SU508472A1 - "Method for the production of fine-grained graphite material - Google Patents

Description

The invention relates to a method for producing a fine-grained graphite material used as a structural material in various parts of the technique. A known method for producing graphite fine-grained material based on calcined coke and high-temperature pitch, including preliminary grinding of coke, introduction of pitch, joint grinding and coke pitch, pressing, roasting and graphitization. However, by this method, when grinding and coke with pitch together, the pitch is transformed into a plastic state, which impairs the interaction of coke with pitch, increases the anisotropy and worsens the physical and mechanical characteristics of the resulting graphite material. The aim of the invention is to improve the physicomechanical characteristics of the material obtained and to improve its isotropy. This is achieved by the fact that preliminary grinding of coke is carried out with the addition of 10-40 wt. % solid carbon dioxide at a temperature of minus 20 to within 2-10 minutes. The specified amount of solid carbon dioxide provides a reliable mode of grinding and the quality of the press powder. Less than 10 weight. % of solid carbon dioxide effect does not give due to rapid evaporation, more than 40 weight. % - overflows the free working space of the vibration mill and prevents grinding of the mass. During the vibromilling process, solid carbon dioxide gradually passes into a gaseous state, forming an environment that protects the freshly formed surface of coke from oxidation, thereby improving its interaction with the bond; At the same time, solid carbon dioxide takes away the heat of metallic metal bodies heated from the collisions (number of vibrations per minute 1500), which increases the crushability of the calcined carbon filler and prevents the heat from being transferred from a solid to a plastic state. The method is as follows. Prokaleiiy coke (grain size less than 1 mm) with the addition of 10-40% by weight of coke solid carbon dioxide (carbon dioxide) in the form of couscous with a size of not more than 80 mm load S vibrating mill and subjected to grinding 3 for 2-10 min at a temperature of minus 20- 0 ° C, then coal tar pitch is introduced in the amount of 32-35 wt. % with softening temperature of 135-150 ° C and continue grinding for 10-20 minutes to obtain a crc. powder. The granulometric composition of the press powder is presented below. Cell size of slit, mm Content of fraction on С1те,% 0.151.0 0.098.0 Residue (I-91.0, 0.09) The processing cycle can be repeated with the press powder obtained. The prepared press powder is used to form blocks with a diameter of up to 500 mm in an unheated mold at room temperature and a specific pressure of 300-700 kgf / cm. at 380 hours, the blocks are burned with a lump of P1, e and with a short schedule with the speed of speed s, 0 ° С, / hour Temperature, С Up to 400 400-600 600-800 1000 -1100 1100-13008 Exposure at a temperature of 1300 ° С for 24 hours. The burned blocks graphitize up to 2500 ° С with a temperature rise rate of 40 ° С / hour. The duration of the process is 60 hours. Example. In a vibratory mill with a capacity of 400 liters, 27 kg of calcined coke of the CNPS brand (, 3278-62) with a grain size less than 1 mm and 5 kg of solid carbon dioxide are loaded, the coke is milled in the presence of solid carbon dioxide for 5 min in the temperature range from minus 20 to 0 ° C. Then, 13 kg of solid pitch with softening temperature of 140 ° and grain size less than 10 mm are loaded into the vibrating mill, and coke and pitch are ground together for 10 minutes. After unloading the press powder cycle repeat JOT. From the thus obtained press powder is pressed at beats. pressure of 600 kgf / cm blocks with a diameter of 340X300 mm. The blocks are regional CIG on a 380-hour schedule, and then graphitized to 2500 ° C. For comparison, graphitized blocks are prepared according to the example, but without the addition of solid carbon dioxide (a known method). The table presents data on the physicomechanical characteristics of the samples cut parallel to (1) and perpendicular to (II) the axis of extrusion from graphite material obtained from the known (without the addition of solid carbon dioxide) and the proposed methods.

The table below shows that the graphite material obtained by the described method is more isotropic and has higher physicomechanical characteristics than the material obtained by a known method.

Formula of the invention; Method of obtaining fine-grained graphite material based on calcined coke and high-temperature pitch, including preliminary grinding of coke, introduction of pitch, joint grinding and mixing 56

ka with coke, pressing, roasting and graphite; preliminary grinding of coke is carried out with an addition, characterized in that, with a view to weight. % of solid carbon dioxide dioxide and improvement of the physical isotropy at a temperature from minus 20 to 0 ° С

co-mechanical characteristics of the material, for 2-10 min.

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