A method and apparatus for extracting bitumen and other hydrocarbons from oil-wetted tar sands and converting it to useful petroleum products, the method comprising first mixing the tar sands material with a condensate consisting oil material and agitating the resulting slurry. After agitating the slurry it is passed through a dual-phase centrifuge and the bitumen and heavy end hydrocarbons are removed, while the light end hydrocarbons remain in the centrifuge cake. The centrifuge cake is heated as it passes through an indirect fired rotary thermal desorber and the hydrocarbon material evaporates are cooled in a quench tank to be collected in the quench supply and recovery tank. The process can also be applied to materials which have become contaminated by hydrocarbons, to extract and remove the hydrocarbons. Another embodiment of the process involves using the indirect fired rotary thermal desorber to treat either tar sands material or a centrifuge cake and quenching the hydrocarbon material evaporates within the quench tank to be collected in the quench supply and recovery tank.