JPS587686B2 - Sankatetsuofukumu Zairiyounoyoukaibutsukangennohouhou narahi souchi - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement of the invention disclosed in Japanese Patent Publication No. 54-38966, and more particularly to a method for melting and reducing iron oxide-containing materials.

In particular, the invention of Japanese Patent Publication No. 54-38966 relates to such a melting reduction method, in which iron oxide powder or iron oxide-containing material powder is opened in the center of an electrode that acts as a cathode in a DC furnace. The solid carbonaceous material floating in and/or above the melt constitutes the anode.

The method according to the present invention is an improvement on the method disclosed in Japanese Patent Publication No. 54-38966.

The method according to the invention comprises the steps of: a continuous stream of iron oxide material being mixed with a controlled amount of stream of carbonaceous material and slagging agent (if used); It is characterized in that the electrode is connected as a cathode through a supply hole in the electrode to an electric arc furnace which is supplied with a direct current that is generated between the electrode and the molten metal.

1 "Flow of a controlled amount of carbonaceous material" means a flow of such amount that the carbon requirements for the reduction of the iron oxide remaining in the iron oxide material and the carbon content of the resulting iron molten metal are met. do.

The method according to the invention therefore complements the method according to Japanese Patent Publication No. 54-38966, in which case the very feed hole in the electrode can be used as a feed pipe for the mixed material, which is not required separately. It is easier from a manufacturing point of view than using a supply pipe.

Of course, it is also possible to use a separate feed tube in the conventional manner, and the feed holes in the electrodes may be covered by a suitable lining.

It is a surprising advantage that the reduction can be made to take place not by dissolved carbon in the bath, but by carbon introduced into the feed tube in the electrode.

The invention also relates to an apparatus for smelting and reducing iron oxide materials for carrying out the above-described method.

In this device, a feed hole or a feed channel for feeding material containing iron oxide and carbonaceous material and a slag forming agent is provided in one or more electrodes connected as a cathode of a DC electric arc furnace. It is located in

This type of furnace offers simplifications compared to when a separate feed tube is used within the cathode.

The method and apparatus according to the invention will be described in detail below with reference to the drawings.

Figure 1 shows graphite or Sodelberg type (
A hollow electrode 1 is shown (i.e. made as a sheet steel cover filled with an electrode compound).

The electrode 1 is provided with a feed channel or feed hole 2, which may be formed directly in the electrode 1 or may be constituted by a lining or a special feed channel (not shown in the drawings). .

A supply pipe 3 is arranged in the supply hole 2 in the upper part of the electrode 1 , and the supply pipe 3 is sealed to the upper part of the electrode 1 by a seal 4 .

Said seal 4 is preferably annular and is in contact with the electrode 1.

Number 5 indicates the bushing for electrode 1.

The bush 5 will be explained in more detail later.

Number 6 is the negative current connection.

In FIG. 1, two valves 7, 8 are shown,
These valves 7, 8 are opened and closed at different times, through which powdered material is fed batchwise downwards via the feed pipe 3, and gases, e.g. carbon oxides, are forced upwards from the back of the furnace. Backflow toward the supply pipe 3 is prevented.

FIG. 2 shows an alternative type of feed pipe 3 according to FIG. 1, into which a so-called sector feeder 9 of the conventional type is inserted.

FIG. 3 shows a further alternative supply mechanism, in which the supply tube 3 terminates in a collar 11 which is sealingly arranged on the electrode 1.

However, normally the supply tube 3 is allowed to protrude slightly into the electrode through the portion of the collar 11.

In the method according to the invention, the continuous stream of iron oxide material is mixed with the carbonaceous material and the slag product (if this is used).
This mixture is fed to the DC electric arc furnace through the feed pipe 3 and then through the electrode 1 in the manner shown in FIG.

The electrode 1 is connected as a cathode, and the charge constitutes the anode of the electric arc furnace in the conventional manner.

By 'controlled flow of carbonaceous material' is meant a flow of such a quantity that the carbon requirements for the reduction of the iron oxide remaining in the iron oxide material and the carbon content of the resulting iron melt are met. do.

The mixture is introduced into the feed hole 2 in such a way that there is no backflow of gas through the feed hole 2, and in the illustrated embodiment a plurality of valves are provided, as indicated by 7 and 8 in FIG. These are arranged to open at different times.

It is also possible to use so-called sector feeders 9 to prevent gases, such as carbon oxides, from flowing upwards from the electric arc furnace, such as carbon oxides, from flowing back.

When it is necessary to use an inert gas in the melting reduction process, the inert gas can be introduced, for example, through an inlet (not shown) established between the supply pipe 3 and the electrode 1, or through the supply Preferably, the supply is carried out below the supply pipe 3 by means of a lance (not shown) which is inserted into the hole 2 .

Advantageously, the electrode 1 is provided with a cooling space (this will be explained below), for example a built-in cooling coil;
Electrode 1 must be made of graphite, copper or a copper alloy.

The present invention also relates to an apparatus for melting and reducing iron oxide, which is disclosed in Japanese Patent Publication No. 54-38966.

The apparatus consists of a furnace supplied with direct current or a container with at least one hollow electrode acting as a cathode, with a refractory supply pipe for the material at least along a part of the extension of said cathode. is located.

In the device disclosed in Japanese Patent Publication No. 54-38966, the supply pipe is described as a fire-resistant pipe, but this does not necessarily have to be made of ceramic material, and may be made of metal. However, this has been difficult to achieve in the past for reasons of electrical isolation.

The present invention aims to solve this problem, in which the supply pipe is made of an electrically conductive metallic material and is provided as part of and/or surrounding the supply pipe. It has an electrically insulating part inserted as an insulator between it and the electrode.

In this way, metal tubes can be used for the electrodes, such metal tubes often offering metallurgical benefits and being simple from a manufacturing standpoint.

The invention is illustrated in greater detail in FIGS. 4, 5 and 6, in which a hollow cathode is shown with a feed tube provided with an insulator along the length of the feed tube. FIG. 5 shows another embodiment of this supply tube, and FIG. 6 shows details of the invention.

FIG. 4 shows a furnace having a cathode 1 and a molten metal 22, and 23 is a slag layer.

The cathode 1 is made of graphite or copper and has an internal cooling water coil 24, preferably a helical tube, connected to a cooling fluid supply (not shown).

The apparatus is equipped with a central supply pipe 12 for supplying powdered material containing iron oxide and additives in accordance with Japanese Patent Publication No. 54-38966.

It is desirable that the supply tube 12 can be made of materials other than ceramic materials, and this is made possible by the present invention.

In the present invention, the supply pipe is made of a conductive metal material such as steel or copper, and is used as a part 13 of the supply pipe (see FIG. 4) and/or as a part of the supply pipe 12 and the surrounding electrode 1. It has an electrically insulating part inserted therebetween as an insulator 14 (see FIG. 5).

The electrical insulation part 13 according to FIG.
2, the electrical insulation 13 prevents electrical contact between the lower and upper parts of the supply tube 12.

As usual, the supply to the furnace takes place through the supply pipe 12.

FIG. 6 shows an alternative embodiment to the supply pipe 12, which supply pipe 15 is provided with an internal passage 16 for the passage of cooling liquid.

The supply pipe 15 therefore allows high temperatures and can be made of copper or a copper alloy, but of course it can also be made of steel.

FIG. 4 illustrates one form of cooling the electrodes.

In the illustrated embodiment, the electrode 1 is constructed in the form of a cooling water coil 24 connected to a cooling fluid supply (not shown).

Because of the cooling liquid, such an arrangement is particularly suitable for non-consumable electrodes.

In the embodiment described in Japanese Patent Publication No. 54-38966, the furnace walls and the furnace roof are made of graphite or a carbon-containing refractory material, so that the electrodes are electrically insulated from the roof at the drop-in line. .

The problems conventionally occurring with furnace materials of the type mentioned above are thus eliminated.

This is explained in more detail in FIG.
The figure shows a hollow electrode 17 which is placed through the furnace roof 25 and is electrically insulated from the furnace roof 25 at 18.

In yet another embodiment of the apparatus described in Japanese Patent Publication No. 54-38966, which is also applicable to the present invention, a solution to the cooling conditions within the furnace is desired.

According to the invention, this is achieved by configuring the furnace walls and/or the furnace roof to be completely or partially air- and liquid-cooled.

This is shown in more detail in FIG.

FIG. 7 shows a so-called tube panel 19 provided with a space for conveying cooling water, which panel is arranged outside the usual lining coating 20 of the furnace walls and/or the furnace roof. has been done.

It is often desired to replace the bottom electrical contacts of a furnace according to Japanese Patent Publication No. 54-38966 with other corresponding forms of electrical contacts.

This is achieved by another embodiment of the invention shown in FIG.

FIG. 8 shows a corresponding electrode 21 extending downwardly through the roof 25 of the furnace to the molten metal.

The number of such electrodes is two or more (only one of which is shown in FIG. 8), and these electrodes 21 are preferably arranged symmetrically around electrode 17, which is preferably a cathode. should be placed.

Said counterelectrode 21 may extend downwardly through the roof 25 of the furnace to the molten metal or may be arranged, for example, through the furnace wall of the furnace vessel, although this embodiment is not shown in FIG. Not yet.

As mentioned above, the charge consists of solid powdered material, but it can also be wholly or partially molten material.

In said method, an inert gas may also be fed through a lance placed in the feed hole 2, ie the hole into which the mixture is introduced.

The invention may be varied in many ways within the scope of the following claims.

[Brief explanation of drawings]

FIG. 1 is a sectional view of an embodiment of the hollow electrode and supply tube according to the present invention; FIGS. 2 and 3 are schematic diagrams showing another embodiment of the supply tube shown in FIG. 1; The figure is a sectional view of a main part of an embodiment of a hollow electrode having a supply pipe in which an insulator is arranged in the longitudinal direction; FIG. 5 is a sectional view of a main part showing an alternative embodiment of the supply pipe of FIG. 4; 6 is a cross-sectional view of still another alternative embodiment of the feed pipe of FIG. 4; FIG. 7 is a fragmentary view of a tube panel that may be used in the present invention; FIG. 1 is a cross-sectional view of an embodiment of the present invention arranged in a 1... Electrode: 2... Supply hole; 3...
...Supply pipe; 4... Seal; 5...
Bush; γ, 8...Valve, 11...Color.

Claims (1)

[Claims] 1. A continuous stream of iron oxide-containing material is mixed with a stream of carbonaceous material and slag former, if present, and this mixture is then passed through a furnace bottom contact with one or more electrodes connected to the cathode of a DC power source. is introduced through a central passage in the electrode of the arc furnace which is connected to the anode of the DC power source, thus creating a DC arc between the electrode and the molten metal, which arc strikes the molten metal surface. In a method for smelting and reducing iron oxide-containing materials, the flow of carbonaceous material is The gas and the material are arranged to meet the carbon requirements for reduction of residual oxides in the iron oxide-containing material and carbon inclusion in the resulting iron molten metal, and the gas and the material are passed through a central passage of the electrode. Means for preventing backflow is provided, said backflow prevention means comprising a plurality of valves or so-called sectors arranged in the supply passage of said mixture and opened and closed at different times to prevent gases from flowing back out of the furnace. - A method for melting and reducing iron oxide-containing materials, which is a feeder, in which a reaction occurs to produce reduced iron, and the thus reduced iron is tapped out from the furnace. .