Process for preparing crystals of anhydrous sodium sulfide
AssigneeSankyo Kasei Kabushiki Kaisha
InventorsKannosuke Maeda, Yoshio Aoyama
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Abstract
Disclosed is a process for preparing crystals of anhydrous sodium sulfide, the process being characterized in that the process comprises the steps of heating a water-containing non-crystalline sodium sulfide at a temperature of about 30.degree. to about 89.degree. C. under a pressure of about 500 torr or less for about 2 hours or longer in a first-stage heating step and further heating the sodium sulfide at a temperature of about 90.degree. to about 200.degree. C. under atmospheric pressure or reduced pressure for about 2 hours or longer in a second-stage heating step.
Claims8
A process for preparing cubic-system crystals of anhydrous sodium sulfide comprising,
- heating a water-containing non-crystalline solid state sodium sulfide, which sodium sulfide remains in the solid state throughout the entire process, at a temperature of about 30.degree. to about 89.degree. C. under a pressure of about 500 torr or less for about 2 hours or longer in a first-stage heating step and
- further heating the solid state sodium sulfide at a temperature of about 90.degree. to about 200.degree. C. under atmospheric pressure or reduced pressure for about 2 hours or longer in a second-stage heating step to form said anhydrous sodium sulfide.
Dependencies are inferred from the claim text.