Abstract: Hot waste gas is desulfurized in a spray drying-absorption process performed in an absorption chamber wherein a fluidized layer of partially reacted absorbent is maintained in the bottom area. Improved conditions are obtained for the reaction between absorbent and sulfur oxides in the waste gas, whereby the use of inexpensive absorbents of relatively low reactivity, such as limestone, comes into consideration.

Abstract: A process and apparatus for removing total reduced sulfur compounds (TRS), especially H.sub.2 S and mercaptans from industrial gases is disclosed wherein an aqueous suspension of an active manganese dioxide is contacted with the industrial gas by atomizing the aqueous suspension in a spray dryer and contacting the atomized droplets with the industrial gas at a temperature sufficient to substantially completely evaporate the water in the atomized droplets. In preferred practice, the dried powder produced by the spray dry process is recovered as a particle layer in a bag filter unit through which the industrial gas is caused to flow.