Abstract: An improved system for recovering CO.sub.2 from flue gases containing SO.sub.2 at low CO.sub.2 partial pressure. The system includes the use of K.sub.2 CO.sub.3 as the solvent, regeneration of the solvent, and removal of SO.sub.2 and SO.sub.4.

Abstract: Oil shale or tar sands is extracted under non-thermally destructive conditions with a solvent liquid containing a compound having the general formula: ##STR1## where M is a carbon, sulfur, or phosphorus atom,R.sup.2 and R.sup.3 are each a hydrogen atom or a lower alkyl group,R and R.sup.1 are each a lower alkyl group, another ##STR2## a monocyclic aromatic group, or R.sup.1 can be another ##STR3## or R.sup.1 and R.sup.2 together can represent the atoms necessary to close a heterocyclic ring, andn=1 where M=phosphorus and is otherwise 0,to substantially remove the non-fixed carbon content of the oil shale or tar sands, leaving a solid residue of fixed carbon, ash minerals, and non-extractable matter.

Abstract: Sub-divided coal is extracted under non-thermally destructive conditions with a solvent liquid containing a compound having the general formula: ##STR1## where M is a carbon, sulfur, or phosphorus atom,R.sup.2 and R.sup.3 are each a hydrogen atom or a lower alkyl group,R and R.sup.1 are each a lower alkyl group, another ##STR2## a monocyclic aromatic group, or R.sup.1 can be another ##STR3## or R.sup.1 and R.sup.2 together can represent the atoms necessary to close a heterocyclic ring, andn=1 where M=phosphorus and is otherwise 0,to substantially remove the non-fixed carbon content of the coal, leaving a solid residue of the fixed coal carbon, ash and non-extractable matter.