Process for preparing crystals of anhydrous sodium sulfide.

摘要

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 to about 89 DEG 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 to about 200 DEG C under atmospheric pressure or reduced pressure for about 2 hours or longer in a second-stage heating step.