| 摘要 |
<p>Highly metallized, non-pyrophoric pellets are produced from a finely-divided iron ore concentrate by preparing a moistened mixture of the ore concentrate, a finely-divided carbonaceous material in an amount at least sufficient to reduce all the iron oxide to metallic iron, about 1 to about 30 weight % of a bonding agent, such as burned or hydrated lime, and 0 to up to about 3 weight % of a siliceous material (as available SiO2), such as silica, forming green pellets from this mixture, drying the green pellets to a moisture content of 5% or less, hydrothermally hardening the dried, green pellets by contacting them with steam under pressure, and metallizing the hardened pellets by tumbling them in a reduction furnace, such as a rotary kiln, at a reduction temperature of about 1033 DEG C. up to the melting point of the metallized pellets and in the presence melting point of the metallized pellets and in the presence of a substantially non-oxidizing atmosphere for a sufficient time to reduce a substantial portion of the iron oxide therein to metallic iron. In a preferred embodiment, a charring coal is fed into the rotary kiln along with the hardened pellets and is charred during pellet metallization. The resulting char, after separation from the metallized pellets and comminution, is recycled for use as the carbonaceous material in the starting mixture.</p> |
