Abstract: A method for producing a honeycomb structure, the method comprising the steps of: kneading a forming raw material containing a cordierite forming material and then forming it to produce a honeycomb formed body; and firing the honeycomb formed body to provide a honeycomb structure. In the producing method, from 0.1 to 6.0 parts by mass of a magnesium silicate mineral having a 2:1 ribbon type structure per 100 parts by mass of the cordierite forming material is added to the forming raw material.

Abstract: A ceramic filter having a pillar-shaped honeycomb structure, wherein when observing a plurality of pores from a surface of partition walls with a laser microscope and plotting an equivalent circle diameter (?m) of each pore on an X-axis and a pore depth (?m) of each pore on a Y-axis on a two-dimensional coordinate system, a slope of a regression line (y/x) obtained by a least squares method in a range of 20?x?40 is 0 to 0.20, an average value of the pore depth of the plurality of pores is 2.5 ?m to 5.0 ?m, and a number density of the plurality of pores is 600/mm2 to 2450/mm2.

Abstract: A circumferential coating material to be applied to a circumferential surface of a honeycomb structure made of ceramics formed by extrusion, the circumferential coating material including a ceramic raw material that forms a circumferential coating layer, wherein the ceramic raw material contains: a ceramic mixture of first ceramic particles having particulate shapes, and second ceramic particles having particulate shapes and an average particle diameter different from an average particle diameter of the first ceramic particles; and a fiber material having an elongated strip-like shape, wherein the ceramic mixture has particle size distribution including at least two local maximum values, and the fiber material has an average fiber length ranging from 30 to 100 ?m in a longitudinal direction.

Abstract: A ceramic filter having a pillar-shaped honeycomb structure, wherein when observing a plurality of pores from a surface of partition walls with a laser microscope and plotting an equivalent circle diameter (?m) of each pore on an X-axis and a pore depth (?m) of each pore on a Y-axis on a two-dimensional coordinate system, a slope of a regression line (y/x) obtained by a least squares method in a range of 20?x?40 is 0 to 0.20, an average value of the pore depth of the plurality of pores is 2.5 ?m to 5.0 ?m, and a number density of the plurality of pores is 600/mm2 to 2450/mm2.

Abstract: A method for producing a honeycomb structure, the method comprising the steps of: kneading a forming raw material containing a cordierite forming material and then forming it to produce a honeycomb formed body; and firing the honeycomb formed body to provide a honeycomb structure. In the producing method, from 0.1 to 6.0 parts by mass of a magnesium silicate mineral having a 2:1 ribbon type structure per 100 parts by mass of the cordierite forming material is added to the forming raw material.

Abstract: A circumferential coating material to be applied to a circumferential surface of a honeycomb structure made of ceramics formed by extrusion, the circumferential coating material including a ceramic raw material that forms a circumferential coating layer, wherein the ceramic raw material contains: a ceramic mixture of first ceramic particles having particulate shapes, and second ceramic particles having particulate shapes and an average particle diameter different from an average particle diameter of the first ceramic particles; and a fiber material having an elongated strip-like shape, wherein the ceramic mixture has particle size distribution including at least two local maximum values, and the fiber material has an average fiber length ranging from 30 to 100 ?m in a longitudinal direction.

Abstract: A plugged honeycomb structure including particulate matter (PM) trapping layers disposed on the surfaces of the partition walls extending up to inflow side end faces of the plugging portions that plug outflow cells so that adjacent PM-trapping layers with the partition walls and the plugging portion therebetween are disposed so as to continue on the inflow side end faces of the plugging portions. The PM-trapping layers are extended up to the inflow side end faces of the plugging portions to form protruding portions having a protrusion height corresponding with 0.1 to 2 times the length of a side of the outflow cells from the inflow side end faces of the plugging portions toward the outside of the cell extension direction.

Abstract: The honeycomb filter is constructed as a diesel particulate filter having a filtration function for filtering out the particulate matter included in an exhaust emission of a diesel engine. The honeycomb filter has a honeycomb structure as a base and inlet opening cells with surface layers formed on respective inner surfaces thereof. The surface layer has zero film thickness in an inlet peripheral region. Separation vortexes are generated in the inlet peripheral regions. The zero film thickness of the surface layers in the inlet peripheral regions naturally causes non-flaking of the surface layers induced by the separation vortexes generated in the inlet peripheral regions and thereby leads to non-production of flakes. In the non-existent condition of flakes, the overall surface layers are not collapsed by collision of the flakes.

Abstract: In a plugged honeycomb structure 1A of the present invention, the PM-trapping layers 14 disposed on the surfaces of the partition walls 4 are extended up to inflow side end faces of the plugging portions 13 plugging outflow cells 3b so that adjacent PM-trapping layers 14 with the partition walls 4 and the plugging portion 13 therebetween are disposed so as to continue on the inflow side end faces of the plugging portions 13 and that the PM-trapping layers 14 extended up to the inflow side end faces of the plugging portions 13 form protruding portions 15 having a protrusion height corresponding with 0.1 to 2 times the length L of a side of the outflow cells 3b from the inflow side end faces of the plugging portions 13 toward the outside of the cell extension direction.

Abstract: The honeycomb filter 10 is constructed as a diesel particulate filter (DPF) having a filtration function for filtering out the PM (particulate matter) included in an exhaust emission of a diesel engine. The honeycomb filter 10 has a honeycomb structure 12 as a base and inlet opening cells 16 with surface layers 26 formed on respective inner surfaces thereof. The surface layer 26 has zero film thickness in an inlet peripheral region 28. Separation vortexes are generated in the inlet peripheral regions 28. The zero film thickness of the surface layers 26 in the inlet peripheral regions 28 naturally causes non-flaking of the surface layers 26 induced by the separation vortexes generated in the inlet peripheral regions 28 and thereby leads to non-production of flakes. In the non-existent condition of flakes, the overall surface layers 26 are not collapsed by collision of the flakes.

Abstract: A self-curable inorganic composition consisting of(A) an alkali silicate as a binder,(B) about 30 to about 300% by weight, based on the solids content of the binder (A), of a hardener composed of (i) 100 parts by weight of a compound selected from the group consisting of calcium sulfite and calcium thiosulfate, (ii) about 50 to about 300 parts by weight of calcium silicate, (iii) about 40 to about 300 parts by weight of zinc oxide, and (iv) 0 to about 150 parts by weight of an aluminum-containing inorganic compound selected from the group consisting of aluminum hydroxide, alumina and hydrated alumina,(C) 0 to about 20% by weight, based on the weight of the composition in the uncured state, of another additive selected from the group consisting of coloring agents, thickeners, water repellents, curing retarders, dispersants, defoamers and levelling agents, and(D) 0 to about 80% by weight, based on the weight of the composition in the uncured state, of a filler, aggregate or reinforcing material.

Abstract: A method of purifying the raw brine used in the elecrolysis of the aqueous NaCl or KCl solution by removing the Mg and Ca ions from said brine, which comprises contacting said brine with a member selected from the group consisting of(a) the chelate-forming water-insoluble resins capable of forming an intramolecular complex with the Mg and Ca ions, said resins being selected from the class consisting of the styrene-butadiene copolymer resins containing the group >N--CH.sub.2 COOH, the epichlorohydrin polymer resins containing the group >N--CH.sub.2 COOH, the N-phenyl glycine-glycidyl methacrylate copolymer resins containing the group >N--CH.sub.2 COCH and the styrene-divinylbenzene copolymer resins containing the group >N--CH.sub.2 COOH; and(b) the water-insoluble adsorbent solids adsorptively supporting a chelate-forming compound selected from the group consisting of the aminoacetic acids containing at least one >N--CH.sub.

Abstract: A method of purifying the raw brine used in the electrolysis of the aqueous NaCl or KCl solution by removing the Mg and Ca ions from said brine, which comprises contacting said brine with a member selected from the group consisting ofA. the chelate-forming water-insoluble resins capable of forming an intramolecular complex with the Mg and Ca ions said resins being selected from the class consisting of the styrene-butadiene copolymer resins containing the group .ltoreq.N--CH.sub.2 COOH, the epichlorohydrin polymer resins containing the group >N--CH.sub.2 COOH, the N-phenyl glycine-glycidyl methacrylate copolymer resins containing the group >N--CH.sub.2 COOH and the styrene-divinylbenzene copolymer resins containing the group >N--CH.sub.2 COOH; andB. the water-insoluble adsorbent solids adsorptively supporting a chelate-forming compound selected from the group consisting of the aminoacetic acids containing at least one >N--CH.sub.