Abstract: An apparatus for dissolving a powder in a liquid solvent, wherein it comprises a vertically axes rotary bowl, means for introducing the powder and the liquid solvent into the bowl, and a fixed cylindrical member arranged coaxially within the bowl and having on its outer face at least one first helicoidal ramp oriented with respect to the bowl rotation direction in such a way that it ensures the raising of the solution up to means ensuring the removal thereof from the bowl.

Abstract: Vortex apparatus for the continuous production of a precipitate by reacting together at least two reactants wherein it comprises a rotary bowl, having a vertical axis a fixed cylinder arranged coaxially within the bowl in order to define with the latter an annular raising chamber, thus providing a fluid flow connection with a reaction chamber defined within the fixed cylinder, reactant inlet pipes issuing into the upper part of the reaction chamber in the vicinity of the axis of the bowl, at least one weir fixed to the rotary bowl at the upper end of the raising chamber and a turbine fixed to the rotary bowl in the lower part of the reaction chamber, so as to produce a vortex in the latter and ensure the raising of part of the precipitate into the raising chamber.