MOLTEN IRON PRELIMINARY TREATMENT METHOD AND STIRRER FOR MOLTEN IRON PRELIMINARY TREATMENT

摘要

The purpose of the present invention is to reduce vibration in a stirring device comprising a rotating shaft and impeller even if the rotational speed of the impeller is increased to improve reaction efficiency in molten iron preliminary treatment which is carried out while the stirrer is used to agitate the molten iron by rotating the impeller while immersed in the molten iron. This molten iron preliminary treatment method is a molten iron preliminary treatment method in which an impeller (3) attached to a tip part of a rotating shaft (2) is immersed in molten iron (5) within a smelting vessel (4) and in which the molten iron and an additive (6) is stirred by rotating the impeller that is immersed. Stirring is carried out with the resonant frequency of a primary curve of the rotating shaft is made larger than the rotational frequency of the impeller stirring the molten iron.