Sumitomo Chemical Company, Limited

Osamu Yamanishi

Kousuke Uoe

Hidekatsu Kawazu

Keiichiro Suzuki

Seiichi Hamano

Kazuya Tsuchimoto

The method for producing a fired body of the invention has the steps of: preparing a starting material mixture; molding the mixture to obtain a green molded body; a first heating step to make the molded body contain residual carbon-containing substances in a furnace by increasing the temperature of the furnace while introducing an oxygen containing gas; and a second heating step to obtain a fired body by further increasing the temperature of the furnace without introducing the oxygen containing gas; wherein the conditions for the first heating step are set so that when the molded body is allowed to stand after the first heating step in an oxygen-containing atmosphere at 900&#xb0; C., the temperature at the center section of the molded body is at least 20&#xb0; C. higher than the temperature of the atmosphere in the furnace.

Method for producing fired body and firing furnace used therefor

A high-strength &#x3b1;-alumina formed body with a low soda content, of which pore distribution is controlled, can be provided in an easy and inexpensive manner. The &#x3b1;-alumina formed body can be produced by a method comprising calcining a gibbsite-phase aluminum hydroxide to obtain rehydratable alumina powder; forming the rehydratable alumina powder in the presence of water to obtain a formed body; maintaining the formed body in the presence of water at about 110-200&#xb0; C., to rehydrate the formed body; and calcining the rehydrated formed body at about 1200&#xb0; C. or higher. The &#x3b1;-alumina formed body is useful as a carrier for catalysts, chemicals, microbes for food leftover disposal and the like.

Method for producing &#x3b1;-alumina formed body

A spherical porous ceramic body and the production method thereof are provided. As to the porous ceramic body, the total volume of the pores having a pore radius of from 1.8 nm to 100 &#x3bc;m is about 0.25 cm/g or more, the mode of pore radius of the pores is from about 1 &#x3bc;m to about 6 &#x3bc;m and the packing density is from about 0.7 g/cmto about 1 g/cm. The porous ceramic body is suitably used as a carrier for a catalyst and has high mechanical strength.

Spherical porous ceramic body and method for producing the same

An activated alumina formed body with a high bulk density and a large macro-pore volume is provided. The activated alumina formed body can be produced by a method comprising the steps of calcining a gibbsite-phase aluminum hydroxide having a median particle size of from about 10 &#x3bc;m to about 35 &#x3bc;m and a packed bulk density of from about 1.05 g/cmto about 1.3 g/cmto obtain an at least partially rehydratable alumina powder; forming the rehydratable alumina powder in the presence of water; maintaining the formed body in the presence of water to rehydrate the formed body; and calcining the rehydrated formed body to obtain an activated alumina formed body. The activated alumina formed body is usable as an adsorbent, a catalyst supporting precious metal or the like.

Activated alumina formed body and method for producing the same

There is provided a process for the production of a transition alumina by thermally decomposing an aluminum sulfate wherein the thermal decomposition is carried out under an atmosphere comprising a reducing substance, and the transition alumina produced by the process has a specific BET surface are of not smaller than 400 m.sup.2 /g.

Process for production of transition alumina

A heat resistant transition alumina produced by mixing aluminum sulfate and a lanthanum compound, heating the mixture, and then thermally decomposing the mixture, and a process for producing the heat resistant transition alumina. The heat resistant transition alumina has a high BET specific surface area, and an excellent heat resistance as exhibiting a less reduction in the BET specific surface area even under temperatures of 1000.degree. C. or higher, and exhibits a high porosity even when coated onto other catalyst supports having a lower specific surface area, and is producibile at a lower cost.

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Niihama, Japan

Osamu Yamanishi