Abstract: Multi-grades dynamic state magnetizing roasting is suitable for handling the powder low-grade oxidized ore.Refractory iron ore material about -3 mm diameter is declined by gravity through drying and dehydrating stage,preheating and roasting stage,cooling stage, traveled against to ascending high temperature wind current in furnace.Reactions of heat transfer and mass transfer are finished efficiently.The technology has properties such as high efficiency,low unit energy exhaustion,fast reaction,full magnetic reduction and can be used to deal with many kinds of oxidized iron.Designs of temperature and wind current matching are fulfilled in this system, balance and stabilization of temperature,pressure and reductive atmosphere are ensured in the processing.The roasted product can be separated by low intensity magnetic separator efficiently.Advantages such as high efficiency,low exhaustion and environmental protection are proved in research.Good separation indexes are also obtained in production.

Key words: Oxidized iron, Magnetizing roasting, Multi-grades dynamic state