| 摘要 |
<p>Materials from the metallurgical industry containing zinc, lead and iron oxides are worked up by the rotary-kiln volatilising process in a rotary kiln. A mixture of these materials with sluggishly reacting, carbon-containing material is charged into the rotary kiln and thermally treated under reducing conditions. In the end zone of the rotary kiln, hot air having a temperature of from 500 to 900 DEG C is blown onto the charge, with a charge temperature of from 1200 to 1500 DEG C being set in the end zone, ZnO being largely reduced by metallic iron present in the charge and the metallic iron being largely reoxidised again at the same time. The temperature and composition of the waste gas (off gas) is set in such a way that autothermic afterburning outside the rotary kiln is possible by addition of air. The afterburned waste gas is cooled and purified.</p> |
