The influence of the temperature field of the oven on the properties of thermally expanded graphite

The purpose of this work was the development of a new method for determining the particles soaring flight velocity as a function of furnace temperature field. A comparative study of graphite magnetic particles motion velocities, intercalated graphite compounds and thermografenite in a gravitational-falling layer in a reactor has been made. An electro-contact sensor has been developed for electrically conductive particles. When the graphite particles, intercalated graphite and thermographite compounds hit the sensor, the contact closes and is fixed by a high-speed recorder. For non-conductive particles, a piezoelectric sensor has been developed. It fixed the moment of the particles dynamic tangency. The difference between two pulses made it possible to determine the time of the particles motion. The distance between the sensor positions that is relative to time gives the particles velocity. The conditions under which the particles of the processed materials reach the whirling velocity have been determined. When intercalated graphite compounds particles move in the high-temperature zone, their thermal expansion occurs with a sharp increase in the volume of the particles and thermografenite formation. It has been found that the thermal expansion of intercalated graphite compounds does not practically occur below 250°C. The most intense temperature factor is manifested in the temperature range 400÷600°C. In the temperature range 800÷1000°C, the thermal expansion of intercalated graphite compounds is completed. Investigations carried out in the temperature range 300÷1000°C showed a significant decrease in thermografenite particles soaring flight velocity from 0,8 m/s (for intercalated graphite compounds) to 0,35 m/s (thermografenite). At the same time, the bulk density of the material decreases from 200 kg/m3 for intercalated graphite compounds to 6 kg/m3 for thermografenite