Abstract
The volatile matter content shows very characteristic change during the carbonization process, that is to say, it decreases suddenly in the temperature range of 300-450°C. From the various experimental facts the authors assume this decrease to be the distillation of the primary tar and, employing the extrapolating curve of the variation line of volatile matter in the range of above 400-450°C to the low carbon percent (ideal carbonization line;V.M.=-0.0192 (C%) 2+1.54 (C%) +29.2), the volatile matter content and the C% of coals, the primary tar content can be calculated.It exists the good accordance between this calculated values and the experimental ones.
