Abstract
We have examined 7 specimens of Takashima Coal Mine Senseki, through Washerbility tests, measuring the degree of decrepitation, decrepitation removing tests, etc.
In general, we have found that the Takashima Senseki has such the principal properties in common with others, recognized by the previous investigators, as follows;
1. Unusual increase of ash contents are observed on most of the “Observed curve” of Senseki.
2. Natural (or primary) decrepitations of Senseki can be removed once at least, by the preheating treatments at about 400°C.
3. In many cases, however, considerable amounts of decrepitations are regenerated in couse of time, namely “Secondary decrepitation.”
4. Complete removals of decrepitations, including the secondary decrapitation, would not be expected unless the high temperature preheating adoped, such as 900°C or more.
Acknowleging the close relativity exists between the degree of carbonization and decrepitation as to Senseki, through the above tests and also study of the analytical data in this line, we would like to set forth our opinion on the theory of Senseki decrepitation.
