JPH01215918A - Method for detecting slag foaming in converter - Google Patents

Abstract

PURPOSE:To predict the development of slag foaming and to prevent the development of slopping by measuring furnace temp. with a temp. sensor arranging at the prescribed part in a furnace body at the time of steelmaking refining with oxygen-blowing in the converter and comparing the above temp. with the slag foaming temp. CONSTITUTION:The molten iron 13 in the converter 1 is charged, and by blowing oxygen gas from the top-blowing lance 12, the carbon content is oxidized and decarbonized to produce the molten steel. In this case, by fitting the temp. sensor 15 at the upper position of steel tapping hole 14, etc., in the converter, the temp. in the furnace is continuously measured. The molten slag 17 comes to the foaming state in accordance with progressing the decarbonizing reaction and the measured temp. is raised with the temp. sensor 15, according to raise the temp. in the furnace. In this case, beforehand the developing temp. of the molten slag foaming is actually measured, and by comparing this temp., the developing of slag foaming is predicted and the development of the slag forming with the adjustment, etc., of oxygen supplying quantity from a lance 12 is prevented and the development of slopping is prevented from occurring, to stabilize the converter operation.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an improvement in a method for detecting forming of slag in a converter, which monitors the forming state of slag generated during converter blowing.

(Prior art) Generally, during blowing in a converter, the molten slag turns into slag depending on various conditions such as slag composition, viscosity, and oxygen content in the slag, resulting in excessive foaming of the slag. As it progresses, so-called slopping occurs. When this slopping occurs, it not only affects the molten steel composition and total tapping yield, but also reduces work efficiency, reduces the calorie content of the recovered gas, and worsens the working environment due to the generation of red smoke.

Problems such as damage to various devices occur. Therefore, it is essential to quickly grasp the situation inside the converter and prevent the occurrence of slopping in order to properly operate the converter.

Therefore, conventionally, various methods for monitoring the situation inside the converter have been proposed due to two or more needs.

For example, ■ a method for estimating the slag level and slag condition by understanding vibration changes in lances, furnace bodies, etc. or changes in vibration waveforms during converter blowing, ■ methods for estimating slag levels and conditions, etc. A method of understanding radiant energy as temperature and predicting the occurrence of sloping from the temperature change, ■
Further, as shown in FIG. 3, an antenna waveguide 2 as a sensor is installed above the furnace mouth of the converter 1, and microwaves are directly projected into the furnace through the microwave generator 3 and the antenna waveguide 2. The reflected wave is transmitted to the antenna waveguide 2,
There is a slag forming measurement method using a microwave level meter that estimates the amount of slag forming by capturing the amount of slag forming. In the figure, 4 is a water-cooled protection tube, 5 is a signal processing circuit, and 6 is a lance. (2) Furthermore, there is a method of estimating the slag level or slag condition from changes in acoustic frequency, acoustic intensity, etc. generated from inside the converter.

(Problems to be Solved by the Invention) However, the above detection method has various problems as described below.

First, methods (1) and (2) above do not provide highly accurate estimation results because the cause of slopping is not solely due to the amount of slag, and are still not sufficient. In particular, in method (2), a radiation thermometer or the like is installed at the top of the furnace to measure the temperature, but in practice it is often located about 10 meters away from the molten steel surface, and as a result, it is sensitive to various environmental conditions inside the furnace. It is difficult to accurately detect the occurrence of sloping from temperature changes.

In the method (2) above, an antenna waveguide 2 that functions as a sensor is provided in the upper part of the furnace;
There is a problem that the tip of the furnace is damaged early by dust or flames inside the furnace.

Furthermore, the method (2) above is an indirect measurement method because the slag level, slag condition, etc. are determined from the acoustic frequency etc. from inside the furnace, and the slag level etc. cannot be determined quantitatively. Further, the sound intensity of the sound generated from inside the furnace changes greatly not only depending on the forming situation but also due to changes in the pressure inside the furnace depending on the amount of oxygen supplied.

The present invention solves the various problems arising from the conventional techniques as described above, and provides a method for detecting slag forming in a converter furnace that directly measures the temperature inside the furnace and detects the occurrence of slag forming with high accuracy. purpose.

(Means and effects for solving the problem) The method for detecting forming of slag in a converter according to the present invention uses a temperature measurement sensor installed in the tapping port of the converter or an opening provided in the side wall at a desired position. The temperature inside the furnace is measured, and forming is performed based on the measured temperature inside the furnace measured by this temperature sensor, that is, the tendency of the measured temperature inside the furnace to increase due to the rise of slag, or the difference between the measured temperature inside the furnace and the forming temperature that can be known in advance. Excessive slag forming is detected by determining the situation or by detecting the contact temperature of the slag using a temperature measurement sensor.

(Example) Hereinafter, an example of the method of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional structural diagram of a converter applied to the method of the present invention, and one side of the converter body 11 receives molten steel 13 in the furnace after blowing with a lance 12 after charging hot metal. A tapping port 14 for tapping steel into a ladle (not shown) of the truck is provided, and a temperature measuring sensor 15 such as a thermocouple sensor is inserted into the tapping port 14. This temperature measurement sensor 15 is installed so that its tip portion protrudes further inward than the inner wall of the furnace body 11, and continuously measures the temperature inside the furnace body. An output device 16 such as a recorder is connected to the output side of the temperature measurement sensor 15. 17 is a slag.

Therefore, as the slag 17 rises in the furnace body 11, it approaches the tapping port 14, but as the slag approaches, the temperature measured by the temperature measurement sensor 15 rises, or the tip of the temperature measurement sensor 15 reaches the slag. When it comes into contact with 17, it shows an even higher measured temperature. As a result, if the rising trend of the measured temperature or the temperature at which forming occurs is known in advance, it is possible to easily predict the occurrence of such slag forming.
lll can do it.

Next, an example of detecting forming will be specifically explained using FIG. 2. Immediately after charging the hot metal into the furnace body 11, the temperature measurement sensor 15 measured the atmospheric temperature in the furnace of about 500° C. as shown in the figure. Thereafter, the atmospheric temperature inside the furnace body 11 gradually rises due to the exothermic action caused by the Si removal reaction at the initial stage of blowing. After that, the period shifts to the blowing work period using the lance 12, and here it is called the peak period of decarbonization, where C+O→CO
The reaction of CO+O+CO9 takes place, and the temperature gradually rises due to the heat of reaction, so that the temperature measurement sensor 1
In No. 5, the atmospheric temperature inside the furnace was measured at 1300°C to 1500°C.

Here, if there is no forming in the slag 17, the temperature will remain as it is during the peak carbon removal period, and furthermore, at the end of the blowing period, Fe combustion will occur and the atmospheric temperature in the furnace will begin to gradually decrease.
The blowing work ends when the temperature drops to approximately 900°C.

However, when forming of the slag 17 occurs in the furnace body 11, the atmospheric temperature in the furnace exceeds 1500°C and begins to rise, and when the slag 17 contacts the tip of the temperature measurement sensor 15, the temperature measurement sensor 15 reaches 1600°C.
We came to measure the temperature in °C.

Therefore, if an output device 16 such as a recorder is connected to the output side of the temperature measurement sensor 15, the occurrence of forming of the slag 17 can be immediately predicted from the change in the measured temperature, and the experiment can be repeated multiple times. If the temperature at which forming occurs is ascertained, the occurrence of slopping can be predicted if the difference between the temperature measured by the temperature measurement sensor 15 and the temperature at which forming occurs, which can be known in advance, falls within a predetermined range. Moreover, the occurrence of excessive forming and even slopping can be determined based on the temperature when the slag 17 contacts the temperature measurement sensor] 5 without predicting the occurrence of forming.

In the above embodiment, the temperature measurement sensor 15 was inserted using the tap hole 14, but a sensor insertion hole is provided separately from the tap hole 14, and the temperature measurement sensor 15 is inserted into this insertion hole. You can. Further, although a recorder is used as the output device 16, the output of the temperature measurement sensor 15 may be digitally converted and displayed, or forming may be performed when the analog value or the digital value obtained by signal conversion reaches a predetermined value. A configuration may also be adopted in which a control signal for inhibiting is output and the amount of oxygen blown is adjusted in response to this signal. Other 1 The present invention can be implemented with various modifications without departing from the gist thereof.

(Effects of the Invention) As described in detail above, according to the present invention, a temperature measurement sensor is inserted into the opening provided in the tapping port of the furnace body or in the side wall portion at a desired position, and this sensor measures the temperature inside the furnace. The temperature is continuously measured and the occurrence of slag foaming or slopping in the converter is detected from the temperature rise trend or the relationship between the measured temperature and the forming slag temperature, so the condition of the slag inside the converter can be detected. Provides a method for detecting slag forming in a converter that can accurately predict the occurrence of slag forming and, by extension, slopping, and that can prevent the occurrence of slopping and ensure stable operation of the converter. can.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional structural diagram of a converter according to an embodiment of the method of the present invention;
The figure is a diagram of temperature changes inside the furnace during converter operation.
The figure is a sectional view of a converter illustrating a conventional method. 11...furnace body, 13...molten steel, 14...steel tapping port, 1
5... Temperature measurement sensor, 16... Output device, 17.
...Slag. Applicant's agent Patent attorney Takehiko Suzue

Claims (1)

[Claims] A temperature measurement sensor is installed in the tapping port of the converter or an opening provided in the side wall at a required position, and the rising trend of the temperature measured in the furnace measured by this temperature sensor or the temperature measured in the furnace can be known in advance. A method for detecting slag forming in a converter, characterized by detecting the occurrence of slag forming based on the difference between the forming temperature and the forming temperature.