MANUFACTURE OF SINTERING RAW MATERIAL FROM DUST IN IRON MANUFACTURING

PURPOSE:To obtain a sintering raw material having the optimum particle size by cracking coarse dust in the first half part in a rotary drier and executing pelletizing in the latter half part as well as providing a dam in the vicinity of an outlet and prolonging the residence time of the dust. CONSTITUTION:The amounts of dry dust and wet dust generated in an iron mill are regulated and the water content in the raw material is regulated to 16 to 20%, and the raw material is fed to a rotary drier 24. The first half part of the rotary drier 24 is provided with a lifter 50 or a chain 52 to crack coarse dust particles 2. In the subsequent latter half part, the raw material is pelletized while its powdering is prevented. A dam 54 is provided in the vicinity of the outlet of the rotary drier 24 to prolong the residence time of the dust in the pelletization acting area. After the pelletization, the ratio of the dust discharged as coarse particles is reduced, and a classifying effect can be shown. Furthermore, the combustion of a burner 38 is controlled to regulate the water content in the sintering material after dried and pelletized to 10 to 14%.