JPS637314A - Blowing method for desiliconizing agent - Google Patents

Abstract

PURPOSE:To improve workability and desiliconizing efficiency by calculating the total blowing amt. of a desiliconizing material, determining the effective blowing amt. to an inclined pouring spout from an empirical value and distributing and blowing a desiliconizing agent to the inclined pouring spout and molten iron pan. CONSTITUTION:The weight of the molten iron received in the molten iron pan 5 is measured by a weight-measuring instrument 7 and the flow rate of tapping is calculated. The content of silicon in the molten iron flowing in a tapping spout 3 is measured by a silicon analyzer 8 and the total blowing amt. of the desiliconizing material is calculated from the measured value and the flow rate of tapping. The effective blowable amt. of the desiliconizing material to the inclined pouring spout 4 is then determined from the content of the silica in the molten iron and the flow rate of tapping based on the empirical value. The distribution ratio of the desiliconizing agent to the inclined pouring spout 4 and the molten iron pan 5 is calculated from such amt. and the opening degree of the distributing valve 6 is controlled, by which the adequate amt. of the desiliconizing agent is blown to the two systems.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for blowing a desiliconizing agent in desiliconizing treatment of hot metal.

[Conventional technology]

Hot metal preliminary treatment for the purpose of desiliconizing hot metal is described in Japanese Patent Application Laid-open No. 56
-217, JP-A-61-52312, etc.

Among these, Japanese Patent Application Laid-Open No. 61-52312 proposes a method in which a powder desiliconizing agent is accelerated by a carrier gas and poured into the hot metal flow falling from the hot metal spit into the pouring tube. Since the total amount of desiliconizing agent is concentrated, desiliconization can be performed without any problem when the tapped iron S1 value is relatively low, but when the tapped iron Si value is high, the total amount of desiliconizing agent is necessarily increased in proportion to it. There is a need to. In this case, the injected desiliconizing agent does not react completely, that is, it does not turn into slag, so the unreacted desiliconizing agent sticks to the pouring point and blocks the flow path, resulting in deterioration of the fluidity of the hot metal and slag. As a result, hot metal overflows from the pouring hole and disrupts the tapping operation. Therefore, it is necessary to constantly remove the deposits attached to the tilting gutter, which greatly affects work efficiency.

Furthermore, as described above, unreacted desiliconizing agent adheres to the pouring trough and the like, so there is a disadvantage that the absolute amount of desiliconizing agent relative to the tapped S1 value is insufficient and desiliconization cannot be achieved to the desired S1 value.

[Problem that the invention seeks to solve]

Therefore, the present invention aims to solve the above-mentioned drawbacks, and specifically aims to improve workability and desiliconization efficiency by distributing and injecting a desiliconizing agent into the tilting trough and the hot metal ladle. The purpose is to

[Means for solving problems]

In the present invention, a desiliconizing agent is injected into J14 and the hot metal ladle 5 to perform a desiliconizing process. In order to distribute the silicon material between the pouring iron and the hot metal ladle for the most effective desiliconization treatment, first measure the weight of the pig iron being received in the hot metal ladle using the weighing device 7.
The amount of silicon content (VT) in the hot metal flowing through the tapping liter is measured using the silicon analyzer thermal conductivity meter 8, and this value and the tapping flow rate (T /min) and the blown-in amount ω) (referred to as the total blown-in amount) of the desiliconizing material. Next, use Figure 3 to determine the most effective amount to blow into the tilting trough. This chart is determined by the structure of the tilting gutter and is drawn from empirical values (actual values). Using this chart, determine the possible amount of injectable desiliconizing material 0 (V min) (the most effective amount) from the silicon content of the hot metal and the tapping flow rate (T, 4>). The injected desiliconizing agent becomes unreacted substances and sticks to the gutter, causing the hot metal to overflow, or unnecessary desiliconizing substances are injected.Therefore, if the amount of desiliconizing agent is injected near the bottom of the wire in the silicone company, It can remove silicon most effectively.

Next, the amount of injection into the hot metal ladle (outside K) is the total amount of injection (K2
The amount to be blown into the tilting gutter (Kgf6) k is subtracted from 9).

A distribution ratio is calculated from these amounts, and the desiliconization material to be transported is blown into the tilting trough and the hot metal ladle by automatically adjusting the opening degree of the distribution valve 6.

Although not shown, the desiliconizing material may be directly transported from the supply source to the tilting trough and the hot metal ladle and blown into it according to the distribution ratio without using a distribution valve.

〔Example〕

The method of the present invention was carried out under the conditions shown in Table 1, and a powdered desiliconizing agent was blown into the tilting trough and, if necessary, into the hot metal ladle using a carrier gas. As a result, the tap iron flow rate is 3V and 9″V
At f+, the desiliconizing agent consumption rate is 15 Kl/7, SiO during tapping.
, 35%, the desiliconizing agent was injected only through the tilting gutter, and the Si value in the hot metal after desiliconization could be lowered to about 0.15%.

- Direction desiliconizing agent consumption 35 KfT, SiO during tapping, 50
%, it is possible to desiliconize without using a hot metal ladle nozzle if the tap flow rate is 3 to 2, but if the tap flow is 5
When reaching T10, it is necessary to inject a large amount of desiliconizing agent according to the amount of pig iron tapped. It was possible to carry out desiliconization without exceeding the limit point where the unreacted desiliconizing agent adhered to the iron and the hot metal overflowed, and the amount of desiliconization was the same as when the tapping flow rate was three wheels. .

Table 1 Desiliconization treatment conditions for hot metal [Effects of the invention] As shown in Figure 4, the Sl value before desiliconization that can reduce the Sl value after desiliconization to 0.20% or less is 0 in the conventional method. .4
While it is less than 3%, in this method, it is 0°50
% or less, and the range of desiliconization was expanded. In addition, the opening of the distribution valve can be fully automatically adjusted, making it possible to inject the appropriate amount of desiliconizing agent into both systems, eliminating the need to remove unreacted desiliconizing agent in the tilting trough, and As shown in the figure
It has become possible to effectively inject a larger amount of desiliconizing agent than with conventional methods.

[Brief explanation of the drawing]

FIG. 1 is a schematic perspective view of an apparatus showing an embodiment of the present invention, and FIG.
The figure is a block diagram illustrating the procedure for injecting a desiliconizing material according to the present invention. FIG. 3 is a chart for determining the amount of air that can be blown into a tilting gutter according to the present invention. Figure 4 is an implementation result diagram showing the change in desiliconization rate due to the difference in the S1 content before desiliconization when the present invention is implemented in comparison with the conventional method. Comparison diagram of silica basic unit. 1; Transfer pipe for desiliconized material 2a: Tilt gutter blowing nozzle 2b: Hot metal ladle blowing nozzle 3 Two tap holes 4: Tilt gutter 5: Hot metal 'A' 6: Distribution valve 7, measuring instrument 8: Silicon analyzer patent applicant Nisshin Steel Co., Ltd. Figure 1

Claims (1)

[Claims] 1) In a method for desiliconizing hot metal by injecting a desiliconizing substance consisting of a powder desiliconizing agent and a carrier gas into a tilting trough and a hot metal ladle, Measure and calculate the amount of tapped iron (T/min) flowing into the tilting runner, measure the silicon content (Kg/T) in the hot metal before desiliconization, that is, the hot metal in the tap runner (3),
From the silicon content (Kg/T) and the tapping flow rate (T/min), the injection amount (Kg/min) of the desiliconizing material (referred to as the total injection amount) is calculated, and the total injection amount (Kg/min) is calculated. In order to effectively distribute and inject the amount (minutes) into the tilting trough and the hot metal ladle, the optimum injection amount (Kg/minute) is determined using the past performance values of each, and these injection amounts (Kg/minute) are calculated. 1. A method for injecting a desiliconizing agent, characterized in that a distribution ratio is calculated from the distribution ratio, and a desiliconizing substance is automatically injected in accordance with this distribution ratio. 2) The desiliconized material to be transported is passed through the distribution valve (6) according to the distribution ratio.
2. A method for blowing a desiliconizing agent according to claim 1, wherein the opening degree of the desiliconizing agent is adjusted to automatically blow the desiliconizing agent into the tilting trough and the hot metal ladle. 3) A method for injecting a desiliconizing agent, characterized in that the desiliconizing agent is automatically injected from a supply source into a tilting trough and a hot metal ladle through respective conveying pipes according to a distribution ratio.