Kawatetsu Mining Co., Ltd.

Kawasaki Steel Corporation

Kawasaki Mining Co. Ltd.

Kawatetsu Minig Co., Ltd.

Yoshio Aso

Hidefumi Konnai

Atsushi Nakamura

Tadao Shimizu

Akira Seki

Fumio Sudo

Yuuki Narita

Shunro Nagata

Kunihiko Ishizaka

The potassium titanate of the present invention comprises particles of a diameter of 3 &mgr;m or less and a length of 5 &mgr;m or more with a ratio of the length to the diameter of 3:1 or more, at a content in number of 3% or less, with no hazardous particles contained therein from the respect of health and hygiene. The potassium titanate can be produced by heating a Ti source and a K source as the raw materials to a final TiO,:K,O ratio of 5.5:1 to 6.5:1 at a temperature elevation rate of 20&deg; C./min in the temperature region above 800&deg; C.

Non-fibrous potassium titanate and method for producing the same

The potassium titanate of the present invention comprises particles of a diameter of 3 .mu.m or less and a length of 5 .mu.m or more with a ratio of the length to the diameter of 3:1 or more, at a content in number of 3% or less, with no hazardous particles contained therein from the respect of health and hygiene. The potassium titanate can be produced by heating a Ti source and a K source as the raw materials to a final TiO.sub.2 :K.sub.2 O ratio of 5.5:1 to 6.5:1 at a temperature elevation rate of 20.degree. C./min in the temperature region above 800.degree. C.

Potassium titanate substantially free of respirable fibers and method

Whiskers having a diameter of 0.1-10 .mu.m and a length of 5-200 .mu.m are pelletized and granulated into agglomerates which have a size of 0.1-10 mm and a bulk density of 0.2-1.0 kg/liter. To pelletize, powders of whiskers are moistened with water while mixing to form primary aggregates. Then, the powders and the primary aggregates are subjected to a rolling movement to cause the primary aggregates to grow into secondary aggregates having desired size distribution. Finally, the secondary aggregates are dried to obtain pelletized or granulated agglomerates of whiskers. Handling of whiskers is facilitated because the agglomerates are less bulky and less likely to fly up in the air. When blended into molding materials for fiber reinforcement, however, the agglomerates are readily disintegrated back into separated individual fibers to provide homogeneous dispersion.

Method of making agglomerate of whiskers or short fibers

Agglomerate of whiskers or short fibers

This invention concerns a process for purifying silica produced from an alkali silicate aqueous solution, which usually contains more than 200 ppm of impurities, to silica containing less than 30 ppm of impurities. Concretely, the purification process of silica comprises: dispersing silica gel, containing a lot of impurities, in water and filtering the solution; dispersing the filtered out silica gel again in an aqueous solution of pH 2 or less and filtering the aqueous solution; putting the silica gel to heat-treatment and acid-treatment with continuous stirring in order to break the inside siloxane link and dissolve out impurities therefrom and filtering the acid solution; rinsing a produced cake with pure water to wash away the inside residual solution and drying the cake.

Process for purifying silica

A method of stabilizing a steel making slag composed mainly of dicalcium silicate is disclosed, which comprises adding a boron-containing mineral obtained by adjusting an amount of crystal water to 4-12% by weight, whereby the powdering of the slag is prevented in the cooling.

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Chiba, Japan

Yoshio Aso