PURPOSE: To control powdering of pellets in reduction in a rotary kiln by adding a specified amt. of MgO to principal raw material such as fine iron ore or iron- contg. dust and pelletizing the MgO-added material after which the resulting raw pellets are dried, preheated, and calcined on a traveling grate.
CONSTITUTION: 1W5% of MgO is added to principal raw material such as fine iron ore or iron-contg. dust, and the MgO-added material is pelletized. The resulting raw pellets are dried, preheated, and calcined on a traveling grate to form hardened pellets, which are then treated with a reducing gas or a solid reducing material in a rotary kiln. The concn. of O2 in the sintering atmosphere gas is pref. about 1W5, esp. about 1W2%, and the crushing strength of the hardened pellets is enhanced. Since the pellet strength is well maintained in the reduction in the kiln, powdering does not occur, and no powder deposits on the kiln wall. In addn., the reducing gas readily diffuses in the pellets, so the metal grade of product pellets rises, and the desulfurization and dezincification rates are enhanced.
NAGANO MASANORI
ITOU MASAHARU
YATSUNAMI KAZUHARU
YAMAMOTO RIYOUJI
SHIOBARA KATSUAKI
NAKAMURA YUTAKA
KOKAN MINING CO LTD
| JPS5319531A | 1978-02-22 |