Double solvent extraction of organic constituents from tar sands. [light naphtha/methanol solvent system]

Extraction of hydrocarbons from tar sands with a light naphtha/methanol solvent system results in rapid decrepitation of the tar-sand aggregate and separation of organic matter into three phases. Distribution of the extracted and non-extracted organic material is among the phases. The most desirable, non-polar organic materials are recovered from the light naphtha phase; more polar soluble constituents are recovered from the methanol phase; and less desirable asphaltenes separate as a precipitate.