JPS63203713A - Method for blowing treating agent in molten iron trough - Google Patents

Abstract

PURPOSE:To prevent stay of slag flowing and to sufficiently utilize treating effect under continuous flowing by blowing a molten iron treating agent from upper part at a specific angle to the molten iron flow toward the molten iron flowing direction. CONSTITUTION:The molten iron treating agent 4 from a lance 3 is blown from the upper part at 85-60 deg. angle toward molten iron flowing direction into the molten iron flow 2, flowing in the molten iron trough 1 in a blast furnace. In this way, the slag 5 formed by reaction is flowed toward downstream. Therefore, reaction between the slag and metal, becomes insufficient, and unfavorable reaction of rephosphorizing, resulfurizing, decarbonizing, etc., can be restrained.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a method of injecting a treating agent such as a dephosphorizing agent into hot metal tapped from a blast furnace in a hot metal trough.

(Prior Art) Conventionally, when performing dephosphorization treatment etc. in a blast furnace molten metal trough, a so-called overlay method in which a powdered treatment agent is placed on top of the molten metal flow flowing through the molten metal trough, or a lance is applied to the molten metal flow. There was an injection method in which the tip of the tank was inserted and the powdered treatment agent in the tank was blown into the hot metal along with an inert gas for transport.

However, in the former overlay method, the contact between the treatment agent and the hot metal is poor and the reaction rate is slow, resulting in a long treatment time, and the reaction continues even after the hot metal is placed in the ladle, resulting in slag forming, etc. There were problems in terms of safety, workability, yield, etc.

In addition, the latter injection method can solve the problems that existed with the top-down method, but since the lance is immersed in hot metal, the lance is severely eroded and cannot withstand long-term use. There was a problem in that the bottom of the hot metal trough was eroded by the chemical.

Therefore, in order to solve this problem, as shown in Fig. 2, a treatment agent 4 is introduced into the hot metal flow using a conveying gas from a lance 3 installed vertically away from the scene of the hot metal flow 2 flowing through the hot metal sluice 1. Japanese Patent Publication No. Sho 61-45681 discloses a method of injecting into the air.

(Problems to be Solved by the Invention) The above method can solve the problems that existed in the overlay method and the injection method, but according to research and experiments by the present inventors, this method Since 5 tends to stagnate, there was a problem in that the processing characteristics under continuous flow were not fully utilized.

The present invention has been made in view of this problem, and it is an object of the present invention to provide a method that can prevent slag stagnation and make full use of the processing characteristics under continuous flow.

(Means for Solving the Problems) The present invention provides a method for injecting a hot metal treatment agent into a hot metal flow flowing through a blast furnace hot metal gutter, in which the hot metal treatment agent is injected at an angle of 85 to 60'' from above the hot metal flow. This is a method of blowing a treating agent into a hot metal trough, which aims at blowing the treating agent into the flow direction of the hot metal.

In the method of the present invention, the blowing angle of the treatment agent with respect to the hot metal flow is set to 85 to 60 degrees in the flow direction of the hot metal.
This is because if the angle exceeds 5°, the slag flow becomes poor and the processing characteristics under continuous flow cannot be fully utilized. Further, if the angle is less than 60°, it becomes difficult for the treatment agent to be immersed in the hot metal flow, resulting in deterioration of treatment capacity.

That is, the gist of the present invention is to inject the processing agent so that the slag formed by the injection of the processing agent always changes to a slag that does not contain P2O (hereinafter referred to as "renewal").

In other words, when a treatment agent is injected into hot metal, a reaction occurs.

Then, a subsequent reaction occurs, and when the treatment agent 4 is blown in at an angle in the flow direction of the hot metal as in the method of the present invention shown in Fig. 1, the slag 5 formed by the above equation (2) moves downstream. As a result, the reaction between slag and metal shown in equation 0 becomes insufficient, and undesirable reactions such as rephosphorization, resulfurization, and decarburization can be suppressed.

(Function) A method for injecting a treatment agent into a hot metal gutter according to the present invention is a method of injecting a hot metal treatment agent into a hot metal flow flowing through a blast furnace hot metal gutter, in which the hot metal treatment agent is applied to the hot metal flow from above the hot metal flow.
Since the hot metal is blown at an angle of ~60° in the flow direction of the hot metal, the formed slag is constantly renewed.

(Example) Hereinafter, the results of dephosphorization treatment in a hot metal trough by applying the method of the present invention will be described.

Hot metal flows through the hot metal trough at a flow rate of 10 TON/min, and a dephosphorizing agent having the composition shown in Table 1 below is added to the hot metal flow at 5 Nm of N8 gas.
80 kg of hot metal was injected per 1 turn of hot metal using a 1/min.

At this time, adjust the angle of the lance to 60', 75°, 85°, 90°.
(conventional method) and investigated the slag flow and the achieved phosphorus concentration. The results are shown in Table 2 below.

Table 1 Dephosphorizing agent composition (unit: weight %) Table 2 As is clear from Table 2 above, according to the method of the present invention, the slag flow is good and the CP concentration is low. This is considered to be the result of suppressing rephosphorization.In other words, the amount of decarburization is suppressed, and the FeO of the slag
Considering the high concentration, it can be seen that the reaction shown in equation 0 above is suppressed.

Although this embodiment has described dephosphorization treatment, it goes without saying that the method of the present invention is effective in processes such as desiliconization treatment and desulfurization treatment that do not suppress resulfurization and decarburization.

(Effects of the Invention) As explained above, the present invention provides a method for injecting a hot metal treatment agent into a hot metal flow flowing through a blast furnace hot metal gutter, in which the hot metal treatment agent is injected at an angle of 85 to 60 degrees from above the hot metal flow. Since the hot metal is blown in the flow direction of the hot metal, the slag formed along the flow direction of the hot metal constantly flows out, and the slag surface at the injection point is constantly renewed, suppressing rephosphorization.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic explanatory diagram of the method of the present invention, and FIG. 2 is a schematic explanatory diagram of the conventional method. 1 is a hot metal trough, 2 is a hot metal flow, 3 is a lance, and 4 is a treatment agent. Hz diagram Figure 2

Claims (1)

[Claims] (1) A method of injecting a hot metal treatment agent into a hot metal flow flowing through a blast furnace hot metal gutter, characterized in that the hot metal treatment agent is injected into the hot metal flow from above at an angle of 85 to 60 degrees in the flow direction of the hot metal. A method of blowing a treatment agent into a hot metal trough.