KuzSTU creates a technology for obtaining valuable raw materials from coal tar

The study was carried out by scientists of the Kuzbass State Technical University within the framework of the complex scientific and technical program “Clean Coal - Green Kuzbass”. During the experiment it was found that the temperature at which the atmospheric-vacuum distillation of tar, significantly affects the characteristics of the obtained coal pitch. In particular, the softening point of the pitch, the content of substances insoluble in toluene and the yield of volatile substances depend on this temperature. In this case, the coal ash obtained at the output, suitable for use in the electrode industry.

Coal pitch is a complex mixture consisting mainly of condensed aromatic hydrocarbons and other aromatic compounds. Most of the coal pitch produced is used in the non-ferrous metals industry.

In electrode manufacturing, coal pitch is used as a binder for solid high-carbon materials. It must moisten these materials well. When heating a mixture of solid carbon materials and coal pitch, the pitch should sinter and provide a high yield of coke. The ability of coal pitch to form a large amount of coke residue in the carbonization process is explained by its complex polyaromatic structure: it consists of more than 10 thousand different compounds. This important property of coal pitch is necessary for its use as a binder.

Standard characteristics of pecks include softening point, volatile yield, coke number, ash content and the amount of substances insoluble in quinoline and toluene. All of these parameters are determined by standardized analyses, which allow to assess the suitability of the pitch for various applications.

The Institute of Chemical, Oil and Gas Technologies of KuzSTU carried out unique research on the production of coal tar pitch. During the experiments coal tar provided by the industrial partner of KuzSTU - PJSC “Koks” was used. The purpose of the research is to determine how the temperature affects the quality of the obtained pitch. For this purpose coal tar was subjected to atmospheric-vacuum distillation at different temperatures.

The analysis of the obtained samples showed that coal pitch obtained by atmospheric-vacuum distillation of tar meets all the requirements for this material for electrode production. At the same time the quality of coal pitch is greatly affected by the temperature at which the tar distillation was carried out. With its increase the softening temperature and the content of insoluble substances in toluene increase, and the yield of volatile compounds, on the contrary, decreases.