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.

A new integrated method to capture polluted CO.sub.2 using CaO produced from phosphogypsum calcination using sulfur as non-CO.sub.2 fuel where (1) both pollutants of phosphogypsum and CO.sub.2 are transformed into environmentally neutral or useful products such as limestone or clinker and sulfuric acid; (2) low-CO.sub.2 CaO produced from calcination of phosphogypsum with sulfur as fuel can be used to produce low-CO.sub.2 clinker that replaces the use of high-CO.sub.2 limestone as raw material; (3) the use of sulfur as fuel to calcine phosphogypsum allows the production of low-cost sulfuric acid.

A method of recovering desalinated activated alumina (AA) beads from a composition including salt laden (high salt absorbed) activated alumna (AA) beads and free anions and free cations, comprising the step of electrodialysis of the composition to reduce salt content of the activated alumina (AA) beads to produce a stream comprising the desalinated activated alumina (AA) beads.

A method of recovering desalinated activated alumina (AA) beads from a composition including salt laden (high salt absorbed) activated alumna (AA) beads and free anions and free cations, comprising the step of electrodialysis of the composition to reduce salt content of the activated alumina (AA) beads to produce a stream comprising the desalinated activated alumina (AA) beads.

A new integrated method to capture polluted CO.sub.2 using CaO produced from phosphogypsum calcination using sulfur as non-CO.sub.2 fuel where (1) both pollutants of phosphogypsum and CO.sub.2 are transformed into environmentally neutral or useful products such as limestone or clinker and sulfuric acid; (2) low-CO.sub.2 CaO produced from calcination of phosphogypsum with sulfur as fuel can be used to produce low-CO.sub.2 clinker that replaces the use of high-CO.sub.2 limestone as raw material; (3) the use of sulfur as fuel to calcine phosphogypsum allows the production of low-cost sulfuric acid.

In one aspect, a pottery plaster formulation with increased water absorption, comprising alpha stucco, continuously-calcined-in-a-kettle stucco, and a combination of Rochelle salt and one or more of the following: potassium sulfate and/or a phosphate compound. In another aspect, pottery plaster molds with increased water absorption and methods of making and using the pottery plaster molds for slip casting ceramic items.

In one aspect, a pottery plaster formulation with increased water absorption, comprising alpha stucco, continuously-calcined-in-a-kettle stucco, and a combination of Rochelle salt and one or more of the following: potassium sulfate and/or a phosphate compound. In another aspect, pottery plaster molds with increased water absorption and methods of making and using the pottery plaster molds for slip casting ceramic items.

A method of processing plasterboards or plasterboard for recover a calcium sulphate source for producing a hydraulic binder, includes comminuting plasterboards or a gypsum fraction thereof so as to obtain plasterboard particles and, thereafter, subjecting the plasterboard particles to a heat treatment at an elevated temperature so as to volatilize and/or decompose organic components present in the plasterboard particles.

The invention pertains to a process for modifying gypsum, wherein a continuous feed of raw gypsum is provided; the water content of the raw gypsum is determined in the continuous feed by near infrared spectroscopy (NIR) measurement; the raw gypsum is calcined in a calcination unit at a fire rate to remove water from the raw gypsum and to obtain a continuous feed of calcined gypsum having a water content within a selected range; a water content of the calcined gypsum is determined by near infrared spectroscopy, and the fire rate is adjusted based on the water content of the raw gypsum and of the calcined gypsum. Further, the invention pertains to an apparatus for performing said process.