JPS637316A - Predicting method for slopping - Google Patents

Abstract

PURPOSE:To exactly predict the generation of slopping by projecting microwaves from a lance plunged into a converter toward the inside wall surface of the converter, capturing the reflected microwaves and measuring a slag foaming condition. CONSTITUTION:A molten metal 4 and molten slag 5 are pushed toward an inside side face 6 of a refining vessel (converter) 1 when gaseous oxygen is blown out of the lance 2 plunged into the converter. The microwaves 9 passing a waveguide pipe 8 are projected from a projection port 7 opened at the required height position of the lance 2 to the side face 6 and the reflected waves thereof are again inputted to the port 7 so as to be introduced to a detector. The microwave output is constant if there are no obstructions in the way of the microwaves in this stage. The microwave output increases or decreases when the slag 5 and molten metal 4 enter the way of the microwaves on starting of slag foaming. The arrival of the slag foaming at the position of the projected microwaves 9 is thus detected. The generation of the slopping is thereby exactly predicted.

Description

Detailed Description of the Invention (Field of Application in Industry-1-) The present invention relates to a refining process in which various chemical reactions occur in a refining vessel in a converter in the steel manufacturing sector that performs gas blowing using a lance. This invention relates to a method for detecting the occurrence of slopping due to slag generated in a machine.

(Prior Art) Slag foaming during converter blowing is a fluctuation in the slag level due to bubbles caused by gas generation caused by blowing conditions, slag components, etc., and causes sloping. Therefore, JP-A-53-118161/publication, JP-A-57-
137411, JP 57-140812, JP 58-28654, JP 59-
A method has been proposed in which microwaves are projected toward slag and the state of slag slag is detected from the reflected waves, as described in Publication No. 41409.

(Problems to be Solved by the Invention) However, the above-mentioned proposed methods all project microwaves from the -L side of the converter opening and detect the slag level by receiving the reflected microwaves. Because it is a converter, there is a relatively long distance between the detection device and the slag, and the output of the reflected microwave is small. It was not possible to accurately determine the slag level 4111.

Incidentally, the lj force of the reflected microwave is inversely proportional to the fourth power of IUIE, and in the case of the proposed method η, there is a distance of 15 to 20 m from the detection device to the slag surface. Also, the inner diameter is 5900φ
Taking the converter as an example, the furnace 1-1 has a diameter of 3300φ.

In view of the point -1-, the present invention provides a novel slopping prediction method in which microwaves are projected toward the inner surface of a converter from a lance plunged into the converter, etc., and reflected microwaves are captured. (Means for Solving the Problems) The present invention projects microwaves from a part of a lance that enters a refining container toward the inner surface of the container, and generates a signal from the output of the reflected microwaves. The present invention is characterized by a slopping prediction method that measures the slag forming state and predicts the occurrence of slopping.

(Function) The present invention emits microwaves in stages from a lance inserted into the refining container toward the inner surface of the container, and captures the reflected microwaves. The projection and reflection distance can be extremely short, within 3 m compared to the conventional 15 to 20 m, and the output of the reflected microwave is large, and there is no problem of a blind spot for slag detection.

(Example) The method of the present invention will be explained below with reference to the drawings.

Figure 1 shows the inside of a converter (1), in which a blowing lance (2) is inserted, and the hole in this lance (2) is
The molten metal (4) and molten slag (5) are pushed toward the inner surface (6) of the converter as shown in the figure by the oxygen gas O1 blown out from 3). In addition, at the point where the lance (2) enters the converter, a projection (7) is opened at a required height from the lower end of the lance, and a waveguide attached to the inner pipe wall of the lance (2) is opened. (8) is connected, and the microwave (
9) is projected from the projection IN (7) to the inner surface (G) of the converter, and the reflected wave is transmitted manually to the projection 1.1 (7) through the waveguide (8) to a detector not shown. At this moment, Rance (2
) and the inner surface of the converter (6) is the distance between the lance (2) during blowing.
) and the vibration is almost constant, so if there are no obstacles in the way of this microwave, the microwave output will be constant. However, when slag forming begins and slag (5) and molten metal (4) enter the path of the microwave, the microwave output increases and decreases, making it impossible to detect that slag forming has reached the position of the projected microwave (9). , this allows us to know about slopping.

It is desirable to blow out purge gas from the projection port (7) to prevent metal or slag from entering the projection port (7).

Moreover, more accurate prediction can be made by providing multiple detection points in the vertical and longitudinal direction of the lance (2). To explain this with reference to Fig. 2, microwave projections 1.1 (7) at three points A, B, and C are provided at different positions below -I on the side wall of the lance (2), and a microwave generator (10 ) is sent to each projection 1-1 (7) through the waveguide (8),
The reflected microwaves are then projected onto the inner surface (8) of the converter, and the reflected microwaves are transmitted from the waveguide (8) to the microwave circuit (11).
) to operate the transmission, and the signal slag/processor (12) converts it into a slag detection signal to be sent to the manual device (13). Third
Figures (a) and (b) are the display outputs in this case, and (a) is (i?
"-J' waveform, and is not caused by slug forming. On the other hand, b) is caused by slug forming, and the slug forming speed can also be estimated from the time difference between the detection outputs at points A and 81C. (14) This is a purge gas.

Furthermore, although not shown in the drawings, if two or more detection points are arranged in the circumferential direction of the lance (2), the accuracy of slopping prediction can be further improved.

(Effects of the Invention) (1) As described in detail, according to the method of the present invention, accurate slopping prediction can be made. In addition, since the microwave projection point is located inside the refining vessel, a single sealed operation can be performed in a converter or the like, and CO gas can theoretically be recovered as close as 11''.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing an embodiment in which the method of the present invention is applied to a converter, Fig. 2 is a sectional view showing another embodiment, and Fig. 3(a) (
b) is the slag detection output (, -
It is a No. 1 waveform diagram. (ri... converter, (2)... blowing lance, (4)...
... Molten metal, (5) ... Molten slag, (6) ... Converter inner surface, (7) ... Projection [1, (8) ... Waveguide,
(9)...Microwave. Figure 1

Claims (1)

[Claims] A lance is inserted into a refining container and molten steel is refined using gas injected from the lance, in which microwaves are projected from the part of the lance that enters the refining container toward the inner surface of the container, and the reflected microwaves are A slopping prediction method that measures the slag forming state from the output of the slag and predicts the occurrence of slopping.