This invention is directed to an improved process for conversion of H.sub.2 S to sulfur, using MOST(Mobil Offgas Sulfur Treatment) catalyst or sorbent. The sorbent is typically a magnesium-aluminate spinel, with oxidation promoters such as ceria and vanadia. H.sub.2 S from the feed gas is used to regenerate sulfated sorbent, simultaneously producing elemental sulfur which is then condensed out. The improvement involves recycling a portion of the effluent from a downstream burner to mix with the feed to the sorbent. Thus some of the stoichiometric oxygen required for conversion of H.sub.2 S to S is supplied in the form of SO.sub.2 by this pre-combustion step, instead of coming totally from the oxidized/sulfated solid sorbent. This can decrease the amount of sorbent required, as well as the frequency of regenerations, thus reducing process cost. The hot recycle gas also helps to heat the feed stream.