JPS63137113A - Method and apparatus for smelting reduction - Google Patents

Abstract

PURPOSE:To smoothly execute slag off while avoiding flow out of carbonic material by vacuum-sucking the slag stored by partition weir in the furnace and then tapping molten metal at the time of executing smelting-reduction in the horizontal-type smelting-reduction furnace having semicircular cylindrical shape at the lower part thereof. CONSTITUTION:Gas is blowed into the molten metal from a tuyere 3 at the lower part of smelting reduction furnace body 1 having for example, cylindrical shape. The weir 8 partitioning surface part of slag layer (b) at the time of executing slag-off in the inner part of the body 1 is arranged near at least the one end 6a of end plate part 6. Therefore, the molten metal (a) between the end plate part 6a and the weir 8 has relatively a little stirring effect by blowing gas injected from top blowing lances 4, and as the motion of molten metal (a) receiving directly kinetic energy of blowing gas is eased by the weir 8, it is become to calm. Therefore, in this part, separation of the molten metal (a) with the slag layer (b) is promoted, and the carbonic material (c) floating up on the slag layer (b) is cut off by the weir 8. In this result, by bringing a suction hole 11 into contact with the slag layer (b) in this part, only the slag is effectively removed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method and apparatus for producing molten metal by melting and reducing oxide-based raw materials such as iron ore and pre-reduced products with solid carbon.

[Conventional technology]

BACKGROUND ART In order to reduce iron ore to produce hot metal, methods such as using a blast furnace and melting iron ore raw material reduced in a shaft furnace in an electric furnace have been conventionally used.

However, in the method using a blast furnace, a large amount of coke is used as a heat source and reducing agent. In addition, iron ore, which is an iron source, is usually charged into a blast furnace as sintered ore in order to improve air permeability and reducibility within the furnace. Therefore, the blast furnace method requires coke oven equipment for dry distilling highly caking coal and sintering equipment for producing sintered ore. Therefore, it has the disadvantage of not only requiring a large amount of equipment costs, but also a large amount of energy and labor, leading to a rise in processing costs.Also, strong coking coal has a disadvantage in that it requires a large amount of energy and labor, leading to a rise in processing costs. There is also the problem that supply tends to be unstable due to unevenly distributed and poor crops.

On the other hand, the method of reducing iron ore using a shaft furnace requires pre-treatment to pelletize the iron ore, and has the disadvantage that it consumes a large amount of expensive natural gas as a reducing agent and heat source.

As an alternative to such conventional hot metal production techniques, the smelting reduction method is attracting attention. The smelting reduction furnace used in this method was developed with the aim of producing molten iron alloys using smaller-scale equipment without being restricted by the raw materials used. There are furnace types, mixed pig iron furnace types, etc.

Among these types, mixed iron furnace type smelting reduction furnaces have a large bath surface and are therefore considered promising as they can actively carry out interfacial reactions between the molten metal and molten slag. Furthermore, since the size of the bath surface is determined as appropriate depending on the length of the furnace, it is possible to freely select the bath surface according to the production volume.

The present inventors also developed a furnace of this type that could blow gas under certain conditions, and filed a patent application for this in 1983.
It was previously filed as No.-86794.

[Problem that the invention seeks to solve]

However, although this smelting reduction furnace is equipped with a slag opening and a tap opening, the slag opening is particularly affected by the vertical blowing, shaking the scene, slopping, spitting, and slag forming. In addition to being constantly licked by slag and molten metal, it is also subject to significant thermal effects, so opening and closing the slag tap requires the same amount of work as a blast furnace, and equipment also requires tapping.

In addition, the slag level changes not only due to fluctuations in the molten metal and slag produced as a result of smelting reduction, but also depending on the state of melting of bricks in the furnace. Therefore, the distance between the slag tap and the top surface of the slag changes greatly, and in a smelting reduction furnace that rotates the furnace body to tap the slag, such as a mixed iron furnace, the rotation angle changes greatly. Equal tilt control becomes complicated.

From a different perspective, the tilting angle must be increased (when removing slag, it is necessary to pull up the lance due to the equipment configuration, and there are cases where blowing has to be interrupted.

Furthermore, as the melting of the refractory in the furnace progresses, the surface area of the slag surface becomes larger than when the furnace was new, so the thickness of the slag floating above it becomes thinner even if the amount of slag is the same. This makes it increasingly difficult to separate and take out the slag from the molten metal by tilting the furnace body. Furthermore, during the blowing operation, the molten metal and the slag layer are stirred and mixed, and an appropriate means for efficiently discharging only the slag under such conditions has not yet been developed.

Furthermore, when the slag is discharged, the carbonaceous material floating in the slag layer is discharged together with the slag, reducing the efficiency of using the carbonaceous material.

Therefore, an object of the present invention is to smoothly discharge the slag while avoiding the outflow of carbonaceous material in such a mixed pig iron smelting reduction furnace.

[Means for solving problems]

In order to achieve the object, the continuous smelting reduction method of the present invention performs smelting reduction using a horizontal smelting reduction furnace having at least a semi-cylindrical wall at its lower part. The feature is that hot water is released after vacuum suctioning the slag accumulated in the dividing weir.

Further, a melting reduction apparatus for carrying out this method has at least a lower part of a horizontal melting reduction furnace having a semi-cylindrical wall surface,
A weir that partitions only the surface of the slag during slag extraction is provided near one or both of the end plates at both ends of the furnace body, and a vacuum is created that faces the slag collected in the section surrounded by the weir during slag extraction. It is characterized in that a suction device is attached or a suction tube of a vacuum suction device can be inserted.

What about the weir here? 8. So that the molten metal and the lower layer of slag can flow under the weir,
It is preferable that the lower part is partially or completely open.

C Effect] In the present invention, slag is discharged by suctioning and removing the slag that has collected in a portion of the furnace partitioned by a weir, without providing a slag discharge port on the furnace wall.

Therefore, stable slag discharge is possible regardless of the amount of molten metal and slag.

This weir is designed to partition only the surface part of the slag layer, so the carbonaceous material floating on the surface of the slag layer is less likely to flow into the layer during slag suction, resulting in wasted carbonaceous material. is prevented. Furthermore, since this weir is provided near the end plate, even during blowing, the movement of hot water in the slag suction section is relaxed and calmed considerably, so that slag can be discharged stably. Furthermore, since no slag discharge port is provided on the furnace wall due to the equipment configuration, there are no restrictions on the installation of incidental equipment such as a pig iron ladle placed around the furnace.

〔Example〕

Hereinafter, the features of the present invention will be specifically explained using examples with reference to the drawings.

FIG. 1 is a perspective view showing the melting reduction apparatus of this embodiment.

The melting reduction furnace main body l in this embodiment is formed into a cylindrical shape, and is placed on the rotation mechanism 2 with the axis of the cylinder horizontal. Note that the smelting reduction furnace body 1 is not restricted to a cylindrical shape, and as long as it has the lower part shape of a semicircular cane that can rotate about a horizontal axis, even if its upper part protrudes upward or forms a flat surface. It's okay to do so.

A plurality of tuyeres 3 for blowing gas into the molten metal bath are arranged in the lower part of the melting reduction furnace main body 1 in the longitudinal direction of the furnace. From these tuyere 3, oxygen, Co,, N,
, an inert gas and a cooling gas such as propane gas. Or use them as a carrier gas,
It is also possible to inject powder ore.

Furthermore, an opening 5 for inserting the top blowing lance 4 into the furnace is provided in the upper part of the melting reduction furnace main body 1. A plurality of top blow lances 4 are arranged in accordance with the axial length of the furnace, and corresponding openings 5 are bored in the furnace wall. As shown in FIG. 1, this opening 5 has an area such that a plurality of top blow lances 4 can be inserted into the furnace at once. Alternatively, a plurality of openings 5 may be formed in the furnace wall corresponding to each top blowing lance 4.

This opening 5 is designed to open the smelting reduction furnace main body 1 according to the amount of molten metal with the top blowing lance 4 inserted so as to maintain a constant depth from the surface of the molten metal that increases by smelting reduction to the tuyere 3. In order to rotate it, it is provided long along the circumferential direction of the melting reduction furnace main body 1. Alternatively, it is also possible to further rotate the smelting reduction furnace main body 1 to form a length such that the molten metal can be tapped without the need to pull out the top blowing lance 4. In this case, tapping can be performed without interrupting the blowing operation, so the operating efficiency of the melting and reduction furnace is improved.

End plate portions 6a constitute both ends of the melting reduction furnace main body 1.

One of the parts 6b is provided with a lower hot water outlet. In this example,
Although the tapping lower is provided only on the end plate 6a side, the tapping lower can also be provided on the other end plate 6b side or in the longitudinal direction of the furnace without being restricted by this.

However, in order to increase the amount of molten metal produced, it is preferable to provide the tapping lower in the lower part of the furnace as much as possible.

As shown in Fig. 2, the weir 8 partitions only the surface part of the slag layer during slag discharge, and allows the molten metal [a] and slag below to flow in the direction of the furnace longitudinal direction. , the lower part is open.

The molten metal riI4a located between the mirror plate part 6a and the weir 8 has a relatively small stirring effect due to the blowing gas ejected from the top blowing lance 4, and the molten metal riI4a that is directly affected by the kinetic energy of the blowing gas has a relatively small stirring effect. The movement has been alleviated by Weir 8, so it has calmed down. Therefore, in this part, the molten metal a
The separation between the slag layer and the slag layer is promoted. From this point of view, it is preferable to judge the distance from the outermost top blow lance 4 to the weir 8 based on the movement of the slag surface, etc. Further, the carbonaceous material C floating in the slag layer is blocked by the slag suction head 8, and the amount of carbonaceous material C floating in the slag layer can be suppressed to a minimum amount from flowing between the end plate portion 6a and the weir 8.

A gear 9a is attached to one end of the melting reduction furnace body 1, and the driving force of the motor 10 is transmitted via the gear 2a of the rotation mechanism 2. Further, a gear 9b is similarly attached to the other end of the smelting reduction furnace main body 1, and this gear 9b
meshes with the gear 2b on the driven side. by this,
The melting reduction furnace body 1 rotates around its axis. In addition,
The gears 9a, 9b and the gears 2a, 2b are meshed by simply placing the melting and reducing furnace body 1 on the rotating mechanism 2 so that it can be easily removed when the body 1 is lifted up. When doing so, it becomes easy to move the smelting reduction furnace body 1 whose furnace wall refractories have been damaged by using several charges, for example, to a repair site.

FIG. 2 shows a state in which a predetermined amount of slag accumulates due to continued melting and reduction of iron ore using this melting and reducing apparatus, and it becomes necessary to discharge the slag. As described above, most of the carbonaceous material C does not flow between the head plate portion 6a and the weir 8, and the molten metal a and the slag layer are maintained in a calm state. Therefore, separation of the slag layer from the molten metal a is promoted. A suction port 11 of a vacuum suction device is made to face this slag lb. Then, only the slag on the surface can be efficiently discharged. Along with this sludge, slag flows from the left side of weir 8 in Figure 2 to weir 8.
As the slag flows between the weir 8 and the end plate 6a, the slag existing at the front of the furnace is discharged. It is preferable to measure the height of the slag layer with a measuring means and adjust the height of the suction port 11 based on the measured value. Furthermore, if the height of the suction port 11 is controlled in accordance with the surface of the slag layer that decreases as the slag is discharged, the slag can be efficiently discharged. Alternatively, it is also possible to calculate the production amounts of the molten metal a and the slag layer using the smelting conditions of the charged raw material 1 as data, and adjust the height of the suction port 11 based on the calculation results.

After discharging the slag in this way, the tapping lower is opened to tap the molten metal.If the smelting and reduction furnace main body 1 is rotated so that the tapping lower is positioned downward during this tapping, the subsequent smelting process is performed. 1 amount of molten gold to be used as seed water for
Most of the generated molten metal a can be taken out, leaving behind.

〔Effect of the invention〕

As explained above, in the present invention, the slag collected in the area divided by the weir is removed by vacuum suction without providing a slag outlet on the furnace wall, so the furnace body is rotated to remove the slag. It becomes possible to discharge the slag in a state where it is sufficiently separated from the molten metal and carbonaceous material. Therefore, post-treatment of the discharged slag becomes easy and waste of carbonaceous material can be avoided. Further, since there is no slag discharge port in the furnace body, there is an increased degree of freedom in arranging incidental equipment such as a bottom blower device etc. around the furnace, making it easier both in terms of equipment and operation. Thus, according to the present invention, when
A melt reduction method with excellent productivity becomes possible.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing the smelting reduction 'A' position of the embodiment of the present invention, and FIG. 2 is a sectional view showing the inside of the furnace during slag discharge.

Claims (1)

[Claims] 1. When performing melting reduction using a horizontal melting reduction furnace having at least a semi-cylindrical wall at the lower part, vacuum suction is applied to slag accumulated in a weir that partitions the inside of the melting reduction furnace. A melting reduction method characterized by tapping the hot water after heating. 2. At least the lower part of the horizontal slag reduction furnace has a semi-cylindrical wall surface, and a weir that partitions only the surface part of the slag at the time of slag extraction is provided near one or both of the mirror plates at both ends of the furnace body. A melting and reducing apparatus characterized by being equipped with a vacuum suction device or into which a suction pipe of a vacuum suction device can be inserted so as to face the slag collected in a section surrounded by a weir during slag processing. 3. The lower part of the weir described in claim 2 is partially or completely open so that the molten metal and the lower layer of slag can flow through the weir. Melting reduction equipment.