| 摘要 |
<p>In a multi-stage fluidized bed process for the reduction of iron ore a carbonaceous fuel and oxygen-containing gas are burnt in an intermediate stage under such conditions that the ore is reduced to ferrous oxide while heat is provided for the subsequent reduction to metal. The gases produced in this zone pass to the initial zone, where the ore is pre-heated and pre-reduced while the gases undergo a catalytic reaction in the presence of ferric oxide, carbon monoxide and water vapour reacting to form carbon dioxide and hydrogen. The gases leaving the initial zone are cooled to remove water and treated to remove carbon dioxide, after which they are pre-heated and circulated through the one or more reduction stages which follow the intermediate stage and in which the ferrous oxide is reduced to metallic iron. It is said that by operating in this way problems of carbon deposition in the apparatus due to catalytic decomposition of carbon monoxide are eliminated. Preferred temperatures and gas ratios for the various zones are given.</p> |
