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AssigneesMitsui Mining & Smelting Co., Ltd., Tokyo Kokyu Rozai Co., Ltd.
InventorsHiroshi Uchiyama, Kazunobu Kakimoto, Yoshio Fujiwara, Shigeru Yamagishi, Junshiro Hayakawa
Estimating the term…
A filter medium which permits an increased amount of filtration. The filter medium can be prepared by blending 100 parts by weight of aggregate particles, 5-18 parts by weight of an inorganic bonding material having a chemical composition of about 10-50% by weight of SiO.sub.2 and about 5-20% by weight of B.sub.2 O.sub.3 and containing at least 70% by weight of a non-vitreous substance such as talc or boric acid, and about 3-15 parts by weight of a combustible substance such as wheat flour, kneading the mixture with a caking material and water, molding the kneaded mixture, drying it, and then calcining the dried mixture at a temperature not lower than about 1100.degree.C. The size and number of the air-permeable pores in the filter medium can be controlled by adjusting the amounts of the bonding material and combustible substance.
A filter medium which permits an increased amount of filtration and having a grade number of about 100 to about 300, a bulk density of about 1.70 to about 2.27 and an apparent porosity of about 39.0 to about 51.0%, said filter medium being prepared from starting materials comprising
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