Method of extraction of sulphur and sulphur compounds from blast furnace slag and apparatus therefor

摘要

PICT:0733916/III/1 PICT:0733916/III/2 PICT:0733916/III/3 Sulphur and sulphur compounds (carbon bisulphide and sulphur dioxide are referred to) are extracted from molten slag flowing upwardly or downwardly in a closed chamber, the height of which is the largest dimension, by injecting air and/or other oxygen-containing substances, e.g. carbon dioxide, or finely dividid calcium carbonate or sulphate, into the melt at the base of the chamber, the rate of injection being controlled in relation to the rate of slag flow so that the oxygen introduced is substantially wholly consumed. Molten slag enters lined receptacle 1 at 3 and is withdrawn at 4, while air enters at 5 and products are withdrawn at 6. The chamber at the air injection point should be as small as possible, but large enough that the slag flow is not impeded. The chamber between the air injection openings 6, 7 (Figs. 3, 4) should be rectangular, with the openings arranged in opposite longer sides, say in a plurality of rows and offset relative to each other. As shown opening 7 is a blast slit, and all openings slope down towards the base of the chamber. The ratio of the cross-section in square mms. of the injection opening to the periphery in mms. should be as small as possible, preferably 1 : 5. In an alternative arrangement (Fig. 2, not shown) a riser tube is connected to the slag outlet to reduce the head on the slag bath, and this riser tube may extend above the slag inlet to reverse the flow. The injection openings may be water-cooled (Fig. 5, not shown).