JPS627814A - Slag coating method - Google Patents

Abstract

PURPOSE:To coat a converter inner wall with slag in a short time after tapping, by tapping molten steel after a steel making refining by the converter, throwing a reducing agent to a residual molten slag to lower its temp. by endothermic reaction in reduction of iron oxide in the molten slag and increasing the viscosity. CONSTITUTION:The refined molten steel in converter operation is tapped, and the excess molten slag is discharged while leaving a prescribed quantity of molten slag in the furnace. About 1/3 of quick lime, dolomite, etc. being flux to be used in next time charging is thrown to the remaining slag, and a suitable quantity of cokes being the reducing agent is added. After lowering the temp. of molten slag and increasing its viscosity by the reduction endothermic reaction of iron oxide in the molten slag due to the addition of flux being cooling material and cokes, the converter is turned and moved slightly. Thereby, the slag for protecting inner wall of the converter is coated in a short time after tapping.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] This invention relates to slag coating of the inner wall of a converter, and particularly to shortening of the coating time.

[Conventional technology]

Converter operation involves the following process: blowing → tapping → slag, and a predetermined amount of slag remains in the slag. This remaining slag is then deposited on the inner wall of the converter.
Before the next pig iron is received, it is coated to protect the inside walls of the converter in the next operation.

[Problem that the invention seeks to solve]

In the conventional slag coating method as described above, the temperature of the slag after being discharged is very high, its viscosity is low, and it is difficult to harden. Therefore, in order to coat the inner wall of the converter with slag to a specified thickness, the slag must be heated to a specified viscosity. There was a problem in that the slag coating had to be cooled down until it retained its strength, which took time, and the slag coating reduced the efficiency of converter operation.

[Means for solving problems]

In the slag coating method according to the present invention, after converter slag is discharged,
A reducing agent is poured into the remaining slag, and then the slag is coated on the inner wall of the converter.

[Effect]

In this invention, since the reducing agent reduces iron oxide in the slag, the amount of iron oxide in the slag decreases, and the slag is endothermically cooled by this reduction, increasing the viscosity of the slag.

〔Example〕

Next, one embodiment of the present invention will be described.

First, in converter operation, after blowing and tapping, a predetermined amount of graphite is left and slag is discharged. The amount of graphs to remain is 10
kli'/T-steel ~30kl? / T-
A range of steel is appropriate. Next, a solvent (burnt lime, dolomite) to be used in the next charge is added to the remaining slag.
Add about 1/3 of the amount. Further, coke powder is added as a reducing agent. The amount of coke powder added is 0.0
5 kg/T-5teel ~0.10 kli'
/T-ste@l range is appropriate. The iron oxide contained in the remaining slag is reduced by the injected coke powder,
The endotherm caused by this reduction causes a significant temperature drop and increases its viscosity.

Finally, the converter is rotated and tilted to coat the inner wall of the converter with this slag. As shown in FIG. 1, the time required for coating was approximately 5 minutes, which was half the time required for conventional coating.

[Effects of the Invention] As explained above, the invention described above reduces the iron oxide in the graph to increase the viscosity of the graph by introducing a reducing agent into the remaining slag, and the temperature of the graph increases due to the endothermic endotherm caused by this reduction. Since the viscosity is further increased by lowering the viscosity, graph coating can be applied in a short time, which has the effect of improving the efficiency of converter operation.

[Brief explanation of drawings]

FIG. 1 is a graph showing the relationship between the required coating time and the coating amount for the prior art and the present invention.

Claims (1)

[Claims] A slag coating method characterized by adding a reducing agent into the slag left after the converter slag is discharged, and then coating the inner wall of the converter with the slag.