GB666752A - Production of sulfur dioxide - Google Patents

Abstract

Sulphur dioxide is obtained by the oxidation of a sulphur-containing raw material which yields sulphur dioxide on oxidation or sulphur on distillation by contacting the material with a dense turbulent fluidized mass of a finely divided solid oxygen carrier having an oxidizing potential <PICT:0666752/III/1> sufficient to oxidize sulphur completely to sulphur dioxide but insufficient to oxidize the sulphur beyond sulphur dioxide, at a temperature sufficiently high to cause the reaction but below the sintering temperature of the carrier and withdrawing substantially pure sulphur dioxide from the mass. Finely ground iron pyrites is fed from a hopper 1 into a dense fluidized mass of ferric oxide particles having a temperature of 700-900 DEG C in a generator 5, pure sulphur dioxide leaving through a line 17. The ferric oxide is converted to ferrous-ferric oxide which passes in fluidized form through a line 20 to the top part of a ferric oxide regenerator 25 where ferric oxide is produced by the action of air at a temperature of 850-1100 DEG C supplied through a line 29. The regenerated fluidized ferric oxide returns to the generator 5 through a pipe 40. Preferably, part or all of the spent solids withdrawn from generator 5 are passed to a fluidized soaking vessel 45 to prolong the contact of the sulphide with the iron oxide on their way to the regenerator 25, the oxidation being completed if desired by the admission of a little air through a line 49. Sulphur dioxide may be recycled from line 17 through lines 18 and 9 to the bottom of the generator 5, and if pure sulphur dioxide is to be produced in the soaker 45, through a line 48. Sulphur vapour, hydrogen sulphide, ferrous sulphide or arsenopyrites may be fed to the generator 5 instead of iron pyrites.