GB705397A - Sulphur recovery process - Google Patents

Abstract

At least part of the sulphur is separated from spent iron oxide by maintaining the spent oxide in finely divided form as a fluidized bed at a temperature above the melting point of sulphur, e.g. 250-450 DEG F., and using superheated steam as fluidizing gas. The spent oxide may be up to 100 m particle size and the steam velocity should be 1-2 ft./sec. The bed stratifies into an upper sulphur-rich phase and a lower oxide-rich phase, which phases at 250-350 DEG F. may be separately withdrawn when the oxide-rich phase is returned to a gas purification system. The sulphur-rich phase may be used as impure sulphur, or the sulphur may be solvent extracted therefrom. The conditions of fluidizing may be so adjusted that the withdrawn phase is virtually a scum of sulphur on top of the bed. Alternatively, the sulphur-rich phase may be chilled, to below the sulphur melting point, by injecting liquid water into the bed in amount not exceeding that which will be wholly evaporated, and the resulting mixture of solid sulphur and oxide particles may be separated by fluidization with cold air in the same or a second vessel or by elutriation. As a further alternative, the sulphur-rich phase may be withdrawn to a second vessel and then chilled with water therein. The treatment temperature may be increased to 350-450 DEG F., when the sulphur is steam distilled from the fluidized bed. Specifications 554,227, 568,913, 586,914, 590,456 and 601,723 are referred to.