| 摘要 |
<p>1,135,755. Reducing iron ores to magnetite. PULLMAN Inc. 2 Dec., 1965 [7 Dec., 1964], No. 24255/68. Divided out of 1,135,753. Heading C1A. A non-magnetic iron ore is reduced to magnetite by contact at 800-1400‹ F. first with a gas which is reducing with respect to Fe 3 O 4 to reduce at least part of the ore to FeO and then with a gas which is reducing with respect to Fe 2 O 3 but oxidizing with respect to FeO to convert a major part of the reduced material to Fe 3 O 4 . In Fig. 1, reduction reactor 140 contains fluidized beds 142 and 144, separated by arc-shaped baffle 138. Ore is fed from line 130 into bed 142, passes through orifice 146 into bed 144, is removed via line 152, and may be quenched with water in 150. Beds 142 and 144 are fed with gases from partial oxidation furnaces 160 and 170 respectively (their composition being controlled by valves in the feed lines), and with recycle gases from line 66. The conditions in bed 142 preferably correspond to 90-100% conversion to Fe 3 O 4 , and some Fe may be formed. The gases fed to bed 144 have a composition such that oxidation beyond Fe 3 O 4 cannot occur. The ore is preheated (as described in Specification 1,135,754) first in cyclones 18 and 12, and then in fluidized bed heating zone 110 or in transfer line heatexchanger 210 (Fig. 2, not shown), effluents from zone 110 and reactor 140 being recycled to cyclone 12. Alternatively, only the effluent from 140 may be used, or the effluents from beds 142 and 144 may be recycled separately.</p> |
