A gypsum wallboard having a core with a central core layer and one or more densified layers is disclosed. At least one densified layer contains salt absorbent particles of zeolite and/or hydrotalcite to improve adhesion of the gypsum core to a cover sheet. Also, methods of making the gypsum wallboard and a wall system for employing the gypsum wallboard are disclosed.

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.

In general, the present invention is directed to a method of making a gypsum board. The method comprises: applying a phosphorus containing compound to a first gypsum composition to provide a phosphorus modified gypsum composition; calcining the phosphorus modified gypsum composition to provide a calcined gypsum composition; preparing a gypsum slurry by combining water and the calcined gypsum composition; depositing the gypsum slurry on a first facing material; providing a second facing material on the gypsum slurry; and allowing the calcined gypsum to convert to calcium sulfate dihydrate.

DTPA-coated synthetic calcined gypsum is provided with alpha-like properties and obtained by spray-coating the synthetic caclined gypsum with DTPA. Cementitious compositions comprising DTPA-coated synthetic calcined gypsum and low water demand are provided as well. Methods for controlling an open time of a cementitious slurry by increasing or decreasing the amount of DTPA-coated synthetic calcined gypsum in the slurry are provided as well.

The present invention provides a device for smelting and regenerating phosphogypsum using high-temperature ceramsite and method for using same, where a rotary kiln is used to accept high-temperature ceramic granules that have been calcined and formed. The residual heat of the high-temperature ceramic granules allows them to be fully mixed with the phosphogypsum. On one hand, the high temperature of the ceramic granules achieves high-temperature dehydration of the phosphogypsum. On the other hand, the porous adsorption property of the ceramic granules can facilitate full absorption of some harmful substances in the phosphogypsum, thereby realizing the purification of the phosphogypsum. In addition, because the dehydrated phosphogypsum is generally in a suspended state, the rotary kiln of the present invention is equipped with a discharge outlet at the end. The discharge outlet uses a combination of a cyclone dust aspirator and a baghouse dust collector, which can draw out the phosphogypsum that has been fully dehydrated and is suspended in the rotary kiln, thereby realizing its complete collection without any leakage and achieving zero pollution.

The present invention provides a device for smelting and regenerating phosphogypsum using high-temperature ceramsite and method for using same, where a rotary kiln is used to accept high-temperature ceramic granules that have been calcined and formed. The residual heat of the high-temperature ceramic granules allows them to be fully mixed with the phosphogypsum. On one hand, the high temperature of the ceramic granules achieves high-temperature dehydration of the phosphogypsum. On the other hand, the porous adsorption property of the ceramic granules can facilitate full absorption of some harmful substances in the phosphogypsum, thereby realizing the purification of the phosphogypsum. In addition, because the dehydrated phosphogypsum is generally in a suspended state, the rotary kiln of the present invention is equipped with a discharge outlet at the end. The discharge outlet uses a combination of a cyclone dust aspirator and a baghouse dust collector, which can draw out the phosphogypsum that has been fully dehydrated and is suspended in the rotary kiln, thereby realizing its complete collection without any leakage and achieving zero pollution.

The present disclosure relates generally to a water-resistant gypsum board including a gypsum core with a first major surface and a second, opposing major surface; a first liner having a first major surface and a second, opposing major surface, the first liner comprising at at least the first major surface thereof a condensation product of a polysiloxane comprising at least one silanol, the first major surface of the first liner being disposed against the first major surface of the gypsum core; and a second liner having a first major surface and a second, opposing major surface, the first major surface of the second liner being disposed against the second major surface of the gypsum core.

The present disclosure relates generally to a water-resistant gypsum board including a gypsum core with a first major surface and a second, opposing major surface; a first liner having a first major surface and a second, opposing major surface, the first liner comprising at at least the first major surface thereof a condensation product of a polysiloxane comprising at least one silanol, the first major surface of the first liner being disposed against the first major surface of the gypsum core; and a second liner having a first major surface and a second, opposing major surface, the first major surface of the second liner being disposed against the second major surface of the gypsum core.

The present disclosure provides a hydraulic phosphogypsum (PG)-based cementitious material, and a preparation method and use thereof, belonging to the technical field of cementitious materials. The present disclosure provides a hydraulic PG-based cementitious material, including the following raw materials: modified PG particles and an auxiliary active powder, where the modified PG particles have a dosage of 50 wt % to 95 wt %; the modified PG particles are obtained by conducting modification on original PG particles through a calcareous material, and the calcareous material has a mass 3% to 5% of that of the original PG particles; and the original PG particles have typical dimensions of: a length of 50 m to 200 m and an aspect ratio of 1.5 to 5; and at least 80% of materials in the auxiliary active powder have a particle size of less than or equal to 60 m. In the present disclosure, the hydraulic PG-based cementitious material adopts a particle accumulation method of gap grading. The modified PG particles have a dosage up to 95 wt %, and can form a hydraulic structure after hydration. Therefore, the cementitious material can be applied in various occasions.

Provided are a bubble-containing gypsum slurry and a method for producing the same, whereby, in bubble-containing gypsum slurries of the same specific gravity, a bubble size in the gypsum slurry can be increased with a small amount of a foaming component.

A bubble-containing gypsum slurry containing, a hydraulic powder containing gypsum, water, the following component (A1), optionally the following component (A2), and the following component (B), component (A1): an alkyl or alkenyl sulfate or a salt thereof, component (A2): one or more selected from surfactants other than component (A1), and component (B): a nonionic compound with a Log P of 0 or more and 3.0 or less, wherein a mass ratio of a content of component (B) to a total content of components (A1) and (A2), (B)/[(A1)+(A2)], is 0.05 or more and 0.5 or less.