The present invention is one kind of roasting apparatus for reducing powdered hematite, brown iron ore and siderite into magnetite. The roasting apparatus consists of suspended preheater, flash roaster, air valve, pipeline, hot blast stove and other parts. The suspended preheater consists of 3-5 preheating stages arranged up and down. The flash roaster consists of upper volute, feed port, reaction chamber and lower volute connected via pipeline with the hot blast stove. The fine middlings through preheating in the preheater is reduced in the flash roaster into magnetite product, which is made to pass through the last preheating stage and weak magnetic separation to obtain high grade iron ore concentrate with TFe>60 %. Compared with a rotary kiln, the present invention has low investment, great ore treating capacity, fast ore reduction, low power consumption and other advantages. |