Rotary hearth furnace and screw thereof for discharging reduced iron

A reduced iron discharging screw for discharging reduced iron on a hearth of a rotary furnace, said reduced iron discharging screw comprising:

• a rotary shaft having an internal passage for a liquid coolant;
• a spiral blade provided at an outer periphery of said rotary shaft;
• and
• a corrosion protective refractory layer provided at the outer periphery of said rotary shaft.

A rotary hearth furnace comprising:

• a furnace body having a hearth and inner and outer side walls, each including through holes;
• a reduced iron discharging screw having a rotary shaft and a spiral blade dimensioned to pass through said through holes, said reduced iron discharging screw being mounted in said furnace body at a location to discharge reduced iron on the hearth from a discharge port of the furnace body, wherein axial ends of said rotary shaft extend through said through holes to the exterior of said furnace body;
• hatch members removably mounted to said axial ends of said rotary shaft, said hatch members externally closing said through holes;
• a first outer screw supporting device comprising means for removing said reduced iron discharging screw from said furnace body via one of said through holes, and a movable bogie position able to support the removed reduced iron discharging screw;
• and
• a second inner screw supporting device comprising a reciprocatable member having an end detachably connectable to said axial ends of said rotary shaft, and means for moving the reciprocatable member so as to draw the reduced iron discharging screw out of said furnace body.