Production of elemental sulphur from non-ferrous smelter gas

Most non-ferrous raw materials are associated with sulphur. To extract the metals, the sulphur is recovered typically as sulphuric acid or liquid SO(2). On the other hand, natural gas may contain over 20% of hydrogen sulphide (H(2)S) and a huge quantity of elemental sulphur is produced through oil and gas refining processes in the world. A large fraction of the sulphur mined from natural sources is eventually returned to the earth as fertilizers, by-products of desulphurisation and neutralisation processes, or as fugitives to the atmosphere. However, the supply and demand for sulphur are in imbalance. Such situation urges to develop a new smelting process without sulphuric acid production. This paper briefly reviews the global sulphur balance and the technologies for recovering elemental sulphur. The core of this paper is a proposal to convert SO(2) gas to elemental sulphur by using organic materials. Some results of thermodynamic calculations and experiments are presented.