GB600326A - Improvements in and relating to the separation of particulate materials - Google Patents

Abstract

<PICT:0600326/III/1> <PICT:0600326/III/2> A process for separating particulate material of desired particle size from a mixture containing material of larger particle size, which process may be used in the production of hydrogen as described in Specification 578,323, comprises passing a gas and/or vapour through a bed of the mixture contained in a stationary vessel with a conical bottom, at a velocity sufficient to maintain the material of desired size in the fluid state, avoiding the production of an entrained stream, but insufficient to prevent the larger particles from moving to the conical bottom of the vessel where they distribute the gas across the bed. The velocity of the gas may, however, be increased at the upper surface of the bed for the purpose of removing the desired particle size in an entrained stream. In the production of hydrogen, the mixture is metallic iron, iron oxide and larger particles due to agglomeration of the smaller particles. In the arrangement shown in Fig. 1, the mixture is fed through a pipe 2 to a vessel 1 through which is forced a gas from a ring main 9 and tuyeres 10. Larger material is removed from the bottom under the control of a slide valve 8. The smaller material is entrained through a pipe 3. In a modification, the top of the vessel is conical, decreasing in cross-section to that of a narrow outlet. In a further arrangement, the smaller material flows over a weir to an outlet. In the arrangement shown in Fig. 4, the smaller material flows through a channel 3 to an outlet pipe 15 where it is entrained upwardly by steam passed through a pipe 16. Specification 582,055, [Group XII], also is referred to.