Abstract: Refractories obtained by molding a refractory raw material composition containing a refractory raw material including graphite grains having an average grain size of 500 nm or less or a refractory raw material including graphite grains obtained by graphitizing carbon black and a refractory filler. Or refractories containing carbonaceous grains (A) selected from carbon black or graphite grains obtained by graphitizing carbon black and having a DBP absorption (x) of 80 ml/100 g or more, carbonaceous grains (B) selected from carbon black and graphite grains obtained by graphitizing carbon black and having a DBP absorption (x) of less than 80 ml/100 g, and a refractory filler. Refractories excellent in corrosion resistance, oxidation resistance and thermal shock resistance, especially carbon-contained refractories having a low carbon content are thereby provided.

Abstract: Disclosed is a monolithic refractory comprising 1 to 30 weight parts of pitch having 65 to 90 wt.-% of fixed carbon and a softening point of 250.degree. to 350.degree. C. to form a carbon bond, relative to 100 weight parts of refractory material so as to form carbon bond. The monolithic refractory can contain 0.01 to 0.5 weight parts of carbon fiber. The composition of the invention may be used as any type of monolithic refractory such as gunning material, casting material, in particular, aqueous type casting material, burning type hot repairing mix, mortar, Tamping material, and any basic, neutral, or acid refractory material may be used. The monolithic refractory is capable of solving the drawbacks of the conventional monolithic refractories such as rupture, lack of low shrinkage, low bonding strength, low hot strength, and having both superior strength and superior applicability.

Abstract: The present invention relates to an injection material for the hot repairing of a blast furnace and an injection method of applying the same. An injection material comprising a refractory material, which was previously adjusted in particle size, a binder, a hardening agent and a hardening-accelerator is fed to a pressure pump having a mixing function and applied to a portion to be repaired of a blast furnace with mixing in said pump. Thus, since the hardening ingredient is not added until the pump portion, the workability of the repair material can be secured in of a blast furnace to be repaired, said injection material being mixed in said pump. Thus, the injection repairing of the blast furnace can be achieved without being influenced by an atmosphere within the furnace.

Abstract: Glass ceramics used as dental material, artifical bone, etc. which contain 0.01 to 25 parts by weight of alkali metal oxides (R.sub.2 O), such as Li.sub.2 O, Na.sub.2 O, K.sub.2 O, Rb.sub.2 O, and Cs.sub.2 O, in 100 parts by weight of CaO-Al.sub.2 O.sub.3 -P.sub.2 O.sub.5 system material. During the casting for obtaining the glass ceramics, the molten fluid is sufficiently distributed to the fine corners of a mold, and the temperature for crystallization is low. Also, the time required for the crystallization is short and the crystalline formed shows no internal defects, and has high bending strength.

Abstract: Long potassium titanate fibers (100-3000 .mu.m) made by heat reaction in gas permeable calcination vessel, made of material containing at least 25 wt %, preferably at least 50 wt %, MgO to prevent plugging of the vessel during the reaction and maintain gas permeation.

Abstract: Calcium phosphate glass-ceramics of high strength and toughness is disclosed. These materials are excellent for artificial dental or bone materials. The strength and toughness of these materials are improved substantially in comparison with conventionally used calcium phosphate glass-ceramics by adding rare earth oxide in them. For dental materials, good aesthetic appearance to natural teeth is also obtained by adding one type, or two or more types of compounds selected from oxides of iron, manganese, cerium, titanium, nickel, zinc, cobalt, tungsten, chromium, and vanadium as color component. Also, if necessary, Al.sub.2 O.sub.3 and/or SiO.sub.2 is contained as coloring assistant agent in that composite. Moreover it is possible to adjust the color tone of each individual's teeth. The rare earth oxide, coloring component, and coloring assistant agent added are incorporated in crystals of calcium phosphate. Consequently, they cause no elution during use.

Abstract: Dental materials using calcium phosphate glass-ceramics and having the color tone with high approximation to that of natural teeth. In those dental materials, calcium phosphate composite, nickel oxide and one or more other type of compounds selected from oxides of iron, manganese, cerium, titanium and tungsten, are contained as coloring component. Also, if necessary, Al.sub.2 O.sub.3 and/or SiO.sub.2 is contained as a color assisting agent in that composite. The calcium phosphate glass-ceramic according to this invention consists of the same components as that of natural teeth. Besides, it is possible to adjust the color tone delicately to match with the color tone of each individual`s teeth. Moreover, the coloring components are incorporated in crystals of calcium phosphate. Consequently, they cause no elution during use and are therefore ideal as dental material.

Abstract: The present invention relates to silicon nitride composite refractories having silicon nitride bonds therein and having an increased thermal shock-resistance, an improved molten steel-resistance and an improved mechanical strength, which consists of silicon nitride at 20 to 60 wt %, refractory materials at 10 to 50 wt % and boron nitirde at 1 to 30 wt %, or additionally carbon fibers of 0.5 to 10 wt %. The above described characteristics can be realized because the silicon nitride bonds are bonding structures.

Abstract: A forsterite-carbon refractory containing forsterite material, carbonaceous material, silicon carbide and magnesia refractory material.

Abstract: The invention relates to carbon-bonded magnesia carbon bricks for use in converters, ladles, ladle refinery, mixing cars, mixing furnaces, etc., and the method for obtaining such carbon-bonded magnesia carbon bricks having high properties in respect of resistance to thermal and structural spalling, slag resistance, thermal strength, shock resistance, etc. thereby enabling to conform to the gradually intensified operational conditions of said converters and the like by means of 60-97 weight % sintered magnesia clinker of bulk specific gravity above 3.40, 3-40 weight % carbonaceous material and a carbon-bonding formative agent.

Abstract: Fibrous compounds having a ratio of length to diameter of at least 10 of the formula MO.TiO.sub.2 wherein M is a bivalent metal and processes for preparing these compounds are described. Preferably M is selected from the group consisting of barium, strontium, calcium, magnesium, cobalt, lead, zinc, beryllium, and cadmium. The processes for preparing the compounds utilize fibrous potassium titanate hydrates or fibrous titanium dioxide hydrates both having a ratio of length to diameter of at least 10 as the starting material to prepare the compounds.

Abstract: A novel noncrystalline fibrous potassium titanate and a process for preparing said titanate fiber by calcination of a mixture of potassium compound(s) and titanium compound(s) at a temperature of from 800.degree. C. to the melting point of the mixture to obtain whiskers formed on the surface thereof; and an improved process for preparing fibrous potassium hexatitanate which comprises calcining hydrated fibrous potassium titanate at a temperature of 500.degree. to 900.degree. C. or which comprises kneading a mixture of potassium compound(s) and titanium compound(s), and calcining the thus kneaded mixture at a temperature of 1150.degree. to 1300.degree. C. to obtain fibers from the inside of the bulk of the calcined mixture are described.

Abstract: Disclosed is a substance which is obtained by coating the surface of a specific iron-containing substance, through a specific procedure, with a material composed mainly of aluminum sulfate. The substance thus produced is useful as a catalyst for the removal of nitrogen oxides from an exhaust gas.

Abstract: An excellent catalyst for the reduction of nitrogen oxides is obtained by mixing a specific aluminum-containing substance with a specific iron-containing substance in water and baking the resultant precipitate.

Abstract: Disclosed is a substance which is obtained by calcining an iron hydroxide or a water-containing iron oxide and coating the surface of the resultant calcined product with alumina. This substance is useful as a catalyst in the removal of nitrogen oxides from an exhaust gas containing the nitrogen oxides.

Abstract: An alumina-chrome refractory composition comprises 30-60% by weight of alumina-silica type material containing 50-95% by weight of alumina with the major part in coarse particle size, and 70-40% by weight of chrome type material with the major part in fine particle size. In a modification, the alumina-chrome refractory composition comprises 70-99% by weight of a mix consisting of the alumina-silica type material and chrome type material in the above percentages, and 1-30% by weight of at least one of the materials selected from the group consisting of alumina, zircon, zirconia, magnesia, spinel, clay, silicon carbide and titanium oxide in fine particle size ranges.