This research examines the use of coal-processing wastes of Shubarkol deposit (Kazakhstan) in obtaining useful materials such as carbon fibers. For our experiments, mesophase pitch was obtained by coal tar heat treatment at 773 K. Spinnable solution was prepared by crushing mesophase pitch into the pieces with adding poly(methylmethacrylate) as a fiber-forming material and 1,2-dichloroethane as a solvent.
The method for obtaining coumarone-indene resins with methacrylic fragments (CIRM) was developed with the addition of methyl methacrylate, using a light fraction of coal tar and its fraction boiling within 423–463 К. CIRM was obtained via radical cooligomerization using 2,2'-azobis (2-methyl-propionitrile) as the initiator. The effect of the initiator amount, temperature and reaction time on the yield, softening temperature and molecular weight of CIRM has been established. The structure of the synthesized CIRM has been confirmed by IR and NMR spectroscopy.
Coumarone-indene resins with epoxy groups (CIRE) have been obtained using light fraction of coal tar or fraction with the distillation range of 423–463 K based on it. Styrene and glycidyl methacrylate were used as modifiers. CIRE were synthesized via radical cooligomerization using monoperoxide derivative of dioxyphenylpropane diglycidyl ether (PO) as an initiator. Thermal stability of PO has been studied. The effect of initiator amount, reaction temperature and time on the yield and softening temperature of CIRE has been determined.
We have investigated the formation of mesophase carbon microbeads in tar pitch generated by the coal coking in a steelmaking plant. Pitches were obtained at different distillation temperatures (643, 673 and 723 K). The distilled samples were then thermally treated in nitrogen atmosphere either at 723 K for 8 h (T1) for at 703 K for 4 h (T2). A new phase appears, seen in optical microscopy with a polarizing filter. Samples subjected to the T1 thermal treatment were found to form a discontinuous fluid phase distinct from the main phase.
The results are given for studying the coal tar carbonaceous dispersed phase with a number of microscopes of various principles of operation. High trend is shown for the dispersed particles to form stabile aggregates and to adsorb other tar compounds on their surface. The conclusion is made that the selective extraction of the dispersed phase from the coal tar is fundamentally impossible. The well-founded hypothesis is expressed about the technological practicability of the tar dispersed phase aggregates destruction for the quality upgrading of the tar-based products.