NL7208446A - Calcium sulphate semihydrate - by roasting mixt of calcium sulphate anhydrite and semihydrate and/or dihydrate, and addi - Google Patents
Calcium sulphate semihydrate - by roasting mixt of calcium sulphate anhydrite and semihydrate and/or dihydrate, and addiInfo
- Publication number
- NL7208446A NL7208446A NL7208446A NL7208446A NL7208446A NL 7208446 A NL7208446 A NL 7208446A NL 7208446 A NL7208446 A NL 7208446A NL 7208446 A NL7208446 A NL 7208446A NL 7208446 A NL7208446 A NL 7208446A
- Authority
- NL
- Netherlands
- Prior art keywords
- calcium sulphate
- mixt
- semihydrate
- dihydrate
- roasting
- Prior art date
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
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Life Sciences & Earth Sciences (AREA)
- Geology (AREA)
- Inorganic Chemistry (AREA)
- Compounds Of Alkaline-Earth Elements, Aluminum Or Rare-Earth Metals (AREA)
Abstract
Calcium sulphate hemihydrate, for use in the gypsum industry, is prepd. from a mixt. of calcium sulphate-anhydrite and calcium sulphate hemihydrate and/or dihydrate by (a) roasting the mixt. at above 200 degrees C, esp. 450 degrees C, (b) cooling, and (c) adding calcium sulphate dihydrate to the mixt. when it is cooled to 200-250 degrees C in such an amount that a stoichiometric water of hydration content is produced, and practically the whole mixt. is converted into calcium sulphate hemihydrate. Large scale economical prodn. esp. from waste gypsum produced from phosphoric acid prepn.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
NL7208446A NL7208446A (en) | 1972-06-20 | 1972-06-20 | Calcium sulphate semihydrate - by roasting mixt of calcium sulphate anhydrite and semihydrate and/or dihydrate, and addi |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
NL7208446A NL7208446A (en) | 1972-06-20 | 1972-06-20 | Calcium sulphate semihydrate - by roasting mixt of calcium sulphate anhydrite and semihydrate and/or dihydrate, and addi |
Publications (1)
Publication Number | Publication Date |
---|---|
NL7208446A true NL7208446A (en) | 1973-12-27 |
Family
ID=19816315
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
NL7208446A NL7208446A (en) | 1972-06-20 | 1972-06-20 | Calcium sulphate semihydrate - by roasting mixt of calcium sulphate anhydrite and semihydrate and/or dihydrate, and addi |
Country Status (1)
Country | Link |
---|---|
NL (1) | NL7208446A (en) |
-
1972
- 1972-06-20 NL NL7208446A patent/NL7208446A/en unknown
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