Abstract: A multi-stage coal liquefaction method in which coal is slurried with a primary light solvent, such as toluene, hexane and/or cyclohexane, and a process-derived primary heavy solvent. The coal-primary solvent slurry is treated under coal-liquefying conditions to form a first feed solution containing coal liquefaction products. The first feed solution is treated by a multi-stage supercritical solvent extraction procedure. The final heavy phase produced by this procedure is mixed with a secondary solvent, such as pentane, to produce a second feed mixture, which is treated in a second multi-stage supercritical solvent extraction procedure. Heavy phases recovered from the separate stages of both solvent extraction procedures are blended to provide a recycled primary heavy solvent.

Abstract: A method of liquefying coal in which coal is mixed with a process solvent comprising at least partially hydrogenated coal tar material to produce a coal-solvent slurry. This slurry is treated under coal-liquefying conditions, preferably including a hydrogen atmosphere and elevated temperatures, to produce a solution containing coal liquefaction products. These products are recovered from the solution. Recovered, process-derived solvent material may be recycled in order to supplement the at least partially hydrogenated coal tar material as an ingredient of the process solvent.

Abstract: A process for the solvent refining of coal to distillable, pentane soluble products using a dephenolated and denitrogenated recycle solvent and a recycled, pentane-insoluble, solvent-refined coal material, which process provides enhanced oil-make in the conversion of coal.

Abstract: An improved process for thermal solvent refining or hydroliquefaction of non-anthracitic coal at elevated temperatures under hydrogen pressure in a hydrogen donor solvent comprises pretreating the coal with a binary mixture of an aromatic hydrocarbon and an aliphatic alcohol at a temperature below 300.degree. C. before the hydroliquefaction step. This treatment generally increases both conversion of coal and yields of oil.

Abstract: Disclosed is a process for removing mineral matter from Rundle oil-shale by contacting the oil-shale with (a) an ammonium salt solution and (b) an organic solvent, at a temperature from about 0.degree. C. to about 300.degree. C. for a time which is sufficient to substantially separate at least about 80 wt. % of the carbonate mineral matter from the oil-shale.