Coarse Dust Briquetting for Reuse in the Converter
摘要
Within the dedusting process after the converter of the steel mill, coarse and fine dust is generated. These dusts have different chemical compositions. There are significant differences, particularly in the zinc, burnt lime, and metallic iron content. Therefore, the dust is partly passed on to external recyclers and some is recycled internally. Internal recycling means that the dust is briquetted, and the briquettes are reused as iron and lime carriers and as coolants in the converter. However, the coarse dust alone cannot be moulded into briquettes in the hot briquetting process at voestalpine Stahl GmbH. One method of forming briquettes in hot briquetting is to mix the coarse dust with fine dust to make it suitable for briquetting. As an alternative to the addition of fine dust, voestalpine Stahl GmbH is pushing ahead with the moulding of pure coarse dust briquettes. A research project was carried out for this purpose, and, after a series of tests, a spraying system was installed which sprays a graphite suspension onto the roller presses, thus enabling the moulding of pure coarse dust briquettes. In addition to the good moulding of the briquettes, the surface is sealed by the graphite suspension and the briquettes are more stable regarding disintegration than those not sprayed.