Screw conveyor for discharging reduced iron from rotary hearth reduction furnace

Abstract

The invention provides a screw conveyor for discharging reduced iron from a rotary hearth reduction furnace in which the rate of operation of the rotary hearth reduction furnace can be enhanced by prolonging the abrasion life of the screw blades of screw conveyor thereby reducing maintenance frequency of the screw conveyor. In the screw conveyor (5) which is disposed in the rotary hearth reduction furnace for producing reduced iron by loading a pellet composed of a metal oxide and a carbon material onto a rotary hearth rotating in a horizontal plane and then by heating (reduction), and which discharges reduced iron to the outside of the furnace, a rotating shaft and screw blades formed spirally on the outer circumference of the rotating shaft are provided, and the lead angle theta (rad) of the screw blade (5a) is set to satisfy the condition 0.6 rad <= theta <= 0.79rad. Furthermore, the ratio (h / D) between the height (h) of the screw blade and the outside diameter (D) of the screw conveyor is set smaller than 0.2, and the ratio (t / h) between the thickness (t) and the height (h) of the screw blade is set at 0.12 or above.

Description

field of invention [0001] The present invention relates to a screw conveyor for discharging reduced iron. The screw conveyor is arranged in a rotary hearth type reduction furnace and is used for discharging reduced iron to the outside of the furnace. Background technique [0002] A rotary hearth type reduction furnace has been used in the manufacture of reduced iron. The rotary hearth type reduction furnace makes iron ore, iron powder and other metal oxides and carbon materials into pellets, and the pellets are loaded on the bottom of the rotary furnace and heated (reduced) to produce reduction iron, and the rotary hearth is rotated on a horizontal plane in a rotary hearth type reduction furnace (refer to Patent Documents 1, 2, and 3). [0003] Figure 5 It is a schematic diagram showing an example of a rotary hearth type reduction furnace. exist Figure 5 In this method, reduced iron is manufactured by charging pellets from a pellet loading port 22 onto a rotary hearth 21...

AI Technical Summary

Problems solved by technology

[0011] However, in the device described in Patent Document 4, in order to make the pressing force of the screw conveyor within a predetermined range, it is necessary to adjust the pressing force of the screw conveyor determined by the lifting cylinder.

Here, when the pressing force of the screw conveyor is incorrectly adjusted, the apparent self-weight of the screw conveyor may be excessively reduced

Moreover, when springs are used to reduce the pressing force of the screw conveyor determined by the lifting cylinder, parts such as springs are added, which increases the cost.

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