Abstract: A gypsum dryer/calciner (1) includes a calcining space (2), a first pipe (4) exhibiting an inlet connected to a source of hot gases (3) and an outlet emerging in the calcining space (2); a second pipe (5) exhibiting an inlet connected to a source of gypsum (8) and an outlet emerging in the calcining space, the second pipe being concentric with the first pipe; a force-feeding screw (6) positioned at least partially in the second pipe, the said screw carrying the gypsum along in the calcining space. A process for calcining gypsum and to the plaster capable of being obtained by this process.

Abstract: To provide a cement manufacturing apparatus and the like capable of increasing quantity of fly ash used in the apparatus while controlling unburned carbon content in cement within a permissible range. The cement manufacturing apparatus and the like comprises a removal means for removing unburned carbon from gypsum, and a grinding means for grinding gypsum from which unburned carbon is removed by the removal means together with clinker to generate cement. With the apparatus, total unburned carbon content in cement can be reduced, and the quantity of fly ash used in the apparatus can be increased by the reduced amount of unburned carbon. The removal means can remove unburned carbon contained in gypsum as well as unburned carbon contained in fly ash, and the grinding means may grind the fly ash from which unburned carbon is removed together with the gypsum, from which unburned carbon is removed, and clinker.

Abstract: A method of producing a foamed plaster comprises the following steps: (a) mixing plaster of Paris and calcium carbonate; (b) supplying water, and (c) adding phosphoric acid. The phosphoric acid reacts with the calcium carbonate to release gaseous carbon dioxide. It also reacts with any steel present to form an insoluble iron phosphate coating.

Abstract: A variety of methods and compositions are disclosed herein, including, in one embodiment, a method comprising: introducing a settable composition into a subterranean formation, wherein the settable composition comprises: a cementitious component comprising a hydraulic cement and cement kiln dust; a swellable particle; and water; and allowing the settable composition to set in the subterranean formation. Another embodiment comprises a settable composition comprising: a cementitious component comprising a hydraulic cement and cement kiln dust, a swellable particle, and water.

Abstract: A gypsum slurry includes water, a hydraulic component including stucco and a polycarboxylate dispersant. The dispersant has two repeating units wherein the first repeating unit is an olefinic unsaturated mono-carboxylic acid repeating unit or an ester or salt, and the second repeating unit is a vinyl or allyl group bound to a polyether by an ether linkage. The slurry can be made into a gypsum panel.

Abstract: A composition and method for forming a composite material comprising a mixture of component A and component B, component A comprising gypsum and an inhibitor; and component B comprising an accelerator, wherein at least one of component A and component B further comprises a polymer binder having a Tg of below ?23° C. or wherein the Shore D hardness of the composite material when cured is less than 70; the method comprising providing a first slurry mixture of component A and a second slurry mixture of component B and blending the first slurry mixture and the second slurry mixture to form a soft composite using a weight ratio of from 10:1 to 1:2.

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: The present invention relates in general to implantable compositions, and method for preparing same, containing a calcium salt-containing component, optionally demineralized bone, a plurality of discrete fibers, optionally a flow additive, and optionally continuous reinforcing fibers or an array of organized fibers in the form of mesh. Advantageously, the discrete fibers have a specific aspect ratio (length/diameter) from about 50:1 to about 1000:1. The addition of a small amount of discrete fibers and/or the continuous reinforcing fibers or fiber mesh can cause drastic increases in certain mechanical properties including flexural strength, flexural toughness, and/or screw pullout strength.

Abstract: An improved gypsum slurry that includes water, calcium sulfate hemihydrate, a polycarboxylate dispersant and a modifier. The modifier is chemically configured to improve the efficacy of the polycarboxylate dispersant. Preferred modifiers include cement, lime, slaked lime, soda ash, carbonates, silicates and phosphates.

Abstract: A gypsum slurry includes calcium sulfate hemihydrate, water and calcium sulfate dihydrate is coated with a hydrophilic, dispersible coating. The coating is less soluble than the calcium sulfate hemihydrate to delay exposure of the landplaster to the remainder of the slurry, preventing premature crystallization and the early stiffening that accompanies it. Another embodiment is a gypsum slurry that includes calcium sulfate hemihydrate, a polycarboxylate dispersant, water and coated calcium sulfate dihydrate. In this case, the hydrophilic, dispersible coating is selected to serve as a modifier to enhance the ability of the dispersant to fluidize the gypsum slurry.

Abstract: The present invention relates to a joint compound composition for building elements, particularly paper-faced plasterboards. This composition comprises: a) 50 to 60% of calcium sulphate hemihydrate; b) 5 to 15% of an organic binder in powder form; and c) 0.05 to 0.2% of a water repellent. The invention also relates to a method producing a structure, such as a partition, a wall trim or a ceiling. According to this method: building elements are juxtaposed; the joint compound composition according to the invention is mixed with water so as to obtain a joint compound; the space between the building elements is filled by means of the joint compound obtained above, without using a tape; and the joint compound is left to harden.

Abstract: A process is disclosed for making a blend of alpha- and beta-stucco including a slurry calcination step to produce alpha calcium sulfate hemihydrate followed by a fluidized bed calcination step to produce beta calcium sulfate hemihydrate. The process starts with 50-75% gypsum-containing solids slurry, and then steam calcines the slurry in a first reactor to form partially calcined gypsum slurry which contains calcium sulfate dihydrate and alpha calcium sulfate hemihydrate. The partially calcined slurry is then dewatered. Then the filter cake is fed into a kettle to complete the calcination process by converting the calcium sulfate dihydrate of the filter cake material into beta calcium sulfate hemihydrate.

Abstract: The present invention is based on solid-state reaction or reactions in the presence of small amounts of water, between phospho gypsum and agglutinating-neutralizing agents, principally though the application of oxy and hydroxy compounds, without discounting use of the respective carbonates of magnesium, aluminum and principally calcium, in addition to mixtures of these, and the subsequent preparation of self-hardening pellets which facilitate transport and handling. The technological process associated with the invention notably simplifies both the number and type of individual operations, and the preparation of pellets from mixtures of phosphor gypsum; it also reduces energy costs by operating at low temperatures (150°C.) during short periods (1-2 hours), while reducing the quantity of neutralizing agents, and minimizing the volume of water required for the process.

Abstract: A slurry is made including water, at least 50% by weight calcium sulfate hemihydrate, and a specific polycarboxylate dispersant prepared using at least three repeating units. A first repeating unit is a vinyl ether-type repeating unit. A second repeating unit includes a maleic acid-type repeating unit. A third repeating unit includes an acrylic acid-type repeating unit. The polymer dispersant has a molecular weight of from about 20,000 to about 80,000 Daltons. The slurry made from this composition can be made at reduced water levels to speed drying and reduce drying costs.

Abstract: The invention is a composition of an architectural papier-mâché, and articles made therewith. Articles formed from using the architectural papier-mâché have excellent weather resistance, and can be used outdoors, as well as indoors. The composition is comprised of cellulose insulation and a joint compound. Cellulose insulation is a paper-based material, like newsprint or phonebook paper that is shredded and chemically treated with boric acid, which imparts resistance to mold, mildew, fungus, insects, moisture and flammable combustion.

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: An embodiment of the present invention includes a method of cementing in a subterranean formation comprising: providing an extended settable composition comprising hydraulic cement, cement kiln dust, water, and a set retarding additive, wherein the extended settable composition is capable of remaining in a pumpable fluid state for at least about 1 day; adding a cement set accelerator to the extended settable composition; introducing the extended settable composition into a well bore; and allowing the extended settable composition to set. Another embodiment of the present invention includes a method of cementing in a subterranean formation comprising: providing an extended settable composition comprising hydraulic cement, cement kiln dust, water, and a set retarding additive; storing the extended settable composition; adding a cement set accelerator to the extended settable composition; introducing the extended settable composition into a well bore; and allowing the extended settable composition to set.

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 method for providing effective mercury release control during gypsum calcination is disclosed. The method comprises providing a reactor and gypsum containing mercury; providing a mercury sorbent, such as activated carbon and/or derivatives thereof in the reactor; and calcining the gypsum in the reactor to form stucco. The mercury contaminant present in the gypsum is sorbed by the mercury sorbent during the calcination process. The mercury content of the stucco is substantially similar in amount to the mercury content of the uncalcined gypsum.

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: An acoustical panel includes an acoustical layer having an interlocking matrix of calcium sulfate dihydrate, polyethylene glycol and at least one of the group fibers, a lightweight aggregate and mixtures thereof. The acoustical layer has voids in the interlocking matrix that are configured to absorb sound. The polyethylene glycol is selected to agglomerate dust at temperatures generated by friction when the panel is cut. A method of making the acoustical panel includes making a slurry comprising calcium sulfate hemihydrate, polyethylene glycol, water and at least one of the group consisting of a lightweight aggregate, fibers and combinations thereof. Foam is added to the slurry, preferably at the mixer discharge. A continuous strip of acoustical layer material is formed from the slurry. The acoustical panels are formed by cutting the strip into individual panels. Finally, the partially hydrated calcium sulfate hemihydrate is allowed to fully set.

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 method is provided which uses an improved emulsion to imparting water-resistance to gypsum products. In one embodiment, gypsum products comprise calcium sulfate dihydrate and an emulsion which comprises a saponified wax, a nonsaponifiable wax, an alkyl phenol, a surfactant/dispersant salt of polynaphthalenesulfonic acid, and carboxymethylcellulose. Optionally, the emulsions may contain a preservative, e.g., a biocide (mildewcide, fungicide, etc.). These gypsum products resist the uptake of water and therefore resist biological infestation without addition of a preservative.

Abstract: Magnetic receptive Paints and coatings have been developed to allow one to paint a wall with this coating and apply magnets to this surface. The further development of magnetic receptive compounds lends itself to creating a one step process where one applies a magnetic receptive plaster or compound to a wall with a viscosity sufficient to smooth with a trowel leaving a magnetic receptive surface. In other applications one could spray a compound on a given surface.

Abstract: A burnt product is produced by burning a raw material containing chromium, in which the fine-grained portion is removed. Even in the burnt product produced from a raw material containing chromium, the chromium (VI) content is reduced.

Abstract: Compositions and methods for producing a manufactured product, a method for making a liquid absorbent, and processes for disposal of flammable liquids with a flue gas desulfurization by-product. The compositions for the manufactured products combine a binder and the by-product. The composition contains a greater percentage by weight of the by-product than the binder. The methods for producing manufactured products include dewatering the gypsum-depleted waste stream to reduce a water content, and forming the manufactured product. The method for making a liquid absorbent includes dewatering, granulating, drying, heating, and packaging a granulated gypsum-depleted composition as the liquid absorbent. The processes for disposal of flammable liquids include distributing a by-product into contact with flammable liquid, absorbing the liquid, transporting, and igniting the flammable liquid. The artificial soils are a combination of by-product and animal waste.

Abstract: The acoustical product of the present invention comprises an acoustical product including a matrix of calcium sulfate dihydrate crystals and expanded perlite distributed throughout the matrix. The expanded perlite has a particle size distribution with at least 10% of the perlite having a particle diameter of 700 microns or more, and the amount of expanded perlite to calcium sulfate dihydrate is about 35% to about 75% by weight, based upon the dry weight of the calcium sulfate dihydrate. A dispersing agent and glass fibers having a particle length of about ¼ inch to about 1 inch are dispersed throughout the gypsum matrix.

Abstract: A waterproof cements mortar or concrete compound is described. The waterproof compound contains a synergically effective quantity of a composition of water repelling and water reducing agents that are added to the waterproof compound as it is manufactured. Also described are synergic compositions for waterproofing and manufacturing methods for producing said waterproof compounds.

Abstract: The preparation of gypsum parts (dihydrate calcium sulfate) with high mechanical resistance is obtained with the aid of water layers with nanometric thickness. Calcium sulfate is used, dihydrate as well as hemihydrate, to obtain parts from these two materials, pure or mixed, especially to use in construction work, where the parts are prepared by compressing their slightly humidified powders.

Abstract: Disclosed are formulations adapted to form a foamed cementitious composition, the foamed cementitious composition itself, a method of forming a hydraulic binder foam, and a method of conveying and applying the resulting foam to a substrate. A pumpable cementitious slurry is formed, the slurry is mixed with a gas such as air, and is subjected to mechanically created turbulence to generate gas bubbles and create a foam, which preferably is stabilized by a foam stabilizing agent such as polyvinyl alcohol present in the slurry. The foam is then conveyed to a nozzle or other suitable dispense point from which it is applied, for example sprayed, preferably uniformly, onto a substrate to be coated. Prior to dispensing, a set accelerator is preferably injected, which causes the foam to gel, which in turn improves the hangability of the product on a substrate. The spray material adheres to the substrate and hardens to form an insulative coating on the substrate.

Abstract: The invention provides a set gypsum-containing product having increased resistance to permanent deformation and a method for preparing it comprising forming a mixture of a calcium sulfate material, water, and an appropriate amount of one or more enhancing materials chosen from condensed phosphoric acids, each of which comprises 2 or more phosphoric acid units; and salts or ions of condensed phosphates, each of which comprises 2 or more phosphate units. The mixture is then maintained under conditions sufficient for the calcium sulfate material to form a set gypsum material.

Abstract: The object of the invention is a drying compound comprising from 50 to 85% of FGD gypsum and/or natural or processed gypsum, in mass percentages based on the total mass of the compound, presenting the following particle size characteristics: (i) a d50 from 35 to 70 ?m and (ii) a span (d90?d10/d50) lower than 2. The object of the invention is also a preparation process of the compound according to the invention. Finally, the object of the invention is a building process of a structure using this compound.

Abstract: A materials system and methods are provided to enable the formation of articles by three dimensional printing. The materials system includes particulate mixtures having a whitening agent and a solid particulate additive comprising an acid, the latter adapted for modifying a cure rate of an infiltrant. The materials system also includes aqueous fluids including optical brightening agents.

Abstract: A cementitious veneer and laminate composition is provided. The cementitious laminate composition includes a substrate, a primer layer applied to the substrate, the primer layer comprising a mixture of polyvinyl alcohol catalyst, Portland cement, and sand; and a cementitious veneer layer applied to the primer layer, the veneer layer comprising a mixture of magnesium sulfate, filler, magnesium oxide, gypsum cement, and polyvinyl alcohol catalyst. The polyvinyl alcohol catalyst comprises a mixture of polyvinyl alcohol fibers dissolved in water and mixed with butylene carbonate. The veneer layer is applied to the substrate and primer layer by means including spraying and manual spreading. The veneer layer can be ornamentally manipulated either before or after curing of the veneer layer. The veneer composition can be formed into laminated tiles or panels for use in building applications.

Abstract: A kit for preparing a hardenable cementitious composition includes a pre-proportioned cementitious material component and at least one pre-formulated and pre-proportioned liquid additive component, wherein the cementitious material and liquid components are mixed with together to prepare a cementitious material that possesses end application properties. Also disclosed is a method for preparing a hardenable cementitious composition using the kit and a method for repairing a flas in a cementitious structure using the hardenable cementitious composition.

Abstract: Composition comprising water- and air-hardenable binders and its use notably to the preparation of a product having the aspect and the properties of a natural stone. Composition comprising water- and air-hardenable binders, exhibiting after hardening properties comparable at least to those of a natural stone or of a concrete, characterised in that it includes, as binders: natural and air-borne hydraulic lime, and moulding plaster.

Abstract: A gypsum slurry includes calcium sulfate hemihydrate, water and calcium sulfate dihydrate, where the calcium sulfate dihydrate is added downstream of the mixer. In an optional embodiment, the a gypsum slurry includes calcium sulfate hemihydrate, a polycarboxylate dispersant, water and coated calcium sulfate dihydrate. In this case, the hydrophilic, dispersible coating is selected to serve as a modifier to enhance the ability of the dispersant to fluidize the gypsum slurry.

Abstract: A cementitious composition including cement, water, and a rheology modifying additive (RMA) is provided. The inclusion of the RMA improves the cementitiuous composition's response to vibration, and dampens out differences due to minor fluctuations in initial slump of the composition. The RMA may include a dispersant for cementitiuous compositions. The cementitious composition may optionally include other admixtures or additives known in the industry. A method for making the cementitious composition is also provided.

Abstract: A gypsum composition comprising water, stucco, clay, an amine compound, a polyoxyalkylene, and a comb-branched copolymer is disclosed. The gypsum composition has improved fluidity. A method for preparing the gypsum composition is also disclosed. The method comprises mixing the components to form a slurry, casting the slurry into a product, and drying the product.

Abstract: A process for treating beta calcium sulfate hemihydrate is disclosed. The process comprises exposing beta calcium sulfate hemihydrate to steam at a pressure above atmospheric pressure.

Abstract: This method relates to making a joint compound that includes predispersing a dedusting agent in water to make a predispersed dedusting agent. Dry components, including at least one filler, are combined to make a dry mixture. Process water is pumped into a vessel and the predispersed dedusting agent is introduced to the vessel. The dry mixture is then added to the vessel and all components are blended to make a homogeneous product.

Abstract: A construction assembly includes a plurality of plaster boards, each of the plaster boards having a plaster body and at least one sheet of liner, the liner including an inner surface attached to the plaster body and an outer surface having an outer face; wherein said plaster boards are assembled creating at least one joint; and a joint-pointing coat jointing said plaster boards to form a substantially plane outer surface including the outer surface of said at least one joint and said outer surface of said liner, wherein the composition of the joint-pointing coat is adapted for the finishing of said at least one joint; wherein both the joint-pointing coat in the dry state and the outer face of the sheet of liner are adapted to form an overall surface having a substantially homogeneous coloration.

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 (CaSO4O.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: Methods and compositions for wellbore treating fluids, especially cementitious compositions that include interground cement clinker and zeolite, with and without gypsum.

Abstract: Methods for cementing and cement compositions are provided, wherein the cement composition comprises cementitious material and an aqueous suspension of zeolite and a chromate reducing agent.

Abstract: A conformable coating for application to a soil substrate for barrier, adhesive, and planting properties includes a mixture of recycled or virgin materials, including organic fibrous material from wood based material and cotton based material, and gypsum bearing materials to which an effective amount of psyllium and its processes derivatives are added to form a solids mixture, which is diluted with an amount of water sufficient to provide a flowable consistency.

Abstract: A building material adapted for controlling growth of vegetative fungi from spores having a compressed calcium sulfate layer, a paper layer over the sulfate layer, an adhesive for securing the paper layer to the sulfate layer; an amount of between about 30 wt % to 50 wt % of a salt of formic acid disposed on the paper layer thereby forming sheet rock with an ionic lattice on the surface to prevent vegetative growth from fungi spores, and a paint, an adhesive, a sealant, and an insulation each containing an antifungal amount of a salt of formic acid, such as potassium formate.

Abstract: A gypsum composition comprising water, stucco, clay, an amine compound, a polyoxyalkylene, and a comb-branched copolymer is disclosed. The gypsum composition has improved fluidity. A method for preparing the gypsum composition is also disclosed. The method comprises mixing the components to form a slurry, casting the slurry into a product, and drying the product.

Abstract: A method for producing a set gypsum-containing product comprising an interlocking matrix of set gypsum wherein said method comprises applying to said set gypsum one or more enhancing materials selected from the group consisting of phosphoric acid; condensed phosphoric acids, each of which comprises 2 or more phosphoric acid units; and salts or ions of condensed phosphates, each of which comprises 2 or more phosphate units, and monobasic salts or monovalent ions of orthophosphates.

Abstract: An apparatus for calcining gypsum including a housing having a bottom wall, open top, and a plurality of side walls extending therebetween. A fixture is located adjacent the open top for receiving gypsum from a source and transferring the gypsum into the housing. At least one burner is connected to the housing and operable for combusting an air-fuel mixture to heat the gypsum. At least one serpentine burner conduit extends from the burner through the housing and terminates through a support floor of the apparatus. The exhaust flow is then directed through a fluidization pad and into the gypsum to further heat the gypsum product. An agitation mechanism is operable to mix the gypsum adjacent the fluidization pad to prevent pockets of gypsum from coagulating and preventing fluidization of the gypsum.