Abstract: A method for removing metal pieces contained in gypsum board wastes from the gypsum board wastes by means of a drum magnetic separator, wherein the method comprises the step of dropping cut pieces obtained by cutting the gypsum board wastes at fixed intervals “D” on the drum magnetic separator at a drop height “h”; and the drop height “h” is 0.8 to 3 times the interval “D”.

Abstract: A method of manufacturing hemihydrate gypsum powders for the production of a gypsum molded product from gypsum board waste, comprising at least the following two steps in a random order: a compression step for compressing gypsum obtained from gypsum board waste; and a baking step for converting dihydrate gypsum obtained from gypsum board waste to hemihydrate gypsum.

Abstract: A method for removing metal pieces contained in gypsum board wastes from the gypsum board wastes by means of a drum magnetic separator, wherein the method comprises the step of dropping cut pieces obtained by cutting the gypsum board wastes at fixed intervals “D” on the drum magnetic separator at a drop height “h”; and the drop height “h” is 0.8 to 3 times the interval “D”.

Abstract: A stripping liquid of the present invention is used for separating the paper from a plaster/paper laminate such as waste plasterboard, and comprises an aqueous solution of an alkali metal salt or an ammonium salt of carboxylic acid. The stripping liquid is fed onto the surface (paper surface) of the plaster/paper laminate so as to infiltrate into the bonding surface between the plaster and the paper, so that the carboxylate is made present on the bonding surface. Upon stripping off the paper in the presence of the carboxylate, it is allowed to entirely separate the paper from the plaster. Upon mixing the stripping liquid and a nonionic surfactant or a water-soluble organic solvent together, further, the stripping liquid can be quickly and reliably infiltrated into the bonding surface between the plaster and the paper.

Abstract: A cement setting accelerator comprising calcium hydroxide particles having an average particle diameter of 3 ?m or less, and a cement composition comprising 100 parts by weight of a cement and 0.05 to 10 parts by weight of the above setting accelerator. A wet ground product of calcium hydroxide or a fine precipitate formed by a reaction between a calcium salt and an alkali hydroxide can be used as the above calcium hydroxide particles. This setting accelerator shows a high setting accelerating effect and does not exert a bad influence upon the quality, especially durability of a hardened product of the cement composition.

Abstract: A stripping liquid of the present invention is used for separating the paper from a plaster/paper laminate such as waste plasterboard, and comprises an aqueous solution of an alkali metal salt or an ammonium salt of carboxylic acid. The stripping liquid is fed onto the surface (paper surface) of the plaster/paper laminate so as to infiltrate into the bonding surface between the plaster and the paper, so that the carboxylate is made present on the bonding surface. Upon stripping off the paper in the presence of the carboxylate, it is allowed to entirely separate the paper from the plaster. Upon mixing the stripping liquid and a nonionic surfactant or a water-soluble organic solvent together, further, the stripping liquid can be quickly and reliably infiltrated into the bonding surface between the plaster and the paper.

Abstract: A cement setting accelerator comprising calcium hydroxide particles having an average particle diameter of 3 ?m or less, and a cement composition comprising 100 parts by weight of a cement and 0.05 to 10 parts by weight of the above setting accelerator. A wet ground product of calcium hydroxide or a fine precipitate formed by a reaction between a calcium salt and an alkali hydroxide can be used as the above calcium hydroxide particles. This setting accelerator shows a high setting accelerating effect and does not exert a bad influence upon the quality, especially durability of a hardened product of the cement composition.

Abstract: Amorphous sodium silicate-metal sulfate composite powder having water softening power and having small hygroscopicity, and useful as a detergent builder is provided. This amorphous sodium silicate-metal sulfate composite powder is characterized in that it contains a metal sulfate, for example, sodium sulfate, as solid solution, and when the SiO.sub.2 /Na.sub.2 O molar ratio is expressed by n and the specific surface area thereof is expressed by S (m.sup.2 /g), n and S satisfy the following expressions:1.60.ltoreq.n.ltoreq.2.800.10.ltoreq.S.ltoreq.2.00, provided that it is assumed that the molar number of Na.sub.2 O is the molar number of Na.sub.2 O based on sodium silicate, and does not contain the molar number of Na.sub.2 O based on sodium sulfate in the case where the metal sulfate is sodium sulfate. This powder is prepared by grinding sodium silicate cullet containing the metal sulfate as solid solution.

Abstract: Amorphous sodium silicate powder exhibiting excellent water softening power and suitable as a detergent builder is provided. This amorphous sodium silicate powder is characterized in that when the molar ratio of SiO.sub.2 /Na.sub.2 O is expressed by n and the specific surface area thereof is expressed by S(m.sup.2 /g), the following expressions:1.20.ltoreq.n.ltoreq.1.600.10.ltoreq.S.ltoreq.0.90and0.008.times.n.sup.8.6 .ltoreq.S.ltoreq.0.063.times.n.sup.8.1are satisfied.

Abstract: There is provided a composite oxide represented by the formulaiR.sub.2 O.jAl.sub.2 O.sub.3.kTiO.sub.2.mSiO.sub.2.nH.sub.2 Owherein R denotes an alkali metal, i is 0.3 to 1, k is 0 to 0.9, j+k=1, m is 7 to 70 and n is 0.2 to 0.4, said composite oxide being amorphous, and its cumulative specific pore volume of pores having a pore radius of 10.sup.4 A or less being 2.0 to 3.0 cc/g. This composite oxide can be produced by a process which comprises a first reaction step of adding an acid aqueous solution capable of forming a silicate by reaction with an alkali silicate to 7 to 10% by weight, calculated as silica, of an alkali silicate aqueous solution in the presence of a salt at 10 to 45.degree. C. such that a neutralization ratio becomes 20 to 40%, and a second reaction step of heating the reaction solution obtained in the above reaction at temperature of 90.degree. C.

Abstract: There is provided a composite oxide represented by the formulaiR.sub.2 O.jAl.sub.2 O.sub.3.kTiO.sub.2.mSiO.sub.2.nH.sub.2 Owherein R denotes an alkali metal, i is 0.3 to 1, k is 0 to 0.9, j+k=1, m is 7 to 70 and n is 0.2 to 0.4,said composite oxide being amorphous, and its cumulative specific pore volume of pores having a pore radius of 10.sup.4 A or less being 2.0 to 3.0 cc/g. This composite oxide can be produced by a process which comprises a first reaction step of adding an acid aqueous solution capable of forming a silicate by reaction with an alkali silicate to 7 to 10% by weight, calculated as silica, of an alkali silicate aqueous solution in the presence of a salt at 10.degree. to 45.degree. C. such that a neutralization ratio becomes 20 to 40%, and a second reaction step of heating the reaction solution obtained in the above reaction at a temperature of 90.degree. C.

Abstract: Disclosed is a process for the preparation of an anorthite sintered body, which comprises preparing a formed body of at least one powder selected from the group consisting of (i) a calcium type zeolite having an SiO.sub.2 /Al.sub.2 O.sub.3 molar ratio lower than 3, (ii) an amorphous calcination product obtained by calcining said calcium type zeolite and (iii) a mixture of said calcium type zeolite or said amorphous calcination product and an alkaline earth metal compound, and sintering the formed body at a temperature lower than 1000.degree. C.

Abstract: An alkaline earth metal aluminosilicate sintered body is obtained by molding a starting mixture of a zeolite having an alkaline earth metal form and an SiO.sub.2 /Al.sub.2 O.sub.3 molar ratio not higher than 3.0 and a boron compound such as boron oxide, and firing the molded body at a temperature lower than 1,000.degree. C. An amorphous calcination product formed by calcining the zeolite may also be used in the starting mixture with the boron compound. This process allows the range of firing temperatures suitable for formation of a sintered body to be varied over a range of from about 50.degree. to 150.degree. C. or more while also allowing lower firing temperatures than in the absence of the boron compound to be used while still obtaining the desired densified sintered body.

Abstract: Disclosed is a liquid-absorbing shaped body comprising a fibrous material and an inorganic powder in which the volume of fine pores having a pore radius less than 0.5.mu. is at least 2.5 cc/g. This shaped body is excellent in the liquid-absorbing capacity and liquid-retaining property to various kinds of liquids.

Abstract: Disclosed is an alkali calcium silicate having two different X-ray diffraction patterns: (1) with diffraction peaks at spacings (d) of 11.8-12.2 A, 6 A and 3 A or (2) with diffraction peaks at spacings (d) of 13.0-13.4 A, 6.7 A and 3.1 A. This silicate is in the fibrous or micaceous form and is valuable as a drying agent or an ion exchange agent. This silicate is prepared by hydrothermal reaction of an aqueous suspension having a specific composition of the starting components.

Abstract: Disclosed is an alkali calcium silicate having two different X-ray diffraction patterns (1) with diffraction peaks at spacings (d) of 11.8-12.2 A, 6 A and 3 A or (2) with diffraction peaks at spacings (d) of 13.0-13.4 A, 6.7 A and 3.1 A. This silicate is in the fibrous or micaceous form and is valuable as a drying agent or an ion exchange agent. This silicate is prepared by hydrothermal reaction of an aqueous suspension having a specific composition of the starting components.

Abstract: A process for producing calcium silicate of the rational formula 2CaO.3SiO.sub.2.nSiO.sub.2.mH.sub.2 O wherein m is a number of more than 0, and n is a number of 0.1 to 10 from a silicate compound and a calcium compound, which comprises contacting a water-soluble silicate compound with a calcium compound in an aqueous medium, and heating them to a temperature of 150.degree. to 250.degree. C., the amount of the aqueous medium being 5 to 100 times the weight of the calcium silicate obtained, and a process for producing calcium silicate or a calcium silicate-gypsum composite, which comprises adding a water-soluble silicate or its aqueous solution gradually to an aqueous suspension of gypsum, and heating the mixture to a temperature of 150.degree. to 250.degree. C. The calcium silicate and the calcium silicate-gypsum composite, which have a structure composed of an assembly of petal-like flakes, are useful as an adsorbent carrier, a delusterant or a filtration aid.