Abstract: 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.

Abstract: A high temperature resistant filtration material is produced having outer layers of a nonwoven fabric made of fibers of an aromatic polyamide having repeating units of the formula ##SPC1##A first inner layer of nonwoven fabric made of glass fibers and a second inner layer woven from yarns of glass or said aromatic polyamide. The fibers of the layers are interentangled by needling to form an integral structure.

Abstract: A molded material comprising CaCO.sub.3 and/or MgCO.sub.3 is made and used as a reaction bed through which carbonated water is run to make mineral water.