GB848617A - Improvements in or relating to the preparation of anhydrite - Google Patents
Improvements in or relating to the preparation of anhydriteInfo
- Publication number
- GB848617A GB848617A GB41377/58A GB4137758A GB848617A GB 848617 A GB848617 A GB 848617A GB 41377/58 A GB41377/58 A GB 41377/58A GB 4137758 A GB4137758 A GB 4137758A GB 848617 A GB848617 A GB 848617A
- Authority
- GB
- United Kingdom
- Prior art keywords
- slurry
- anhydrite
- acid
- sulphuric acid
- gypsum
- 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
Links
Classifications
-
- 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
- C04B11/05—Calcium sulfate cements obtaining anhydrite, e.g. Keene's cement
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Ceramic Engineering (AREA)
- Materials Engineering (AREA)
- Structural Engineering (AREA)
- Organic Chemistry (AREA)
- Compounds Of Alkaline-Earth Elements, Aluminum Or Rare-Earth Metals (AREA)
Abstract
Anhydrite, having a particle size of 0.4 to 0.8 microns, is prepared by forming a slurry of gypsum of size 200 mesh (United States Standard) or less, and containing from 20-50% solids, adding between 5 and 50% of the slurry with rapid agitation, to a sulphuric acid of 74-80% concentration at a starting temperature below 70 DEG C., the slurry being added to the acid at a rate of from 0.0125 to 1.0 part calculated as CaSO4 for each part of sulphuric acid calculated as 60 degrees Baum<\>e acid per minute, and maintaining the temperature between 20 DEG C. and 80 DEG C.; adding the remainder of the slurry, and heating to between 80 DEG C. and boiling to convert all the gypsum to anhydrite. Preferably the acid concentration at the end of the first addition is between 20 and 50%. The gypsum slurry may be prepared by treating lime or limestone of less than 200 mesh, which preferably contains less than 0.1% of colour-degrading impurities, with waste sulphuric acid, which may contain between 0.1 and 2.0 grams of suspended titanium dioxide per litre, to give a slurry with an acid concentration of between 1 and 100 grams of sulphuric acid per litre. The anhydrite product may be used in the preparation of anhydrite-titanium dioxide pigments, for example by the coprecipitation method.
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US848617XA | 1957-12-26 | 1957-12-26 |
Publications (1)
Publication Number | Publication Date |
---|---|
GB848617A true GB848617A (en) | 1960-09-21 |
Family
ID=22187683
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB41377/58A Expired GB848617A (en) | 1957-12-26 | 1958-12-22 | Improvements in or relating to the preparation of anhydrite |
Country Status (1)
Country | Link |
---|---|
GB (1) | GB848617A (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4387083A (en) * | 1978-12-13 | 1983-06-07 | Stamicarbon, B.V. | Process for the preparation of calcium sulphate anhydrite and calcium sulphate anhydrite obtained by this process |
EP0112317A1 (en) * | 1982-12-22 | 1984-06-27 | Boliden Aktiebolag | A method for re-crystallizing gypsum |
DE3605393C1 (en) * | 1986-02-20 | 1987-09-03 | Knauf Westdeutsche Gips | Process for the preparation of anhydrous calcium sulphate (anhydrite) |
-
1958
- 1958-12-22 GB GB41377/58A patent/GB848617A/en not_active Expired
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4387083A (en) * | 1978-12-13 | 1983-06-07 | Stamicarbon, B.V. | Process for the preparation of calcium sulphate anhydrite and calcium sulphate anhydrite obtained by this process |
EP0112317A1 (en) * | 1982-12-22 | 1984-06-27 | Boliden Aktiebolag | A method for re-crystallizing gypsum |
DE3605393C1 (en) * | 1986-02-20 | 1987-09-03 | Knauf Westdeutsche Gips | Process for the preparation of anhydrous calcium sulphate (anhydrite) |
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