JP2012112021A - Recovering method and recovering device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a recovering method and a recovering device capable of efficiently recovering TiOfrom blast furnace slag.SOLUTION: The blast furnace slag discharged from iron ore in a blast furnace for iron manufacture is heated to a temperature lower than a melting point of TiOas it is discharged without any cooling treatment, a material of which melting point is lower than that of TiOis separated and removed from the blast furnace slag, the blast furnace slag from which the material has been removed is heated to a temperature equal to or higher than the melting point of TiOand lower than the melting point (for example, the melting point of AlO) of a material of which melting point is higher than that of TiO, and TiOis separated from the blast furnace slag and recovered while it is in a form of an oxide.

Description

The present invention relates to a recovery method and a recovery apparatus for separating and recovering titanium oxide (TiO ₂ ) from a residue (blast furnace slag) discharged from iron ore of a blast furnace for iron making.

In general, a large amount of blast furnace slag is discharged as industrial waste from a blast furnace for iron making. The blast furnace slag contains iron ore oxide and a deoxidizer, a reducing agent oxide, sulfide and the like to be fed into the blast furnace together with the iron ore oxide. Blast furnace slag thrown away as industrial waste may contain about 10% TiO ₂ .

The present invention is intended to separating and recovering TiO ₂ from the blast furnace slag, it could not be found directly related art. As technologies related to the present invention, Patent Literatures 1 to 5 are listed.

JP-A-8-188833 Japanese Patent Laid-Open No. 10-130041 JP-A-11-19625 JP 2007-85561 A JP 2009-127094 A

If TiO ₂ can be efficiently recovered from the blast furnace slag, the blast furnace slag as industrial waste can be effectively used as a resource, and the insufficient rare metal Ti can be supplemented, and the amount of industrial waste can be reduced.
Accordingly, an object of the present invention is to provide a recovery method and the recovery apparatus capable of recovering the TiO ₂ efficiently than blast furnace slag.

In order to achieve the above object, a recovery method according to an embodiment of the present invention is based on the melting point of TiO ₂ as it is without cooling the blast furnace slag discharged from the iron ore of the iron ore smelting furnace from the discharged state. The blast furnace slag having a melting point lower than the melting point of TiO ₂ is separated and removed from the blast furnace slag and the blast furnace slag from which the substance has been removed is equal to or higher than the melting point of TiO ₂ and is contained in the TiO ₂ slag. _The material is heated to a temperature lower than the melting point of the substance having a melting point higher than ₂ (for example, the melting point of Al ₂ O ₃ ), and TiO ₂ is separated from the blast furnace slag and recovered as an oxide.

If you try to recover the TiO ₂ from the substances that contain TiO ₂ for example by vacuum evaporation, it is necessary to heat the material to near the melting point of TiO _2, since the melting point of the TiO ₂ is very hot, the heat A huge amount of energy is required, and TiO ₂ cannot be efficiently recovered. The present inventors have included a large amount of TiO ₂ in the blast furnace slag discharged from the iron ore of the blast furnace for iron making, and such blast furnace slag is in a very high temperature state when discharged from the blast furnace. We paid attention to the circumstances unique to blast furnace slag. That is, the present invention uses the blast furnace slag discharged from the iron ore of the blast furnace for iron making to recover the blast furnace slag, which is the object to be processed, without using the cooling process from the discharged state. The required energy can be reduced as much as possible. Therefore, TiO ₂ can be efficiently recovered from the blast furnace slag.

Also, when trying to recover Ti as blast furnace slag, it is necessary to make the processing area for recovery almost vacuum so that Ti is not oxidized, but enormous energy is required to make the processing area vacuum. There are problems such as a large amount of equipment for making the processing area highly airtight. Therefore, in the present invention, TiO ₂ is separated from the blast furnace slag and recovered as an oxide. Therefore, TiO ₂ can be efficiently recovered from the blast furnace slag.

In the recovery method according to the present invention, from the process of the TiO ₂ recovered while the oxide is separated from the blast furnace slag, a gas containing a fine powder of TiO ₂ separated from the blast furnace slag, fine powder of TiO ₂ The precipitate may be collected by precipitation into a liquid.
Thereby, the fine powder of TiO ₂ can be collected.

In the recovery method according to the present invention, in the step of precipitating the TiO ₂ fine powder into the liquid, the TiO ₂ fine powder is collected from the gas containing the TiO ₂ fine powder using centrifugal force and collected. A shower may be ejected onto the fine powder of TiO ₂ to precipitate the liquid.
Thus, it is possible to efficiently recover the fine powder of TiO _2.

In the recovery method according to the present invention, the step of separating and removing the substance having a melting point lower than the melting point of TiO ₂ from the blast furnace slag and the step of separating the TiO ₂ from the blast furnace slag and recovering the oxide as it is are 1 Torr. The reaction may be performed under reduced pressure or normal pressure in a range of ˜760 Torr.

As a result, the number of pumps can be reduced, the equipment cost is low, the amount of power used can be reduced, and the energy cost is low. That is, according to the present invention, the equipment cost is reduced and the running cost is reduced. In addition, maintenance is also easy.
The step of separating and removing the substance having a melting point lower than the melting point of TiO ₂ from the blast furnace slag removes each metal oxide and sulfide constituting the substance at a reduced pressure. Each may be separated and recovered separately at each melting point.

A recovery apparatus according to another aspect of the present invention is a first heating apparatus for heating blast furnace slag discharged from iron ore of a blast furnace for iron making to a temperature lower than the melting point of TiO ₂ as it is without performing cooling treatment from the discharged state. 1 of the furnace, and means for removing from said first furnace vaporized material from the blast furnace slag by the heating, the material blast furnace slag has been removed by the TiO ₂ above the melting point, of TiO ₂ contained in the blast furnace slag A second furnace for heating to a temperature lower than the melting point of the substance having a melting point higher than the melting point (for example, the melting point of Al ₂ O ₃ ), and means for recovering TiO ₂ evaporated from the blast furnace slag by the heating as an oxide. It comprises.

In the present invention, the blast furnace slag discharged from the iron ore of the blast furnace for iron making is used as it is in the recovery process without performing the cooling process from the discharged state, so that the energy required for heating the blast furnace slag as the object to be processed Can be made as small as possible. Therefore, TiO ₂ can be efficiently recovered from the blast furnace slag. In the present invention, since TiO ₂ is separated from the blast furnace slag and recovered as an oxide, TiO ₂ can be efficiently recovered from the blast furnace slag.

In the recovery apparatus according to the present invention, the recovery means has a liquid tank for precipitating TiO ₂ fine powder evaporated from the blast furnace slag into a liquid, and the liquid tank is a precipitate whose liquid surface is exposed to the outside. You may have a thing collection part.
Thereby, the fine powder of TiO ₂ can be collected.

The collection | recovery apparatus which concerns on this invention may be arrange | positioned in the liquid of the said liquid tank, and may have the conveyor for carrying the deposit which settled in the said liquid tank outside via the said deposit collection part.
Thereby, it becomes possible to collect the fine powder of TiO ₂ while continuously operating the apparatus.

Recovery apparatus according to the present invention is placed on top of the liquid surface of the liquid bath, a gas containing a fine powder of TiO _2, a centrifugal separation means for the dust collecting a fine powder of TiO ₂ with the centrifugal force, the and ejecting the shower to a fine powder of the dust collecting the TiO ₂ may have a shower head for precipitation in the liquid.
Thus, it is possible to efficiently recover the fine powder of TiO _2.
In the recovery apparatus according to the present invention, the first and second furnaces may be under a reduced pressure or a normal pressure in a range of 1 Torr to 760 Torr.
As a result, the number of pumps can be reduced, the equipment cost is low, the amount of power used can be reduced, and the energy cost is low. That is, according to the present invention, the equipment cost is reduced and the running cost is reduced. In addition, maintenance is also easy.

The recovery device according to the present invention further includes a water tank cooling chamber that cools the blast furnace slag after TiO ₂ is recovered by the recovery means, and a power generation device that generates electric power using boiling water in the water tank cooling chamber. May be.

According to the present invention, TiO ₂ can be efficiently recovered from blast furnace slag.

It is a block diagram which shows the structure of the collection | recovery apparatus which concerns on one Embodiment of this invention. It is sectional drawing which shows the 1st and 2nd liquid collection | recovery apparatus shown in FIG. It is a flowchart which shows the collection | recovery method which concerns on one Embodiment of this invention. It is a component table | surface of a blast furnace slag. It is a table | surface which shows melting | fusing point and boiling point of the component which comprises a blast furnace slag.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram showing a configuration of a recovery apparatus according to an embodiment of the present invention.

  As shown in FIG. 1, the recovery device 10 includes a preheating furnace 11, a soaking furnace 12, a first vacuum evaporator 13, a second vacuum evaporator 14, a moving chamber 15, and a water tank cooling chamber 16. And have. The preheating furnace 11, the soaking furnace 12, the first reduced pressure evaporation furnace 13, the second reduced pressure evaporation furnace 14, the moving chamber 15 and the water tank cooling chamber 16 constitute a continuous furnace connected in this order. These spaces are partitioned so as to be openable and closable by open / close doors. The preheating furnace 11 is provided with a carry-in port into which a blast furnace slag that is an object to be treated is carried. The water tank cooling chamber 16 is provided with a carry-out port through which the treated blast furnace slag is carried out.

The blast furnace slag contains CaO, MgO, SiO ₂ , Al ₂ O ₃ , TiO ₂ , TFe, S, and the like, and the measured results of each component are shown in FIG. The melting point and boiling point of each component are as shown in FIG.

  The blast furnace slag is mounted on, for example, a tray, and the tray is carried from the carry-in port by a conveying means, and the preheating furnace 11, the soaking furnace 12, the first vacuum evaporator 13, the second vacuum evaporator 14, and the moving chamber. 15 and the water tank cooling chamber 16 are carried in order, and are carried out from the carry-out port. That is, the collection device 10 processes the processing object in a batch manner.

  A first liquid recovery device 21 is connected to the first vacuum evaporation furnace 13, and a second liquid recovery device 22, a filter 23, and a vacuum pump (oil rotary pump) 24 are connected to the first liquid recovery device 21. They are connected in that order. Similarly, a first liquid recovery device 31 is connected to the second vacuum evaporator 14, and a second liquid recovery device 32, a filter 33, and a vacuum pump 34 are connected to the first liquid recovery device 31. Connected in order.

  The preheating furnace 11 is a furnace in which the blast furnace slag discharged from the blast furnace is directly carried in without being cooled, and is provided with a carry-in port and a carry-out port having an open / close door. Here, in the preheating furnace 11, the soaking furnace 12, the moving chamber 15, and the water tank cooling chamber 16, the processing object is processed under normal pressure, not under reduced pressure. Here, the cooling treatment includes not only the case where the blast furnace slag is actively cooled, but also the case where the temperature of the blast furnace slag is intended to be lowered by leaving the blast furnace slag in the atmosphere to some extent.

Since the preheating furnace 11, the soaking furnace 12, the first reduced pressure evaporation furnace 13, and the second reduced pressure evaporation furnace 14 become extremely high temperature, the furnace body has a double wall structure. The space between the double walls is depressurized to suppress heat transfer due to convection and conduction. Thereby, the furnaces 11-14 set the furnace body outer surface temperature to 80 degrees C or less, prevent heat dissipation, implement | achieve energy saving, and also aim at the improvement of safety | security.
The preheating furnace 11 has, for example, gas heating or an oil heating device as means for heating the blast furnace slag to about 1000 ° C.

  The soaking furnace 12 includes an electric resistance heater heating, a low frequency heating, a plasma heating device, and the like as means for heating the blast furnace slag carried from the preheating furnace 11 to about 1700 ° C.

The first reduced pressure evaporation furnace 13 heats the slag loaded with the slag heated to about 1700 ° C. in the soaking furnace 12 to a temperature lower than the melting point of TiO ₂ , for example, 1850 ° C. Examples of the heating means include electric resistance heater heating, low frequency heating, and a plasma heating device. Thereby, substances such as SiO ₂ , Fe oxide, and sulfide having a melting point lower than that of TiO ₂ are evaporated and separated from the blast furnace slag. The inside of the first reduced pressure evaporation furnace 13 is preferably set to a certain level of reduced pressure, but may be at normal pressure. The range is preferably about 1 Torr to 760 Torr (normal pressure, reduced pressure).
FIG. 2 is a cross-sectional view showing the configuration of the first and second liquid recovery devices 21 and 22 shown in FIG.

As shown in FIG. 2, the first liquid recovery device 21 is connected to the first reduced pressure evaporation furnace 13 by, for example, a pipe 25. By pulling the inside of the first liquid recovery device 21 with the vacuum pump 24, the SiO ₂ , Fe oxide, sulfide that has been heated to 1850 ° C. in the first vacuum evaporator 13 and evaporated from the blast furnace slag via the pipe 25. A gas containing a substance (fine powder) such as an object can be drawn into the first liquid recovery device 21.

Here, the recovered material, such as SiO ₂ and Fe oxide, is an ultrafine metal oxide (fine powder). This recovery is therefore very difficult. In the first liquid recovery apparatus 21 according to the present embodiment, the following technique is employed to recover these fine powders.

  The first liquid recovery device 21 includes a liquid tank 211 in which a liquid mainly composed of vacuum oil is stored, a liquid recovery main body 212 that covers a part of the liquid tank 211 so as to form a decompressed space therein, And an automatic conveyor 213 that conveys the precipitate in the liquid tank to the outside of the liquid tank. The liquid tank 211 is exposed to the outside except for the portion covered by the liquid recovery body 212, and there is a part of the liquid level in the atmosphere.

  The liquid recovery body 212 has a side wall 214 and a ceiling 215, and a pipe 25 from the first reduced pressure evaporation furnace 13 is connected to the side wall 214. The ceiling 215 stores the liquid tank 211 in the liquid recovery body 212. A shower portion 216 for ejecting the same liquid as the liquid from the vicinity of the ceiling in a shower shape. A centrifuge 217 is provided at a position below the shower unit 216 and higher than the liquid recovery body 212 side opening of the pipe 25 connected to the liquid surface and the first vacuum evaporator 13. Is connected to the second liquid recovery device 22, and a pipe 218 is connected to the other end in the vicinity of the ceiling 215.

Therefore, substances (fine powder) such as SiO ₂ , Fe oxide, and sulfide sucked into the reduced pressure space inside the liquid recovery body 212 are collected by the centrifugal separator 217 toward the inner wall inside the body recovery body 212. Is done. The collected substance (fine powder) is dropped by the liquid shower from the vicinity of the ceiling 215 to the liquid tank 211 in which the liquid mainly composed of vacuum oil is stored, and becomes a precipitate in the liquid tank.

  Further, the automatic conveyor 213 has a horizontal moving part 213a and an obliquely upward moving part 213b, and the horizontal moving part 213a moves horizontally in the liquid covered by the liquid recovery body 212 so that the sediment in the tank is placed on the conveyor. The precipitate can be collected and carried out from the liquid surface of the liquid tank 211 to the outside by the obliquely upward moving portion 213b.

  Further, the liquid recovery body 212 is isolated from the outside air by the liquid in the liquid tank 211, and the liquid tank 211 serves to keep the inside of the liquid recovery body 212 at a reduced pressure level with the liquid level in the liquid recovery body 212. ing.

  Thereby, deposits can be collected without stopping the vacuum pump 24 due to the vacuum seal with liquid. This makes it possible to collect the precipitate without stopping the operation of the apparatus, which is efficient and reduces the running cost.

  The second liquid recovery apparatus 22 is connected to the vicinity of the ceiling 215 of the liquid recovery main body 212 of the first liquid recovery apparatus 21 by a pipe 218, and a liquid tank 221 in which a liquid mainly composed of vacuum oil is stored. And a liquid recovery body 222 that covers the upper part of the liquid tank 221 so as to form a decompression space therein. The liquid in the second liquid recovery device 22 is preferably the same liquid as the first liquid recovery device 21.

The liquid recovery main body 222 has a side wall 222a and a ceiling 222b. A pipe 218 from the first liquid recovery device 21 is connected to the side wall 222a, and the liquid stored in the liquid tank 221 in the liquid recovery main body 222 It has a shower part 223 that ejects the same liquid in the form of a shower from the vicinity of the ceiling, and a pipe 224 that has one end connected to the vicinity of the ceiling 222 b and the other end connected to the filter 23.
The inside of the liquid recovery body 222 is depressurized by the vacuum pump 24 through the filter 23 to 1 Torr to 760 Torr.

  Since the first liquid recovery device 21 has a liquid tank 211, the liquid coming from the liquid tank 211 and the fine powder, decomposition gas, toxic gas, and harmful substances that cannot be removed by the first liquid recovery device 21 when evacuated. Various substances are drawn. For this reason, in addition to the first liquid recovery apparatus 21, a second liquid recovery apparatus 22 as a powder settling tank is provided in front of the vacuum pump 24 of the recovery apparatus.

  The filter 23 filters various substances such as fine powder, decomposition gas, toxic gas, and harmful substances that cannot be removed by the second liquid recovery device 22. The filter 23 is connected to the second liquid recovery device 22 and the vacuum pump 24. Arranged between.

  The vacuum pump 24 uses a liquid mainly composed of vacuum oil that does not have a boiling point when the liquid recovery bodies 212 and 222 of the first and second liquid recovery devices 21 and 22 are in a reduced pressure space of, for example, 4 Torr. Is for. Of course, it is not limited to one vacuum pump 24, and for example, a plurality of vacuum pumps such as an oil seal pump such as a booster pump can be connected in series.

  The recovery device 10 can reduce the number of pumps such as the vacuum pump 24 because of the reduced pressure processing (1 Torr to 760 Torr), the equipment cost is low, the power consumption can be reduced, and the energy cost is low. Become. That is, according to the present invention, the equipment cost is reduced and the running cost is reduced. In addition, maintenance is also easy. Note that when processing is performed at a pressure close to 760 Torr (normal pressure), the liquid may be water. In this case, a water-sealed water seal pump is used instead of the vacuum pump 24. In that case, the incidental equipment is not changed.

The second reduced pressure evaporation furnace 14 is disposed between the first reduced pressure evaporation furnace 13 and the moving chamber 15. The blast furnace slag heated to 1850 ° C. in the first reduced pressure evaporation furnace 13 is converted into the melting point of TiO ₂ . 1870 ° C. or higher, and is heated to a temperature below the melting point of Al ₂ O ₃ . The inside of the second reduced pressure evaporation furnace 14 is reduced to 1 Torr to 760 Torr (normal pressure) like the first reduced pressure evaporation furnace 13.

Similar to the first vacuum evaporator 13, the second vacuum evaporator 14 is connected to the first liquid recovery device 31 by a pipe 35. As a result, the gas containing fine powder of TiO ₂ evaporated from the blast furnace slag heated to 1870 ° C. or higher in the second vacuum evaporator 14 to a temperature lower than the melting point of Al ₂ O ₃ is supplied to the first liquid recovery device 31. The TiO ₂ that has been pulled in and separated from the blast furnace slag is recovered as an oxide.

  Here, the first liquid recovery device 31, the second liquid recovery device 32, the filter 33, and the vacuum pump 34 connected to the second vacuum evaporation furnace 14 are structurally connected to the first vacuum evaporation furnace 13. The same as the connected first liquid recovery device 21, second liquid recovery device 22, filter 23, and vacuum pump 24.

However, the gas containing the fine powder of TiO ₂ is sucked into the first liquid recovery device 31 connected to the second reduced pressure evaporation furnace 14 through the pipe 35. The recovered material is also TiO _2.

  The moving chamber 15 is disposed between the second reduced pressure evaporation furnace 14 and the water tank cooling chamber 16, and cools the blast furnace slag carried out from the second reduced pressure evaporation furnace 14 to some extent and passes it to the water tank cooling chamber 16. Have a role.

  The water tank cooling chamber 16 is disposed after the moving chamber 15. For example, the water tank cooling chamber 16 is provided with a dropping device that automatically reverses the blast furnace slag loaded on the tray and drops only the blast furnace slag into the cooling water tank. This dropping device controls the reversal speed, etc. so that it drops little by little, because when the ultra-high temperature slag is put into a cooling water tank that stores a large amount of water at once, the water will expand greatly and cause a steam explosion. .

Next, a recovery method of TiO ₂ by the recovery device 10 will be described.
FIG. 3 is a flowchart showing a TiO ₂ recovery method.

The blast furnace slag discharged from the iron ore of the blast furnace for iron making is carried into the preheating furnace 11 of the recovery apparatus 10 as it is without cooling from the separated state, and the blast furnace slag is preheated to 1000 ° C. at normal pressure in the air ( Step 301).
Next, the blast furnace slag preheated to 1000 ° C. in the preheating furnace 11 is carried into the soaking furnace 12 and heated to 1700 ° C. at normal pressure in air (step 302).

Next, the blast furnace slag heated to 1700 ° C. in the soaking furnace 12 is carried into the first vacuum evaporator 13, and the pressure is reduced to 1 Torr to 760 Torr (normal pressure) in the first vacuum evaporator 13. Heat to a temperature lower than the melting point of ₂ (1870 ° C.) (step 303). Here, since the highest melting point among the substances described later is 1650 ° C. of SiO ₂ , it is heated to a temperature of 1680 ° C. to 1850 ° C., for example. Thereby, substances such as SiO ₂ , Fe oxide and sulfide having a melting point lower than that of TiO ₂ are evaporated and separated from the blast furnace slag into the gas (step 304).

In the case of recovering only SiO ₂ is, Fe oxides lower than the SiO ₂ mp melting point sulfide the two components to separate and recover the same kind of way as described above, then only the SiO ₂ 1650 ° C. ~ It is recovered alone at a temperature of 1850 ° C. and a pressure of 1 Torr to 760 Torr. By doing so, high-purity SiO ₂ can be obtained.

Fine powder in the gas, which is a substance such as SiO ₂ , Fe oxide, sulfide, etc., separated from the blast furnace slag, passes through the pipe 25 into the liquid recovery body 212 of the first liquid recovery device 21 by the vacuum pump 24. Aspiration is performed (step 305).

Substances (fine powder) such as SiO ₂ , Fe oxide, and sulfide sucked into the reduced pressure space inside the liquid recovery body 212 are collected by the centrifugal separator 217 toward the inner wall inside the liquid recovery body 212. The Then, the collected substance (fine powder) is dropped into the liquid tank 211 in which a liquid mainly composed of vacuum oil is stored by a liquid shower from the vicinity of the ceiling 215, and settles in the liquid tank 211 (step) 306). The liquid shower is preferably used by circulating the liquid.

The horizontally moving portion of the automatic conveyor 213 moves horizontally in the liquid to collect the substance precipitated in the liquid tank 211 on the conveyor, and the diagonally upward moving portion of the automatic conveyor 213 causes the SiO ₂ , Fe oxide, and sulfide. A precipitate such as a thing is carried out from the liquid surface of the liquid tank 211 to the outside and collected (step 307).

  The gas inside the liquid recovery body 212 of the first liquid recovery device 21 (gas containing various substances such as fine powder and decomposition gas that could not be removed by the first liquid recovery device 21) is supplied by the vacuum pump 24 described above. The liquid is sucked into the second liquid recovery device 22 (step 308). Accordingly, various substances are dropped into the liquid tank 221 by the shower in the liquid recovery main body 222 of the second liquid recovery apparatus 22 and are precipitated in the liquid tank 221. This deposit is collected from the cleaning port 225.

  When there is a substance that has not been recovered in the second liquid recovery device 22 as described above, it is filtered by the filter 23 provided in front of the vacuum pump 24 and finally discharged as a harmless gas (step) 309).

Next, the blast furnace slag heated to a temperature of 1680 ° C. to 1850 ° C. in the first vacuum evaporator 13 is carried into the second vacuum evaporator 14, and 1 Torr to 760 Torr in the second vacuum evaporator 14. The pressure is reduced to (normal pressure) and heated to a temperature not lower than the melting point of TiO ₂ (1870 ° C.) and lower than the melting point of Al ₂ O ₃ (step 310). For example, by using a temperature between directly above the melting point of TiO ₂ (1870 ° C.) and immediately below the melting point of Al ₂ O ₃ at 2050 ° C., the oxide of TiO ₂ can be recovered with high purity.

Accordingly, TiO ₂ is evaporated, is separated from the blast furnace slag in the gas (step 311). The following is the same as the recovery of SiO ₂ , Fe oxide, sulfide, etc., and the description thereof is omitted (Steps 312 to 316).

Next, the blast furnace slag heated to a temperature not lower than the melting point of TiO ₂ at 1870 ° C. and lower than the melting point of Al ₂ O ₃ by the second reduced pressure evaporation furnace 14 is carried into the moving chamber 15 (step 317). It cools with gas, such as air, and is carried in into the water tank cooling chamber 16 after that (step 318).
MgO, CaO, Al ₂ O _{3 and the} like cooled by this water tank cooling chamber are recovered as a residue (step 319).

  As described above, in the present invention, the blast furnace slag discharged from the iron ore of the blast furnace for iron making is carried into the preheating furnace 11, the soaking furnace 12, and the first vacuum evaporator 13 without being cooled from the separated state. As a result, the energy for heating in the preheating furnace 11 or the like can be kept small.

Further, in the first evaporation under reduced pressure furnace 13 is heated to a temperature lower than the melting point of the TiO _2, the melting point is carried into the second vacuum evaporation furnace 14 after the separation of the lower substance than TiO ₂ from the blast furnace slag, since further the heating to the melting point of the TiO _2, it can be easily and TiO ₂ separated and recovered. Therefore, by separating and recovering precious TiO ₂ oxides and effectively using blast furnace slag as industrial waste as a resource, the amount of industrial waste and the like can be reduced at the same time to make up for the lack of rare metal. .

  Further, the preheating furnace 11, the soaking furnace 12, the moving chamber 15, and the water tank cooling chamber 16 are all an atmospheric pressure oxidation furnace or an atmospheric pressure oxidation chamber in the air. Only the first and second reduced pressure evaporation furnaces 13 and 14 and the first and second liquid recovery apparatuses (liquid recovery main body) related facilities serve as a reduced pressure chamber. Therefore, as compared with a case where all are vacuum chambers (the entire furnace apparatus is a vacuum apparatus), there are many oxidation furnaces, equipment is low, and running costs are low.

In addition to recovering useful substances and the like with the first liquid recovery device as a recovery device, a second liquid recovery device and a filter are also provided. This becomes a pollution prevention device and reduces the capacity of the vacuum pump. Prevents and further reduces the failure and prolongs pump life.
Furthermore, since the number of vacuum pumps for reducing pressure processing (1 Torr to 760 Torr) is small, the equipment cost is low and the amount of power used is low, resulting in an inexpensive energy cost.
The embodiment of the present invention has been described above, but the present invention is not limited to this, and various modifications can be made based on the technical idea of the present invention.

The energy at the time of the above-mentioned slag cooling is very large, and the water in the cooling water tank constantly boils. Therefore, it is preferable to provide a steam power generation device (reference numeral 17 in FIG. 1) that performs steam power generation using the boiling water. Thus, the generated electricity can be used as electricity for this equipment or can be diverted to other purposes, thereby saving energy and reducing running costs.
For example, the recovered TiO ₂ may be configured to directly recover metallic Ti by a method such as a Kroll method or a Hunter method such as an electrolytic method of a 2000 ° C. melt in a separate chamber using the recovered high temperature.
The apparatus shown in the above embodiment is basically a continuous furnace, but may be constituted by a single furnace in the case of low frequency heating or plasma heating.

DESCRIPTION OF SYMBOLS 10 Recovery apparatus 11 Preheating furnace 12 Soaking furnace 13 1st vacuum evaporator 14 2nd vacuum evaporator 15 Moving chamber 16 Water tank cooling chamber 21, 31 1st liquid recovery apparatus 22, 32 2nd liquid recovery apparatus 23 33, Filters 24, 34 Vacuum pump 211 Liquid tank 213 Automatic conveyor 216 Shower unit 217 Centrifugal separator

Claims (11)

The blast furnace slag discharged from the iron ore of the blast furnace for iron making is heated from the discharged state to a temperature lower than the melting point of TiO ₂ as it is without cooling, and a substance having a melting point lower than that of TiO ₂ is added. Separating and removing from the blast furnace slag,
The blast furnace slag in which the material has been removed in the TiO ₂ above the melting point, the melting point of TiO ₂ contained in the blast furnace slag is heated to a temperature below the melting point of the high melting point material, separating the TiO ₂ from the blast furnace slag Recovery method to recover oxide as it is. The recovery method according to claim 1,
The step of separating the TiO ₂ from the blast furnace slag and recovering the oxide as it is includes precipitating the fine powder of TiO ₂ into a liquid from the gas containing the fine powder of TiO ₂ separated from the blast furnace slag, Collection method. The recovery method according to claim 2,
The step of precipitating the TiO ₂ fine powder into the liquid is to collect the TiO ₂ fine powder from the gas containing the TiO ₂ fine powder using a centrifugal force, and to shower the collected TiO ₂ fine powder. A recovery method of ejecting and precipitating in the liquid. It is the collection | recovery method of any one of Claims 1-3,
The step of separating and removing the substance having a melting point lower than the melting point of TiO ₂ from the blast furnace slag and the step of separating the TiO ₂ from the blast furnace slag and recovering it as an oxide are performed under reduced pressure in the range of 1 Torr to 760 Torr or Recovery method performed under normal pressure. A first furnace for heating a blast furnace slag discharged from an iron ore of a blast furnace for iron making to a temperature lower than the melting point of TiO ₂ as it is without performing a cooling process from the discharged state;
Means for removing from the first furnace the material evaporated from the blast furnace slag by the heating;
A _second furnace for heating the blast furnace slag from which the substance has been removed to a temperature that is equal to or higher than the melting point of TiO ₂ and lower than the melting point of the substance having a melting point higher than that of TiO ₂ contained in the blast furnace slag;
And a means for recovering TiO ₂ evaporated from the blast furnace slag by the heating as an oxide. The recovery device according to claim 5,
The recovery means has a liquid tank for precipitating TiO ₂ fine powder evaporated from the blast furnace slag into a liquid,
The liquid tank has a sediment recovery unit in which a liquid surface is exposed to the outside. The recovery device according to claim 6,
A recovery apparatus further comprising a conveyor disposed in the liquid in the liquid tank and configured to carry the precipitate precipitated in the liquid tank to the outside via the precipitate recovery unit. The recovery device according to claim 6,
Is placed on top of the liquid surface of the liquid bath, a gas containing a fine powder of TiO _2, a centrifugal separation means for the dust collecting a fine powder of TiO ₂ with the centrifugal force,
And a shower means for spraying a shower on the collected fine powder of TiO ₂ and precipitating it into the liquid. It is a recovery device given in any 1 paragraph among Claims 5-8,
The first and second furnaces are under a reduced pressure or a normal pressure in a range of 1 Torr to 760 Torr. It is a collection device given in any 1 paragraph among Claims 5-9,
A water tank cooling chamber for cooling the blast furnace slag after TiO ₂ is recovered by the recovery means;
And a power generation device that generates electric power using boiling water in the water tank cooling chamber. It is the collection | recovery method of any one of Claims 1-4,
The step of separating and removing the substance having a melting point lower than the melting point of TiO ₂ from the blast furnace slag removes each metal oxide and sulfide constituting the substance at a reduced pressure for each metal oxide and sulfide. A collection method that separates and collects each melting point separately.

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