| 摘要 |
<p>1,184,573. Extracting iron. STEEP ROCK IRON MINES Ltd. June 26, 1967 [Aug. 30, 1966], No. 29315/67. Heading C7D. [Also in Division F4] The reduction of iron ore to metalized ore is effected in a low temperature blast furnace 59. The ore with a one third to two thirds excess of reduction material, in the form of coke, coal or lignite of #" to 1" particle size, is introduced as a charge into the top 60 of the furnace which is divided into five zones. Air from an annular preheating jacket, and the top and/or bottom of a central air supply pipe 62 of between one tenth and one half the furnace diameter, is introduced to the charge to burn off gases and volatiles at the top of the shaft in zone one and to provide a pre-heating and pre-reduction zone, zone two. Further preheated air is controllably fed to zones three and four to combust part of the reduction material and form combustion and reduction zones respectively in the latter of which a CO/CO 2 ratio of at least 7:1, and an operating temperature no greater than 2400‹ F. are maintained. The reduced charge which has been passed through zones one to four at a controlled rate, is then cooled in zone five to 400‹ F. and removed from the bottom 61 of the furnace. The iron is then separated from the excess reduction material, which is recycled, by magnetic separators (not shown). The air supply and waste gas withdrawal means (not shown) are so co-ordinated that about 5% of the reducing gases produced in the reduction zone are drawn down through the cooling zone five to prevent re-oxidization of the reduced charge, the remainder of the gases passing upwardly through zones three to one. Natural gas, propane, fuel oil or naptha may be introduced into the furnace through central air supply tube 62 to reduce the consumption of the reduction material.</p> |
