Blast furnace, method for operating blast furnace, and method for manufacturing hot air tuyere

Abstract

Disclosed is a novel feature capable of increasing the combustion rate of a solid reducing agent if the solid reducing agent is supplied together with a reducing gas into a blast furnace through a hot air tuyere. In a blast furnace according to the present disclosure, a hot air tuyere comprises a tuyere body, a hot air flow path, a reducing gas blowout port, and a solid reducing agent blowout port. The hot air flow path is defined by an inner wall of the tuyere body, the reducing gas blowout port faces the hot air flow path, and the solid reducing agent blowout port faces the hot air flow path. A reducing gas blown out from the reducing gas blowout port contains a hydrogen-based reducing gas, and a solid reducing agent blown out from the solid reducing agent blowout port contains carbon. The length L1 between a tip end of the tuyere body and the center of the reducing gas blowout port is shorter than the length L2 between the tip end of the tuyere body and the center of the solid reducing agent blowout port, and the length L1 between the tip end of the tuyere body and the center of the reducing gas blowout port is from 50 to 120 mm.