A method of producing a gypsum binder, the method including dehydrating of gypsum raw material lumps by heating in a gaseous medium with further drying, cooling, and milling stages, wherein the heating gypsum raw material lumps is performed either by: (i) placing the lumps in a heating medium set to a temperature exceeding the temperature under which dehydration and formation of gypsum α-hemihydrate occurs; and/or (ii) placing the lumps in a heating medium having a high rate of temperature increase such that a temperature higher than the temperature under which dehydration and formation of gypsum α-hemihydrate occurs is reached; wherein a heating time is selected sufficient for completion of the process of gypsum α-modification formation within the gypsum lumps, and wherein the heating is performed under atmospheric pressure through lump surface.

A method of producing a gypsum binder, the method including dehydrating of gypsum raw material lumps by heating in a gaseous medium with further drying, cooling, and milling stages, wherein the heating gypsum raw material lumps is performed either by: (i) placing the lumps in a heating medium set to a temperature exceeding the temperature under which dehydration and formation of gypsum α-hemihydrate occurs; and/or (ii) placing the lumps in a heating medium having a high rate of temperature increase such that a temperature higher than the temperature under which dehydration and formation of gypsum α-hemihydrate occurs is reached; wherein a heating time is selected sufficient for completion of the process of gypsum α-modification formation within the gypsum lumps, and wherein the heating is performed under atmospheric pressure through lump surface.

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 process for manufacturing pellets includes providing a first supply of a first material and a second supply of a binder including a second material in respective storage units. The first supply of the first material is mixed in a counter-current mixer with the second supply of the binder and water to produce a plurality of pellets. The mixing occurs simultaneously with pelletizing in the mixer. The plurality of pellets are discharged from the mixer.

A method of producing a gypsum binder, the method including dehydrating of gypsum raw material lumps by heating in a gaseous medium with further drying, cooling, and milling stages, wherein the heating gypsum raw material lumps is performed either by: (i) placing the lumps in a heating medium set to a temperature exceeding the temperature under which dehydration and formation of gypsum -hemihydrate occurs; and/or (ii) placing the lumps in a heating medium having a high rate of temperature increase such that a temperature higher than the temperature under which dehydration and formation of gypsum -hemihydrate occurs is reached; wherein a heating time is selected sufficient for completion of the process of gypsum -modification formation within the gypsum lumps, and wherein the heating is performed under atmospheric pressure through lump surface.

A method of producing a gypsum binder, the method including dehydrating of gypsum raw material lumps by heating in a gaseous medium with further drying, cooling, and milling stages, wherein the heating gypsum raw material lumps is performed either by: (i) placing the lumps in a heating medium set to a temperature exceeding the temperature under which dehydration and formation of gypsum -hemihydrate occurs; and/or (ii) placing the lumps in a heating medium having a high rate of temperature increase such that a temperature higher than the temperature under which dehydration and formation of gypsum -hemihydrate occurs is reached; wherein a heating time is selected sufficient for completion of the process of gypsum -modification formation within the gypsum lumps, and wherein the heating is performed under atmospheric pressure through lump surface.