| 摘要 |
Pitch having a Kramer-Sarnow softening point between 70 DEG and 190 DEG C is heated to a temperature in the range of 40 DEG to 100 DEG C above the softening point thereof. There is thus obtained a molten mass having non-molten particles distributed therein. A filtering operation under a pressure greater than atmospheric pressure is carried out to remove the particles from the molten mass. The molten mass may then be treated in different ways. According to one embodiment, the molten mass is held at a temperature between 280 DEG and 350 DEG C to distill off low molecular weight components of the pitch and the resulting product is thereafter shaped by extrusion to the form of strands. According to another embodiment, the molten mass is cooled, ground to particulate form and contacted with an aliphatic solvent having a boiling point between 60 DEG and 70 DEG C. This solvent dissolves a portion of the ground mass and, after separation of the solvent from the residue, the latter is heated to a molten state and thereafter extruded into the form of strands. In either embodiment, the previously mentioned filtering operation provides for a greater homogeneity of the strands since the non-molten particles, which could form a second phase, are substantially completely eliminated. In both embodiments, the strands obtained are dusted with finely divided activated carbon which has been impregnated with a liquid oxidizing agent. The dusted strands are oxidized in an oxidizing atmosphere at temperatures between 300 DEG and 400 DEG C. The oxidation increases the melt-resistance of the strands. The oxidized strands are next carbonized, the increased melt-resistance thereof preventing melting of the strands during the carbonizing treatment. If desired, the strands may also be graphitized. The method described enables carbon-containing or graphite-containing strands suitable for many applications to be produced in a much shorter time than was possible heretofore.
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