JPH0545535B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for removing slag and the like remaining in a receiving trough used, for example, when charging molten slag into a heating furnace.

[Conventional technology]

Molten slag generated in large quantities from blast furnaces is cooled and
After processing crushed stone, blast furnace cement, ground improvement material,
It is used as a material for concrete aggregate, etc. Furthermore, this blast furnace slag is also used as a raw material for rock wool, which is a high value-added product.

When using the conventional method of manufacturing rock wool from blast furnace slag, crushed stone slag is melted again in an electric furnace, cupola, etc. after a component adjustment material is added as necessary, and this is turned into fibers using an appropriate fluid pressure. was. However, when the blast furnace slag is once cooled, crushed and solidified and then melted again, a large amount of energy is required for the remelting, resulting in a disadvantage that the unit cost of producing rock wool becomes high.

Therefore, a method of producing rock wool that reduces energy consumption by directly charging blast furnace slag in a molten state into a heating furnace such as an electric furnace is attracting attention. Methods for producing rock wool from blast furnace slag in such a molten state include JP-A-59-189284, JP-A-59-131534,
There are Japanese Patent Application Laid-open No. 60-134186, etc.

However, molten slag is inherently highly viscous. Moreover, since the material is gradually introduced into a heating furnace such as an electric furnace, the temperature decreases during the charging process. As a result, slag tends to stick to the input port of the heating furnace, the receiving trough that guides the molten slag into the heating furnace, etc., and this sticking of slag becomes a hindrance to subsequent work.

On the other hand, slag stuck to various containers and the like has been removed by inverting the containers. This method is a simple removal method when there is a work space where the container can be turned over. However, when trying to apply this to a receiving gutter located above the heating furnace, a simple reversing mechanism cannot be adopted due to the positional relationship between the receiving gutter and the heating furnace. In other words, the receiving gutter should be placed high above the heating furnace, or the receiving gutter should be rotated horizontally to avoid the fixed slag discharged from the heating furnace from falling on the heating furnace. It is necessary to invert it in the space where it is created. Therefore, the drive mechanism required to move the receiving gutter becomes complicated.

Alternatively, a method of discharging the stuck slag in the receiving trough using human or mechanical power may be considered, but when such a method is used, it is difficult to ensure that the fixed slag is completely discharged. Furthermore, personnel costs etc. cannot be ignored.

Therefore, the present inventors have developed a method and apparatus for easily removing slag stuck inside a receiving gutter by utilizing the adhering state of the slag which is affected by the shape of the receiving gutter without using a particularly complicated drive mechanism. This was first filed as Japanese Patent Application No. 108790 (1988).

According to this prior application, the slag remaining in the molten slag receiving gutter is left to cool and solidify by blocking the spout of the receiving gutter with a stopper just before the end of charging the molten slag into the heating furnace. By tilting the receiving gutter and then raising the stopper, it is separated from the inner wall of the receiving gutter and discharged. Further, the slag stuck to the stopper is removed by a scraper and then discharged in the same manner.

[Problem to be solved by the invention]

The reason we adopted this method of discharging molten slag after it has solidified is to prevent the risk of the molten slag scattering as splash when it falls into the slag receiving container. It was hot.

However, it has been found that when attempting to remove the slag after it has been left to cool and solidify, the slag forms large lumps, causing problems due to the impact of falling. Moreover, this large lump of slag causes blockage in the middle of the slag discharge chute, which prevents smooth slag discharge. In particular, around the stopper where heat dissipation is low, the amount of slag remaining in the receiving gutter is large and thick, and as the molten slag is gradually cooled when the stopper is closed, it becomes a strong crystalline lump and becomes a rapidly cooled thin layer. Unlike the glassy, brittle layer, it does not fragment within the sludge chute, further promoting blockage during the fall of the chute. In addition, in order to crush and remove the slag that has clogged the slag discharge chute, it is necessary to perform heavy labor using bits in a high-temperature atmosphere, and this has tended to be avoided by workers. In addition, large lumps of slag require a lot of effort in subsequent processing steps.

In order to solve this problem, it is conceivable to reduce the amount of slag remaining when the stopper is closed by reducing the capacity of the receiving gutter.
However, if you use a receiving gutter with a small capacity,
As the surface area of the molten slag in the receiving gutter becomes smaller, it becomes necessary to strictly control the operation of injecting molten slag into the receiving gutter from the slag pot. When injecting slag, if the amount injected from the slag pan fluctuates, the level of hot water in the receiving gutter will fluctuate greatly, creating the risk of overflow. Further, in some cases, the injection port may be exposed, causing problems such as the inability to maintain sealing.

Another solution could be to increase the diameter of the slag chute to facilitate the passage of large slag. However, in this case, it is necessary to increase the size of the slag discharge chute and to design the slag discharge chute so that it can withstand the impact of falling large slag blocks. This results in a rise in equipment costs. Further, when large lumps of slag are discharged, a noise problem arises due to the impact sound of falling.

The present invention was devised to solve the problems of the prior application, and aims to prevent the slag remaining in the receiving trough from being discharged in large lumps.

[Means to solve the problem]

In order to achieve the objective, the slag removal method of the present invention includes a method for charging molten slag into a heating furnace through a bottom spout of a molten slag receiving trough whose lower inner surface is rounded and opened upward. Immediately before the end of the loading operation, the receiving gutter spout is closed by a stopper disposed so as to be movable up and down, and the receiving gutter is immediately tilted by the rotational force of the drive mechanism and maintained in an inclined state to receive the molten slag remaining inside. Letting the slag flow out of the gutter, and then lifting the stopper to peel off the slag stuck to the inner wall of the receiving gutter;
On the other hand, the slag stuck to the stopper is peeled off by a scraper that scrapes the entire circumference of the stopper installed above the stopper, and the peeled slag is discharged to the outside of the receiving gutter by its own weight.

[Effect]

Immediately after the spout of the receiving gutter is closed by the stopper, the slag remaining in the receiving gutter is solidified in a thin layer that contacts the receiving gutter and the stopper, but the inside is still in a flowable state. Therefore, if the receiving gutter is tilted at this time, a portion of the molten slag can be easily discharged. This makes it possible to reduce the layer thickness of the slag around the stopper. BACKGROUND ART The operation of injecting molten slag from a receiving trough into a heating furnace such as an electric furnace is performed slowly over a long period of time in order to maintain a constant level of molten metal in the furnace. Therefore, at the end of the pouring operation, the temperature of the molten slag in the receiving trough has dropped considerably and its viscosity has increased. Since the slag at such a low temperature is discharged, the slag that flows out when the receiving gutter is tilted falls in a gentle flow, and there is no risk of splashing. Furthermore, since the slag discharged in a molten state at this time is not the entire amount of slag remaining in the receiving gutter, the risk thereof is further reduced.

After the molten slag is discharged in this way, what remains in the receiving gutter is mainly slag that has adhered to the inner wall of the receiving gutter and the outer surface of the stopper, and is thick and has large lumps. There are no parts. Therefore, by the subsequent lifting of the stopper, it is easily peeled off from the inner wall of the receiving gutter and discharged in the form of small lumps. Further, since the amount of cylindrical slag stuck around the stopper is small, it is easily broken into small pieces by the scraper and discharged.

〔Example〕

Hereinafter, features of the present invention will be specifically explained with reference to embodiments shown in the drawings. The present invention is based on the earlier patent application filed in 1983.
-It uses the same equipment as No. 108790.

FIG. 1 shows a state in which the receiving trough used in the embodiment of the present invention is placed above an electric furnace serving as a heating furnace.
FIG. 2 is a plan view thereof.

The receiving gutter 1 is tiltably arranged above the electric furnace 2, as shown by the dashed line in FIG. In this example, the receiving gutter 1 is tilted by rotating a frame supporting and fixing the receiving gutter by an electric drive mechanism 3 (see FIG. 2). Further, a stopper 5 is provided inside the receiving gutter 1 so as to be movable up and down by a hydraulic cylinder so as to close the spout 4 thereof.

In the example shown in FIG. 1, the tip of the stopper 5 is provided with a small diameter portion 6 whose diameter is suddenly tapered, so that the spout 4 can be instantly closed.
However, without providing such a small diameter portion 6,
It is also possible to use a so-called needle-type stopper 5 whose diameter gradually decreases, and in this case, it is possible to adjust the flow rate of slag flowing out from the spout 4 according to the vertical position of the stopper 5. Become.

Further, a cylindrical scraper 7 fixed to the receiving gutter 1 is provided above the stopper 5. The scraper 7 is located at a position higher than the molten slag level in the receiving trough during molten slag injection, and its inner diameter is slightly larger than the outer diameter of the stopper (approximately 5
mm), and when the stopper 5 rises, it has the function of scraping off stuck objects such as slag adhering to the stopper 5.

The receiving gutter 1 has a cross-sectional shape as shown in FIG. 3, for example. That is, the inner wall 1a is
The part that comes into contact with the slag is formed into a rounded shape that opens upward so that the slag can be easily peeled off. As a result, even if slag is not partially but completely adhered to the lower inner wall 1a of the receiving gutter 1, the slag is solidified on the adhesion surface, and the adhering slag can be peeled off all at once with uniform force. becomes possible. Note that this receiving gutter 1 is made of cast steel such as SC42. Further, a flange 1b is formed around the spout 4, and by providing a separate sealing device (not shown) between the flange 1b and the electric furnace 2, the inlet of the electric furnace 2 can be closed. It becomes possible to seal. This prevents the graphite refractories constituting heating parts such as the inner walls and electrodes of the electric furnace 2 from being oxidized by the atmosphere that has entered the electric furnace 2 .

Slag is charged into the receiving trough 1 from a container (not shown) such as a ladle car, and the slag is charged into the electric furnace 2 through the spout 4. The charging of slag into the electric furnace 2 takes time,
As charging progresses, the temperature of the slag decreases. For example, the temperature of slag, which is normally around 1350℃, drops to around 1300℃ at the end of charging. As the temperature decreases, the viscosity of the slag increases.

Therefore, when the spout 4 of the receiving trough 1 is closed by the stopper 5 immediately before the end of the charging operation, molten slag with increased viscosity remains in the receiving trough 1. Therefore, the receiving gutter 1 is tilted at an angle of about 45 to 60 degrees while the spout 4 is kept closed.
The molten slag is then discharged from the gutter 1 in a molten state, except for those stuck to the inner wall 1a and around the stopper 5. By discharging this molten slag,
The amount of slag remaining in the receiving gutter 1 is small.

At this time, the parts of the receiving trough where the slag is thin are rapidly cooled by metal fittings, so the slag cracks midway through solidification, and some slag flakes off and falls when the receiving trough tilts.

However, the slag around the stopper is thicker than the rest, and the slag with low thermal conductivity has a slow cooling rate and is cooled while enclosing the stopper.

Next, while maintaining the receiving gutter 1 in the tilted state,
As indicated by the dashed line in Fig. 1, by raising the stopper 5, the thin slag layer that is in contact with the receiving gutter side is rapidly cooled and solidified, and there is no adhesion to metal objects, and the slag shrinks. The slag is in a state where it is easy to peel off, and the slag that has adhered and solidified around the stopper 5 and the inner wall 1a of the receiving trough 1 is lifted up. As a result, the slag is separated from the inner wall 1a of the receiving gutter 1. Further, when the stopper 5 is raised, the slag adhering to the periphery of the stopper 5 due to the lifting force is scraped off by the scraper 7 and peeled off from the stopper 5.

At this time, since the amount of slag stuck to the inner wall 1a of the receiving gutter 1 and the stopper 5 is small, the thickness thereof is small. Therefore, the peeled slag does not form into large lumps.

The slag peeled off from the inner wall of the receiving gutter 1 and around the stopper 5 in this way becomes a small lump and falls from the receiving gutter 1 maintained in an inclined state, and is transferred to an appropriate receiving device (not shown). and transported to a collection point.

〔Effect of the invention〕

As explained above, in the present invention, a part of the slag remaining in the receiving gutter at the end of the injection of molten slag into the heating furnace is discharged in a molten state, and then the slag is discharged from the inner wall of the receiving gutter and around the stopper. The stuck slag is peeled off by the lifting force of the stopper and the scraper. At this time, since the layer thickness of the fixed slag is small, the peeled slag becomes small lump-like. Therefore, it becomes possible to perform the discharge work easily. In this way, according to the present invention, rock wool can be produced from molten slag under stable operating conditions without being bothered by slag sticking.

[Brief explanation of the drawing]

FIG. 1 shows an example in which the receiving gutter used in the embodiment of the present invention is arranged in the upper part of an electric furnace, FIG. 2 is a plan view thereof, and FIG. 3 is a cross-sectional view of the receiving gutter.

Claims (1)

[Claims] 1. When charging molten slag into the heating furnace through the bottom spout of the molten slag receiving gutter whose lower inner surface is rounded and open upward, the spout of the receiving gutter can be moved up and down just before the end of the charging operation. The receiving gutter is immediately tilted by the rotational force of the drive mechanism to maintain the inclined state so that the molten slag remaining inside the receiving gutter is received and flows out to the outside of the gutter;
Next, by raising the stopper, the slag stuck to the inner wall of the receiving gutter is peeled off, and on the other hand, the slag stuck to the stopper is peeled off by a scraper that scrapes the entire circumference of the stopper installed above the stopper. A method for removing slag from a molten slag receiving gutter, characterized in that the molten slag is discharged by its own weight to the outside of the receiving gutter.