26,595. Hall, W. A. Sept. 11. Sulphur is obtained, in a development of the process of Specification 20,758/12, from the sulphides of zinc, copper, and lead, by treating these with a reducing-flame, and a limited amount of steam, or of water which will be converted into steam, insufficient itself to decompose the sulphide to any considerable extent, but sufficient to prevent substantial loss due to formation of sulphur dioxide and carbon oxysulphide. In these circumstances more air can be admitted with the producer-gas used than would otherwise be practicable, giving better combustion, higher temperature, &c. Preferably a furnace of mechanical type is used, containing superposed shelves for the sulphides, which it is necessary to agitate as much as possible. The furnace is heated internally by producer-gas and air, the air being so regulated as to give a flame sufficiently reducing to combine with free oxygen. The steam or water passes through inlets, preferably located between the shelves, and is provided, preferably, in larger quantity between the lower shelves of the furnace. The furnace having reached the proper temperature the metal sulphide is led into it, preferably in a continuous stream, with the least practicable admission of air. A slight internal pressure may be maintained by means of the expanded gases. The combustion products pass up through a long discharge pipe into which may be passed more steam to react, at the lower temperatures reached, with carbon oxysulphide forming hydrogen sulphide and carbon dioxide; the hydrogen sulphide then reacts with excess of sulphur dioxide. Thus the products of combustion are led from the discharge pipe, surcharged with sulphur vapour and without any appreciable admixture of sulphur dioxide, and to a condenser or gaswashing apparatus, such as the Thiesen apparatus, wherein the sulphur is precipitated.