| 摘要 |
A low-impurity coke suitable for the production of electrodes for aluminium manufacture is prepared by extracting coal volatile matter content greater than about 28% by weight on a dry ash free basis with a highly aromatic hydrocarbon extractant of which the middle 90% boils in the range 250 DEG to 350 DEG C at a temperature of about 380 DEG to 450 DEG C, in the liquid phase, insoluble matter is separated off and the extract is heated to remove distillable oil and coked wherein the residence time of coal in the extraction step is controlled and the weight ratio of extractant to coal during extraction is maintained greater than 3:1 to maintain a substantially constant specific resistivity of the filter cake. |
