| 摘要 |
<p>Iron pyrites are roasted yielding sulphur dioxide and haematite Fe2O3 which is subsequently reduced to yield magnetic iron oxide Fe3O4 which is then separated using a magnetic method, the iron oxide thus separated is used for pig iron and steel manufacture. The pyrites may initially be crushed, preferably heated at 800-1100 DEG C., if desired on a fluidized bed, steam, sulphur dioxide (used for sulphuric acid production) and ashes containing Fe2O3 are produced, said ashes are introduced into a reducing zone at 800-1000 DEG C. where reduction is effected by gases obtained from burning coke or fuel oil separately or added to the reduction zone. The reduction zone may be a rotary furnace or a fluidized bed furnace, the atmosphere being mainly hydrogen and carbon monoxide. The reduced cinders are cooled, ground to a particle size of 0.2-0.05 mm. and then the iron content separated by magnetic means. Cinders obtained from a cyclone or dust collector of the initial fluidized bed roasting may be mixed with the roasted ores and passed to the reduction furnace.</p> |
