JPS644614B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention involves excitation of light emission by causing a discharge between the surface of molten iron or molten steel and an electrode rod in the refining and casting process of pig iron or steel, etc. The present invention relates to an analysis method in which molten iron, molten steel, etc. are automatically analyzed by transmitting the information to a spectrometer.

In general, in the refining and casting process of pig iron or steel, it is recommended to perform controls based on molten iron or molten steel composition information as appropriate in order to improve the refining accuracy, improve the yield, and shorten the total steelmaking time. I have to.
Conventional means of capturing this type of molten iron or molten steel composition information include, for example, in converter blowing.
There are carbon determinator method and sampling/analysis method. In the carbon determinator method, molten steel is sampled in a small container, the solidification temperature of the molten steel is measured using a thermocouple, and the carbon content is estimated from a comparison table prepared in advance between carbon content and solidification temperature. be. However, in this case, only carbon is obtained as an element, and there is a drawback that the temperature measurement error of the thermocouple affects the carbon measurement error, and furthermore, it takes about 10 seconds from sampling to completion of solidification. It was hot. Incidentally, the longer the time from sampling to the completion of solidification, the lower the temperature of the molten steel will be, resulting in a lower efficiency. On the other hand, in the sampling/analysis method, for example, molten steel is sampled with a probe attached to the tip of a sublance (usually a small container housed in a heat-resistant paper tube), and the sample is sent to an analysis room using an air chute, etc. A solidified sample (molten steel sample) is cut, the cut surface is polished, and the light emitted when the polished surface is irradiated with high energy is analyzed using a spectrometer. In this case, although it has the advantage of being able to analyze most elements with high precision, it has the disadvantage of requiring several minutes from sampling to completion of analysis, and the labor and labor involved in cutting and polishing as preliminary processing. It required staff. Moreover, it requires equipment such as a cutting machine and polishing machine required for the above-mentioned work, as well as equipment such as an air chute for transporting the sample to the analysis room, resulting in disadvantages such as an increase in the size of the equipment as a whole.

The present invention was created in view of the above-mentioned drawbacks of conventional analytical methods and to solve these problems. The gist of the present invention is a method for analyzing molten iron, steel, etc. using a sublance in a converter, ladle, or other refining vessel. A sub-lance provided with an electrode and with a gas injection port and an optical fiber end facing is inserted and lowered into the refining container, and inert gas is injected from the gas injection port to eliminate slag directly under the sub-lance. The molten steel surface is exposed, and when the tip of the molten steel surface sensing small electrode reaches the molten steel surface, a high voltage is applied to the light emitting electrode to excite spark discharge light emission between the molten steel surface and the excitation. The emitted light is received by the end of the optical fiber, and the received light is transmitted to a spectroscopic analyzer.

According to the present invention according to the above-mentioned summary, it is possible to analyze molten steel, etc. without performing operations such as collecting a sample during the refining process in a converter or other refining vessel, so the analysis time is reduced. It is possible to shorten the processing time and automate the analysis work, thereby contributing to the realization of fully automatic control in refining operations.

The method of the present invention will be explained below based on the embodiments shown in the drawings.

FIG. 1 is a system diagram showing the entire system when the method of the present invention is applied to converter blowing work. In the figure, 1 is a converter, and 2 is a sub-lance as an analysis tube. As shown in FIG. 2, a light-emitting electrode rod 3 made of silver, tungsten, or the like is screwed into the center of the tip end surface (lower end surface in the drawing) of the sublance 2. As shown in FIG. The tip of the electrode rod 3 has a conical shape and projects downward from the tip surface of the sub-lance 2. Further, a plurality of gas injection ports 4 are opened around the electrode rod 3 on the tip surface of the sub-lance 2 . The injection port 4 communicates with a gas supply source (not shown) via a communication path 5 and a hose 6 continuous thereto. Reference numeral 7 denotes a jig that is fitted and fixed to the outer circumferential surface of the distal end of the sub-lance 2, and can be replaced at will. The jig 7 has a tubular shape, for example, made by wrapping heat-resistant paper to a predetermined thickness, and an optical fiber 8 and a small electrode rod 9 for sensing the surface of the molten steel are embedded in the tube wall. The tip of the optical fiber 8 is exposed on the inner wall surface of the jig 7 so as to face the tip side of the light emitting electrode rod 3, and the rear end is connected to the spectroscopic analyzer 11 in the analysis room via the connector 10. The optical fiber 12 is connected to the The small electrode rod 9 protrudes downward from the distal end surface of the jig 7, and is connected to the light emitting electrode rod 3.
It is set downward by a predetermined length. The small electrode rod 9 and the light emitting electrode rod 3 are connected to a power supply circuit 13. 14 is a circuit that controls the motor for lifting and lowering the sublance; 15 is a display that displays data from the spectroscopic analyzer 11; and 16 is a circuit that controls the entire converter blowing operation based on the data obtained by the spectroscopic analyzer 11. This is a computer that performs process control.

Next, the analysis method of the present invention will be explained based on the embodiment configured as described above and with reference to FIGS. 1 to 4.

Inside the converter 1, a main lance (not shown)
When the predetermined pure oxygen blowing work is completed, the computer 16 that performs process control sends a signal to the circuit 14 that controls the sublance lifting motor to lower the sublance 2. In the case of the sublance 2, the injection port 4 is opened on the tip surface of the sublance 2.
Since the gas from the gas supply source (in this case, argon gas is used) is injected, as the sub-lance 2 approaches the slag 17, the injected gas flows into the slag 17 as shown in FIG. Start blowing away. Then, the tip of the jig 7 is attached to the slug 1.
A space 17 that does not interfere with the molten steel 18 is bored in the slag 17 to expose the surface 18a of the molten steel 18. When the sub-lance 2 further descends and the tip of the small electrode rod 9 reaches the molten steel surface 18a, the small electrode rod 9 is electrically short-circuited, and the molten steel 18 and the converter 1 are discharged from the small electrode rod 9.
A circuit is formed through which the ground rod 19 flows to the ground. The power supply circuit 13 detects the short circuit and outputs a signal to the control circuit 14 of the sub-lance lifting motor to switch the lowering operation of the sub-lance 2 to the upward operation, and at the same time applies high voltage to the light-emitting electrode rod 3. . As a result, a spark discharge is generated between the tip of the light-emitting electrode rod 3 and the molten steel surface 18a, and the molten steel 18 is excited to emit light. The optical fiber 8 receives the emitted light at that time, and the optical fiber 12
is transmitted to the spectroscopic analyzer 11 in the analysis room. The spectrometer 11 detects the type, amount, temperature, etc. of the element from the spectrum of the emitted light, displays this on the display 15, and sends it to the computer 16 that manages the entire process of the blowing work. A comparison is made with the set target value, and if the target value is reached, the blowing work is determined to be complete, and if it is less than the target value, the remaining blowing work is instructed until the target value is reached.

Normally, light with a wavelength smaller than 2000 Å has the property of being absorbed by oxygen in the atmosphere, but in the case of the present invention, even during the above spark discharge, light with a wavelength smaller than 2000 Å is absorbed by the gas (in this case, is argon gas)
Since the injection is performed continuously, Sublance 2
The atmosphere between the tip of the molten steel surface 18a and the molten steel surface 18a can be replaced with air and filled with argon gas,
Therefore, without attenuating the light of elements such as C, P, and S whose wavelength λ is smaller than 2000 Å,
It can be transmitted to the optical fiber 8 via argon gas. As a result, C, Si, Mn, P,
Each element such as S can be analyzed easily.

According to experiments, it took only 15 seconds from the start of Sublance 2's descent to the time it received the analysis results. It is clear from this fact how superior the method of the present invention is.

By the way, although the above-mentioned example is a case of converter blowing, the method of the present invention is not limited to the above-mentioned specific equipment, and is also applicable to the analysis of molten steel or molten iron during ladle refining or casting processes. Needless to say, it is also applicable to

As explained above, the method for analyzing iron, steel, etc. according to the present invention uses a sublance that is equipped with a small electrode for sensing the surface of molten steel and a light emitting electrode at the tip, and faces a gas injection port and an end of an optical fiber. It is inserted into a furnace, ladle, or other refining container, and the exposed molten steel surface from which slag has been removed excites discharge light emission, and the light emission is received by an optical fiber and transmitted to a spectrometer in the analysis room. Therefore, analysis can be performed instantaneously without taking any steps to collect and prepare samples, and the time required for analysis is significantly shortened. In addition, there is no need for the work of cutting and polishing samples as in the past, as well as the need for personnel, and it can also contribute to fully automatic control in refining operations for steel, etc. Furthermore, there is no need for large-scale equipment such as an air chute for transporting the sample to the analysis laboratory, which is advantageous in terms of cost.

[Brief explanation of the drawing]

Fig. 1 is an overall system diagram showing the case where the method of the present invention is applied to converter blowing, Fig. 2 is an enlarged vertical cross-sectional view of the main part of the tip of the sub-lance, and Fig. 3 is the tip of the sub-lance showing its way down. An enlarged longitudinal cross-sectional view of the main parts of
FIG. 4 is an enlarged longitudinal cross-sectional view of the main part of the tip of the sublance, showing a state in which light emission is excited. 2... Analysis tube body (sublance), 3... Electrode rod,
8, 12... Optical fiber, 18a... Molten steel surface.

Claims (1)

[Claims] 1.A method for analyzing molten iron, steel, etc. using a sublance in a converter, ladle, or other refining vessel, which is equipped with a small electrode for sensing the molten steel surface and a light emitting electrode at the tip, and a gas injection port. A sublance with the end of the optical fiber facing is inserted and lowered into the refining vessel, and inert gas is injected from the gas injection port to remove the slag directly under the sublance and expose the surface of the molten steel. When the tip of the small surface sensing electrode reaches the molten steel surface, a high voltage is applied to the light emitting electrode to excite spark discharge light emission between the tip and the molten steel surface, and the excited light emission is transferred to the end of the optical fiber. A method for analyzing iron, steel, etc., characterized in that the received light is transmitted to a spectroscopic analyzer.