JPS6070116A - Method for preventing forming in spout desiliconization method - Google Patents

Abstract

PURPOSE:To prevent economically and effectively a foaming phenomenon in desiliconization slag by using chaff as a slag foaming inhibitor to be added to a torpedo car. CONSTITUTION:A desiliconizing agent 2 is added to a spout 1 for tapping molten pig iron, and when molten pig iron is received in a torpedo car 3, through the spout 1, bagged chaff 6 is added to the car 3 as a foaming inhibitor by about 10kg per car. In the car 3, a layer of desiliconization slag 5 is broken by the reaction of the chaff 6 with the slag 5, so gaseous CO or CO2 produced by the reaction of oxygen in the agent 2 with carbon in the molten pig iron escapes from the layer and diffuses from the car 3. A foaming phenomenon in the slag 5 is reduced by the release of the said gas.

Description

[Detailed Description of the Invention] This invention is an economical and effective way to reduce the slag phenomenon of desiliconization slag that occurs in a torpedo in a gutter desiliconization method in which hot metal is desanded on the tapwater of a blast furnace. Regarding how to prevent it.

As one of the pretreatment methods for hot metal, a trough desiliconization method has recently been widely used, in which a desiliconizing agent is introduced into the tap trough of a blast furnace to remove sand from the hot metal. Figure 1 shows an example of the method for desiliconizing the trough.
In this method, the molten pig iron is de-sanded during the process up to step (3) of Toby (page 2). (4) is desanded hot metal, and (5) is desiliconized slag.

However, in this gutter desiliconization method, torpedo (3)
The desiliconization slag (5) expands in volume inside the torpedo and overflows outside the torpedo, which is extremely dangerous. This expansion phenomenon of the desiliconization slag is called forming. The cause of this forming is Co or CO2 produced by the reaction between oxygen in the desanding agent and carbon in the hot metal, as shown in Figure 2.
It is thought that the gas is obstructed by the desiliconizing slag (5) floating on the inner bath surface of the torpedo (3) and is not sufficiently dissipated outside the torpedo, pushing up the desiliconizing slag (5). Therefore, in order to prevent forming, the layer of desiliconization slag should be broken by some means to release the Co and CO2 gases.

Therefore, the conventional method has been to charge a mixture of converter slag (70%) and tar (30%) into the torpedo. This method uses approximately 30kl of the above-mentioned anti-foaming agent per torpedo. Co, CO,
This is a method to remove 2 gases. Therefore, in the gutter desiliconization method, the anti-foaming agent costs extra in addition to the desiliconization agent.

The inventors have developed a method for preventing forming IE in a gutter desiliconization method.
After investigating various ways to reduce the cost of the agent as much as possible, it was discovered that rice husks, which are cheaper than conventional converter slag and tar, are effective in preventing foaming.

That is, the forming prevention method according to the present invention is a method in which a desiliconizing agent is introduced into a blast furnace tap trough and then a forming inhibitor is added into a torpedo to prevent forming of desanded slag. This method is characterized by using rice husk as an inhibitor.

It is effective in breaking the desanding slag layer within the rice husks. The reason for this is thought to be that CO2 gas is generated when rice husks are burned, but this is accompanied by rapid volumetric expansion.

Therefore, if rice husk is used as a foaming prevention agent, the foaming prevention wall can be reduced to about 10% of the conventional foaming prevention wall, which is very economical.

An embodiment of the present invention will be described below with reference to FIG.

That is, the desiliconizing agent (2) is put into the tap runner (1), and when the iron is received from the tap runner into the torpedo (3), the rice husks (6) packed in bags are placed in the torpedo (3) as a forming prevention agent. 3) Put it inside. The amount of rice husk added is not particularly limited, but since it has a higher anti-foaming rate than conventional antifoaming agents, the amount of rice husk added to the torpedo is about 10% higher than that of conventional antifoaming agents. (Conventionally about 30 kg) is sufficient.

In the torpedo (3), the desanding slag layer is broken by the reaction between the rice husks (6) and the desanding slag (5), and the Co generated by the reaction between oxygen in the desanding agent and carbon in the hot metal. Alternatively, CO2 gas may escape from the breach and dissipate outside the torpedo. This gas release reduces the overbending phenomenon of the desanding slag (5).

Next, embodiments of the invention will be described.

(Page 5) [Example] Approximately 100 units of desiliconizing agent (sintered powder) was added to hot metal (temperature 1500°C) having the components shown in Table 1, which was tapped from a blast furnace, on the tap sluice. After receiving the pig iron into a torpedo with a capacity of 12 m3, approximately 10 kg of rice husk was charged per torpedo. At that time, the thickness of the desanded slag layer inside the torpedo was approximately 800 mm. Met.

Table 2 shows the cost and foaming prevention rate of the 7-honing inhibitor in this example in comparison with the conventional method. Note that the forming prevention rate is a value obtained from actual test data.

Table 2 shows that rice husks are cheaper than conventional foaming inhibitors and have a greater foaming prevention effect.

(Page 6) (Page 7) As explained above, according to the method of this invention, by using rice husks that are cheaper than conventional anti-foaming agents and have a greater anti-foaming effect, approximately r of the conventional method can be reduced. It is economical because it achieves its purpose at a low cost. In addition, a high forming prevention rate means that it is possible to increase the amount of desiliconized pig iron per torpedo, which has the additional benefit of making it easier to connect with the deP and deS processes in steelmaking in terms of temperature reduction. It is also effective.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing a normal gutter desiliconization method, FIG. 2 is an explanatory diagram showing the cause of forming in the same as above, and FIG. 3 is an explanatory diagram showing an embodiment of the present invention. 1... Tapping flue 2... Desiliconizing agent 3... Torpedo 4... Desiliconizing hot metal 5... Desiliconizing slag 6... Rice husk. Patent applicant: Sumitomo Metal Industries, Ltd. 14 opening a60-70116 (3) 111 Figure 2 and \5 Figure 3

Claims (1)

[Claims] In a method in which a desiliconizing agent is introduced into the taper of a blast furnace, and then an anti-foaming agent is added to the torpedo to prevent the desiliconized slag from forming, rice husk is used as an ohming inhibitor for the desiliconized slag in the torpedo. A method for preventing foaming in a gutter desiliconization method.