The influence of pressure on the development of optical anisotropy during carbonization of coal

✍ Scribed by John W. Patrick; Peter D. Green; K.Mark Thomas; Alan Walker

• Publisher: Elsevier Science
• Year: 1989
• Tongue: English
• Weight: 590 KB
• Volume: 68
• Category: Article
• ISSN: 0016-2361
• DOI: 10.1016/0016-2361(89)90315-3

✦ Synopsis

Semicoke residues from high pressure dilatometer tests on a series of bituminous coals, were examined by polarized light microscopy to determine the effects of pressure on the optical anisotropy developed during the plastic stage of the carbonization process. Similar examinations were also carried out with high and low rank coals which had been subjected to different levels of oxidation to determine the additional effects of this factor. The major part of the influence of pressure carbonization on the coke anisotropy takes place at pressures up to 2 MPa, the influence being dependent on the rank of the parent coal. The total volume anisotropy is increased significantly with coke from some low rank coals but the changes in the type or nature of the anisotropy are generally less well marked. In accord with the effects of oxidation on plasticity, oxidation progressively retards the anisotropic development more so with the cokes from lower rank coals, to such an extent that carbonization at pressures up to 4 MPa cannot overcome this effect, the cokes being predominantly isotropic.