A furnace slag amount estimation device (1) includes: an input unit (11) configured to receive input data including furnace shape data for a converter, data on components and temperatures of molten metal and slag before start of or during blowing treatment, and slag height data in a furnace of the converter; a slag bulk density calculation unit (13) configured to calculate a slag bulk density after the converter is tilted, using the input data and a model; a slag volume calculation unit (14) configured to calculate a slag volume in the furnace after the converter is tilted, using the slag height data after the converter is tilted, the furnace shape data, and a model; and a slag weight calculation unit (15) configured to calculate a slag weight in the furnace after the converter is tilted and slag is discharged, using the calculated slag bulk density and the calculated slag volume.

Provided is a lance and an operation method using the same, in which a suction hole allowing source gas to be injected into a container, in which a reaction gas is generated, is included. The suction hole is formed in a source gas passage where the reaction gas is introduced into the passage. Thus the temperature of the gas injected into the container may be easily increased without using any separate heating device, and secondary combustion efficiency may be increased. In addition, the gas sprayed at a high temperature is provided, and thus additional heat may be supplied into the container. Thus, excessive use of fuel used to increase the temperature of the container may be avoided, and thus operation costs may be reduced and operation efficiency and productivity may be increased.

A top-blowing lance includes a refining oxygen gas blowing nozzle having a plurality of ejection openings through which oxygen gas is blown into an iron bath in a reaction vessel, the ejection openings being disposed along a circular orbit at intervals, and a burner nozzle having an axis coaxial with the central axis of the circular orbit, forming a flame inside the refining oxygen gas blowing nozzle, and having ejection openings for blowing a powder heated by the flame into the iron bath, wherein an indicator A that indicates the positional relationship between the ejection openings of the refining oxygen gas blowing nozzle and the ejection openings of the burner nozzle satisfies the specified conditions.

A top-blowing lance includes a refining oxygen gas blowing nozzle having a plurality of ejection openings through which oxygen gas is blown into an iron bath in a reaction vessel, the ejection openings being disposed along a circular orbit at intervals, and a burner nozzle having an axis coaxial with the central axis of the circular orbit, forming a flame inside the refining oxygen gas blowing nozzle, and having ejection openings for blowing a powder heated by the flame into the iron bath, wherein an indicator A that indicates the positional relationship between the ejection openings of the refining oxygen gas blowing nozzle and the ejection openings of the burner nozzle satisfies the specified conditions.

A burner comprises a primary nozzle for injecting an oxygen-rich gas. The primary nozzle is designed as a supersonic nozzle. A coaxial nozzle having an annular outlet opening is provided for injecting a fuel gas. The coaxial nozzle is designed as a subsonic nozzle and is coaxial to the primary nozzle. The primary nozzle has a convergent portion and a divergent portion, which adjoin each other at a radius of the narrowest cross-section. The annular outlet opening is located at an end face of the burner. The fuel gas, in the form of hydrogen or a mixture of hydrogen and a hydrocarbon-containing gas, is injected at a fixed inlet pressure and a fixed inlet volumetric flow rate, with respect to a planned thermal power of the burner. In contrast, the inlet pressure and the inlet volumetric flow rate of the oxygen-rich gas are varied according to the application.

A burner comprises a primary nozzle for injecting an oxygen-rich gas. The primary nozzle is designed as a supersonic nozzle. A coaxial nozzle having an annular outlet opening is provided for injecting a fuel gas. The coaxial nozzle is designed as a subsonic nozzle and is coaxial to the primary nozzle. The primary nozzle has a convergent portion and a divergent portion, which adjoin each other at a radius of the narrowest cross-section. The annular outlet opening is located at an end face of the burner. The fuel gas, in the form of hydrogen or a mixture of hydrogen and a hydrocarbon-containing gas, is injected at a fixed inlet pressure and a fixed inlet volumetric flow rate, with respect to a planned thermal power of the burner. In contrast, the inlet pressure and the inlet volumetric flow rate of the oxygen-rich gas are varied according to the application.