| 摘要 |
<p>Sulphur is recovered from pyritic iron ores by distilling off the labile sulphur in a distillation zone, and roasting the resulting material in a roasting zone, characterized in that a major portion of the roaster gas, composed mainly of nitrogen and sulphur dioxide, is removed from the roasting zone, or from a point between the roasting and distillation zones, cooled, and returned to the roasting zone, and that a minor portion of the roaster gas is passed to the distillation zone, where the sulphur dioxide is reduced, the heat of reduction providing the major portion of the heat for the distillation of the labile sulphur, the distillation being carried out without sintering or melting of the ore. The process may be carried out in shaft furnaces or in fluidized beds. Any non-ferrous metals in the ore may be sulphatized in the roasting zone by the recycled cooled gases. The sulphur dioxide may be reduced in the distillation zone by gaseous reducing agents, which may be derived from pig-iron furnaces or coke oven gas, and may be introduced at a point at or below the distillation zone. Solid reducing agents may also be employed. The raw material may be briquetted and have incorporated in it salts, such as magnesium chloride and sulphate, calcium chloride, and sodium sulphate, which have a catalytic effect on the conversion of nonferrous metals to water-soluble compounds during sulphatizing. The roasted material may be leached or subjected to a chlorodizing roast to recover the non-ferrous metals.</p> |
