• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    The invention relates to a process for the preparation of calcium sulphate anhydrite in which calcium sulphate dihydrate is recrystallized at elevated temperature using concentrated sulphuric acid. …<??>The recrystallization is performed using sulphuric acid at an H2SO2-concentration of 40-65 wt. %, calculated relative to the quantity of liquid phase in the recrystallization mixture. A temperature of between 40 and 90 DEG C and a residence time of 5-30 minutes is applied for the preparation of calcium sulphate anhydrite with an average particle size of 0.5-3 mu , and a temperature of between 20 and 45 DEG C and a residence time of 30 minutes to 3 hours is applied for the preparation of calcium sulphate anhydrite with an average particle size of 10-20 mu . …<??>According to the invention a very pure calcium sulphate anhydrite is obtained, which is suitable for industrial application, for example in the building or paper industry.
    公开号:SU952100A3
    申请号:SU792851660
    申请日:1979-12-12
    公开日:1982-08-15
    发明作者:Антониус Корнелис；Ветерингс Мария；Анна Янсен Йоханнес
    申请人:Стамикарбон Б.В.(Фирма)；
    IPC主号:
    专利说明:

    - is at 2, for 30180 minutes. Recrystallization is carried out in the presence of metal compounds selected from the group containing iron, aluminum, qpoMf, vanadium. The compound of these metals is introduced in an amount of 0.01-1% by metal based on the weight of the recrystallization mixture. A ratio of 0.02-0.2% by weight is preferred. The choice of the proposed intervals, the concentration of time and temperature of the process is determined that for other values of these parameters it is not anhydrite that is formed, but calcium sulfate hemihydrate or has a low yield of the target product. The compound of these metals can be introduced both in solid and in dissolved form. The resulting product has the form of a bar with a ratio of length: width: thickness 10: 10: 2. When polyvalent multivalent ions are used in the crystallization process, particles with a ratio of length: width: thickness 10:10: (8-10) are obtained. A pure product with a particle diameter of 0.5-3 µm / obtained according to the proposed method has a volume weight of 1000 to 1500 g / l and is suitable for use in the manufacture of construction materials. The coarse product with a particle size of 10-20 µm has a bulk weight of 700,100 g / l and can be used as a coating or filler in the paper industry. The mother liquor after separation of the precipitate of the target product can be used for various purposes, for example, for the preparation of ammonium sulfate, ammonium sulfate nitrate, dihydrogenation of natural phosphate. Phosphogypsum is used as a calcium sulfate dihydrite starting material. Example 1 Calcium sulfate dihydrate, obtained by a wet process, as a by-product of the production of phosphoric acid, is introduced into a 0.3 l glass reaction vessel equipped with a stirrer. Then, concentrated 96% sulfuric acid is added in such an amount that the concentration in the liquid phase of the recrystallization mixture is 60% by weight. The temperature in the reaction vessel. support 60 ° C. The mixture is stirred in the reaction vessel for 20 minutes. The resulting mass is then filtered. The precipitate after filtration is washed with cold water and immediately dried at 100 ° C. Using X-ray diffraction, it was shown that the solid product is 100% calcium sulphate. The product has the form of a bar with an average length and width of 2.5 microns and an average thickness of 0.5 microns. Bulk density is about 1100 g / l. Examples 2-6. In the same manner as in Example 1, calcium sulfate dihydrate is subjected to recrystallization with sulfuric acid at various temperatures, acid concentrations and residence times. The results are shown in Table. 1. Table 1
    To which zinc sulphate is added at a zinc weight concentration of 0.1% relative to the total recrystallization mixture. The weight concentration in the recrystallization mixture is 50%, the temperature is maintained at 40 ° C.
    After 1 h, the mass is filtered, and the precipitate after filtration is washed with cold water and dried at 100 ° C.
    The product contains particles in the form of bars with an average length and width of about 12 microns and with an average thickness of 1D-12 microns
    Examples 8 and 9. In the same manner as in Example 7, calcium sulfate dihydrate is recrystallized with sulfuric acid at various temperatures, sulfuric acid concentration, residence time, and metal addition.
    The results are shown in Table. 2. Table 2
    权利要求:
    Claims (2)
    [1]
    Example 10. In the same manner as in Example 1, impure gypsum obtained by the production of phosphoric acid by the wet method 30 is subjected to recrystallization with sulfuric acid at 60 ° C and a residence time of 20 minutes. The weight concentration in the mixture is From Table. 3, it can be seen that most of the impurities enter the liquid phase of the recrystallization solution during recrystallization. The proposed method allows anhydrite with a given particle size to be obtained without first introducing a seed material. Claims 1. Method for producing calcium sulfate anhydrite by recrystallization of its dihydrate by treatment with serum 60%. The product has the same dimensions and volume weight as in example 1.
    As raw, gypsum, and the resulting anhydrite were analyzed for phosphate, fluorine, and individual metals.
    The results are presented in table 3.
    Table 3 with acid at elevated temperature, characterized in that, in order to simplify the process and obtain the target product with a given particle size, the recrystallization is carried out at a sulfuric acid content in the liquid phase of 40-65%, temperature 20-90 ° C for 5180 minutes . 2. The method according to claim 1, characterized in that, in order to obtain crystals with an average size of 0.5-3 microns, the recrystallization is carried out at a temperature of 40-90 ° C for 5-30 minutes. 7 .95210 3. The method according to claim 1, which is carried out in such a way that, in order to obtain crystals with an average size of 10-20 µm, the process is carried out at a temperature of 20-45 ° C for 30180 minutes. 5 4. Method pop. 1, I differ from the fact that recrystallization is carried out in the presence of metal compounds selected from the group consisting of iron, zinc, ashhominium, chromium, 10 vanadium. 08 5. The method according to claim 4, differs from the fact that the compound of these metals is introduced in the amount of 0.01-1% by metal based on the weight of the recrystallized mixture. Sources of information taken into account in the examination 1. US patent 2531977, cl. 23-122, 1950.
    [2]
    2. US Patent No. 2956859, cl. 23-122, I960 ..
    类似技术:
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    同族专利:
    公开号 | 公开日
    JPS5580720A|1980-06-18|
    AT957T|1982-05-15|
    IN154049B|1984-09-15|
    IE49233B1|1985-09-04|
    NL7812109A|1980-06-17|
    US4387083A|1983-06-07|
    IE792402L|1980-06-13|
    EP0012487B1|1982-05-05|
    ES486803A1|1980-06-16|
    EP0012487A1|1980-06-25|
    DE2962749D1|1982-06-24|
    DD147938A5|1981-04-29|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    US2021910A|1935-11-26|Preparation of calcium sulphate |
    US2006342A|1934-05-18|1935-07-02|Krebs Pigment & Color Corp|Process of making anhydrite|
    US2151339A|1935-04-20|1939-03-21|Du Pont|Process of making calcium sulphate|
    US2197953A|1937-12-02|1940-04-23|Du Pont|Process for making anhydrite|
    GB561205A|1942-07-13|1944-05-10|Francis Robert Himsworth|Improvements in or relating to the production of gypsum from anhydrite|
    GB848617A|1957-12-26|1960-09-21|Nat Lead Co|Improvements in or relating to the preparation of anhydrite|
    US2956859A|1957-12-26|1960-10-18|Nat Lead Co|Preparation of anhydrite|
    US2999007A|1958-07-29|1961-09-05|American Cyanamid Co|Process of preparing anhydrite of improved whiteness from off-white gypsum|
    IL23004A|1964-02-27|1969-03-27|Fosindus Co|Process for the purification of residual gypsum produced in the manufacture of phosphoric acid by the reaction of sulphuric acid with natural phosphates|
    GB1101771A|1963-08-14|1968-01-31|Bpb Industries Ltd|Improvements relating to the production of gypsum plaster|
    GB1081895A|1965-11-09|1967-09-06|Occidental Res & Eng|Improvements relating to the production of phosphoric acids|
    US4146568A|1977-08-01|1979-03-27|Olin Corporation|Process for reducing radioactive contamination in waste product gypsum|EP0044005B1|1980-07-14|1984-09-26|HIS Handels- und Industriebedarf GmbH|Production of calcium-sulfate hemihydrate using waste heat, diluted sulfuric acid and sulfuric salts|
    NL8004058A|1980-07-15|1982-02-16|Stamicarbon|PROCESS FOR PREPARING PHOSPHORIC ACID AND CALCIUM SULPHATE ANHYDRITE, AND PHOSPHORIC ACID AND CALCIUM SULPHATE ANHYDRITE OBTAINED BY THIS PROCESS.|
    US4452770A|1981-12-14|1984-06-05|United States Gypsum Company|Phosphoanhydrite process|
    SE440069B|1982-12-22|1985-07-15|Boliden Ab|PROCEDURE FOR RECYCLING GYPS|
    SE8302592L|1983-05-06|1984-11-07|Boliden Ab|PROCEDURE FOR MANUFACTURING FIBER PLASTICS |
    SE8302591L|1983-05-06|1984-11-07|Boliden Ab|PROCEDURE FOR MANUFACTURING FIBER PLASTICS |
    US5169444A|1986-02-20|1992-12-08|Gebruder Knauf Westdeutsche Gipswerke Kg|Process for preparing calcium sulfate anhydrite|
    DE3605393C1|1986-02-20|1987-09-03|Knauf Westdeutsche Gips|Process for the preparation of anhydrous calcium sulphate |
    EP0237802B1|1986-02-20|1990-05-09|Gebr. Knauf Westdeutsche Gipswerke KG|Process for the preparation of calcium sulphate anhydrite and curable calcium sulphates|
    DE3714035C2|1986-07-25|1989-03-30|Gebr. Knauf Westdeutsche Gipswerke Kg, 8715 Iphofen, De|
    GB8701263D0|1987-01-21|1987-02-25|Ecc Int Ltd|Forming concentrated aqueous suspension|
    FR2658075B1|1990-02-14|1992-05-07|Oreal|PHOTOSTABLE FILTERING COSMETIC COMPOSITION CONTAINING A UV-A FILTER AND A BETA, BETA-DIPHENYLACRYLATE OR ALPHA-CYANO-BETA, BETA-DIPHENYLACRYLATE.|
    US5964940A|1998-04-20|1999-10-12|Wilson; Harold W.|Process for increasing the water solubility of gypsum|
    US7556791B2|2006-12-20|2009-07-07|United States Gypsum Company|Gypsum anhydrite fillers and process for making same|
    CN102634843B|2012-04-27|2015-04-22|昆明理工大学|Method for preparing micron-sized calcium sulfate particles and crystal whiskers from phosphogypsum|
    法律状态:
    优先权:
    申请号 | 申请日 | 专利标题
    NL7812109A|NL7812109A|1978-12-13|1978-12-13|PROCESS FOR PREPARING CALCIUM SULPHATE ANHYDRITE AND CALCIUM SULPHATE ANHYDRITE OBTAINED BY THIS PROCESS.|
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