GB1297535A - - Google Patents

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Publication number
GB1297535A
GB1297535A GB1297535DA GB1297535A GB 1297535 A GB1297535 A GB 1297535A GB 1297535D A GB1297535D A GB 1297535DA GB 1297535 A GB1297535 A GB 1297535A
Authority
GB
United Kingdom
Prior art keywords
hemihydrate
dihydrate
dehydration
rehydration
impure
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed filed Critical
Publication of GB1297535A publication Critical patent/GB1297535A/en
Expired legal-status Critical Current

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01F—COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM, CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THE RARE-EARTH METALS
    • C01F11/00—Compounds of calcium, strontium, or barium
    • C01F11/46—Sulfates
    • C01F11/466—Conversion of one form of calcium sulfate to another
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01F—COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM, CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THE RARE-EARTH METALS
    • C01F11/00—Compounds of calcium, strontium, or barium
    • C01F11/46—Sulfates
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B11/00—Calcium sulfate cements
    • C04B11/02—Methods and apparatus for dehydrating gypsum
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2004/00—Particle morphology
    • C01P2004/60—Particles characterised by their size
    • C01P2004/61—Micrometer sized, i.e. from 1-100 micrometer
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2006/00—Physical properties of inorganic compounds
    • C01P2006/10—Solid density

Landscapes

  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Ceramic Engineering (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Geology (AREA)
  • Inorganic Chemistry (AREA)
  • Materials Engineering (AREA)
  • Structural Engineering (AREA)
  • Compounds Of Alkaline-Earth Elements, Aluminum Or Rare-Earth Metals (AREA)

Abstract

1297535 Calcium sulphate hemihydrate GIULINI GmbH GEB 14 May 1970 23496/70 Heading C1A Calcium sulphate hemihydrate is prepared from impure dihydrate in a process comprising an initial dehydration to form hemihydrate and/or soluble anhydute, carried out at above 100‹ C. (e.g. at 120‹ C.) and which may be a dry calcination or hydrothermal dehydration, rehydration of the hemihydrate produced, by suspending in an excess of water at an elevated temperature below 100‹ C. (e.g. 80-95‹ C.), to reform the dihydrate, and conversion of this dihydrate into hemihydrate by either dry calcination or hydrothermal dehydration after separation from the mother liquor. The impure gypsum may be phosphoric acid gypsum or the reaction product of SO 2 with Ca(OH) 2 . Crystallization influencing substances (e.g. magnesium sulphate) may be added during the rehydration.
GB1297535D 1970-05-14 1970-05-14 Expired GB1297535A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB2349670 1970-05-14

Publications (1)

Publication Number Publication Date
GB1297535A true GB1297535A (en) 1972-11-22

Family

ID=10196564

Family Applications (1)

Application Number Title Priority Date Filing Date
GB1297535D Expired GB1297535A (en) 1970-05-14 1970-05-14

Country Status (1)

Country Link
GB (1) GB1297535A (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2640961A1 (en) * 1988-12-22 1990-06-29 Lafarge Platres
WO1990014309A1 (en) * 1989-05-23 1990-11-29 Lafarge Coppee Process for the preparation of purified calcium sulphate dihydrate by aqueous means
EP0818427A2 (en) * 1996-07-08 1998-01-14 SICOWA Verfahrenstechnik für Baustoffe GmbH & Co. KG Process for producing pure calcium sulfate beta-hemihydrate

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2640961A1 (en) * 1988-12-22 1990-06-29 Lafarge Platres
EP0378837A1 (en) * 1988-12-22 1990-07-25 Lafarge Coppee Preparation of calcium sulfate dihydrate having an elongated crystalline structure
WO1990014309A1 (en) * 1989-05-23 1990-11-29 Lafarge Coppee Process for the preparation of purified calcium sulphate dihydrate by aqueous means
FR2647433A1 (en) * 1989-05-23 1990-11-30 Lafarge Coppee Da PROCESS FOR THE AQUEOUS PREPARATION OF PURIFIED CALCIUM SULFATE
EP0406550A1 (en) * 1989-05-23 1991-01-09 Lafarge Coppee Process for the preparation of purified calcium sulfate dihydrate from aqueous solutions
EP0818427A2 (en) * 1996-07-08 1998-01-14 SICOWA Verfahrenstechnik für Baustoffe GmbH & Co. KG Process for producing pure calcium sulfate beta-hemihydrate
EP0818427A3 (en) * 1996-07-08 1998-01-28 SICOWA Verfahrenstechnik für Baustoffe GmbH & Co. KG Process for producing pure calcium sulfate beta-hemihydrate

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Legal Events

Date Code Title Description
PS Patent sealed
PLNP Patent lapsed through nonpayment of renewal fees