Saint-gobain Tm K.k.

Toshiba Monofrax Co., Ltd.

Toshiba Ceramics Co., Ltd.

Yasuo Misu

Hiroshi Sugiyama

Itaru Hashimoto

Toshimitsu Kuboki

Shigeo Endo

Mikiya Fujii

Shuitsu Matsuo

Kimio Hirata

Shinji Tsuchiya

Hidenori Yamaoka

Nobuo Tomura

Hiroaki Kotaka

Haruo Kawashima

Akira Itoh

Fumio Tokuoka

Keiji Morita

Hiroyuki Terada

Koya Abe

Masahiro Ando

Kazuhide Kawai

Makoto Takahashi

The present invention provides a high alumina fused cast refractory that is easily produced and has low porosity and high corrosion resistance, and a method of producing the same. The high alumina fused cast refractory of the present invention has the following chemical composition: 95.0 mass % to 99.5 mass % AlO, 0.20 mass % to 1.50 mass % SiO, 0.05 mass % to 1.50 mass % BO, 0.05 mass % to 1.20 mass % MgO and balance. The method of producing the high alumina fused cast refractory of the present invention includes obtaining a mixture by mixing an AlOsource material, a SiOsource material, a BOsource material and an MgO source material, and fusing the mixture.

High alumina fused cast refractory and method of producing same

A high zirconia electrically fused cast refractory having long time durability with less cracking during production and in the course of temperature rising, excellent in productivity, less forming zircon crystals in the refractory itself and even in contact with molten glass, excellent in bubble foamability to molten glass, less generating cracks even undergoing heat cycles during operation of a glass melting furnace. A high zirconia electrically fused cast refractory comprises, as chemical component, 85 to 95% by weight of ZrO, 0.4 to 2.5% by weight of AlO, 3.5 to 10.0% by weight of SiO, 0.05% by weight or more of NaO, 0.05 to 0.7% by weight of NaO and KO in total, 0.01 to 0.04% by weight of BO, 0.1 to 3.0% by weight of SrO or BaO when one of BaO and SrO is contained, 0.1% by weight or more of SrO and 0.1 to 3.0% by weight of SrO and BaO in total when both of BaO and SrO are contained, 0.01 to 0.2% by weight of CaO, 0.1% by weight or less of MgO, 0.01 to 0.7% by weight of SnO, 0.3% by weight or less of FeOand TiOin total, less than 0.01% by weight of PO, and less than 0.01% by weight of CuO.

High zirconia electrically fused cast refractory

A high zirconia electrically fused cast refractory of high electric resistance having long time durability, less suffering from cracking during production and upon temperature rising, excellent in productivity, less forming zircon crystals even upon heating the refractory in itself and when the refractory is in contact with molten glass, generating less cracks even when undergoing heat cycles during operation of a glass melting furnace is provided. A high zirconia electrically fused cast refractory has, as chemical components, 85 to 95% by weight of ZrO, 0.1 to less than 0.8% by weight of AlO, 3.5 to 10.0% by weight of SiO, less than 0.05% by weight of NaO and KO in total, 0.1 to 1.5% by weight of BO, 0.1% by weight or less of MgO, 0.01 to 0.2% by weight of CaO, in the case where any one of BaO and SrO is contained, from 0.05 to 3.0% by weight of BaO or 0.01 to 3.0% by weight of SrO, or in the case where both of them are contained, 0.01% by weight or more of SrO and from 0.01% to 3.0% by weight in total of SrO and BaO, 0.1 to 0.7% by weight of SnO, 0.3% by weight or less of FeOand TiOin total, less than 0.01% by weight of PO, and less than 0.01% by weight of CuO.

[Problems] To provide a high zirconia fused cast refractory that suffers less cracks in production and on heating, has excellent productivity, is hard to form zircon crystals with the refractory solely and under conditions where the refractory is in contact with molten glass, is hard to suffer cracks on receiving heat cycles in operation of a glass melting furnace, and has durability for a prolonged period of time. [Solution to Problems] A high zirconia fused cast refractory containing, as chemical components, from 85 to 95% by weight of ZrO, from 0.4 to 2.5% by weight of AlO, from 3.5 to 10% by weight of SiO, from 0.05 to 1% by weight in total of NaO and KO, more than 0.04% by weight and 1% by weight or less of BO, 0.02% by weight or less of PO, 0.05% by weight or less of MgO, from 0.01 to 0.2% by weight of CaO, in the case where any one of SrO and BaO is contained, from 0.3 to 3% by weight of SrO or more than 0.5% by weight and 3% by weight or less of BaO, and in the case where both of them are contained, 0.3% by weight or more of SrO and from 0.3 to 3% by weight in total of SrO and BaO, from 0.01 to 0.7% by weight of SnO, and 0.3% by weight or less in total of FeOand TiO.

High zirconia fused cast refractory

A high-zirconia cast refractory material which contains 85-95 wt % of ZrO, 4-12 wt % of SiO, 0.1 to less than 0.8 wt % of AlO, less than 0.04 wt % of NaO, 0.01-0.15 wt % of KO, 0.1-1.5 wt % of BO, 0.01-0.2 wt % of CaO, less than 0.4 wt % of BaO, less than 0.2 wt % of SrO, 0.05-0.4 wt % of YO, and 0.3 wt % or less of FeOand TiOtogether, but does not substantially contain CuO and PO(less than 0.01 wt %), such that the molar ratio of the glass-forming oxides (such as SiOand BO) to the glass-modifying oxides (such as NaO, KO, CaO, MgO, SrO, and BaO) is 20-100, said refractory material having an electric resistance being 200 &#x3a9;&#xb7;cm or higher after standing for 12 hours at 1500&#xb0; C.

High-resistance high-zirconia cast refractory material

A crystalline inorganic fiber or molded body thereof is thermally treated in gas atmosphere containing chlorine. The crystalline inorganic fiber or molded body thereof contains small impurities such as Fe, Cu and Ni. For example, Fe is 15 ppm or less, Cu is 1 ppm or less, and Ni is 0.5 ppm or less.

High-purity crystalline inorganic fiber, molded body thereof, and method of production thereof

Disclosed is a method of manufacturing aluminum nitride, which comprises the steps of preparing a mixed gas consisting essentially of an ammonia gas and at least 0.5% by volume of a hydrocarbon gas, calcining .gamma.-Al.sub.2 O.sub.3 or a precursor thereof at 300.degree. to 1,100.degree. C. so as to prepare the .gamma.-Al.sub.2 O.sub.3 having a moisture content of 1 weight % or less; heating the calcined .gamma.-Al.sub.2 O.sub.3 in the mixed gas at a temperature of 1,200.degree. to 1,700.degree. C., thereby preparing porous aluminum nitride having a specific surface area of 10 m.sup.2 /g or more; and heat-treating the porous aluminum nitride in an atmosphere of an ammonia gas, or a mixed gas of an ammonia gas and an inert gas, at 1600.degree. to 2000.degree. C., so as to make contents of both carbon and oxygen contained in the aluminum nitride 1 weight % or less.

Method of manufacturing aluminum nitride

A molten fiber material flow is rendered into a plurality of fibers by means of a liquid jet such as water jet in place of a pressurized gas or air. The flow moves downwardly in a vertical direction while the water jet cuts it at an inclined angle. The water jet is formed by a single nozzle or plural nozzles of a flat-jet or round-jet type.

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Tokyo, Japan

Yasuo Misu