JPH046875B2 - - Google Patents

Description

Detailed Description of the Invention The present invention provides a molten metal slag removal method in which slag on molten metal is sucked by a suction head, the sucked slag is solidified by water cooling, and sent to a separator, and the separator separates cooling water and solidified slag from gas. Regarding.

In the above method for removing molten metal slag, it is desirable to remove the molten metal slag as quickly as possible by suction in order to improve work efficiency and prevent the molten metal slag from increasing in viscosity and from forming a skin. If the slag is sucked into the slag, there are problems such as an increase in pressure loss in the suction transport pipe and a decrease in the degree of vacuum due to the large amount of water vapor generated due to water cooling, which may lead to problems in transporting the slag. Accurately measuring the amount of suction has become an important issue when controlling the amount of slag suction.

Conventionally, the amount of slag suction is measured by detecting the total weight of the ladle or torpedo car filled with molten metal.
The amount of slag suction was measured from the change in total weight due to slag suction, or the weight of solidified slag collected at the end of the suction conveyance system was measured. However, there is a problem in that an extremely large-scale detection device is required to detect the total weight of the ladle, which reaches several hundred tons, and the amount of slag sucked per minute is several hundred tons per minute. Since the weight is on the order of a kilogram, the change in weight to be detected is extremely small, and there is still a problem of unreliability in terms of detection accuracy. Furthermore, in the latter method, there is a considerable time delay between the measurement time and the suction time, so there is a drawback that the amount of slag suction cannot be properly controlled in real time.

An object of the present invention is to make it possible to measure the amount of slag suction in real time and with high precision using a simple detection device by a rational improvement method in view of the above-mentioned conventional situation.

The characteristic means of the present invention is that pressure is detected on the upstream and downstream sides of the separator, and the amount of slag suctioned by the suction head is measured from the difference between the detected pressures.The functions and effects thereof are as follows. .

In other words, as a result of conducting various experiments regarding pressure changes in the suction system during slag removal by suction, it was found that the relationship shown in FIG. 3 exists. That is, FIG. 2 shows the relationship between the suction pressure P and the slag suction amount G. When the suction pressure _P1 on the upstream side of the separator increases, the slag suction amount G of the suction head decreases rapidly, and As the suction pressure P ₂ increases, the slag suction amount G rapidly increases, and as the difference (P ₂ −P ₁ ) between both suction pressures P ₁ and P ₂ increases, the slag suction amount G gradually increases.
Therefore, the present invention focuses on this, and detects the pressure on the upstream and downstream sides of the separator, and calculates the difference between the detected pressures P ₁ and P ₂ (P ₂ - _{P 1} ).
The slag suction amount G of the suction head is measured based on the correlation shown in Figure 2, and as a result,
The amount of slag suction can be measured by simply detecting the pressure, and the detection device can be made extremely compact and of a simple structure.Moreover, the pressure in the suction system is almost constant against changes in the amount of slag suction. Since it changes simultaneously, it has become possible to measure the amount of slag suction in real time without any time delay with respect to the time when slag is suctioned at the suction head.

Furthermore, the difference in pressure before and after the separator (P ₂ −
Since P ₁ ) is the contrast value in the correlation,
For example, compared to using the detected pressure on either the upstream side or the downstream side as a contrast value, it has become possible to further improve measurement accuracy by amplifying the rate of change of the contrast value.

Also, by the way, if the pressure is detected on either the upstream side or the downstream side, the change in detected pressure may be due to a change in the amount of slag suction, or there may be a blockage in the suction system, a problem with the cooling water supply, etc. However, according to the present invention, the pressure change on the upstream side of the separator, which is directly caused by the change in the amount of water vapor generated,
Because it looks at the change in both the pressure change on the downstream side of the separator, which is directly caused by the change in transfer resistance in the suction system path, it can be determined whether the pressure change is due to a change in the amount of slag suction or another problem. There is also a discernible advantage.

In short, it has become possible to measure the amount of slag suction accurately and with high precision while being extremely advantageous in terms of equipment costs, and in turn, improve the efficiency of slag suction removal work while maintaining smooth slag suction. I ended up getting it.

Next, embodiments of the present invention will be described in detail based on illustrative drawings.

As shown in FIG. 1, the suction head 2 connected to the suction device 1 is vertically lowered by driving the arm 3 that supports it, and the slag S floating on the molten metal L in the ladle 4 at the suction head suction opening is lowered vertically.
By bringing the molten metal slag S into close proximity to the suction port, the slag S on the molten metal is sucked together with air, and the cooling water supplied from the cooling water pipe 5 is jetted against the suction slag in the suction head 2, thereby solidifying the slag into particles. let

Then, the solidified slag, cooling water, air, and water vapor generated due to water cooling are vacuum transferred in a three-phase mixed state to a separator 7 via a suction pipe 6, and the solid and liquid components are separated from the gas by the separator 7. is dehumidified by a condenser 8, that is, water vapor generated during water cooling is condensed, and only air is sucked and discharged by an intake device 1, and the solidified slag and water separated from the gas by a separator 7 are collected in a water tank 9. Furthermore, the precipitated and solidified slag is lifted and recovered by a conveyor 10 installed in the water tank 9.

To control the slag suction amount of the suction head 2, the slag suction amount is continuously measured and
Based on the measurement results, the automatic control device 11 controls the height of the suction head suction port relative to the molten metal slag S so that the measured slag suction amount is maintained at the set value.
The system automatically raises and lowers the suction head to avoid excessive slag suction and prevent the resulting suction transfer problems, while maintaining the slag suction amount as large as possible and improving slag removal work efficiency. At the same time, this prevents the molten metal slag S from becoming highly viscous due to natural cooling and causing so-called crusting, which would impede the suction operation.

To measure the amount of slag suctioned by the suction head 2, first, pressure sensors are attached to each of the bend pipe 12 connecting the suction head 2 and the suction pipe 6, and the exhaust passage 13 connecting the suction device 1 and the condenser 8. 14 and 15 detect the suction system passage pressure P ₁ on the upstream side and the suction system passage (exhaust passage 13) pressure P ₂ on the downstream side of the separator 7 as a boundary.

In Figure 2, a suction head 12 with a suction diameter of 170 mm is placed at a height of 60 to 80 mm above the slag.
This is a graph showing the relationship between the slag suction amount G and the suction pressures P ₁ and P ₂ on the upstream and downstream sides of the separator 7 when the slag in the ladle is suctioned with an air volume of 210 Nm ³ /min. P ₁ from 330mmHg to 360
When the temperature rises to mmHg, the slag suction amount G is 550Kg/
min to 350 Kg/min, and when the suction pressure P ₂ increases from 440 mmHg to 460 mmHg, the slag suction amount G rapidly increases from 300 Kg/min to 500 Kg/min. Compared to this, the suction pressure P ₁ , P ₂
When the difference (P ₂ - P ₁ ) increases from 200 mmHg to 130 mmHg, the slag suction amount G changes from 130 Kg/min to 550
It can be seen that it gradually increases to Kg/min. Therefore, there is a correlation between the difference (P ₂ − _{P 1} ) between the upstream pressure P ₁ and the downstream pressure P ₂ with the separator 7 as the boundary and the slag suction amount G as shown in the thick line in FIG. Taking advantage of this fact, and based on the correlation, the automatic control device 11 continuously measures the slag suction amount G from the detected pressure difference (P ₂ −P ₁ ) for continuous slag suction.

In other words, the amount of slag suction can be measured by simply detecting the pressure before and after the separator 7 in the suction system, thereby simplifying the measuring device, and also because the pressure in the suction system is extremely sensitive to changes in the amount of slag suction. Taking advantage of this fact, the upstream pressure P ₁ and the downstream pressure P ₂ of the separator 7 change in opposite directions with respect to changes in the slag suction amount, and their difference (P ₂ - _{P 1} ) is used to measure the amount of slag suction with no time delay and with high accuracy relative to the point in time when the suction head 2 suctions the slag, thereby improving the controllability of the amount of slag suction. be.

Additionally, a sensor 14 for detecting the pressure in the suction system path,
Various types of sensors known in the art can be used for the sensor 15, and the pressure detection positions thereof can be changed as appropriate as long as they are on the upstream side or the downstream side with respect to the separator 7.

[Brief explanation of drawings]

The drawings show an embodiment of the molten metal slag removal method according to the present invention, FIG. 1 is a schematic system diagram of a molten metal slag removal device, and FIG. 2 is a graph showing the relationship between the slag suction amount and the suction system pressure. . 2... suction head, 7... separator,
L...molten metal, S...slag, G...slag suction amount, _P1 , _P2 ...detected pressure.

Claims (1)

[Claims] 1. A molten metal slag removal method in which the slag S on the molten metal L is sucked by the suction head 2, the sucked slag is solidified by water cooling, and sent to the separator 7, and the separator 7 separates the cooling water and solidified slag from the gas, comprising: The pressure is detected on the upstream side and the downstream side of the separator 7, and the detected pressure is
A molten metal slag removal method in which the slag suction amount G of the suction head 2 is measured from the difference between P ₁ and P ₂ .