results, it was shown that the particle-size compositions or particle-size distributions of closest packing were in good agreement with tendency for those of observations, but the calculated values of packed volume were not agreed with observations.
It was found that, however, the agreement could be achieved by the modification with values as function of number of components and the amount of finest-size component or grading systems coefficient.
And the suitable grading model for refractory batches were discussed.

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The thermal conductivity of AIN was measured by the modulated electron beam technique at high temperatures. The specimens for measurement had different oxygen impurity content of 0.94 wt% to 4.4₉ wt%. The result shows no apparent correlation between the oxygen content and the thermal conductivity. The values of measured thermal conductivity of AIN are about two times higher than that of previous measurements and are comparable with that of Taylor and Lenie. 2 figs., 1 table, 6 refs.

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Formation of Li-O-Li bond in Li₂O⋅xSiO₂ (x=2 or 2.5) glasses obtained through a particular melting process was confirmed. The glasses were prepared by rapid quenching or slow cooling from a given temperature above the liquidus at which the melts were held for an hour after refined at 1450°-1500°C for several hours.
Two characteristic absorption peaks near 1480 and 1430 cm^-1 are found only in the IR spectra of the samples obtained by rapid quenching from a temperature above ca. 1250°C. These peaks were attributed to Li-O-Li bond formed in the glasses. Formation of Li-O-Li bond in the glasses are explained in terms of the dissociation equilibrium in the melts at high temperatures. 1 fig., 2 refs.

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