Solid particles and gaseous materials are separated by passing a suspension of solid particles and gaseous materials into the upper section of a cyclonic separation vessel equipped with a cyclonic swirl zone which may contain vortex stabilizing means and a lower dense bed zone which may contain stripping means, and wherein separated gaseous materials are removed from the upper section of the cyclonic zone and solid particles are passed in the lower dense bed zone, from which particles are removed by aeration through a discharge means which communicates with the dense bed zone.The present process and apparatus are preferably applied in the separation of gaseous materials from solid particles entrained in hot flue gases obtained in the combustion stage of a process for extracting hydrocarbons from hydrocarbon-bearing substrate such as oil shale and tar sand.