Abstract: Process for calcining green coke in at least three heating stages, which comprises preheating the green coke in the first stage, preliminarily calcining the coke in the second stage, cooling the coke; and calcining the coke in the third stage, volatile matter from the second stage being burned during the third stage. The product coke is suitable for preparing graphite electrodes.

Abstract: A process for calcining green coke containing water and combustible volatile matter and obtained by a delayed coking process in three or more stages of heating furnaces which are connected in series, and the control of the temperature and the adjustment of the atmosphere in the respective furnaces can be independently carried out, which process comprises carrying out, in respective furnaces in the indicated order, the steps of:(a) evaporating the water contained in the green coke, and drying and pre-heating the coke;(b) distilling off and burning the volatile matter from the dried coke; and(c) heating and calcining the coke from the step (b).Because each furnace can be controlled independently from the other furnaces in the above described process, it is possible to produce high-grade coke without process difficulties such as the loss of the coke by combustion and the formation of coke ring.