Powder injection lance and method of refining molten iron using the powder injection lance

Abstract

A powder injection lance is provided with: a refining oxygen gas injection nozzle which has multiple ejection openings that are arranged at intervals along a circular trajectory and inject an oxygen gas into an iron bath housed in a reaction vessel; and a burner nozzle which has an axial center coaxial with the central axis of the circular trajectory, and which has an ejection opening which forms a flame on the inside of the refining oxygen gas injection nozzle and which injects into the iron bath a powder to which heat has been transferred by the flame. An indicator showing the positional relation between the ejection opening of the refining oxygen gas injection nozzle and the ejection opening of the burner nozzle fulfills A=1.7(R-r-d/2)/L+tan(theta-12 DEG )-0.0524>0. Here, R is the radius (mm) of the circular trajectory, r is the radius (mm) of the ejection opening of the burner nozzle, d is the diameter (mm) of the ejection openings of the refining oxygen nozzle, theta is the inclination angle (DEG) of the axial center of the refining oxygen gas injection nozzle, and L is the lance height (mm). By this means, the efficiency of heat transfer to the iron bath is improved.

Description

technical field [0001] The present invention relates to a powder injection lance with a spray burning function, and a refining method and a smelting reduction method of molten iron using the powder injection lance. Background technique [0002] From the viewpoint of environmental protection, it is imperative to suppress CO in the steel manufacturing process. 2 emissions. In order to reduce CO 2 In terms of emissions, in the steelmaking process, measures such as increasing the use of cold iron sources such as scrap iron as iron sources and reducing the blending ratio of molten iron have been studied and implemented. The reason for increasing the use of cold iron sources is as follows: When producing steel products, a large amount of energy is required to reduce and melt iron ore in the process of producing molten iron (molten iron) in a blast furnace, and at the same time, also emit large amounts of CO 2 , in contrast, the cold iron source only needs the heat of fusion, s...

AI Technical Summary

Problems solved by technology

In Patent Document 1, although the temperature of molten iron is raised by adding a carbon source to the generated slag, the sulfur contained in the carbon source is mixed in, resulting in an increase in the sulfur concentration in the steel.

In addition, there is a problem that the refining time is prolonged in order to secure the burning time of the carbon source, resulting in an increase in manufacturing cost

In addition, there is also a problem that CO is naturally generated by burning carbon sources. 2 increased production of

[0022] Furthermore, in the methods disclosed in Patent Documents 4, 5, and 6, a top blowing lance consisting of a 4-layer tube or 5-layer tube structure is used, and the dephosphorization agent etc. etc. Reactive powder insufflation

In addition, the amount of injection and the flow rate of propane are low, so it cannot be expected to have a sufficient effect on reducing the ratio of molten iron

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