A fluidized-bed-type apparatus and method for treating gypsum, which activates or improves fluidity of gypsum powder to promote an effect of treatment of gypsum, such as modification or homogenization of the gypsum powder. The apparatus for treating gypsum includes a reactor vessel, a conditioned air supply port, a horizontal partition wall and a plurality of stationary vanes. The wall allows a conditioned air flow to flow upward into a reaction region. The vanes are arranged at an angular interval in a circumferential direction. A fluidized bed of calcined gypsum is provided in the vessel. The vane deflects the conditioned air flow flowing upward into the reaction region, toward a radially outward and circumferential direction of the reaction region. The calcined gypsum makes a saltational fluid motion or saltational movement in the vessel with the air flow.

A fluidized-bed-type apparatus and method for treating gypsum, which activates or improves fluidity of gypsum powder to promote an effect of treatment of gypsum, such as modification or homogenization of the gypsum powder. The apparatus for treating gypsum includes a reactor vessel, a conditioned air supply port, a horizontal partition wall and a plurality of stationary vanes. The wall allows a conditioned air flow to flow upward into a reaction region. The vanes are arranged at an angular interval in a circumferential direction. A fluidized bed of calcined gypsum is provided in the vessel. The vane deflects the conditioned air flow flowing upward into the reaction region, toward a radially outward and circumferential direction of the reaction region. The calcined gypsum makes a saltational fluid motion or saltational movement in the vessel with the air flow.

The present invention is directed to a construction chemical composition for the preparation of gypsum articles, said construction chemical composition comprising fine calcium sulfate and a dispersant being a polyarylether. Further the present invention is directed to a process for preparing said construction chemical composition as well as an article comprising said construction chemical composition.

The present invention is directed to a construction chemical composition for the preparation of gypsum articles, said construction chemical composition comprising fine calcium sulfate and a dispersant being a polyarylether. Further the present invention is directed to a process for preparing said construction chemical composition as well as an article comprising said construction chemical composition.

An accelerator for accelerating the rate of hydration of calcined gypsum is disclosed. The accelerator comprises calcium sulfate dihydrate particles and a starch. The starch has a cold water solubility of at least about 25% (e.g., at least about 35%) and a viscosity of about 25 Brabender Units (BU) or less when the starch is in a 30% aqueous slurry at 92° C. Also disclosed are a method of preparing an accelerator, method of hydrating stucco to form set gypsum, slurry, and method of making gypsum board.

An accelerator for accelerating the rate of hydration of calcined gypsum is disclosed. The accelerator comprises calcium sulfate dihydrate particles and a starch. The starch has a cold water solubility of at least about 25% (e.g., at least about 35%) and a viscosity of about 25 Brabender Units (BU) or less when the starch is in a 30% aqueous slurry at 92° C. Also disclosed are a method of preparing an accelerator, method of hydrating stucco to form set gypsum, slurry, and method of making gypsum board.

A fluidized-bed-type apparatus and method for treating gypsum, which activates or improves fluidity of gypsum powder to promote an effect of treatment of gypsum, such as modification or homogenization of the gypsum powder. The apparatus for treating gypsum includes a reactor vessel, a conditioned air supply port, a horizontal partition wall and a plurality of stationary vanes. The wall allows a conditioned air flow to flow upward into a reaction region. The vanes are arranged at an angular interval in a circumferential direction. A fluidized bed of calcined gypsum is provided in the vessel. The vane deflects the conditioned air flow flowing upward into the reaction region, toward a radially outward and circumferential direction of the reaction region. The calcined gypsum makes a saltational fluid motion or saltational movement in the vessel with the air flow.

A fluidized-bed-type apparatus and method for treating gypsum, which activates or improves fluidity of gypsum powder to promote an effect of treatment of gypsum, such as modification or homogenization of the gypsum powder. The apparatus for treating gypsum includes a reactor vessel, a conditioned air supply port, a horizontal partition wall and a plurality of stationary vanes. The wall allows a conditioned air flow to flow upward into a reaction region. The vanes are arranged at an angular interval in a circumferential direction. A fluidized bed of calcined gypsum is provided in the vessel. The vane deflects the conditioned air flow flowing upward into the reaction region, toward a radially outward and circumferential direction of the reaction region. The calcined gypsum makes a saltational fluid motion or saltational movement in the vessel with the air flow.

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.

A method of producing a supplementary cementitious material, includes providing at least one waste material selected from quarry sludge, aggregate washing sludge and road cleaning sludge, removing excess water from said waste material so as to provide a dry waste material, and either: mixing the dry waste material with a source of calcium sulphate to obtain a raw material mixture, and calcining the raw material mixture at a temperature of 700-900 C. to obtain the supplementary cementitious material, or: calcining the dry waste material at a temperature of 700-900 C. to obtain a calcined waste material, and mixing the calcined waste material with a calcined source of calcium sulphate to obtain the supplementary cementitious material.