Abstract: An apparatus enabling reaction and post-reaction processing in a single assembly including a reaction chamber and a filtration and/or drying chamber adjacent to one another, the chambers being selectively isolated or in communication. A shaft common to both chambers is capable of rotation and axial movement. An agitator arm is fitted to the shaft in the reaction chamber while a smoothing and pressing arm is fitted to the shaft in the filtration and/or drying chamber. The chambers may be formed in a single cylindrical vessel with an intermediate cross wall providing isolation between the chambers. A U-shaped conduit extends between the chambers and by-passes the cross wall to enable communication between the chambers. The conduit may incorporate a valve/pump to facilitate transfer between the chambers. The shaft is journalled through the cross wall and has a bellows apparatus to protect the bearing from the respective chambers.