GB389520A - Smelting sulphide ores to recover elemental sulphur therefrom - Google Patents

Abstract

In a blast furnace method of smelting iron pyrites or other sulphide ore for the production of sulphur in which is employed an amount of coke insufficient to reduce the sulphur dioxide produced, the sulphur dioxide is brought into contact with sufficient hot sulphide to reduce it to sulphur within the furnace, contact being made first with molten, partially desulphurized pyrites and then with the unmelted pyrites of the charge. A hot, dry blast of a temperature of 500 DEG C. or more is employed and the amount of air is so controlled that the atmosphere above the charge is non-oxidizing. A furnace of greater height than usual is employed and by feeding the charge more slowly than usual an abnormally elongated hot smelting zone is obtained. Air is prevented from entering the top of the furnace by the use of suitable charging devices and the temperature in this region is maintained at 350-400 DEG C. by regulating the depth of the charge. The reaction is facilitated by the addition of lime or magnesia, preferably the latter, e.g. in the form of dolomitic lime, the minimum temperature for the reaction being thereby reduced. The gases leaving the furnace may be passed through a dust collector or an electrostatic precipitator and then through a condenser. Sulphur dioxide, hydrogen sulphide and carbon oxysulphide in the gases are treated to recover sulphur by passage over a catalyst such as porous alumina or bauxite, further sulphur dioxide being added if necessary, e.g. by adjustment of the blast.