Effect of calcination conditions of self-sintering mesocarbon microbeads on the characteristics of resulting graphite

Mesocarbon microbeads are now-a-days used as a prominent self-sintering precursor for the production of high density monolithic graphite. The quality of this graphite is highly dependent on the characteristics of these microbeads, such as the quinoline and toluene insoluble contents, beta-resins content and volatile matter content, which in turn, can be controlled to desired values by suitable treatments of their extraction and calcination. In the present paper, the authors give an account of the study conducted to see the effect of calcination conditions of mesocarbon microbeads on the characteristics of the resulting graphite. A calcination at a temperature in the range of 280-320 degrees C for 30 min. under an ambient pressure of nitrogen, or at a temperature of 245-310 degrees C for 10 min. under a reduced pressure (5 cm Hg) of nitrogen, results in mesocarbon microbeads having a quinoline insoluble content of 83.6-89.8%, toluene insoluble content of 94.4-99.7%, beta-resins content of 6.8-11.9% and a volatile matter content of 10.2-13.5%. Such microbeads have been found to lead to a monolithic graphite possessing a bulk density 1.91-2.02 g cm(-3), bending strength of 62-70 MPa, Shore hardness of 58-69, electrical resistivity of 2.1-2.6 m Omega cm and a degree of anisotropy of 1.02-1.05. (C) 2000 Kluwer Academic Publishers.