GB856838A - Method of converting excessively moist, plastic, and greasy ores into lump form on a sintering band - Google Patents

Abstract

In a method of converting excessively moist, plastic and greasy ores into lump form on a sinter band by two-zone sintering such material with a wide range of grain size, preferably up to 35 mm., is bedded in the lower layer, the upper layer consisting at least mainly of material previously dried and roasted in the lower layer of a previous operation. The upper layer may include small quantities of fines from the upper layer of the previous operation and/or the finer portion from undried ores screenable without drying. Any portions of moist ore above 50 mm. may be separated and disintegrated. The coarser portions from the lower layer, preferably over 8 mm., can be taken directly to the blast furnace. Crude ore which is too moist even for the lower layer may be rendered gas-permeable by admixture with return material, e.g. 10 to 18% In treating several differing ores simultaneously the moist portions of ore may be exclusively bedded in the lower layer and the finer portions with return material in the upper layer. With a single kind of ore the lower layer may be exclusively of crude ore and the upper layer a mixture of crude ore and return material, the proportion of the latter increasing with moistness. The heat may be supplied partly by solid fuels and partly by hot gases.