Abstract: The present disclosure relates to no fiber calcined gypsum and methods of making the same using a multi-stage (typically two-stage) calcination process. The first stage is a high temperature calcination and nucleation stage. The second stage is a lower temperature calcination and crystal growth stage which produces product slurry containing calcined gypsum particles having large, acicular calcined gypsum crystal morphology for use in making gypsum fiberboard.

Abstract: The present invention relates to the production of a ternesite-belite-calcium sulfoaluminate (ferrite) clinker. The invention also relates to the use of alternative raw materials for clinker production, for example raw materials based on industrial byproducts, including those of low quality, such as lump slag and ash having a low glass content and/or a high free lime content and/or a high content of crystalline high-temperature phases, as well as naturally occurring rocks and rock glasses of comparative chemical composition.

Abstract: Surfactant-coated hemihydrate gypsum which is coated with 0.01 to 1 part by weight of a surfactant based on 100 parts by weight of hemihydrate gypsum, wherein the residual rate of the surfactant when the surfactant-coated hemihydrate gypsum is heated up to 300° C. is not less than 40 wt % of the amount of the surfactant before heating.

Abstract: An inorganic material board, which is a cured mat formed by dehydrating a slurry including 30 to 53 wt % of blast furnace slag, 2 to 5 wt % of gypsum having an average particle size of 200 to 2000 ?m, 5 to 11 wt % of alkaline material, 5 to 15 wt % of reinforcing fibers, and 31 to 50 wt % of inorganic admixture with respect to a total solid content, and in which a weight ratio of the blast furnace slag to the gypsum to the alkaline material is 1:0.05 to 0.15:0.15 to 0.35. It is desirable that the blast furnace slag has a specific surface area of 3000 to 5000.

Abstract: A system includes a conveyor providing an agricultural grade gypsum, a pump providing a fluid, a mixing device configured to mix the agricultural grade gypsum provided by the conveyor with the fluid provided by the pump to produce a gypsum slurry, and a slurry pump configured to pump the gypsum slurry from the mixing device to a storage tank.

Abstract: The present invention relates to a system and associated method for the production of gypsum in manufacturing plant. More specifically, the invention relates to the production of alpha-type gypsum in a gypsum board manufacturing plant. The system yields increased efficiencies by capturing heat given off during processing steps and using that heat to reduce the energy needed for calcination. The invention finds particular application in the production alpha-type gypsum. The present invention is described in greater detail hereinafter in conjunction with the following specific embodiments.

Abstract: In a first embodiment of the invention, aged brushite is combined with calcium sulfate hemihydrate and water to make a gypsum slurry. Aged brushite slurry behaves similarly to calcium sulfate dihydrate to act as a seed crystal and rapidly initiate crystallization. The brushite slurry does not require the addition of a coating to maintain its activity over time compared to calcium sulfate dihydrate set accelerators. A gypsum-based product made using brushite slurry as the set accelerator is a second embodiment. The product has the brushite molecules integrated as part of the calcium sulfate dihydrate matrix and is distributed throughout the matrix.

Abstract: A method for producing a cement-containing material having a low content of soluble Cr (VI), the method including providing a cement-containing material with metallic sulphate particles coated with at least one product of the hydrolysis of a collagen material.

Abstract: The present invention relates to a system and associated method for the production of gypsum in manufacturing plant. More specifically, the invention relates to the production of alpha-type gypsum in a gypsum board manufacturing plant. The system yields increased efficiencies by capturing heat given off during processing steps and using that heat to reduce the energy needed for calcination. The invention finds particular application in the production alpha-type gypsum. The present invention is described in greater detail hereinafter in conjunction with the following specific embodiments.

Abstract: A process for producing alpha-hemihydrate gypsum from dihydrate gypsum includes feeding a slurry comprising the dihydrate gypsum and water into a heating tube, heating the heating tube at a temperature effective to generate steam and pressure from the water, wherein the steam and pressure are effective to convert the dihydrate gypsum to the alpha-hemihydrate gypsum, and withdrawing the alpha-hemihydrate gypsum from the heating tube.

Abstract: Effective use of dispersants in wallboard containing foam results from a method where stucco is mixed with a first dispersant and a first quantity of water to form a gypsum slurry. A soap is blended with a second dispersant and a second quantity of water to make a foam. Subsequently, the foam is combined with the slurry. Choice of different first and second dispersants and their relative amounts allows control of the size distribution of the foam bubbles in the slurry and the resulting voids in the gypsum core. Use of the same dispersant in both the mixer and the foam water provides a boost in efficacy of the dispersant.

Abstract: A light-weight gypsum-based composition is provided which is particularly suitable for use in the production of wall panels. The composition comprises: (i) gypsum; (ii) glass, ceramic or polymer microspheres; and (iii) a coupling agent preferably selected from a silane or metal coupling agent. The resultant panel has good strength properties and has good performance with respect to nailability and cutability. Further, the paper backing commonly used on traditional commercial drywall panels can be optionally eliminated. The composition can also be cast into thicker products. A lightweight wall panel material is provided.

Abstract: A composition is disclosed for a mixture to be used in conjunction with water for preparing a slurry that hydrates to form a high strength flooring compound. The mixture includes from about 50% to about 98% by weight calcium sulfate hemihydrate. A three repeating unit polycarboxylate dispersant is included in the mixture in amounts from about 0.2% to about 10% by weight. The repeating units include a polyether repeating unit, an acrylic acid-type repeating unit and a maleic acid-type repeating unit. A modifier that enhances the efficacy of the dispersant is also a component of the mixture. When combined with recommended amounts of water, a slurry is formed that is useful as a flooring composition.

Abstract: The present invention relates to a system and associated method for the production of gypsum in manufacturing plant. More specifically, the invention relates to the production of alpha-type gypsum in a gypsum board manufacturing plant. The system yields increased efficiencies by capturing heat given off during processing steps and using that heat to reduce the energy needed for calcination. The invention finds particular application in the production alpha-type gypsum. The present invention is described in greater detail hereinafter in conjunction with the following specific embodiments.

Abstract: Gypsum products and method for the preparation thereof are disclosed. The gypsum products comprise an interlocking matrix of set gypsum that is formed from a composition comprising calcined gypsum, water and acoustical tile.

Abstract: Disclosed is an improved alpha-type calcium sulfate hemihydrate. Methods of producing an improved powdered calcium sulfate hemihydrate (CaSO4.½H2O) [alpha-type] compound are disclosed, at least one method including forming calcium sulfate dihydrate (CaSO4.2H2O) into a briquette, calcining the briquette to transform the calcium sulfate dihydrate to calcium sulfate hemihydrate [alpha-type], drying the calcium sulfate hemihydrate [alpha-type] briquette, and optionally grinding the briquette. Also disclosed are methods of producing an improved gypsum plaster including producing the disclosed powdered calcium sulfate hemihydrate [alpha-type] and mixing the powdered calcium sulfate hemihydrate [alpha-type] with water.

Abstract: This invention is directed to a method of reducing the water demand of expanded perlite that includes obtaining a vibrating screen supported at an angle and placing expanded perlite on the vibrating screen. The expanded perlite is moved over the screen past toward a burner at a rate that heats the expanded perlite to a temperature sufficient to anneal it. The expanded perlite is then moved away from the burner and allowed to cool. Another embodiment of this invention is directed to a method of making a gypsum product. The method includes annealing perlite by the method described above, then preparing a slurry of calcium sulfate hemihydrate, additives, water and the annealed perlite. The slurry is formed into the shape of the gypsum product and allowed to set. This process is particularly useful in making gypsum panels and acoustical panels that benefit from the use of lightweight materials.

Abstract: In conjunction with water, a mixture can be used to prepare a sprayable slurry that hydrates to form a machinable plaster composition. The mixture includes from about 80% to about 98% by weight calcium sulfate hemihydrate, from about 1% to about 5% by weight adhesive binder for adhering said plaster mixture to a substrate and from about 0.001% to about 10% of a polysaccharide. The mixture is made into a slurry by the addition of from 10% to about 50 weight water based on the weight of the mixture.

Abstract: The invention provides a process for stabilizing plaster and an apparatus for implementing the moistening part of the process. The process comprises the following steps: a) providing a heated HH-plaster preferably at temperatures over 100° C.; b) feeding the hot plaster in a moistening device having walls heated to at least 100° C.; c) injecting water and/or steam into the moistening device in conditions that such not yet moistened surfaces of the plaster are exposed to the injected water and/or steam; d) maintaining an atmosphere in the moistening device at a level of the dew point in the range of 75 to 99° C.; e) feeding the moistened blend into a curing device; f) maintaining an atmosphere in the curing device above 75° C. for at least 3 minutes; g) feeding the moistened and cured blend into a drying device; and h) drying said moistened and cured blend.

Abstract: This invention provides facing materials for cementitious boards such as those including Portland cement or gypsum cores. The preferred facing material includes, in a first embodiment, a facing layer having an areal weight of about 300 grams/M2, and an air permeability rating of no greater than about 300 CFM/ft2 (FG 436-910 test method). The facing layer reduces the penetration of a slurry of cementitious material during the manufacture of a cementitious board, while permitting the water vapor from the slurry to pass therethrough. The facing materials of this invention can be designed to substantially eliminate the fouling of rolls used in continuous processing of such boards without the use, or with greatly reduced use, of costly viscosity control agents in the slurry.

Abstract: An antimicrobial cementitious composition for imparting antimicrobial characteristics to cement comprises cement and an antimicrobial agent selected from the group consisting of an ortho-phenyl phenol or salt thereof, a tolyl diiodomethyl sulfone, a zinc pyrithione, an oxathiazine, an azole, a chlorothalonil, and a triazine diamine; combinations of agents also may be employed.

Abstract: A gypsum composition including gypsum, water, and a surfactant composition of alkyl sulfates of formula H(CH2)nOSO3?M+, in which n is from 6 to 16, the mean number of carbon atoms in the alkyl sulfate composition nm being between 10 and 11, and M is a monovalent cation. A process for the preparation of the gypsum composition and a gypsum board obtainable from this composition. Finally, a process for the manufacture of gypsum boards. Application for the manufacture of foamed gypsum boards.

Abstract: A composition and method for treating a surface is described. In one embodiment, the composition comprises about 10% to 90% by weight of cement, about 10% to 90% by weight of plaster, about 0.01% to about 20% by weight of lime, and about 0% to about 30% by weight of perlite. In another embodiment, the composition comprises plaster, cement, perlite, lime, joint compound and water, wherein the plaster, cement, perlite, and lime are in a ratio of about 10-90: 10-90: 0-30: 0.01-20 by weight. In another embodiment, the composition is prepared by a method comprising: (a) providing a first mixture comprising plaster, cement, perlite, and lime; (b) converting the first mixture to a second mixture by a method selected from the group consisting of stirring the first mixture, passing the first mixture through a strainer, and milling the first mixture; and (c) mixing the second mixture with joint compound and water to obtain the composition.

Abstract: A mold-resistant gypsum panel includes a core of an interlocking matrix of calcium sulfate dihydrate crystals, a facing material on at least one side of the panel and a salt of pyrithione dispersed through both the core and the facing materials. A method of making a mold-resistant gypsum product is also provided. A slurry of calcined gypsum, water and a water-soluble pyrithione salt is formed, then deposited on a sheet of facing material. The slurry on the facing material is shaped into a panel and maintained under conditions sufficient for the calcined gypsum to react with the water to form a core comprising an interlocking matrix of set gypsum crystals. Heating of the panel causes evaporation of the water that did not react with the calcined gypsum.

Abstract: A method of producing a water resistant fibre-cement product. The water repelling agent can be added or applied to the fibre-cement or indeed the material forming the fibre cement at a number of different stages in the process. The resultant material has increased water impermeability over conventional fibre-cement products.

Abstract: A gypsum wallboard that exhibits antimicrobial characteristics is disclosed. A method for making the wallboard is also disclosed. Suitable antimicrobial agents that may be applied to the wallboard or any components thereof include propiconazole, sodium pyrithione, tolyl diiodomethyl sulfone; tebuconazole; thiabendazole; 3-iodo-2-propynyl butylcarbamate; and mixtures thereof.

Abstract: I provide a multi-part aqueous gypsum dental casting composition having gypsum and water and wherein (a) one or more of a first compound is mixed in the gypsum and/or water; or (b) one or more of the first compound and one or more of a second compound are mixed in the gypsum and/or water; or (c) one or more of the first compound and one or more of an acid are mixed in the gypsum and/or water; or (d) one or more of the first compound and one or more of the second compound and one or more of the acid are mixed in the gypsum and/or water; or (e) two or more of the acids and optionally one or more of the second compound are mixed in the gypsum and/or water; and (f) the gypsum and water are maintained separately and mixed when the casting is to be prepared. Also provided are the dosage sized containers for the above, along with the dosage size containers having gypsum enhancers.

Abstract: A method for coating the sawed edges of gypsum wallboard to prevent dusting of gypsum particles in clean rooms. The method includes applying a water-dispersible polymers to the sawed edges of gypsum wallboard. The polymer forms a water-insoluble salt through an ion exchange with the calcium found in gypsum wallboard. The result is a tough, tack free, fast-drying coating that substantially reduces the levels of airborne gypsum particles that come from the sawed edges of gypsum wallboards.

Abstract: I provide a multi-part aqueous gypsum dental casting composition having gypsum and water and wherein (a) one or more of a first compound is mixed in the gypsum and/or water; or (b) one or more of the first compound and one or more of a second compound are mixed in the gypsum and/or water; or (c) one or more of the first compound and one or more of an acid are mixed in the gypsum and/or water; or (d) one or more of the first compound and one or more of the second compound and one or more of the acid are mixed in the gypsum and/or water; or (e) two or more of the acids and optionally one or more of the second compound are mixed in the gypsum and/or water; and (f) the gypsum and water are maintained separately and mixed when the casting is to be prepared. Also provided are the dosage sized containers for the above, along with the dosage size containers having gypsum enhancers.

Abstract: An additive, a mixture incorporating the additive and a method of formulating a mortar incorporating the additive. The additive is based on calcium sulfoaluminate composed of C3AH6 and CAH10 where C=calcium oxide, A=aluminum oxide and H=water. The admixture includes gypsum and calcium hydroxide. The calcium aluminum hydrates are obtained by hydration of high alumina cement particles to eliminate any lack of hydration in the core of the particle. The method involves the preparation of such particles and the mix incorporates the particles to produce a homogeneously hydrated cement additive.

Abstract: A set accelerator for at least one of accelerating the hydration rate and reducing the set time of an aqueous slurry of calcium sulfate hemihydrate is described. The set accelerator consists of a mixture of ground calcium sulfate dihydrate and zinc sulfate material. Aluminum sulfate material is an optional component of the set accelerator. The set accelerator is particularly useful in accelerating the hydration rates of sprayable plasters. A fluid form of the set accelerator may be made by suspending the solids in water. The fluid form is advantageously used in ready mixed setting type joint compounds.

Abstract: A plaster mixture for forming a machinable composition, includes calcium sulfate hemihydrate; an internal lubricating dispersable binder, and an adhesive binder for adhering the plaster mixture to a substrate. In the preferred embodiment, the composition includes calcium sulfate hemihydrate, a poly(ethylene glycol) internal binder, and an ethylene/vinyl acetate copolymer adhesive binder.

Abstract: A multipart gypsum casting composition comprising a gypsum composition and a water composition where either the water and/or the gypsum composition contains at least two acids selected from the group consisting of oxalic acid, boric acid, phosphoric acid, citric acid, sodium citric acid, trisodium citric acid, tartaric acid, sulfuric acid, acetic acid, formic acid, malic acid, ascorbic acid and aspartic acid.

Abstract: A novel wallboard composition is disclosed comprising a unique combination of synthetic binders selected for their ability to establish a strengthened permanent bond in the final dry state for use in a wallboard composition comprising primarily gypsum, and in a wallboard composition comprising an expanded mineral such as Perlite which largely reduces the amount of gypsum over current gypsum wallboard formulations, thus reducing the weight while maintaining the strength of the wallboard structure. In a preferred embodiment, the lightweight, strengthened wallboard of the present invention also comprises an optional covering veneer that is applied to the top ply of the face paper to provide increased strength, moisture resistance, and fire retardency, and the back paper top ply is treated to provide increased flexural strength.

Abstract: A composition of matter for joint or texture compound used in wallboard applications which incorporates an ingredient which has been reclaimed from waste wallboard panel. A method and system for reconstituting the waste wallboard into the joint compound is also provided. Waste wallboard is thereby recycled so that the waste wallboard does not need to be disposed in a landfill.

Abstract: A composition for accelerating the setting reaction of an aqueous calcined gypsum slurry, and a method of making the same are disclosed. The composition includes a vibratory ball milled mixture of calcium sulfate dihydrate and a surfactant. The composition is prepared by subjecting the mixture to the high-frequency, low-impact grinding action of a vibratory ball mill. The resultant composition has a potency superior to that of conventional gypsum set accelerators.

Abstract: A method of continuously producing a cementitious composition such as joint compound includes pre-mixing at least two dry ingredients and pre-mixing at least two liquid ingredients. The ingredients are provided in a continuous mixing apparatus and at least substantially continuously blended.

Abstract: A method for the reversible agglomeration of fine particles of plaster of Paris (CaSO4.½H2O) and agglomerates made by the method which comprises agitating the fine particles in the presence of an organic polar liquid preferably nearly dry and having some ability to form hydrogen bonds (especially n-propanol) and then drying off most of the liquid whereby the fine particles spontaneously interlink (possibly by mechanical keying) in a way which allows the interlinks to be disrupted so as to release fine particles when the agglomerates are stirred into water by hand. Also a dry precursor mixture comprising the agglomerates containing conventional auxiliary additives for use in mixing with water to make aqueous compositions for use as filler pastes, casting materials or plaster slurries.

Abstract: The present invention relates to water-resistant gypsum compositions, methods of making such composition, as well as manufacturing methods and products comprising such compositions.

Abstract: Disclosed is a process of making foamed compositions of water, gypsum, and either or both of alpha-olefin sulfonates and/or amphoteric surfactants of formula (a) or (b)R.sup.4 --(OC.sub.3 H.sub.6).sub.0-1 --(C(O)NH(CH.sub.2).sub.1-3).sub.0-1 --N(Z.sup.1) (Z.sup.2).sub.0-1 --ZCOOX (a)R.sup.4 --(OC.sub.3 H.sub.6).sub.0-1 --(C(O)NH(CH.sub.2).sub.1-3).sub.0-1 --N(Z.sup.1) (Z.sup.2).sub.0-1 --ZSO.sub.3 X (b)wherein X is --H, a sodium, calcium, potassium, lithium or ammonium cation, or an amine of the formula --N.sup.+ H(C.sub.1-20 alkyl).sub.2 or --N.sup.+ H.sub.2 (C.sub.1-20 alkyl); or when a Z.sup.2 group is present there is no X group on --ZCOOX; R.sup.4 is straight or branched alkyl or alkylene, or cyclic or heterocyclic aromatic which is optionally substituted with alkyl, and contains 4 to 40 carbon atoms and 0-5 carbon-carbon double bonds; Z.sup.1 and Z.sup.2 are independently of each other H, C.sub.f H.sub.2f+1 or C.sub.f H.sub.2f OH wherein f is 1 to 6 and preferably 1, 2 or 3 or, in formula (a), one of Z.

Abstract: A process for increasing the water solubility of gypsum in which gypsum is ground to about 5 to 50 mesh U.S. Standard Sieve Size, about 5 to 95 parts by weight of ground gypsum are mixed with about 2 to 25 parts by weight concentrated sulfuric acid having a concentration of about 93 to 98.5% H.sub.2 SO.sub.4, optionally in the presence of about 5 to 20 parts by weight water, and the resulting product is dried at a temperature of about 100-125.degree. C. to form a water-soluble, granular, solid, free-flowing gypsum product having a water solubility increased by about 2- to greater than 350-fold.

Abstract: A method of preparation of gypsum wallboard, as well as a core composition suitable for use therein, are disclosed. The core composition includes a slurry of calcium sulfate hemihydrate (stucco), water, and calcium aluminum lignosulfonate and/or aluminum lignosulfonate.

Abstract: A cement composition comprising fine aggregate, preferably sand, in an amount of about 10 to about 25 wt %; blast furnace slag cement, in an amount of about 20 to about 35 wt %; gypsum, in an amount of about 20 to about 35 wt %; Portland cement, in an amount of about 4 to about 30 wt %; and cement plasticizer in an amount of about 0.3 to about 3 wt %. The dry cement composition may be formulated with aggregate and water to prepare a flowable liquid, self-leveling and self-smoothing coating material that may be applied to a substrate such as a floor substrate. The applied coating requires no manual finishing or smoothing, yet hardens to form a level, very smooth coating that possesses excellent compressive strength.

Abstract: A method of controlling the ratio of hydration time (HT) to open time (OT) in the manufacture of composite materials from a mixture containing hydratable calcium sulphate such as gypsum binders, aggregates, fibers, water additives and other additives is disclosed. The method includes adding a retarder-accelerator combination such as Retardan and potassium sulphate to the mixture and applying pressure. The retarder-accelerator combination and application of pressure provide advantageous reduction in the ratio HT:OT. More particularly, HT:OT can be reduced to less than 1.

Abstract: A process for the production of a ready-mixed setting-type joint compound includes the use of calcium sulfate hemihydrate, water, and a set-retarding agent. The retarder includes a polymer composition including acrylic acid and acrylamide monomer units, for example a copolymer (or a mixture of copolymers) of acrylic acid and acrylamide or a blend of a homopolymer of acrylic acid and a homopolymer of acrylamide. The joint compound can be combined with an accelerator including a metallic salt. The joint compound of the invention can be formulated either as a lightweight joint compound or as a conventional weight joint compound. The joint compounds provide short setting times, reduced shrinkage, reduced preparation time, and beneficial application properties.

Abstract: A method and apparatus is disclosed for the continuous calcining of gypsum material in a high-efficiency, refractoryless kettle preferably heated by a multiple series of separate immersion tube burner coils, each coil operating within a specific calcining zone inside the kettle. The lowest, i.e., initial, burner tube coil is formed with a low profile to permit use of a small initial gypsum charge, and hence, a quick kettle start-up cycle. That low profile initial burner design also helps keep the agitator motor's load at a minimum during cycle start-up. Due to the immersion tube burner coil construction, no refractory structure for the kettle is required. Also, no separate hot pit structure is required, as the kettle is used to merely hold the material being calcined and no residual heat is present. A relatively thin kettle can be constructed, as it need only withstand relatively low operating temperatures.

Abstract: A hydraulic cement composition is disclosed which utilizes as part of an expansive component novel coated particles of high alumina cement. The particles have a core of substantially unhydrated high alumina cement and an outer layer of hydration products of the core, which outer layer delays the reaction of the particles with other materials in the composition. By varying the nature and relative amounts of the coated particles the amount the cement composition may expand and the setting time of the cement may be varied. The coated particles may be formed by partial hydration, drying and grinding of a mixture of high alumina cement powder alone with water.

Abstract: A process for the production of a ready-mixed setting-type joint compound includes the use of calcium sulfate hemihydrate, water, and a set-retarding agent. The retarder includes a polymer composition including acrylic acid and acrylamide monomer units, for example a copolymer (or a mixture of copolymers) of acrylic acid and acrylamide or a blend of a homopolymer of acrylic acid and a homopolymer of acrylamide. The joint compound can be combined with an accelerator including a metallic salt. The joint compound of the invention can be formulated either as a lightweight joint compound or as a conventional weight joint compound. The joint compounds provide short setting times, reduced shrinkage, reduced preparation time, and beneficial application properties.

Abstract: The invention provides a method of making gypsum products such as plasterboard from foamed gypsum plaster slurry. The method uses a first mixing chamber 10 containing a high speed rotor 14 and inlets 18, 19 for gypsum plaster and water. The initial dispersion of gypsum plaster and water foamed in the first chamber passes directly and continuously into a second chamber 25 containing a low speed rotor 29. Preformed foam is introduced into the second chamber through an inlet 33, and the foamed slurry product leaves the second chamber through an outlet 34, to be formed into plasterboard.

Abstract: Binder compositions are provided which are principally composed of a lime-containing flyash, and optionally hydratable gypsum, with a small amount of a property improving additive. The compositions are capable of setting when mixed with sufficient water to form a hardened material having a high degree of compressive strength after only about 1 hour following set. In selected embodiments, compositions are provided for floor underlayment, road patch and exterior statuary applications. Compressive strengths starting at about 600 psi can be achieved within 1 hour after set with adequate working time for construction applications.