風化炭の石炭組織学的考察
1973 年 52 巻 12 号 p. 885-895
詳細
1973 年 52 巻 12 号 p. 885-895
When we attempt to predict coking properties of a coal by the petrographical method, sometimes we confused and got miss evaluation after the coal had been oxidized.
Japanese iron works used to employ many kinds of coals through all over the world which are more or less oxidized.
We studied transitions of physical and chemical properties of coals which were artificially and naturally weathered, especially from petrographical view point. The artificial weathered coals were prepared under air below of 70°C.
The results are as follows:
1) The “Reflectance” of Vitrinit decreased at the first time and then increased. The distribution of the “Reflectance” of a coal was spreaded.
2) The amount of the “Psudo-vitrinit” increased as the coals were oxdized.
3) The Volatile Matter decreases, Oxygen contents increase, the “Free swelling Index” decreases, moreover the “maximum fluidity” in a coals measured by “Giessler plastometer” remarkably decreases as they were weathered.
4) Cokes of weathered coal by microscopy, and noticed that the particles of the oxidized coal did not swell and did not adhere together.
5) By means of X-ray diffraction, the graphitization of the cokes from the low rank weathered coals decrease, but in the cokes from the high rank weathered coals this tendency can not be found.
6) We studied by means of the Infra-Red absorption, what kinds of chemical changs took place during weathering. The absorption of the wave number 1720cm-1 increased. This will indicate the increase of the amount of -C=0 bond.
7) The compensative calculation method to predict a coking property of a weath-ered coal11 from C/O ratio of elementary analysis has been veparted, but the oxygen analysis is uncertain, so we propose a following method: if we could exactly distinguish the “Psudo-Vitrinit” or oxidzed coal from the “Vitrinit”, so these “maceral” should be considered as “Inerts” and wecan predict the coking property more exactly. Now we measure the distributtion of the reflectances of a coal and the Vitrinit of which the reflec-tances are higher 0.2 than the mean reflectance of them should be considered as “Inerts”.
