Arrangement for the entrainment of particulate materials

In a process for the production of titanium dioxide by the vapour phase oxidation of titanium tetrachloride in a reactor at an elevated temperature, inert particulate material being entrained in a carrier gas under conditions of pressure variation of at least 0.34 bars due to the effect of process variables and being passed through the reactor and/or pipe-work used in the process to reduce or prevent the formation of scale on the interior surfaces thereof, the improvement which comprises;

• feeding the inert particulate material into the carrier gas by a mechanical feeding device having an inlet for inert particulate material associated with a hopper fed inlet conduit and an outlet for inert particulate material associated with conduit means for providing a stream of carrier gas so as to entrain particulate material issuing from the outlet from the feeding device, and in that the pressure difference between the feeding device inlet and outlet are substantially eliminated by the provision of gas flow interconnection means directly connecting the said inlet or said inlet conduit with said outlet or with the associated conduit means, and in that the feed of inert particulate material is below 150 Kg per tonne of titanium dioxide produced.