autoclave process gypsum to alpha hemihydrate

autoclave process gypsum to alpha hemihydrate

Autoclave (Alpha Hemihydrate) - Gypmak

Autoclave (Alpha Hemihydrate) The chemical structure of alpha gypsum (CaSO4 + 1 / 2H2O) is the same as the beta plaster. There are differences in crystal structure resulting from the production process. For the production of alpha plaster high pressure autoclave kiln is used. Autoclave is a word of Greek origin and means self-locking.

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Autoclave‐Free Formation of α‐Hemihydrate Gypsum

Autoclave‐Free Formation of α‐Hemihydrate Gypsum. March 2005. Journal of the American Ceramic Society 74 (5):1117 - 1124. DOI: 10.1111/j.1151-2916.1991.tb04351.x. Authors: Alfred Zürz ...

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Process for making calcium sulfate alpha-hemihydrate

In this process, calcium sulfate dihydrate pieces, namely naturally occurring gypsum pieces, are fed to an autoclave and are converted to calcium sulfate alpha-hemihydrate pieces in the autoclave in the presence of saturated steam at a temperature of 130° to 135° C.

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PRODUCTION OF CALCIUM SULPHATE ALPHA

2000-12-4 · resulting alpha-hemihydrate developed at various ratios and had different properties, depending on the acid solution concentration and the gypsum/acid solution mixing ratio. An alpha-hemihydrate composed of smooth, compact, acicular monocrystals, which according to reference data promises the best utilitarian aspect, was obtained using 20 wt.% acid

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Process for preparing calcium sulfate alpha hemihydrate ...

1990-1-26 · FIELD OF THE INVENTION. The invention relates to a process for the preparation of calcium sulfate alpha hemihydrate. THE RELATED ART. Various processes are known for the preparation of calcium sulfate alpha hemihydrate, namely so-called wet processes, wherein raw gypsum is continuously passed in a suspension through an autoclave and converted to calcium sulfate

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Alpha Gypsum: k-sentials

ALPHA SPECIAL GYPSUMS - FROM FGD GYPSUM TO HEMIHYDRATE. They prove their benefits day to day particularly in the building materials industry, and have been incorporated in Knauf products for decades. Even customers from other sectors have come to appreciate their excellent product properties. With Blaine values of ≥ 1700 to ≥ 2900 cm²/g ...

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Preparation of alpha-calcium sulfate hemihydrate from

2016-6-15 · This work develops a new class of salt solution method to prepare alpha-calcium sulfate hemihydrate (α-HH) from flue gas desulfurization (FGD) gypsum in trace K 2 SO 4-contained 4.0 M Ca(NO 3) 2 aqueous solution at 95 °C under atmospheric pressure. The driving force for the phase transition is provided by the concentrated Ca(NO 3) 2 solution through decreasing the water activity.

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Synthesis of alpha hemihydrate particles with lithium and ...

2017-7-15 · The hydrothermal method is efficient in synthesizing alpha calcium sulfate hemihydrate (α-CSH) particles from flue gas desulfurization gypsum. This study investigates the effects of LiCl·H 2 O solution with different carboxylates on the conversion process. Under optimal operating conditions, hexahedral column shaped crystals are obtained to ...

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Pilot scale preparation of α-calcium sulfate hemihydrate ...

2012-8-1 · Brosig A. Calcining technologies for the conversion of FGD gypsum into alpha and beta hemihydrate gypsum. In: Proceedings of the 6th international conference on natural and FGD gypsum, Toronto, Ontario, Canada, May 2000; Process Research

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Autoclave‐Free Formation of α‐Hemihydrate Gypsum

Autoclave‐Free Formation of α‐Hemihydrate Gypsum. March 2005. Journal of the American Ceramic Society 74 (5):1117 - 1124. DOI: 10.1111/j.1151-2916.1991.tb04351.x. Authors: Alfred Zürz ...

Read More
Preparation of alpha-calcium sulfate hemihydrate from

2016-6-15 · This work develops a new class of salt solution method to prepare alpha-calcium sulfate hemihydrate (α-HH) from flue gas desulfurization (FGD) gypsum in trace K 2 SO 4-contained 4.0 M Ca(NO 3) 2 aqueous solution at 95 °C under atmospheric pressure. The driving force for the phase transition is provided by the concentrated Ca(NO 3) 2 solution through decreasing the water activity.

Read More
Pilot scale preparation of α-calcium sulfate hemihydrate ...

2012-8-1 · Brosig A. Calcining technologies for the conversion of FGD gypsum into alpha and beta hemihydrate gypsum. In: Proceedings of the 6th international conference on natural and FGD gypsum, Toronto, Ontario, Canada, May 2000; Process Research

Read More
Synthesis of alpha hemihydrate particles with lithium and ...

2017-7-15 · The hydrothermal method is efficient in synthesizing alpha calcium sulfate hemihydrate (α-CSH) particles from flue gas desulfurization gypsum. This study investigates the effects of LiCl·H 2 O solution with different carboxylates on the conversion process. Under optimal operating conditions, hexahedral column shaped crystals are obtained to ...

Read More
Process for preparing calcium sulfate alpha hemihydrate ...

1990-1-26 · FIELD OF THE INVENTION. The invention relates to a process for the preparation of calcium sulfate alpha hemihydrate. THE RELATED ART. Various processes are known for the preparation of calcium sulfate alpha hemihydrate, namely so-called wet processes, wherein raw gypsum is continuously passed in a suspension through an autoclave and converted to calcium sulfate

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PROCESS FOR PRODUCING ALPHA-HEMIHYDRATE

2008-2-14 · A process for producing alpha-hemihydrate gypsum from dihydrate gypsum, comprising: mixing the dihydrate gypsum with water to form a slurry; pumping the slurry into a heating tube at a flowrate effective for the slurry to have an average residence time in the heating tube of less than or equal to about 10 minutes; heating the heating tube at a ...

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PRODUCTION OF CALCIUM SULPHATE ALPHA

2000-12-4 · resulting alpha-hemihydrate developed at various ratios and had different properties, depending on the acid solution concentration and the gypsum/acid solution mixing ratio. An alpha-hemihydrate composed of smooth, compact, acicular monocrystals, which according to reference data promises the best utilitarian aspect, was obtained using 20 wt.% acid

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Alpha-Type Calcium Sulfate Hemihydrate Compositions -

2008-6-26 · Transformation of the calcium sulfate dihydrate to alpha-hemihydrate by this process usually takes at least six hours. The autoclave is then emptied. The alpha-hemihydrate gypsum is introduced into a drying chamber in the baskets and dried under standard pressure at

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A Facile Synthesis Process and Evaluations of α-Calcium ...

Alpha-calcium sulfate hemihydrate (α-HH) has been used effectively in grafting through its desired features to support bone regeneration. In recent years, many synthetic methods have been proposed. Among them, the autoclave method for manufacturing α-HH is best suited for cost-savings due to its simple operation and limited use of additives.

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Determination of Calcium Sulfate Hemihydrate

2016-1-1 · For alpha-hemihydrate the obtained values of microstress are 0.00011...0.00044, for beta-hemihydrate they exceed 0.001. ... Introduction It is common knowledge thatdepending on calcination conditions of gypsum rock different forms of calcium sulfate hemihydrate can be obtained. Thermal treatment of gypsum rockcarried out either in autoclave in ...

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PRODUCTION OF CALCIUM SULPHATE ALPHA

2000-12-4 · resulting alpha-hemihydrate developed at various ratios and had different properties, depending on the acid solution concentration and the gypsum/acid solution mixing ratio. An alpha-hemihydrate composed of smooth, compact, acicular monocrystals, which according to reference data promises the best utilitarian aspect, was obtained using 20 wt.% acid

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Autoclaved gypsum plaster from selenite and by-product ...

Investigations were carried out to produce an autoclaved gypsum plaster (α-hemihydrate) by heating the naturally occurring selenite and by-product phosphogypsum under steam pressure in an autoclave.

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Studies on the Preparation of Calcium Sulfate Hemihydrate ...

Studies on the Preparation of Calcium Sulfate Hemihydrate by an Autoclave Process. ... The preparation of α-hemihydrate gypsum (α-HH) is an important way to achieve high-value utilization of FGD ...

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Lump process alpha gypsum - United States Gypsum

An improved "lump" process for producing alpha gypsum, calcium sulfate hemihydrate, from natural gypsum rock of the type wherein lumps of gypsum rock particles (a minimum of about 1/2 inch or 1.3 cm. in size) are calcined to low water-demand alpha hemihydrate by autoclaving in a saturated steam atmosphere, quickly dried and pulverized is disclosed.

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Distribution behavior of arsenate into α-calcium sulfate ...

Transforming gypsum into α-calcium sulfate hemihydrate (α-HH) provides a promising utilization pathway for the abundant amount of chemical gypsum. The transformation follows the route of "dissolution-recrystallization", during which the arsenic pollutant in gypsum is released into the solution, and

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Preparation of alpha-calcium sulfate hemihydrate from

2016-6-15 · This work develops a new class of salt solution method to prepare alpha-calcium sulfate hemihydrate (α-HH) from flue gas desulfurization (FGD) gypsum in trace K 2 SO 4-contained 4.0 M Ca(NO 3) 2 aqueous solution at 95 °C under atmospheric pressure. The driving force for the phase transition is provided by the concentrated Ca(NO 3) 2 solution through decreasing the water activity.

Read More
Pilot scale preparation of α-calcium sulfate hemihydrate ...

2012-8-1 · Brosig A. Calcining technologies for the conversion of FGD gypsum into alpha and beta hemihydrate gypsum. In: Proceedings of the 6th international conference on natural and FGD gypsum, Toronto, Ontario, Canada, May 2000; Process Research

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PLASTER PLANT - Gypmak

Autoclave (Alpha Hemihydrate) ABOUT US Gyp to Inc. all the technologies that produce a gypsum and develop this technology and was founded with the goal of being a global leader in this sector.

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Review of Global Gypsum Conference & Exhibition 2019 ...

2019-10-24 · Three technologies currently exist for the production of alpha hemihydrate gypsum from phosphogypsum: the autoclave process, the hydrothermal process and the normal pressure salt process, but each has its own disadvantages, including high energy

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Transformation of flue gas desulfurization (FGD) gypsum

2021-11-4 · A novel way for transformation of flue gas desulfurization (FGD) gypsum, an industrial by-product to β-CaSO 4 ·0.5H 2 O whiskers is investigated for calcium sulfate rich alternative construction material. As the consumption of gypsum products is increasing in construction industry and limited amount of natural gypsum is available, herein facile water treatment is used to generate fine ...

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