A separation process and system for extracting hydrocarbons from a mixture. In some embodiments, a process for separating a bitumen froth stream containing bitumen froth, water and fine solids into a bitumen enriched froth stream and a water and fine solids stream, comprises: (a) receiving the bitumen froth stream in a concentrator vessel, (b) distributing the bitumen froth stream in the concentrator vessel as a substantially uniform and generally horizontal flow of the bitumen froth stream at a first flow velocity, (c) slowing the bitumen froth stream to a second flow velocity, slower than the first flow velocity, in a separation region of the concentrator vessel to promote separation of the bitumen froth from the water and fine solids, and then (d) collecting a bitumen enriched froth stream and (e) collecting a separate water and fine solids stream. Related embodiments of systems and apparatus may also be provided.