In continuously operable apparatus for the processing of powdered moulding compounds, the improvement comprising a housing in the form of a channel and a mixing and kneading member engaged in the channel and having a surface which co-operates with the bottom wall of the channel, in which said bottom wall and said surface of the mixing and kneading member are undulatingly profiled in a manner such that the profiles extend transversely or obliquely with respect to the longitudinal axis of said channel and said member, and drive means, including at least one crank drive, coupled between the housing and said member to cause said member and said housing, while retaining their respective orientations to move relatively to one another to cause the peaks of the undulations on one of the profiled surface and the profiled bottom wall to perform a circular movement in associated valleys in the other of the profiled surface and the profiled bottom wall, whereby the moulding compounds are sheared in said valleys and longitudinally conveyed from valley to valley to a discharge end of the apparatus.