METHOD FOR PRODUCING GYPSUM HAVING EXCELLENT FILTERABILITY

METHOD FOR PRODUCING GYPSUM HAVING EXCELLENT FILTERABILITY

PROBLEM TO BE SOLVED: To utilize rock phosphate which could not be used in the conventional method for producing phosphoric acid by the wet process employing a dihydrate- hemihydrate process, and to provide a method for precisely estimating the amounts of diatomaceous earth and a fluorine-based comp...

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Bibliographische Detailangaben
Hauptverfasser: AMANO SHOZO, HATSUJI HISAKAZU, HATSUDA NOBORU
Format: Patent
Sprache:eng
Schlagworte:
CHEMISTRY
COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM,CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THERARE-EARTH METALS
COMPOUNDS THEREOF
INORGANIC CHEMISTRY
METALLURGY
NON-METALLIC ELEMENTS
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Zusammenfassung:PROBLEM TO BE SOLVED: To utilize rock phosphate which could not be used in the conventional method for producing phosphoric acid by the wet process employing a dihydrate- hemihydrate process, and to provide a method for precisely estimating the amounts of diatomaceous earth and a fluorine-based compound to be added. SOLUTION: In the method for producing phosphoric acid by the wet process employing a dihydrate-hemihydrate process, rock phosphate which could not be used in the conventional process and apparatus is used by adding a fluorine- based compound and/or hemihydrate gypsum to produce gypsum having excellent filterability. Further, by a method where the value obtained by deducting the content of silica in an insoluble component of aqua resia from the total silica content in rock phosphate is regarded as the content of active silica, the amount of a fluorine-based compound to be added, and further the amount of siliceous material such as diatomaceous earth is correctly estimated.