Abstract: A calcining kettle includes an outer kettle shell, an inner kettle shell, an interior heat exchanger assembly defining at least one tortuous path inside a volume defined by the inner kettle shell, and an agitator within the inner kettle shell. The inner kettle shell is disposed within the outer kettle shell such that the inner kettle shell and the outer kettle shell together at least partially define a jacket adjacent the inner kettle shell. The inner kettle shell and the interior heat exchanger assembly at least partially define a processing volume. The agitator is configured to rotate at least one paddle to cause movement of a feedstock material within the processing volume. A heating device may be structured and adapted to circulate a heat transfer fluid in the at least one tortuous path and the jacket. Calcining methods are also disclosed.

Abstract: A calcined gypsum treatment apparatus has an agitating type of cooler provided with a cooling region for cooling the calcined gypsum, and a moisture supplying device for incorporating moisture into the calcined gypsum. The moisture supplying device includes a humid gas-feeding port which introduces humid gas including moisture or steam, directly into the cooling region. The calcined gypsum is introduced through a calcined gypsum introduction port into the cooling region, and the moisture is incorporated into the calcined gypsum to modify the calcined gypsum. The humid gas-feeding port is positioned in vicinity to the calcined gypsum introduction port so as to allow the spouted or delivered flow of the humid gas to be brought into contact with the calcined gypsum immediately after introduced into the cooling region.

Abstract: What is needed is a system that a system that may allow a consumer to adapt a light source to customize a room. Accordingly, the present disclosure relates to a system that may be adapted to a range of features, wherein the system may convey a preference for a sport, sports team, college, or other source of fandom. In some embodiments, a sport cover may be integrated with a feature, such as a fan, wall mount, chandelier, or lamp. In some aspects, the sport cover may comprise a range of customizable attributes, such as colors, sounds, images, and sport cover types. According to the present disclosure, a consumer may change out the light fixture on the fan to with an adaptable or convertible sports cover.

Abstract: A joint compound system includes a set-inhibited, pre-wetted, setting-type, ready-mix joint compound and a set initiator. The set-inhibited, pre-wetted, setting-type joint compound includes a ready-mixed, setting-type joint compound base with a calcium-free phosphate set preventing agent that impedes chemical hydration of a gypsum component of the setting-type joint compound. The joint compound base is free of calcium carbonate. The set initiator includes alum to reinitiate the chemical hydration reactions.

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: The invention concerns an air box (1) in a regenerative thermal oxidiser comprising one or several beds (3) of a heat-storing and heat-transferring material. The air box (1) is connected with a gas inlet/outlet (2) and comprises a gas permeable surface (9) that is turned towards one of said beds (3). The air box (1) is further characterised in that distribution means (4) are provided in said air box (1).

Abstract: An apparatus for continuously calcining gypsum includes a flash calcining impact mill, a feed bin adjacent the impact mill for holding gypsum, and a gypsum feed control mechanism for supplying gypsum from the feed bin to the impact mill at a substantially constant rate. A method for continuously producing calcined gypsum includes the steps of providing a flash calcining impact mill and providing a feed bin adjacent the impact mill, the feed bin containing gypsum to be calcined. A gypsum feed control mechanism is provided for supplying gypsum from the feed bin to the impact mill. Gypsum is supplied from the feed bin to the impact mill at a substantially constant rate, and the impact mill is operated to dry, grind, and calcine the gypsum.

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: Both the drying and also the removal of the water crystalization take place carefully in a respective fluidized bed apparatus (A, B) without any danger of overheating. This is achieved by a complete homogenous fluidization through indirectly heated hot gas. A substantial quantity of energy is transferred via heat exchanger systems (4 or 12) in the fluidized layer. These are heated by heat carrying media. The constructional design of the fluidized bed apparatuses (A, B) which have a rectangular base outline ensures a narrow dwelltime spectrum and a pronounced temperature/moisture profile without the aid of differentially fluidized chambers. Because of the comparatively cold infeed zone and the careful heating which thereby arise the characteristics of the crystals are favourably influenced. The product is characterized by high quality homogenity. In the case of the calcining of moist gypsum no undesired gypsum modifications arise.

Abstract: In a process for the conversion of calcium sulfate dihydrate originating in flue gas desulfurization units into an alpha-hemihydrate, a salt solution is used as a medium. The salt solution consists substantially of concentrated scrubbing liquid from the flue gas desulfurization process containing alkali-earth chloride in a chloride concentration of 10% to 60% by weight.

Abstract: A process, and the product produced thereby, for the preparation of a waste solidification material from hardened fluorogypsum as a by-product of the manufacture of hydrofluoric acid by reacting fluorospar with sulfuric acid, removing hydrogen fluoride from the reaction product, slurrying the by-product with water, placing the slurried by-product fluorogypsum in settlement ponds until the fluorogypsum hardens, the hardened fluorogypsum having a pH of greater than about 5 to about 13, including heating the hardened fluorogypsum to evaporate substantially all water physically mixed with the fluorogypsum and further heating the fluorogypsum to reduce the water chemically bound to calcium sulfate in the fluorogypsum to form about 0.5% to about 9% by weight.

Abstract: A method for treating produced gypsum and, in particular, a method for treating flue-gas desulfurization gypsum forms highly active, modifiable gypsum binders of high strength with simultaneously drying, deagglomerating and dehydrating. Pursuant to the invention, produced gypsum (flue-gas desulfurization gypsum), with a particle size ranging up to 200 .mu.m, to which 10% by weight of milled natural gypsum is optionally added, is dehydrated at a material temperature of 335.degree. to 363.degree. K. and at a pressure ranging from 2.5 to 8 kpa, the dehydration being concluded when anhydrite III constitutes 50% to 100% by weight.

Abstract: The process makes calcium sulfate alpha-hemihydrate or essentially plaster of paris from finely divided gypsum made by desulfurizing flue gas obtain from a power plant fired by brown coal by transforming the calcium sulfate dihydrate in the presence of saturated steam. A molded body is formed from the calcium sulfate dihydrate which has a plurality of pores. The pore volume amounts to 15 to 60% by volume of the total volume of the entire molded body. More than 5% by volume of the pore volume contains air. The molded body is fed to an autoclave. In the presence of a sufficient water quantity in the pores, the crystal habit and the crystal growth of the calcium sulfate alpha-hemihydrate crystals which grow in an aqueous solution phase are controlled by a process temperature in the range between 110.degree. to 180.degree. C. by the pressure of the treatment atmosphere in the autoclave. The molded body is removed from the autoclave after recrystallization transformation and delivered for use.

Abstract: The process makes calcium sulfate alpha-hemihydrate from finely divided calcium sulfate dihydrate by transforming the calcium sulfate dihydrate in the presence of saturated steam. A molded body is formed from the calcium sulfate dihydrate which has a plurality of pores having a pore volume amounting to 15 to 60% by volume of the total volume of the entire molded body. More than 5% by volume of the pore volume contains air. The molded body is fed to the autoclave. In the presence of a sufficient water quantity in the pores the crystal habit and the crystal growth of the calcium sulfate alpha-hemihydrate crystals which grow in an aqueous solution phase are controlled by a process temperature in the range between 110.degree. to 180.degree. C. by the pressure of the process atmosphere in the autoclave. The molded body is removed from the autoclave after recrystallization transformation and delivered for use. Key products of this process and their derivatives are also described.

Abstract: In a method and apparatus for calcining calcium sulphate dihydrate or like heat sensitive material, in which a bed of the material is heated in a vessel (41) by the direct introduction of a hot gas through a tube (21) extending downwardly into the bed, the proportion of insoluble anhydrite (II) in the product is reduced by lowering the temperature of the hot gas before it contacts the material of the bed. This is done by indirect heat exchange through the wall of the tube 21 with a relatively cool substance, for example, powdered gypsum or recycled exhaust gases, in an outer tube (26). The cooling material in the outer tube contacts the material in the bed before the latter is contacted by the hot gas.

Abstract: The present invention relates to the coproduction of a combustible gas stream usable as an energy source, a sulfur-dioxide-containing second gas stream usable as a source of oxidant in the gasification of coal, and a sulfur-dioxide-containing third gas stream usable as a feedstock for the production of sulfuric acid. The process includes heating coal in a coal gasification zone in the presence of an oxygen and sulfur dioxide-containing atmosphere under partial coal gasifying conditions to produce a carbonaceous char and a crude coal gas stream. Sulfur-containing compounds are removed from the coal gas stream and converted to elemental sulfur. The carbonaceous char is combined with gypsum to form a feed mixture. The non-gypsum portion of the feed mixture contains sufficient reducing potential to release substantially all of the sulfur in the gypsum as gaseous compounds of sulfur in a +4 or lower oxidation state.

Abstract: A process, and the product produced thereby, for the preparation of a waste solidification material from hardened fluorogypsum as a by-product of the manufacture of hydrofluoric acid by reacting fluorospar with sulfuric acid, removing hydrogen fluoride from the reaction product, slurrying the by-product with water, placing the slurried by-product fluorogypsum in settlement ponds until the fluorogypsum hardens, the hardened fluorogypsum having a pH of about 3 to about 5, including heating the hardened fluorogypsum to evaporate substantially all water physically mixed with the fluorogypsum and further heating the fluorogypsum to reduce the water chemically bound to calcium sulfate in the fluorogypsum to from about 0.5% to about 9% by weight.

Abstract: Disclosed herein is a method for producing .alpha.-form gypsum hemihydrate, comprising heating an aqueous slurry containing gypsum dihydrate and a salt of sulfosuccinic acid as the catalyst for crystallization, thereby converting gypsum dihydrate into .alpha.-form gypsum hemihydrate.

Abstract: The present invention relates to the coproduction of a combustible feed gas stream useable as an energy source and a sulfur-containing second gas stream useable as a feedstock for the production of sulfuric acid. The process includes heating coal in the presence of an oxygen-lean atmosphere under partial coal gasifying conditions to produce a solid carbonaceous char and a crude coal-gas stream. Sulfur-containing compounds are removed from the coal gas stream and converted to solid sulfur-containing materials. The solid sulfur-containing materials are combined with the solid carbonaceous char and gypsum to form a feed mixture. The non-gypsum portion of the feed mixture contains sufficient reducing potential to release substantially all of the sulfur in the gypsum as gaseous compounds of sulfur in a +4 or lower oxidation state. The feed mixture is heated under reducing conditions to produce a sulfur-containing second gas stream and a solid sintered product.

Abstract: Wet chemical gypsum cake may be directly fed to a continuous kettle calciner to produce a stucco having lowered dispersed consistency. Pre-drying of the chemical gypsum is eliminated and the thus produced stucco may be used in the formulation of building plasters and in gypsum wallboard manufacture that will use less fuel for drying excess gauging water.

Abstract: A calcium sulfate anhydrite material is prepared from a spent absorbent resulting from desulfurization of flue gases. First the sulfite in the spent absorbent is oxidized into sulfate, preferably by heating in an oxygen containing gas, and thereafter the chloride content of the spent absorbent is reduced by heating the spent absorbent at a temperature of 600.degree.-950.degree., preferably 750.degree.-950.degree. C. together with fly ash. Said fly ash may be recovered together with the spent absorbent in the desulfurization process, or it may have been recovered separately and mixed with the spent absorbent.The product may be used as cement additive or for other purposes in which calcium sulfate anhydrite is conventionally utilized.

Abstract: An improved "lump" process for producing alpha gypsum, calcium sulfate hemihydrate, from natural gypsum rock of the type wherein lumps of gypsum rock particles (a minimum of about 1/2 inch or 1.3 cm. in size) are calcined to low water-demand alpha hemihydrate by autoclaving in a saturated steam atmosphere, quickly dried and pulverized is disclosed. The improvement allows the thorough processing of natural gypsum as large sized particles or containing considerable selenite and includes the steps of initiating calcination without crystal habit modifier and, after hemihydrate formation has commenced, adding crystal habit modifier and completing calcination under increased steam pressure.

Abstract: Fast-setting alpha calcium sulfate hemihydrate made from calcium sulfate dihydrate by hydrothermally recrystallizing calcium sulfate dihydrate to form a mixture containing 95%-99% by weight alpha calcium sulfate hemihydrate and 5 to 1% calcium sulfate dihydrate. The dihydrate in this mixture is then converted to beta calcium sulfate hemihydrate by calcining, except for a remainder of up to 0.5 percent of dihydrate, which remains in the mixture.

Abstract: Continuous calcination of gypsum is provided by uniformly feeding uncalcined gypsum into the calcining batch in a kettle to a location below the surface but above the uppermost agitator, and allowing calcined gypsum to be discharged from the kettle through a discharge outlet in the wall of the kettle at the top surface of the calcining gypsum.

Abstract: A continuous calciner, particularly advantageous in converting gypsum to plaster, with two coaxial cylindrical walls, provides for heating air within the inner cylinder and then directing the air, for conveying and heating fine particles, along a spiral path, between the walls of the two coaxial cylinders, extending from one end of the calciner to an exit at the second end.

Abstract: A method of preparing plaster by brief contact between gypsum and a hot gas. The method comprises introducing the gypsum through the axial tube of a nozzle, around which a helical stream of hot gases is created, and bringing the two phases into contact in a vessel at the outlet of the nozzle. The method of the invention makes it possible to vary the quality of plaster produced and to use either dry gypsum or dilute gypsum pastes as the starting material.

Abstract: Naturally occurring or man-produced calcium sulfate dihydrate is subjected to a process which involves concomitant flash calcination, utilizing co-current contact of the gypsum with a gaseous heat source, and self-comminutation to produce the insoluble calcium sulfate anhydrite in relatively pure and finely comminuted form without the use of specially-sized feed rock and extensive mechanically motivated grinding of the product required by prior means known in this art.