Abstract
Hitherto the detection of free sulfur has been made by changing it into sulfide, thiocyanic acid, thiosulfuric acid or others and utilizing their characteristics. In this study, sulfur was subjected to react with manganese oxide(IV) on heating, in order to change it into manganese sulfate, and then the manganese was oxydized into permanganic acid. By doing this, manganese was sharply detected, and consequently sulfur could be sharply detected indirectly. However, part of sulfide and part of sulfate also react similarly with manganese oxide(IV) and produce manganese sulfate, it is necessary to separate them by carbon disulfide, if they are present. Since manganese dioxide reagents sometimes give a positive result for this test, it is better to use manganese dioxide ore instead. In this case, however, a blank test is indispensable.
