Mitsubishi Chemical Industries Limited

Junji Saito

Yasuo Oguri

Naoto Kijima

Mitsuo Uchida

Mitsuru Awata

Tsukasa Kawahara

Soichi Inoue

Takeshi Okano

Kunichi Matsushita

Noriyuki Ariyama

Mitsunobu Abe

Takao Kaneko

Tatsuo Andio

A boehmite having an orthorhombic crystal form in which the ratio of the maximum length in the direction of the a-axis of the crystal to the distance between the opposing crystal faces perpendicular to the c-axis of said crystal is at least 10, said maximum length in the direction of the a-axis of the crystal is at least 2500 .ANG. and said distance between the opposing faces perpendicular to the c-axis of said crystal is 250-900 .ANG..

Boehmite

A boehmite having a crystal form wherein the ratio of the maximum length in the direction of the a-axis to the distance between the opposing crystal faces perpendicular to the c-axis is at least 10.

A process for producing a boehmite shaped product comprises slurrying a mixture of a gibbsite powder and at least one powder selected from the group consisting of powders of pseudo-boehmite, amorphous aluminum hydroxide, alumina cement and .rho.-alumina, molding the slurry thereby obtained and subjecting the molded product to hydrothermal treatment.

Process for producing a boehmite shaped product and a burned boehmite

A process for preparing a calcium silicate shaped product comprises heat-reacting a calcareous source and a siliceous source dispersed in water to obtain an aqueous slurry containing a calcium silicate hydrate having a molar ratio of CaO/SiO.sub.2 being more than 1, adding a siliceous source to the aqueous slurry to bring the molar ratio of CaO/SiO.sub.2 to a level of from 0.85 to 1, and pressfilter-molding the aqueous slurry thereby obtained, followed by steam-curing and drying.

Process for preparing a calcium silicate shaped product

A calcium silicate shaped product is produced by forming an aqueous slurry of calcium silicate hydrate obtained by reacting a calcareous source with a siliceous source dispersed in water under heating; molding said aqueous slurry and heat-treating said molded product under the condition providing the equations (I) and (II);

Process for preparing calcium silicate shaped product

An aqueous slurry of calcium silicate hydrate which is formed by heating a siliceous source and a calcareous source in water to react them and which has the specific property is shaped with a press filter molding and cured by a steam curing under steam pressure to cause a transformation of the calcium silicate hydrate whereby a calcium silicate shaped product having low bulk density and high mechanical strength is obtained. The calcium silicate shaped product is suitable as a lagging product or a heat insulator.

Nitrogen oxides in exhaust gases are catalytically reduced in the presence of oxygen and ammonia at 200.degree. to 600.degree. C. over a catalyst of at least one catalyst component selected from the group consisting of compounds of metals of Groups 1B, 5A, 6A, 7A and 8 of the periodic table, and lanthanides and tin which is supported on a specific carrier comprising a main component of calcium silicate.

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Machida, Japan

Junji Saito