Karchakova V. Scientific-technological bases of optimization of coking coal pitch with electrode fillers

This dissertation defenses the results of theoretical and experimental researches of the interaction between coal tar pitches and the surface carbon fillers regarding managing their quality as a raw material for coals-graphite products. Analysis of the literature made it possible to construct a hypothesis that the wetting of filler surface is a necessary but not sufficient condition for obtaining good pitch composite. As a method for assessing coal tar pitches and their interaction with carbon fillers selected assessment of the strength of semicoke of pitch compositions. This approach gives a fair assessment characteristic for filler-binding interaction. To assess the adhesive interactions of pitches with fillers, there has been used an method of caking for pitches as well as a caking ability by the dynamics of changing in the strength of semi-coke from the pitches with different filler contents. The methods of electron and optical microscopy have been used to study the structure of the filler surface. There have been carried out the tests on the strength of the coking composites as to defining the caking and the caking ability of the coal tar pitch. The factors influencing the formation of the interphase layer of the pitch matrix on the filler surface have been established. It is shown for the first time that a pitch binder in composites with carbon fillers does not form a continuous carbon skeleton. The statistical multifactor models have been constructed and an assessment of the influence of each factor separately, as well as cumulatively on a simulated indicator or a set of indicators has been given. The theoretical assumption that the index of wettability of the pitch cannot be a controlling (and even more rejectionable) indicator for assessing the suitability of the binding agent for the production of high quality electrodes is confirmed. The suction ability characterizes only the very first stage of the production of carbon-carbon composites (mixing) electrodes, not giving adequate information on the formation of one of the most important characteristics of the sintered composite - mechanical strength, including determines the electrical conductivity and consumption of the finished electrode when applied. Thus, the possibilities of controlling the quality indicators of the pitch and, as a result, the strength characteristics of future products from the coke composites have been shown. The thesis materials used in teaching at the National Technical University «Kharkiv Polytechnic Institute», as well as enterprises JSC «ZAPORIZHKOKS», JSC «АKHZ» and JSC «Ukrgrafit». Keywords: coal tar pitch, filler, binder, the surface of fillers, caking, caking ability, coal tar pitch matrix.