著者

石堂 善彦 藤井 欽二郎

出版者

公益社団法人 日本セラミックス協会

雑誌

窯業協會誌 (ISSN:00090255)

巻号頁・発行日

vol.81, no.931, pp.115-117, 1973-03-01 (Released:2010-04-30)

参考文献数

5

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Fused magnesia and magnesia clinker which were pulverized to such a fineness as shown in Table 1, were proven to react rather readily with glacial acetic acid at a temperature from 20° to 65°C. When the fractions of magnesia reacted were followed at each constant temperature by determining magnesium acetate formed in the reaction mixture which was soluble in methanol, the reactions proceeded after Jander's rate-equation except later reaction-stage as shown in Fig. 1 with an apparent activation energy of 21.8kcal/mol, though any diffusion layer didn't be observed around magnesia grains under microscope. In a semi-adiabatic condition, the temperature of the mixture should rise owing to the heat of reaction, resulting in acceleration of the rate of reaction more and more to cause the mixture to boil. These situations were examined at an initial temperature from 30° to 60°C. The results were shown in Fig. 3 in comparison with those obtained by numerical calculation using the rate data at constant temperatures and heat contents of the matters concerning to the reaction system.

著者

藤井 欽二郎 石堂 善彦

出版者

公益社団法人日本セラミックス協会

雑誌

窯業協會誌 (ISSN:18842127)

巻号頁・発行日

vol.73, no.832, pp.13-16, 1965-01-01

被引用文献数

1

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高温における純シリカゲルの変化を再検討した. テトラエチルオルソシリケートから調製した微粉状シリカゲル (I) を圧縮成形してつくった円板は, 石英ガラス容器中, 約1150℃の加熱でガラス化して半透体になる. 白金容器中では, このゲルはクリストバライトに変りやすい. 4塩化珪素を加水分解して塊状に乾燥したシリカゲル (II) は, 上記より多少低温, 1050℃で透明になり, 1100℃では, 少量成分おそらく内包された水分を放出してポッピングを起し始める.

著者

野村 勁 藤井 欽二郎

出版者

公益社団法人日本セラミックス協会

雑誌

窯業協會誌 (ISSN:18842127)

巻号頁・発行日

vol.77, no.888, pp.271-277, 1969-08-01

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The weight loss in nitrogen atmosphere of compact mixed powders of MgO and carbon at temperatures 1400°-1800°C was followed thermogravimetrically.<br>At any given temperature, the reaction proceeded as a first order reaction (activation energy, 43.8kcal/mole) in an early stage, and zero order reaction followed (53.8kcal/mole). It is considered that the zero order reaction is the characteristic of the reaction of this system, and it will be explained as the effusion of gas evolved in the compact from the surface pores at constant rate (1.3mg⋅cm^-2⋅min^-1 at 1700°C) irrespective of mixing ratio, shaping pressure, or sample weight. The partial pressure of gas in the compact was obtained from the Knudsen effusion equation. For 1700°C, 4.24×10^-6 atm was found, and it corresponds to the vapor pressure of MgO at the same temperature.

著者

藤井 欽二郎

出版者

公益社団法人日本セラミックス協会

雑誌

窯業協會誌 (ISSN:18842127)

巻号頁・発行日

vol.73, no.841, 1965-09-01