The development of energy-efficient technology of isostatic graphite production

Energy efficient technical solutions and regulations of pressing, baking and graphitizing of isostatic graphite artifacts were developed, which do not have any analogues in Ukraine and enable specific energy consumption decrease. Parameters of material base for isostatic graphite artifacts obtaining were determined and the requirements for “green” isostatic graphite samples, which are obtained on the pressing stage, were formulated. It was found out that baked coke of needle structure with the average grain diameter (10–30) µm should be used as a filler, and high temperature pitch should be used as a binder. Filler milling is done through a vibrating or jet mill; filler is combined with pitch under 270 ºС. The pressing method is hydrostatic in elastic forms with density of the gained samples not less than 1500 kg/m 3 unity. Rational content of the pressing mixture and energy efficient pressing regulations were determined. It was found out that pressing mixture needs to be better mixed and high temperature binder should be used to obtain isostatic graphite. Physical, mathematical and numerical models of artifacts baking and graphitizing for isostatic graphite obtaining were developed. Relation between thermal and physical, electrical and mechanical properties of isostatic graphite artifacts and technological regulations of baking and graphitization processes was determined. Artifact size also depends on baking and graphitization parameters. It was found out that isostatic graphite baking requires high temperature field unity (low gradient field) and highly low pace of temperature growth, especially in the range of intensive residual gas evolution. It was shown that isostatic graphite production also needs high unity of temperature field. Based on numerical analyses, it was determined that the equipment for isostatic graphite samples baking and graphitization must meet the following thermal processing requirements: radial temperature drop in artifacts must up to 3–5 °С; baking of isostatic graphite artifacts of diameter over 200 mm is impossible in multi- chamber Ridgammer furnaces due to long duration of the process. That`s why 1 chamber furnaces with draw-out hearth or electric furnaces should be used as they will enable temperature gradient in artifacts up to (10–36) K/m. Energy efficient regulations of baking and graphitization of isostatic graphite artifacts were developed based on numerical and experimental researches.