JPH01208425A - Apparatus for recovering available metal from byproduct at the time of producing stainless steel - Google Patents

Abstract

PURPOSE:To recover available metal at good efficiency and thermal economy by charging powdery material from the upper step tuyere group together with oxygen- enriched air and bulky material from raw material charging hole respectively, into a shaft furnace, in the by-product produced at the time of producing a stainless steel. CONSTITUTION:Iron scrap, carbonic material, etc., are charged into the shaft furnace body 1 from the raw material charging hole 6 and the high temp. oxygen-enriched air obtd. in a hot blast generating furnace 13 from lower and upper step tuyere groups 4, 5 is supplied and refined to discharge the produced molten steel and slag from a molten metal tapping hole 2 and slag tapping hole 3, respectively. In the above shaft furnace, furnace exhaust gas is supplied into a drying furnace 12 with a blower 10 through dust removing device 11. Then, after drying the powdery material in the by-product at the time of producing the stainless steel, it is supplied into the shaft furnace through a wind box part 31 via hoppers 38, 34. On the other hand, the bulky material in the by-product is supplied into the shaft furnace from the raw material charging hole 6 together with the above iron scrap, etc. By this method, the contained available metal is recovered from this by-product as molten metal of ferrometal without any pre-working the by-product and any consuming the electric power.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention uses electric power as energy for refining, and it is possible to eliminate dust, sludge, and waste generated in the stainless steel manufacturing process without agglomeration treatment. This relates to pyrometallurgical smelting equipment that reduces and recovers valuable metals from furnace slag.

[Conventional technology and its problems]

During the process of decarburizing chromium-containing hot metal in the production of stainless steel, some of the chromium in the molten steel is inevitably oxidized. Therefore, chromium oxide is contained in the slag generated in the stainless steel refining process. Traditionally, the method for recovering chromium from slag containing chromium oxides has been to use a method in which slag coexists with molten stainless steel in the same furnace.
The mainstream method was to add ferrosilicon from the top of the slag to reduce and recover the chromium oxide in the slag. In this case, as a matter of course, the amount of ferrosilicon (ferroalloy produced by consuming a large amount of electricity) required for reducing the chromium oxide is consumed, and a reduction period for this purpose must be added to the refining operation.

JP-A No. 51-28502 discloses that the slag generated in the above-mentioned decarburization process is taken out into a special ladle with an electrode heating function, and chromium-containing hot metal is heated while the slag is kept in a molten state by electrode heating. Disclosed is a method for recovering metal oxides in slag using silicon in SS fa pig iron by charging it into an electric furnace in which slag is being melted. In this case as well, electricity is consumed to bring the metal into contact with the molten metal, making electricity an essential energy source.

On the other hand, in addition to the above-mentioned slag, dust, pickling sludge, scale, etc. are inevitably generated in the stainless steel manufacturing process, and these by-products also contain valuable metals such as chromium, iron, nickel, etc. Therefore, recovering these valuable metals is important from the standpoint of resource conservation. For this reason, various methods and equipment for recovering valuable metals from such by-products generated in the stainless steel manufacturing process have been proposed.

Japanese Patent Publication No. 51-28515 and Japanese Patent Publication No. 62-20
Publication No. 13 discloses that pickled sludge is dehydrated and dried (dust) [and scales are sufficiently kneaded with a binder to produce briquettes using a pressure molding machine, and this briquette is mixed with a carbonaceous reducing material and a slag material. A method for recovering valuable metals by charging them into an electric furnace and performing reduction smelting is disclosed.

In addition, instead of forming dust into briquettes, a method of making pellets containing carbonaceous materials, pre-reducing the pellets in a rotary furnace, and then feeding them into an electric furnace to recover valuable metals is a method of proceeding with the method. 4
4th Electric Furnace Conf
erencet ISS-AIME December
, 1986.

Furthermore, there is also a method for reducing and refining dust by feeding it into a smelting furnace in its powder form without agglomerating it.

Proceedings of the 44th E
Electric Furnace Con-feren
ce, ISS-AIME, December 19
It has been reported in 86. This method involves mixing dust, carbonaceous materials, and flux, and supplying this mixture using a screw feeder to a smelting furnace using plasma as a heat source for reduction smelting. Alternatively, a plasma torch is installed at the bottom of a shaft furnace filled with coke. In this method, dust is blown into a shaft furnace using plasma through the tuyeres to reduce and smelt the dust.

However, all of these conventionally proposed methods have in common that they use expensive electric power as refining energy.

Several methods have also been proposed for recovering valuable metals contained in dust without using electrical energy.

For example, powdered carbonaceous material, Cab, SiO! After curing dust pellets containing dust in an autoclave to improve pellet strength, the metal oxides in the pellets are reduced in a rotary kiln, and then the pellets are melted in a cupola. 4ngs o
f the 44th Electric Furna
ce Conference++55-AIME, D
1986. However, in this case, although it is possible to save power, the process of agglomerating the dust becomes complicated, and there are problems in actual operation in that an autoclave, which is a high-pressure container, is used.

In this way, dust, sludge, scale, etc. generated during stainless steel manufacturing may be in the form of irregular particles. Various problems have been associated with the recovery of valuable metals from by-products with a large amount of waste, and recovery of valuable metals from slag has also been accompanied by the consumption of a large amount of electricity.

[Purpose of the invention]

The purpose of the present invention is to solve these problems. 5 If it is a valuable metal-containing substance that is generated during the manufacturing of stainless steel, it can be used to identify the source or form of the substance, such as dust, sludge, scale, slag, etc. The purpose of this project is to develop equipment that can treat all of them, regardless of whether they are present, and can produce molten ferrometal containing metals from these by-products in a high yield and thermoeconomically without consuming any electricity. It is something. In other words, by installing one such facility, you can use all the by-products generated during stainless steel manufacturing as processing raw materials to produce molten ferrometal that can be advantageously used as a raw material for stainless steel manufacturing. The aim is to simultaneously achieve waste treatment, resource conservation, and valuable metal recovery.

[Means to achieve the purpose]

The gist of the present invention, which aims to achieve the above-mentioned object, is a shaft furnace having a material charging port at the top of the furnace, a tap outlet and a slag tap at the bottom of the furnace, and a shaft furnace having a material charging port at the bottom of the furnace. an upper tuyere group consisting of a plurality of tuyeres that have a waste gas outlet at the same level and are arranged at the same level; and a plurality of tuyeres arranged at the same level below the upper tuyere group. A shaft furnace main body has a lower tuyere group consisting of several tuyeres installed in the lower part of the furnace belly above the slag outlet, and the furnace gas is sucked through the waste gas outlet and is converted into high-pressure gas. With a waste gas blower that discharges as.

5. A powder drying furnace for drying a water-containing powder material using the high-pressure gas obtained by the waste gas blower as a part or all of the heat source; With a furnace.

An oxygen-enriched air supply pipe line configured to supply oxygen-enriched air heated in the hot air generating furnace to the upper tuyere group and the lower tuyere group.

powder supply equipment that supplies the dry powder obtained in the powder drying furnace to the high temperature oxygen-enriched air sent to the upper tuyere group;
It consists of

Powder-like by-products from the stainless steel manufacturing process are fed into the furnace together with oxygen-enriched air from the upper tuyere group, and block-like by-products are fed into the furnace together with at least steel scraps and carbonaceous material from the material charging port of the shaft furnace. This equipment recovers valuable metals from by-products from the stainless steel manufacturing process.

Here, each of the upper tuyeres has a structure having a wind box behind the nozzle opening, and the above-mentioned powder supply equipment is connected to the wind box of this upper stage tuyere. That is, there is a powder supply pipe communicating with the air box of the upper tuyere, a first hopper consisting of a closed container communicating with this powder supply pipe, and a communication pipe with an on-off valve interposed for this first hopper. Install a powder supply facility consisting of a second hopper connected through the hopper. In this case, the second hopper shall be configured as a container open to the atmosphere and equipped with a heat exchanger to apply heat to the internal powder, and the high pressure gas obtained by the waste gas blower shall be vented to this heat exchanger. Can be done.

In addition, the upper tuyere group and the lower tuyere group are calculated by the following formula (1) and (
Set so that the relationship 2) is satisfied at the same time.

However, Af is the average value (m”) of the internal cross-sectional area of the shaft furnace at the level of the upper tuyere group and the level of the lower tuyere group.

At is the sum of the cross-sectional areas of the nozzle openings of the upper and lower tiers (m”).

L is the vertical distance between the upper and lower tuyere groups (m
), Dpc is the average particle diameter (m) of the carbon material charged from the material charging port, D tu and I)tt are the diameters (m) of the nozzle ports of the upper and lower tuyeres, and ■. and (2) are the flow rates (m''/m1n) of high-temperature oxygen-enriched air per tuyere blown from the upper and lower tuyeres.

In the equipment of the present invention, among the by-products during stainless steel manufacturing, lumps such as converter slag are collected from the material charging port at the top of the furnace, and dust, sludge, scale, powdery slag, etc. The material was fed into the furnace from the upper tuyere group, and the charging location was selected based on the material form.
Steel scraps and carbonaceous material are charged through the material charging port at the top of the furnace, and the various by-products are melted and reduced all at once to produce ferrometal molten metal in which various metals are melted into iron. In addition, the gas inside the furnace is forcibly drawn from the upper part of the shaft furnace and used as a fuel gas or heat source gas to dry the water-containing powder material and raise the temperature of the oxygen-enriched air. The present invention provides a complete device that constitutes a heat utilization cycle and serves as a by-product treatment facility during stainless steel manufacturing.

[Detailed description of the invention]

For a vertical furnace similar to the shaft furnace of the present invention having two upper and lower tuyere stages, see 1, for example, JP-A-57-198205;
Japanese Patent Publication No. Sho 59-18453, Japanese Patent Publication No. Sho 60-1627
18, JP-A-62-167808, and JP-A-62-167809. However, all of these methods used ore (iron ore or chromium ore) as a raw material for melting and reduction.

Therefore, unlike the present invention, the object is not to treat complex substances of indefinite form such as dust, sludge, scale, and slag that are generated during stainless steel manufacturing, but to efficiently melt and reduce iron ore and chromium ore at a high reduction rate. The main focus was on how to achieve this goal. Note that among these publications, JP-A-62-167808 and JP-A-62-167809 disclose a method in which powdery chromium ore is included and entrained in powdered chromium ore injected from the upper tuyere. The powdered slag used here is used as a slag material for melting and reducing chromium ore, and the slag itself is not a material to be smelted.

The present invention uses a shaft furnace with two upper and lower tuyeres similar to those shown in these publications, but since the material to be treated is a complex material with an indeterminate shape, various improvements can be made. This system is inseparably connected to a device that also performs the preliminary processing necessary for loading into the furnace. The configuration of the device will be specifically explained below with reference to the drawings.

In FIG. 1, 1 indicates a shaft furnace main body.

This shaft furnace body 1 has a tap hole 2 at the bottom of the furnace. It has a slag outlet 3 in its upper part, and a group of lower tuyeres 4. It has an upper tuyere group 5 above it.

The top of the furnace has an opening that serves as a material charging port 6, into which bulk material is loaded using a bucket 7 up to the vicinity of the material charging port 6. Further, a waste gas outlet 8 is provided at the upper part of the middle, which is considerably lower than the material charging port 6. In other words, the in-furnace gas is forcibly sucked in from the waste gas outlet 8 from a position lower than the loading height of the in-furnace contents. Before it has cooled down to 100%, it is forcibly sucked out of the furnace from the upper part of the furnace.

This shaft furnace main body 1 has a material charging port 6.

While being weighed by the weigher 9, bulk materials such as steel scrap 1 alloy ferro, carbonaceous material, and converter slag are loaded by the bucket lift 7, and the material layer that descends during the operation of the furnace is compensated for at any time, so that the amount of material during the operation of the furnace is substantially reduced. Ensure that there is always a layer of material up to the top of the upper furnace. On the other hand, heated oxygen-enriched air is introduced into the furnace from the upper tuyere group 5 and the lower tuyere group 4, and at the same time, the upper tuyere group 5 introduces dried powdery substances (in the production of stainless steel). Generated dust, sludge, scale, powder slag, etc.
These substances (hereinafter collectively referred to as powdery by-products) are introduced into the furnace together with the oxygen-enriched air.3 In the equipment of the present invention, there is a processing system and equipment for the materials supplied to the tuyeres. It has one feature in its configuration.

First, a waste gas blower 10 is installed to forcibly extract CO-rich, high-temperature furnace gas from the waste gas outlet 8 in the upper part of the midsection. A dust remover 11 is installed between the waste gas blower 10 and the waste gas outlet 8.
The furnace gas removed in step 1 is sucked into the waste gas blower [10] and discharged as high-temperature, high-pressure gas. The resulting high-temperature, high-pressure gas from the CO lynch is used for primary drying and secondary drying of the powdered by-products that are supplied to the upper tuyere group, and to raise the temperature of the oxygen-enriched air that is supplied to the upper and lower tuyere groups. and for this purpose.

A powder drying furnace 12 that uses this gas as part or all of its heat source to dry the water-containing powder material, and a hot air generating furnace 13 that uses this gas as part or all of its heat source are installed.

The powder drying furnace 12 is a furnace that dries the water-containing powder material using combustion gas from the burner 14 . Gas discharged from the waste gas blower 10 is supplied via a pipe line 15 as part or all of the fuel for the eight-seat 14. As the type of furnace, a fluidized furnace or a rotary furnace can be used, but as shown in Figure 9, the material is continuously supplied from a hopper 17 to a drying furnace main body 16 that brings the combustion gas of the burner 14 into contact with the water-containing powder material, It is preferable that the apparatus be configured as a device equipped with a cyclone 19 for continuously discharging the treated powder into the powder collection container 18 and at the same time collecting fine particles entrained in the exhaust gas. The drying furnace hopper 17 is supplied with moisture-containing powdery by-products such as dust, sludge, scale, powdery slag, etc., which are the processing raw materials of the equipment of the present invention, and are further dried there. - Next drying means not drying completely until the moisture content is zero, but drying so that some moisture remains. Complete drying is not preferable because the amount of fine particles accompanying the dried exhaust gas increases, and the process of transporting the gas to the upper tuyere group 5 also causes dust to be generated, making processing complicated and causing a decrease in yield. Complete drying is carried out in the second hopper (38) provided near the upper tuyere, as will be described later.

On the other hand, air is blown to the upper vane group 5 and the lower tuyere group 4 by interposing a dehumidifier 23 and a hot air generating furnace 13 in the air conduit 22 leading from the air blower 21 that sucks the atmosphere to the upper and lower tuyeres. An oxygen supply pipe 2 is provided between the dehumidifier 23 and the hot air generator 13.
4 is connected. That is, oxygen is introduced into the high-pressure air compressed by the blower 21 through the oxygen supply pipe 24 to enrich the oxygen, and then the temperature is raised in the hot-air generator 13 to produce high-temperature and high-pressure oxygen-enriched air, which is then passed through the upper and lower tuyeres. feed the group. As part or all of the heat source of this hot air generating furnace 13, high-temperature Co')ychi gas obtained by the waste gas blower 10 is used. There are two ways to use it: one is to burn the CO in the gas and use its calorific value, and the other is to use the sensible heat of the gas, and the other is to use only the sensible heat of the gas. is more effective. For this reason, it is advantageous to use a hot air generating furnace which combusts the gas and then exchanges heat between the combustion gas and oxygen-enriched air. For this heat exchange, as shown in Figure 1, an oxygen-enriched air passage 27 is inserted into a combustion gas passage 26 obtained by burning the gas as a part of fuel in a gas burner 25, using a partition wall made of a thermally conductive material. It is expedient to adopt an indirect heat exchange system in which the heat exchanger is disposed through the heat exchanger 28. In addition.

Instead of this indirect heat exchange method, it is also possible to use a Tsutomi hot air stove equipped with a combustion chamber and a heat storage chamber, and use the high-temperature COU Sochi waste gas as part or all of the fuel gas in the combustion chamber. Just use it.

Next, the configuration of the equipment around the tuyere, which is one of the features of the equipment of the present invention, will be explained.

The upper tuyere group 5 is for injecting the powdered by-products with high-temperature oxygen-enriched air while distributing them to each tuyere, and for this purpose, each of them had a wind box part 31 behind the nozzle opening 30. It has a structure. A ladder pipe 32 is connected to the air blower surrounding the shaft furnace at a position away from the nozzle opening 30 to this air box portion 31, and this air header pipe 32 is connected to the air blower pipe line 22 described above. Further, a powder supply pipe 33 is connected to the upper surface of the air box part 31.

Due to this.

The powder supplied from the powder supply pipe 33 is mixed and dispersed in the air box with the jet stream of high-temperature oxygen-enriched air introduced into the air box part 31 from the air blower tube 32, and then is sent into the furnace from the nozzle port 30. is injected into.

The upper end of the powder supply pipe 33 is connected to a first hopper 34 . Further, a constant flow control valve 34 is interposed in the middle of the powder supply pipe 33. The first hopper 34 is a closed container, and the lower end of a communication pipe 37 with an on-off valve 36 interposed therein is connected to its upper surface, and the upper end of this communication pipe 37 is connected to the second hopper 34.
It is connected to the bottom of 8. The second hopper 38 is a closed container with a pressure regulating valve 39.
Powdered by-products that have been primarily dried in the drying oven 12 described above are supplied to the pipe 8 through a pipe 40 and a branch pipe 41. A powder cutoff valve 42 is attached to the branch pipe 41. A heat exchanger 43 is installed inside this second hopper 38, and a part of the high temperature and high pressure waste gas supplied from the waste gas blower 10 is vented to this heat exchanger 43, and the waste gas is Using the sensible heat of the gas, the powdery byproducts in the second hopper 38 are finally heated and dried (secondary drying).The heat exchanger 43 converts a portion of the sensible heat into powdery byproducts. The waste gas after being applied can be supplied to the burner 14 of the drying furnace 12 or the burner 25 of the hot air generating furnace 13 and reused as fuel.

In this way, after primary drying is performed in the drying oven 12 to a moisture content that does not generate dust, the second hopper 3
The powdered by-product material is heated again in the second hopper 38, and the powdered by-product material is secondarily dried until the moisture content becomes substantially zero by releasing substantially all of the attached moisture into the air in the second hopper 38. After passing through the first hopper 34, it is supplied to the wind box section 31. The operation is performed as follows. First, the first ho.
The on-off valve 36 between the pumper 34 and the second hopper 38 remains closed.

The pressure in the second hopper 38 is released to atmospheric pressure. The powder cutoff valve 42 is opened and a predetermined amount of powdered byproduct material is loaded into the second hopper 38, which is open to atmospheric pressure.Then, the cutout valve 42 is closed and the internal pressure of this hopper 38 is reduced to a vacuum. The pressure is increased until it becomes equal to the internal pressure of the high-temperature oxygen-enriched air in section 31. During this time, the heat exchanger 43 heats the powdery byproducts in the hopper 38, and the attached moisture is transferred to the air inside the hopper. - On the other hand, the first housing bar 34 is the on-off valve 3
6 is in the closed state, the pressure is maintained at the same level as the internal pressure of the air box 31 because it communicates with the air box 31 through the powder supply pipe 33 and the constant flow control valve 35. In this state, when the on-off valve 36 is opened, the second hopper 38, the first ho, and the sober 34 are both maintained at the same high pressure (therefore, the high temperature oxygen-enriched air in the wind box 31 does not flow back). ), the heated and dried powdery by-products are transferred to the first hopper 3.
It flows into 4 by gravity. After supplying a predetermined amount of powdered by-products to the first hopper 34, the second hopper 38 is opened to the atmosphere, and the high-pressure air containing moisture at the front stage outlet is discharged to the outside of the system to produce the fifth powdered by-products. The powdery by-product material completely dried in the second hopper 38 is supplied and then the above-mentioned operation is repeated. The air is introduced into the box 31, mixed well with high-temperature oxygen-enriched air, and then injected into the furnace through the nozzle port 30. Since the shape of the powdery by-product is complex and its shape tends to change over time depending on the circumstances at the time, good injection may not be possible unless it is completely dried. However, if this complete drying is performed in the drying oven 127, the above-mentioned problem of dust generation will occur, which will also cause trouble. It has been found that such troubles can be avoided by providing the first hopper 34 and the second hopper 38 and performing the final secondary drying in the second hopper 38 according to the present invention.

Note that in the equipment of the present invention, the lower tuyere group 4 also has a structure provided with a wind box like the upper tuyere group 5; It is not used to inject powdered by-products, but only for injecting hot oxygen-enriched air into the furnace.

With the equipment of the present invention configured as described above, lumps such as converter slag among the by-products generated during stainless steel manufacturing are removed from the material charging port 6 at the top of the furnace, along with steel scraps and carbonaceous material (coke), and in some cases. When carrying out an operation in which the ferroalloy and slag materials are loaded into the shaft furnace main body and the powdered by-products are injected through the upper tuyere group 5, the vertical distance between the upper tuyere group 5 and the lower tuyere group 4 and It was found that it was necessary to set the nozzle opening area of all tuyeres within an appropriate range. This will be explained below.

The high-temperature oxygen-enriched air blown into the shaft furnace through the upper tuyere group 5 and the lower tuyere group 4 causes the carbonaceous material present in the shaft furnace to burn in a reaction as shown in equation (3).

2C+0□=2CO(3) The combustion gas has a high temperature of 2000°C or more, and as it flows to the upper part of the shaft furnace, it heats the carbon material etc. introduced from the top of the furnace. Therefore, high-temperature (red-hot) coke exists in front of each of the upper and lower tuyeres. When dried powdery by-products consisting of dust, sludge, converter slag powder, etc. are continuously blown in from the upper tuyere group 5, they contact the red-hot coke present one tuyere before and rapidly melt. In addition, oxides of valuable metals such as N i + Cr + Fe in the powder are reduced. The same thing happens with the lumpy slag charged from the top of the furnace. The reduction reaction of metal oxides proceeds while absorbing heat, and the heat of the reaction is covered by the heat of combustion of the carbonaceous material. The generated valuable metal melt drips into the bottom of the shaft furnace together with the slag.

In order to efficiently reduce and recover dust, sludge, scale, and valuable metals in converter slag through such melting and reduction, the upper and lower tuyeres must meet the conditions described in (1) and (1) above.
2) It was found that it was necessary to satisfy the condition shown in 2. In other words, the relationship between the shaft furnace cross-sectional area Af and the sum total At of the nozzle opening cross-sectional areas of the upper and lower tuyeres is expressed as Af/
The smaller At becomes.

The molten powder injected from the upper tuyere becomes difficult to penetrate toward the center of the shaft furnace, and selectively drips only on the furnace wall side, where the temperature is relatively low. For this reason, the reduction of valuable metal oxides in the melt, particularly Cr oxides, does not proceed efficiently. It has been found that when Af/At≧20, reduction can proceed efficiently. On the other hand, regarding the vertical distance (L) between the upper and lower tuyere group levels, the air flow rate of the upper and lower separate ports, the diameter of the tuyere, and the average particle size of the carbon material supplied into the shaft furnace are determined. There is an appropriate (L) range depending on the diameter, and beyond that range,
A low-temperature region is created between the upper and lower tuyeres, and a large amount of the molten powder remains in this low-temperature region, inhibiting the smooth dripping of the molten material. The reduction reaction of valuable metal oxides in the melt becomes delayed. However, in determining the scope of (L), the above (
2) It has been found that if the parameters represented by 2 are set within the range, the high temperature state can be maintained at all times during the upper and lower stages, and the reduction reaction of the metal oxide can proceed quickly.

On the other hand, in operation of the equipment of the present invention, the combustion gas generated in front of the upper tuyere and in front of the lower tuyere has a high temperature of over 2000°C, and the sensible heat of the gas is extremely large. Although some of the sensible heat of the combustion gas is consumed in the dissolution of the powdery byproducts injected from the upper tuyere and the reduction reaction of its oxides, the amount consumed is less than the amount of sensible heat possessed by the combustion gas. small. Therefore, in order to improve the thermal efficiency of the shaft furnace, it is necessary to effectively recover the sensible heat of the combustion gas. The carbonaceous material that is combusted by the high-temperature oxygen-enriched air that is blown in from the upper and lower tuyeres is preheated by the combustion gas as it descends from the top of the shaft furnace to the bottom of the furnace, and the sensible heat of the combustion gas is recovered accordingly. Although it is possible.

Heating the carbonaceous material alone is insufficient to recover sensible heat from the combustion gas. By charging converter slag, steel scraps, ferroalloys, etc. from the top of the shaft furnace furnace together with carbonaceous materials, sensible heat recovery from the combustion gas can be achieved, and these converter slags, steel scraps, and ferroalloys will be released as they descend through the furnace. The converter slag becomes high temperature and melts, and in the process of melting and dripping into the carbonaceous layer, Cr in the slag is removed.
+ Valuable metal oxides such as Fe are reduced. The valuable metals that have been reduced and recovered, along with steel scrap and molten ferroalloy, are
It drips into the lower part of the furnace, collects as molten ferrometal at the bottom of the furnace, and can be recovered as molten ferrometal from the tapping port 2. In addition, converter slag, dust, and molten slag mainly composed of Cab, SiO□, etc. in the sludge are discharged from the slag outlet 3 to the outside of the furnace.

In this way, the lumpy converter slag can also be used as a treatment target in the equipment of the present invention, and the sensible heat of the combustion gas generated by the combustion of the carbonaceous material can be used to obtain the lumpy slag and ferrometal molten metal. However, by forcibly extracting the furnace gas from the exhaust gas outlet 8 installed at the upper part of the shaft furnace, the CO content can be effectively used as melting heat for iron sources, etc. CO gas-rich high-temperature gas that maintains a high temperature can be obtained. That is, by forcibly suctioning the gas in the furnace from the upper part of the middle part of the furnace instead of from the top of the furnace, it is possible to take out high-temperature gas in which the oxidation reaction of CO has hardly progressed. This gas is more useful as a fuel gas than the waste gas from iron blast furnaces and cupolas, and has a production capacity of approximately 1000 kcal.
/Nm3. In the equipment of the present invention, this waste gas is transferred to the drying oven 12 as described above. heat exchanger 43
．． By using it as a heat source gas in the hot air generating furnace 13, it is possible to rationally recover valuable metals from various difficult-to-handle by-products generated during stainless steel manufacturing while making full effective use of heat and CO gas in the entire facility. It is configured so that it can be carried out.

As explained above, according to the present invention, valuable metals can be recovered as ferrometal molten metal without consuming electricity by treating all by-products from stainless steel manufacturing that have an indefinite shape and, in some cases, contain a large amount of water. By installing this equipment as an accessory to the original stainless steel refining equipment, the ferrometal molten metal recovered by the nine equipment can be reused as crude molten metal for stainless steel refining. In particular, in the case of converter slag, lumps remain as lumps, and powders remain as powder.

Since the slag can be charged into the equipment of the present invention in its generated form, the equipment is very easy to use in that no special secondary treatment of the slag is required. 1. The equipment of the present invention has a complete cycle in terms of thermal efficiency and effective utilization of waste gas, and the carbon material charged into the furnace undergoes not only the reduction reaction of oxides but also its combustion. The generated heat and gas components are effectively used to recover valuable metals, so it is a very efficient facility, and the above-mentioned objectives have been effectively achieved.

[Brief explanation of the drawing]

FIG. 1 is a schematic sectional view systematically showing the overall equipment arrangement of the equipment of the present invention. 1. Shaft furnace body, 2. Tap spout. 3. Slag outlet, 4. Lower tuyere group, 5. Upper tuyere group, 6. Material charging inlet at the top of the furnace. 7.Charging packet, 8..Waste gas outlet. 10...Waste gas blower, 11...Dust remover, 12...
Drying furnace for powdered by-products, 13.Hot air generating furnace. 14. Burner of drying oven, 21. Blower for tuyere. 22...High-temperature oxygen-enriched air supply pipe line. 23...excluded! 25. Burner of hot air generator. 30...Nozzle opening of tuyere, 31... Wind box part of upper tuyere,
33... Powder supply pipe, 34... First hopper 935...
Constant flow rate regulating valve, 36... Opening/closing valve, 38... Second hopper, 39... Pressure regulating valve, 43... Heat exchanger.

Claims (4)

[Claims] (1) A shaft furnace that has a material charging port at the top of the furnace, a tap hole and a slag tap at the bottom of the furnace, and has a waste gas outlet at the top of the furnace below the material charging port, and is located at the same level. An upper tuyere group consisting of a plurality of tuyeres arranged at the upper tuyere group, and a lower tuyere group consisting of a plurality of tuyeres arranged at the same level at a position below the upper tuyere group. A shaft furnace body installed in the lower part of the furnace belly above the tailings outlet, a waste gas blower that sucks in-furnace gas from the waste gas outlet and discharges it as high-pressure gas, and a a powder drying furnace that dries a water-containing powder material using a part or all of the heat source as a part or all of the high-pressure gas obtained by the waste gas blower; An oxygen-enriched air supply pipe for supplying oxygen-enriched air heated in the furnace to the upper tuyere group and the lower tuyere group; and high-temperature oxygen supplied to the upper tuyere group. Powder supply equipment that supplies the dry powder obtained in the powder drying furnace to enriched air;
Among the by-products during stainless steel manufacturing, powder-like by-products are collected from the upper tuyere group together with oxygen-enriched air, and lump-like products are collected from the material charging port of the shaft furnace together with at least steel scraps and carbonaceous material. Equipment that recovers valuable metals from by-products during stainless steel manufacturing, which are supplied to the furnace. (2) The upper tuyere has a structure with a wind box behind the nozzle opening, and the powder supply equipment includes a powder supply pipe communicating with the wind box of the upper tuyere, and the powder Claim 1, comprising a first hopper consisting of a closed container communicating with a body supply pipe, and a second hopper connected to this first hopper via a communication pipe equipped with an on-off valve. Equipment that recovers valuable metals from by-products during stainless steel manufacturing. (3) A patent in which the second hopper consists of a container open to the atmosphere and equipped with a heat exchanger to apply heat to the powder inside, and the high-pressure gas obtained by the waste gas blower is vented to this heat exchanger. A facility for recovering valuable metals from by-products during the production of stainless steel according to claim 2. (4) The upper tuyere group and the lower tuyere group are calculated by the following formula (1) and (
Equipment for recovering valuable metals from by-products during stainless steel manufacturing according to claim 1, which is set so that the relationship 2) is simultaneously satisfied, Af/At≧20...(1) L≦ 2×10^-^4/√D_p_c・(V_u/D_
t_u+V_L/D_t_l)...(2) However, Af is the average value (m^2) of the internal cross-sectional area of the shaft furnace at the level of the upper and lower tuyere groups, and At is the average value (m^2) of the internal cross-sectional area of the shaft furnace at the level of the upper and lower tuyere groups, and At is the average value of the internal cross-sectional area of the shaft furnace at the level of the upper and lower tuyeres The total cross-sectional area of the nozzle opening (m^2), L is the vertical distance between the upper tuyere group and the lower tuyere group (m), and D_p_c is the average particle diameter of the carbon material charged from the material charging port. (m), D_
t_u and D_t_L are the diameters (m) of the nozzle openings of the upper and lower tuyeres, and V_u and V_L are the flow rates of high-temperature oxygen-enriched air per tuyere (m^) blown from the upper and lower tuyeres. 2/min).