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Patents in Class 423/172

Continuous gypsum calcination process and kettle therefor 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...

US7897134B1 - System and method for calcining gypsum ...

A system ( 100 ) for calcining natural gypsum, synthetic gypsum ( 112 ) or a combination thereof, the system including: a mill ( 114 ) for grinding and drying natural gypsum, synthetic gypsum ( 112 ) or a combination thereof, to produce dried gypsum ( 116 ); a flash calciner ( 118 ) for calcining the dried gypsum to produce an exhaust gas ( 130 ) and calcined gypsum ( …

ABCs of Gypsum - Traditional Building

When the steam from this calcining process is allowed to evaporate freely the resulting plaster is known as a Greek lowercase "β-" or beta gypsum. Plaster of Paris, the β- gypsum form of calcium sulphate hemi-hydrate, is useful for running mouldings and casting and is commonly referred to by trade names such as moulding, casting or pottery ...

US Patent Application for CALCINING KETTLE Patent ...

A plurality of burners is located within the calcining chamber and displaced from the air pad and the at least one rake in a direction toward the dust collecting chamber. The burners being disposed within a bed of gypsum that is …

Calcining processes for natural and synthetic gypsum ...

Calcination in a rotary kiln is a direct, long-time calcining process. During the process, the phases of the CaSO 4 x H 2 O system can be optimally adjusted. Rotary kilns are used for the calcining natural gypsum. In this process, pre-crushed natural gypsum is calcined in parallel flow with the flue gas.

11.16 Gypsum Manufacturing - US EPA

calciners may be operated in either batch or continuous mode. In flash calciners, the gypsum is directly contacted with hot gases, and the stucco product is collected at the bottom of the calciner. At some gypsum plants, drying, grinding, and calcining are performed in heated impact mills. In these mills hot gas contacts gypsum as it is ground.

Continuous gypsum calcination process and kettle therefor ...

The continuous calcination of gypsum process consists of feeding, at a uniform rate, finely ground gypsum, by the drag chain 52, through duct 44 and chute 46, to substantially below the surface 48 of the calcining gypsum 50. Heat is applied to the calcining gypsum from heat source 22. The temperature of the calcining gypsum, at about 10 inches ...

Influence of the Calcination Temperature of Synthetic ...

on the binding properties of innovative gypsum pastes, as well as on masonry and plastering mortars. The calcination process of gypsum binder was carried out at four di erent temperatures ranging from 170 to 190 C. The specimens for testing were prepared on the basis of the obtained raw material with a constant water to gypsum ratio of w/g = 0.75.

Gypsum Drywall | Construction & Demolition Recycling ...

Gypsum drywall consists of approximately 90% gypsum and 10% paper facing and backing. Drywall is manufactured by first calcining the gypsum, a process that heats the mineral to remove part of the water (resulting in CaSO4.1/2H2O). The stucco that is formed is then rehydrated by mixing with water, and the slurry created is spread onto a moving ...

Recycling of phosphogypsum to prepare gypsum plaster ...

Değirmenci used β-hemihydrate PG by calcining at 150 °C to manufacture water-resistance building products. Garg et al. prepared gypsum plaster by heating PG at 150–160 °C. To sum up, calcination achieved better purification …

Gypsum and Gypsum products. Gypsum and Gypsum products …

Gypsum and Gypsum products are available in different forms. Gypsum is chemically known as Calcium sulfate dihydrate. It is a white powdery mineral widely found in nature. It is mainly used for…

gypsum and different types - vornaco

According to the production of gypsum, it is divided into two classes, α-alpha and β-beta gypsum plaster. Alpha gypsum is made by calcining gypsum stone under high pressure. Calcination is a process that drives out the moisture in a substance by heating it to a specific temperature. β-type is made by using a wok or rotary kiln open device.

US Patent for Process for continuously calcining gypsum to ...

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.

Calcination Temperature of Gypsum - bulk-online.com

Calcination Temperature of Gypsum. Dear Engineer, Please note that calcination temp. depends upon the followings--. 1. Raw material quality. 2. Type of calcining--Kettle type calciner or Horizontal rotary kiln. The temp may varies from 80- 400 deg. Anil Seth.

Gypsum calcination - National Gypsum Company

As the calcining gypsum moves downward through the calcining cylinder 26 it is centrifugally forced away from the central axis by the rapidly spiralling hot air. As the gypsum moves downward through the discharge section 30, the frusto-conical shape directs the calcined gypsum inwardly to a central axial opening 88, and thence to a rotary valve 90.

US5437850A - Method for calcining moist gypsum - …

In the case of the calcining of moist gypsum no undesired gypsum modifications arise. Both the drying and also the removal of the water crystalization take place carefully in …

Background Information for the Non-Metallic Minerals ...

A Superior Companies Winkleman Gypsum Div. Dulin Gypsum Dalin Bausite Co. Inc. P Temple Gypsum A Weyerhauser Co. California . 3ypsum Flinkote Co.8 H. M. Holloway 4 Kaiser Cement and Gypsum Corp. * g Kaiser Cement and Gypsum Corp. A Kaiser Gypsum Co. National Gypsum Co. Gold Bond Building Products Q • National Gypsum Co. Gold Bond Building ...

Preparation of high-performance building gypsum by ...

High-performance building gypsum is prepared by FGD gypsum with the addition of CaO. • The CaO addition can broaden the temperature range for calcining FGD gypsum into β-HH. • Calcining FGD with 3 wt% CaO at 200 °C for 2 h to obtain grade 3.0 building gypsum. • Calcining FGD with 5 wt% CaO at 200 °C for 1.5 h to obtain grade 3.0 building gypsum.

Calcining processes for natural and synthetic gypsum ...

Calcination is the essential factor for high-quality further processing of gypsum. Grenzebach's calcining technologies ensure utmost precision in grinding, drying, calcining and classifying the gypsum. Contact Gypsum From raw material to stucco or high-fired plaster – with precisely matched technology TAILORED TO YOUR NEEDS

Grinding and calcining of gypsum with Pfeiffer grinding plants

Thanks to the relatively high temperature level in the gypsum calcining mill, the gypsum is simultaneously calcined. When gypsum is calcined in an atmosphere sat- urated with water vapour at an overpressure of several bars, a-hemihydrate is formed ( Fig. 1). The outstanding feature of this plaster is a relatively regular crystal form.

VOL. IX PART II THE GYPSUM OF MICHIGAN AND THE …

THE GYPSUM OF MICHIGAN AND THE PLASTER INDUSTRY BY G. P. GRIMSLEY ACCOMPANIED BY TWENTY-NINE PLATES PUBLISHED BY AUTHORITY OF THE LAWS OF MICHIGAN ... Four Flue Gypsum Calcining Kettle.....63 27. Cummer Continuous Calcining Kettle. (Sectional view) .64 28. Cummer Continuous Calcining Kettle.

Features and Benefits - Rapidwall

Gypsum (calcium sulphate dihydrate) is a material that calcines at a relatively low temperature (150°C - 180°C) to produce the required hemihydrate product. The proportions and forms of dihydrate, hemihydrate and anhydrite in the plaster product are very sensitive to calcining conditions, particularly temperature.

WO1988001257A1 - Highly efficient calcination of …

the method of this invention comprises charging gypsum into a calcining kettle, heating the kettle and causing the gypsum to become a boiling, …

Calcined gypsum | Article about calcined gypsum by The ...

United States Gypsum Company has been granted a patent for a mixture for use with water as a coating between an adhesive and a floor underlayment made with calcined gypsum.The mixture is comprised of approximately 10-50% by weight based on the mixture of a redispersible, latex polymer; from approximately 50-90% by weight based on the mixture of a surface enhancing …

Gypsum Products in Dentistry: Types, Uses, Properties ...

– Gypsum products are made from gypsum rock, which is a mineral found in various parts of the world. – Gypsum rock is mined, ground into a fine powder, and then processed by heating to form a variety of products. – Chemically, gypsum rock is calcium sulfate di hydrate (CaSO4·2H2O).

Hemihydrate - an overview | ScienceDirect Topics

Another effective method for synthetic gypsum calcining is the use of a horizontal impact calciner. It provides calcination of fine-grained material with high-moisture content. Production is up to 100 tonnes/h. Calcining is conducted in one stage (Gypsum Technik, 2014).

U.S. Gypsum Company | Asbestos Products & Mesothelioma Claims

Prior to the establishment of United States Gypsum Company, there were 30 different gypsum rock and plaster manufacturing companies operating independently in the United States. In 1902, the manufacturers merged together and consolidated their resources with a total of 37 mining and calcining plants.

Grinding and calcining of gypsum with Pfeiffer grinding …

The calcining of gypsum at ambient pressure and at a relatively low air humidity takes place much more frequently. The plaster obtained is b-hemihydrate. Its chemical formula is the same as that of a-hemihydrate. As, however, the crystal water escaping from the intermediate lattice struc -

Preparation of high-performance building gypsum by ...

The high-performance building gypsum can be prepared by calcining the FGD gypsum with 3–5 wt% of CaO addition at 160–220 °C for 1.5–2 h. The building gypsum, produced by the FGD gypsum with 3 wt% of CaO calcined at 160 °C for 1.5 h, meets the grade 1.6 requirements.

Process and apparatus for calcination of gypsum - KNAUF ...

The invention claimed is: 1. Process for dehydrating gypsum, wherein a continuous feed of raw gypsum is provided; 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 …

gypsum calciner With Enhanced Outputs Local After-Sales ...

After calcining, the qualified gypsum powder will be sent to spiral conveyor through hoist. The spiral conveyor will send the calcined gypsum powder to silo for storage, and cool the powder during the process. The dust remover is on the top of silo, the unqualified part will be sent to grinder until it's qualified.

Calcium sulfate | CaSO4 - PubChem

Of the total supply of crude gypsum, 24.5 million tons, including 800,000 tons of byproduct gypsum, 19.1 million tons was calcined for gypsum products, and 5.4 million tons was used mainly as a cement retarder or as agricultural land plaster. The calcined gypsum was sold as prefabricated products or as industrial or building plaster.

Dehydration behaviour and impurity change of phosphogypsum ...

Yang et al. obtained hemihydrate calcium sulfate by calcining PG at 135 °C. In order to obtain calcined gypsum, PG was heated in an electric oven at 150 °C for 2 h, and Garg et al. prepared β-hemihydrate gypsum at 150–160 °C for 4 h.

Calcium Sulphate: Structure, Hydrous and Anhydrous Forms ...

Ans. Plaster of Paris is a white powdered chemical product that is made up of hydrated calcium sulphate and is made by calcining gypsum. Plaster of Paris is made by heating gypsum to 423 degrees Fahrenheit, or 150 degrees Celsius, or 300 degrees Fahrenheit. CaSO 4 (0.5H 2 O) + 1.5H 2 O(CaSO 4) 2 H 2 O + heat (discharged as steam) Ques 2.

Gypsum mill for all requirements | Gebr. Pfeiffer

The intermediate product is calcined in the downstream gypsum calcining kettle. The product properties can be varied. The ground and calcined products with their medium to long setting times are mainly used as basic material in wall plaster or as molding plaster in the ceramic industry and as special plaster.

US20160340244A1 - Method of Curing A Gypsum Calcination ...

Gypsum (calcium sulphate dihydrate) was calcined in a calcination kettle at a temperature of 190° C. for about 1 hour. After calcining, further gypsum (calcium sulphate dihydrate) was added to the calcination product to provide a gypsum-enriched calcination product. This mixture was then transferred to a steam pressure vessel.