KR20230135341A - Method of recovering metal from furnace dust and apparatus for manufacturing the same - Google Patents

Abstract

The present invention relates to a method for recovering metal from steelmaking dust, which sequentially recovers zinc and pig iron from steelmaking dust or DRI manufactured by processing steelmaking dust. The present invention provides a method comprising a first step of roasting steelmaking dust, a second step of performing heat treatment in an inert atmosphere after the first step, a third step of recovering gaseous matter generated from the second step, a fourth step of adding flux to the residue of the third step and heat treating the same, and a fifth step of recovering melt from the slag generated in the fourth step.

Description

Metal recovery method from steelmaking dust and manufacturing device thereof {METHOD OF RECOVERING METAL FROM FURNACE DUST AND APPARATUS FOR MANUFACTURING THE SAME}

The present invention relates to a method for recovering metal from steelmaking dust, and more specifically, recovering metal from steelmaking dust or DRI generated by processing steelmaking dust using a roasting and zinc reduction distillation process device and a crucible device for pig iron recovery. It's about how to do it.

Steelmaking dust is Electric Arc Furnace Dust (EAFD), which is one of the domestic designated wastes. It refers to dust that is inevitably generated in high-temperature electric furnaces at 1,600°C during steel production. When producing 1 ton of iron, more than 15 to 25 kg of dust is generated. As crude steel production in 2018 was about 25 million tons, the amount of dust generated is estimated to be more than 400,000 tons, and the zinc content is about 25%, which is 100,000 tons per year. More than a ton of zinc is generated in the form of dust. Steel dust is currently designated as hazardous waste in major countries, and waste treatment/management is regulated, and various treatment technologies are being developed accordingly.

In particular, steel dust is still used domestically for cement mixing and road paving, but landfilling is currently prohibited overseas due to the issue of heavy metal hazards. Recently, in Korea, various recycling technologies such as zinc oxide and crude zinc oxide are being developed using steelmaking dust, and related companies are also active.

Steelmaking dust varies somewhat depending on the type of scrap iron or processing method, but contains approximately 20-40% zinc (Zn), 10-2% iron (Fe), and lead (Pb), manganese (Mn), and copper ( It contains heavy metals such as Cu) and cadmium (Cd), as well as anions such as chlorine (Cl) and fluorine (F). ZnO is obtained by reducing and distilling Zn into gaseous phase using a rotary reduction kiln, which is called crude zinc oxide (ZnO > 75 wt%). When manufacturing crude zinc oxide, process by-products are generated in the rotary reduction kiln, and this by-product of steelmaking dust treatment is direct reduction iron (reduced iron, 2-6 wt% Zn, 40-60 wt% Fe; DRI).

Steel dust treatment DRI is treated as waste without a separate treatment process and used as landfill, construction, cement material mixture, or road paving material. Currently, about 60,000 tons of by-products (DRI) from the steel dust treatment process are generated annually in Korea, and due to the lack of treatment technology and social interest, they are disposed of by relying on landfill. The by-products of this process contain approximately 5% Zn and 50% Fe, and these by-products are currently processed at a cost of 200,000 to 300,000 won per ton, resulting in an annual cost of more than 10 billion won. Problems of surrounding soil and water pollution caused by landfill are emerging, and the need to develop recycling technology for waste disposed of by landfill is increasing. In addition, when disposed of by landfill, it contains a large amount of iron and zinc, so if it is simply landfilled without extracting the valuable metals, significant economic losses will occur.

Methods for recycling steelmaking dust are divided into dry processing, wet processing, and dry/wet processing, and are used according to the characteristics of the product being manufactured. Dry treatment methods are classified into kiln type, melt reduction type, rotary hearth type, shaft type, etc. depending on the shape of the furnace used. The wet treatment method is a method of recovering zinc by leaching it through chemical methods such as acid and base solutions. Recently, steel dust treatment technology that combines dry/wet processes is being used as an alternative to complement the shortcomings of dry and wet smelting processes.

Existing recycling technology is a process step that creates crude zinc oxide from steelmaking dust. There was no recycling technology for reduced iron (DRI), a secondary by-product generated after the recycling process to recover crude zinc oxide. Accordingly, approximately 60,000 tons of process by-products (DRI) generated after the steel dust recycling process depend on landfill and cover soil use each year. The resulting landfill cost is 200,000 to 300,000 won/ton.

Among the technologies used to manufacture crude zinc oxide, the hydrometallurgical method generates wastewater containing toxic substances during the process. Wastewater treatment costs have a negative impact on manufacturing costs and further cause environmental pollution. Additionally, the process is complex, and if a problem occurs in one step of the process, the entire process needs to be shut down.

One object of the present invention is to provide a method for sequentially recovering zinc and pig iron from steelmaking dust or DRI manufactured by processing steelmaking dust.

Another object of the present invention is to provide a roasting and zinc reduction distillation process apparatus.

As one aspect, the present invention includes a first step of roasting steelmaking dust, a second step of heat treatment in an inert atmosphere after the first step, a third step of recovering gaseous matter generated from the second step, and the first step of heat treatment in an inert atmosphere. A method for recovering metal from steelmaking dust is provided, comprising a fourth step of adding flux to the residue of step three and heat treating it, and a fifth step of recovering melt from the slag generated in the fourth step.

The steelmaking dust may be DRI (Direct Reduction Iron) manufactured by reducing steelmaking dust. Steelmaking dust and DRI contain various impurities and metals, including iron (Fe) and zinc (Zn).

The metal recovered by the method for recovering metal from steelmaking dust may be zinc and iron.

The first step is a roasting process to remove impurities and low-melting point elements, and the temperature conditions can be used at a temperature that can remove impurities and low-melting point elements but does not vaporize zinc, preferably between 500°C and 900°C. It may be ℃. The atmosphere may preferably be an air atmosphere in which vaporized impurities and low melting point elements can be discharged. The reaction holding time is a time for efficiently removing impurities and low melting point elements, and is preferably 1 hour to 5 hours.

The second step and the third step may be a process for selectively recovering zinc in powder form by reducing zinc from steelmaking dust or DRI manufactured by treating steelmaking dust in an inert atmosphere.

The temperature of the second step is a temperature at which zinc can be selectively distilled, and may preferably be 900°C to 1,100°C. The atmosphere can be used to prevent oxidation of zinc and to recover zinc vapor in powder form through gas convection. Preferably, it may be an inert atmosphere, and more preferably, it may be an argon (Ar) atmosphere. there is. The holding time is a holding time that can increase the selective distillation recovery rate of zinc, and is preferably 2 to 5 hours.

A reducing agent may be further added to reduce and distill zinc oxide (ZnO) before or after the second step, and the reducing agent may be carbon powder.

In the third step, the zinc reduced and distilled in the second step can be obtained in powder form.

The fourth step and the fifth step are processes for manufacturing pig iron, and pig iron can be recovered from steelmaking dust or DRI from which zinc is recovered.

In the fourth step, the flux is added to remove impurities including aluminum (Al) in the form of slag, and may preferably include calcium oxide (CaO) and silicon oxide (SiO ₂ ). The temperature in the fourth step is the temperature for reducing melting of iron oxide and forming slag, and is preferably 1,600°C to 1,700°C.

In the fourth step, a reducing agent may be further added to reduce iron oxide to produce pig iron, and the reducing agent may be carbon powder. In order to increase the iron content in pig iron, a reducing agent may be added at an optimal ratio. Preferably, the ratio of DRI to carbon powder may be 5:1 to 20:1.

The first, second, and third steps may use roasting and zinc reduction distillation process equipment. During the roasting process, vaporized impurities and low melting point elements can be removed by operating a motor in an atmospheric atmosphere to apply pressure and opening the first valve of the first gas out line. During zinc reduction distillation, the first valve of the first gas out line is closed and the second valve of the second gas out line is opened in an argon atmosphere to generate convection to move zinc vapor and collect zinc powder.

In the fourth and fifth steps, pig iron can be selectively separated and recovered from slag using a crucible device for recovering pig iron.

As another aspect, the present invention includes a conveyor belt composed of a plurality of unit belts arranged in one direction and a reactor through which the conveyor belt passes, the reactor having a first valve formed. 1 A zinc metal recovery device in which a second gas outline with a gas out line and a second valve is installed, and a gate is formed between the unit belts at the start and end of the reactor to seal the inside of the reactor. provides.

A hopper is installed at the beginning of the conveyor belt to input the raw materials, and a residue recovery area is formed at the end of the conveyor belt to recover residues from which the reaction has been completed in the reactor.

The reactor is divided into a first area and a second area, a first heater and a first gas outline are formed in the first area, and a second heater and a second gas outline are formed in the second area, The first heater and the second heater are heated independently, and the first valve of the first gas outline and the second valve of the second gas outline can be operated independently.

A gate may be formed between the first region and the second region of the reactor to separate and seal the regions, and the gate may be formed between unit belts.

Zinc vapor generated by the reducing agent and heating reaction in the reactor may be discharged through the second gas outline. The second gas outline may be connected to the zinc condensing means, whereby zinc vapor generated in the reactor can be injected into the zinc condensing means through the zinc vapor discharge line.

The zinc condensing means may include an outer tube and an inner tube located inside the outer tube. A sliding rail may be formed on the outer tube to slide and detach the inner tube, so that the inner tube may be detachable from the outer tube. In other words, when recovering zinc, the zinc powder can be easily recovered by separating the inner tube from the outer tube.

A partition may be formed in the inner tube to increase the area in contact with zinc in a gaseous state to induce condensation of zinc. The number of partition walls formed in the inner tube is not limited, but preferably, multiple partitions may be formed. A plurality of partition walls may be formed in a zigzag pattern on the upper and lower sides of the inner tube. This means that by forming a plurality of partition walls at positions that continuously block the movement path of the zinc in the gaseous state flowing inside the inner tube, the zinc in the gaseous state continues to flow. When it hits a plurality of partition walls, it can condense into powdered zinc.

As another aspect, the present invention includes the steps of introducing steelmaking dust and a reducing agent into a reactor through a conveyor belt, closing the gate of the reactor to seal the inside of the reactor, and heating the inside of the reactor using a heater of the reactor. Performing a roasting process by raising the temperature to a first temperature, applying pressure inside the reactor to discharge impurities and vapors of low melting point metal elements generated in the roasting process through a first gas out line, the first gas Closing the out line and raising the inside of the reactor to a second temperature to generate zinc vapor, the zinc vapor is discharged through the second gas out line and recovered in the form of zinc powder in the zinc condensing means, A method for recovering zinc from steelmaking dust using a zinc metal recovery device is provided, wherein the second temperature is higher than the first temperature.

According to the present invention, steelmaking dust and by-products generated by processing steelmaking dust can be stably treated, zinc and pig iron for each application can be produced, and the environmental pollution reduction effect can be realized by applying the technology of the present invention to other industrial wastes.

In addition, it can recycle metal resources such as zinc and iron and replace imported raw materials, and by recycling landfilled or untreated steel dust, new economic effects, resource recycling, and environmental preservation effects can be realized for processing companies.

1 is a process diagram of a method for recovering metal from steelmaking dust or steelmaking dust treated DRI according to the present invention.
Figure 2 is a graph showing the reduction temperature conditions of zinc oxide (ZnO) in the Ellingham-diagram.
Figure 3 is an XRD graph of recovered zinc (Zn) powder.
Figure 4 is a Al ₂ O ₃ -CaO-SiO ₂ ternary phase diagram.
Figure 5 is a FeO-CaO-SiO ₂ ternary phase diagram.
Figure 6 is a top view of a zinc metal recovery device.
Figure 7 is a side view of the zinc metal recovery device.
Figure 8 is a perspective view showing the shape of the inner tube.
Figure 9 is a perspective view showing the inner tube of Figure 8 in an open state.
Figure 10 is a side view of a crucible device for pig iron recovery.

Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings. Since the present invention can be subject to various changes and have various forms, specific embodiments will be illustrated in the drawings and described in detail in the text. However, this is not intended to limit the present invention to a specific disclosed form, and should be understood to include all changes, equivalents, and substitutes included in the spirit and technical scope of the present invention. While describing each drawing, similar reference numerals are used for similar components.

The terms used in this application are only used to describe specific embodiments and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly dictates otherwise. In this application, terms such as “comprise” or “have” are intended to designate the presence of features, steps, operations, components, parts, or combinations thereof described in the specification, but are not intended to indicate the presence of one or more other features or steps. , it should be understood that it does not exclude in advance the possibility of the existence or addition of operations, components, parts, or combinations thereof.

Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by a person of ordinary skill in the technical field to which the present invention pertains. Terms defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning in the context of the related technology, and unless explicitly defined in the present application, should not be interpreted in an ideal or excessively formal sense. No.

Hereinafter, the content of the present invention will be further described along with specific examples.

Example 1: Method for recovering metal from DRI generated by reducing steelmaking dust

The XRF component analysis results of DRI generated by reducing steelmaking dust (hereinafter referred to as steelmaking dust treatment DRI) are shown in Table 1 below.

Element Na Mg Al Si P S Cl wt% 2.02 6.04 1.94 3.78 5.64 2.22 6.06 Element Cr Mn Fe Ni Cu Zn Br wt% 0.876 5.74 54.7 0.0947 0.565 9.75 0.231 Element Pb Ca Zr K Sr. wt% 1.17 6.29 0.0205 3.37 0.0290

Looking at Table 1, steel dust treated DRI contains 54.7% iron and 9.75% zinc, and in addition, heavy metals such as lead, manganese, copper and cadmium, as well as anions such as chlorine and fluorine. You can check what it contains.

Figure 1 is a process diagram of a method for recovering metal from steelmaking dust or steelmaking dust treated DRI of the present invention, Figure 2 is a graph showing the reduction temperature conditions of zinc oxide (ZnO) in the Ellingham-diagram, and Figure 3 is zinc (ZnO) reduction temperature conditions. ) This is an XRD graph of the powder, Figure 4 is an Al ₂ O ₃ -CaO-SiO ₂ ternary phase diagram, and Figure 5 is a FeO-CaO-SiO ₂ ternary phase diagram.

Referring to Figures 1, 2, 3, 4, and 5, iron and zinc can be recovered from steelmaking dust treated DRI. The method of recovering metal from steelmaking dust treated DRI includes a first step of roasting the steelmaking dust treated DRI, a second step of heat treatment in an inert atmosphere after the first step, and recovery of gaseous matter generated from the second step. It provides a method for recovering metal from steelmaking dust, comprising a third step, a fourth step of heat treating the residue of the third step by adding flux, and a fifth step of recovering melt from the slag generated in the fourth step. .

First, in the first step, a roasting process can be performed on the steelmaking dust treated DRI. The roasting process is a process to cause a chemical reaction on the surface of iron ore at a high temperature that does not dissolve the ore, so that reduction can be achieved easily and to crack the surface of the ore to facilitate crushing. Impurities and low melting point in steel dust treatment DRI are removed. The purity of zinc and pig iron can be improved by removing metals. The temperature conditions for the roasting process can be a temperature that can remove impurities and low melting point elements while preventing zinc from vaporizing, and is preferably 500 to 900°C. The atmosphere of the roasting process may preferably be an air atmosphere so that vaporized impurities and low melting point elements can be discharged. The maintenance time of the roasting process is for efficiently removing impurities and low melting point elements, and is preferably 1 to 5 hours. Impurities and low melting point metals can be removed in a vapor state by the roasting process. The XRF component analysis results of DRI after the roasting process can be found in Table 2 below.

Element Result(%) Na 2.31 Mg 1.75 Al 1.47 Si 5.44 P 0.204 S 2.25 Cl 2.75 K 0.22 Ca 6.29 Cr 0.876 Mn 5.76 Fe 58.4 Ni 0.0947 Cu 0.565 Zn 9.86 Br 0.231 Sr. 0.0290 Zr 0.0205 Pb 1.43

Iron increased from 54.7% before roasting to 58.4% after the roasting process, and zinc increased from 9.75% before roasting to 9.86% after the roasting process. Conversely, chlorine decreased from 6.06% to 2.75% and potassium decreased from 3.37% to 0.22%. This means that impurities including chlorine and potassium and low melting point metals were removed through the roasting process.

In the second and third steps, a zinc reduction distillation process can be performed. In the zinc reduction distillation process, zinc powder in the steelmaking dust treated DRI is reduced and distilled in an inert atmosphere to selectively recover zinc powder. The conditions for reduction distillation of zinc were established through Ellingham-diagram and thermodynamic mechanism analysis. The temperature of the zinc reduction distillation process was calculated under temperature conditions at which zinc can be selectively distilled. Preferably, the temperature of the zinc reduction distillation process may be 900 to 1,100°C. The atmosphere of the zinc reduction distillation process was maintained in an inert atmosphere to prevent oxidation of zinc and to recover zinc vapor in powder form through gas convection. Preferably, argon (Ar) gas can be used. At this time, the flow rate can be maintained at 1,000 to 4,000 cc/min. The maintenance time of the zinc reduction distillation process is the optimal time to increase the selective distillation recovery rate of zinc, and is preferably 2 to 5 hours. To reduce zinc oxide (ZnO), carbon powder can be added as a reducing agent, and to reduce and distill zinc oxide, the ratio of raw material to reducing agent can be used at a ratio of 100:1 to 100:4. Zinc oxide is reduced to zinc vapor by a reducing agent, and zinc vapor can be recovered in the form of zinc powder using a zinc condensation means. The results of analyzing the residue after recovering zinc from DRI can be seen in Table 3 below.

Element Result(%) _{Fe2O3 _} 67.2 CaO 8.12 SiO ₂ 6.86 Al ₂ O ₃ 4.3 MgO 2.57 MnO ₂ 6.52 Na ₂ O 1.87 _K2O 0.1 Cr ₂ O ₃ 1.03 SO ₃ 0.75 P ₂ O ₅ 0.24 CuO 0.27 ZnO 0.14

In the residue, iron oxide (Fe ₂ O ₃ ) was found to contain the most at 67.2%, and zinc oxide (ZnO) was found to be mostly recovered at 0.14% and did not remain. Additionally, it can be confirmed that impurities such as calcium (Ca), silicon (Si), aluminum (Al), magnesium (Mg), and manganese (Mn) remain.

The fourth and fifth steps are pig iron manufacturing processes, and pig iron can be manufactured by manufacturing synthetic slag, controlling impurities, and reducing only iron oxide.

First, flux may be added to the residue, and the flux is intended to remove impurities such as aluminum (Al) into slag. Flux additives were selected through thermodynamic mechanism analysis, and calcium oxide (CaO) and silicon oxide (SiO ₂ ) are preferably used. At this time, the flux ratio can be adjusted to increase the iron content in the pig iron. Preferably, the ratio of SiO ₂ :CaO may be 10:3 to 10:20.

A reducing agent may be added to reduce iron oxide to iron, and carbon powder may be preferably used. The optimal addition ratio of the reducing agent can be applied to increase the iron content in the pig iron. Preferably, the ratio of DRI:carbon powder may be 5:1 to 20:1.

Melting conditions and slag composition were established based on the Al ₂ O ₃ -CaO-SiO ₂ ternary phase diagram and the FeO-CaO-SiO ₂ ternary phase diagram. The temperature condition is a temperature for reduction melting of iron oxide and slag composition, and may preferably be 1,600 to 1,700°C. The optimal holding time can be applied to increase the recovery rate of iron, and is preferably 5 to 30 minutes.

When flux is added to the residue and melted, slag containing impurities may be formed in the melt. The melt present at the bottom of the slag may be pig iron. The XRF component analysis results of the recovered pig iron can be found in Table 4 below.

Element wt% Mg 0.219 Al 0.174 Si 11.3 P 0.0299 S 0.0747 Cl 0.0870 Ca 0.138 Cr 0.0642 Mn 0.0590 Fe 87.7 Co 0.0661 Ni 0.0772 Cu 0.103

It can be seen that the percentage of iron in pig iron is the highest at 87.7%. In addition, silicon showed the highest content among impurities at 11.3%, but it can be seen that most impurities were detected in trace amounts of less than 0.25%.

Table 5 below shows the results of iron and zinc in the XRF component analysis of slag.

Element wt% Fe 0.0150 Zn 0.011

You can check the extent of iron and zinc contained in the slag. It was found that the iron and zinc contained were less than 0.02% and were hardly included in the slag.

Device 1: Zinc metal recovery device

Figure 6 is a top view of the zinc metal recovery device, Figure 7 is a side view of the zinc metal recovery device, Figure 8 is a perspective view showing the shape of the inner tube, and Figure 9 is a perspective view showing the inner tube of Figure 8 in an open state.

Referring to FIGS. 6, 7, 8, and 9, the zinc metal recovery device 1000 includes a conveyor belt 1200 composed of a plurality of unit belts 1210 arranged in one direction, and a conveyor belt 1200 passing through the conveyor belt 1200. It may be composed of a reactor 1300. Raw materials may be moved to the reactor 1300 by the conveyor belt 1200, perform a reaction, and then exit out of the reactor 1300. The reactor 1300 includes a first gas out line (Gas out lint, 1310), a first valve that can open and close the first gas out line (1310), a second gas out line (1320), and a second gas. A second valve capable of opening and closing the outline line 1320 may be formed. Additionally, a heater may be installed to heat the temperature inside the reactor 1300. The heater may be formed within the wall of the reactor 1300 or may be formed inside the reactor 1300, but is not limited thereto. This can be done anywhere where the temperature of the reactor can be easily controlled. A gate is formed at the start and end of the reactor 1300 to block the unit belts 1210, thereby sealing the interior of the reactor 1300. The specific configuration will be described later.

A hopper (1100) may be installed at the starting end of the conveyor belt 1210 to facilitate the input of raw materials. The hopper 1100 may have a general funnel shape, but is not limited to this. Raw materials introduced through the hopper 1100 can be placed in a box and moved to the reactor 1300 by the conveyor belt 1200. The raw materials moved into the reactor 1300 undergo a reaction, and the residue upon completion of the reaction is moved to the residue recovery location 1400 by the conveyor belt 1200 to recover the residue.

The reactor 1300 may include an input gate (1330) and an output gate (1340) that allow input and output of raw materials and maintain the interior of the reactor in a vacuum state. A heater is installed in the reactor 1300, so that the temperature can be adjusted to a constant temperature during the roasting and zinc reduction distillation processes. The location of the heater may be formed within the reactor wall or inside the reactor, but is not limited thereto. A first gas outline (Gas out line, 1310), a second gas outline (1320), and a gas inlet line (Gas inlet line (not shown in the drawing)) may be formed on the upper part of the reactor 1300. The reactor 1300 includes a motor and can remove impurities and low melting point elements vaporized through the gas outline 1310 by applying a constant pressure in an atmospheric atmosphere during roasting. In order to create an oxygen-free atmosphere during the zinc reduction distillation process, the gas inside the reactor 1300 may be discharged and argon gas may be injected.

A second gas out line 1320 is disposed at the top of the reactor 1300 to discharge zinc vapor generated within the reactor 1300. During zinc reduction distillation, the first gas outline 1310 is closed and the discharge portion (not shown in the drawing) formed at the upper end of the zinc condensing means 1321 is opened in an argon atmosphere to generate convection, thereby discharging zinc vapor. Zinc powder can be collected by moving it to the zinc condensing means 1321 through the line 1320.

Additionally, the reactor 1300 may be composed of a first area where a roasting process is performed and a second area where a zinc recovery process is performed. At this time, the conveyor belt 1200 may move the raw material box from the first section to the second section. A gate separating the two sections may be formed between the unit belts 1210 of the first section and the second section, and thereby the first section and the second section may be sealed, respectively. Heaters and gas pipes necessary for roasting and zinc recovery processes may be formed in the first section and the second section, respectively. Accordingly, the raw material box in which the roasting process has been completed in the sealed first section can be moved along the conveyor belt to another sealed second section to perform the zinc recovery process.

The zinc condensing means 1321 may be composed of an exterior and inner tubes 135 and 137 located inside the exterior. Rails for sliding the inner tubes 135 and 137 are formed on the exterior, so the inner tubes 135 and 137 can be detached from the exterior. An opening may be formed on the exterior so that the inner tubes 135 and 137 can be taken out. At least one attachable partition may be formed in the inner tubes 135 and 137 by condensing zinc vapor. Additionally, a plurality of partition walls 135a, 137a, and 137b may be formed, and a plurality of partition walls 135a, 137a, and 137b may be formed in a zigzag pattern on the upper side 135 and lower side 137 of the inner tube. Zinc vapor that has passed through the inner tubes 135 and 137 is recovered, and other components continue to flow until they reach the end of the outer tube and can be discharged to the outside through the discharge part.

The inner tube may include an upper member 135 and a lower member 137. Depending on the number of partitions 135a formed on the upper member 135 and the partitions 137a and 137b formed on the lower member 137, the lengths of the upper member 135 and the lower member 137 may be different. However, it is not limited to this. In addition, the shape of the inner tube is shown as a cylindrical shape, but it is not limited to this, and it is possible to change the shape of the inner tube in accordance with the external shape.

The interior of the upper member 135 and lower member 137 of the inner tube can be opened so that the condensed and attached zinc can be recovered. To this end, the upper member 135 and the lower member 137 may be connected with a hinge.

Device 2: Crucible device for pig iron recovery

Figure 10 is a side view of a crucible device for pig iron recovery.

Referring to FIG. 10, the crucible device 2000 for recovering pig iron includes a crucible 2100 into which the residue and plus are input, a silicon carbon (SiC) nozzle 2200 extending from the crucible, and a device for opening and closing the silicon carbon nozzle. It may be composed of a gate valve 2300.

Residue, flux, and reducing agent may be added to the crucible 2100. The crucible 2100 and the gate valve 2300 may be made of mullite, but are not limited thereto. The residue may be steelmaking dust from which zinc was recovered or steel dust-treated DRI, and preferably, may be steelmaking dust-treated DRI from which zinc was recovered. The flux may be a material containing calcium oxide and silicon oxide. The reducing agent may be carbon powder. Sludge may be formed in the upper part of the crucible 2100 by the flux, and pig iron may be formed in the lower part of the crucible 2100 by the reducing agent. At this time, when the gate valve 2300 is opened, the pig iron in the lower part of the crucible is discharged through the nozzle 2200, thereby allowing the pig iron to be selectively separated from the sludge formed in the upper part of the crucible.

Although the present invention has been described above with reference to preferred embodiments, those skilled in the art can make various modifications and changes to the present invention without departing from the spirit and scope of the present invention as set forth in the following patent claims. You will understand that it is possible.

135: upper member
135a: bulkhead
137: lower member
137a: bulkhead
137b: Bulkhead
1000: Roasting and zinc reduction distillation process equipment
1100: Hopper
1200: conveyor belt
1300: reactor
1310: Gas outline
1320: Zinc vapor discharge line
1321: Zinc condensation means
1400: Residue recovery location
2000: Crucible equipment for pig iron recovery
2100 : Crucible
2200: nozzle
2300: gate valve

Claims (22)

A first step of roasting steelmaking dust;
After the first step, a second step of heat treatment in an inert atmosphere;
A third step of recovering gaseous matter generated from the second step;
A fourth step of adding flux to the residue of the third step and heat treating it; and
Comprising a fifth step of recovering melt from the slag generated in the fourth step,
Metal recovery method from steelmaking dust. According to paragraph 1,
The steelmaking dust is characterized in that DRI (Direct Reduction Iron) generated by reducing steelmaking dust is used.
Metal recovery method from steelmaking dust. According to paragraph 1,
Characterized in that the recovered metals are zinc and iron,
Metal recovery method from steelmaking dust. According to paragraph 3,
The temperature conditions of the first step are 500 ℃ to 900 ℃,
The atmosphere of the first stage is an air atmosphere,
The holding time of the first step is 1 hour to 5 hours,
Characterized in removing impurities and low melting point elements by the first step,
Metal recovery method from steelmaking dust. According to paragraph 3,
The temperature of the second step is 900 ℃ to 1,100 ℃,
The atmosphere of the second stage is an inert atmosphere,
Characterized in that the holding time of the second step is 2 to 5 hours.
Metal recovery method from steelmaking dust. According to clause 5,
Characterized in that the inert atmosphere is an argon (Ar) gas atmosphere,
Metal recovery method from steelmaking dust. According to clause 5,
A reducing agent is added before the second step or a reducing agent is added after the second step,
Characterized in that the reducing agent is carbon powder,
Metal recovery method from steelmaking dust. According to paragraph 3,
The metal recovered in the third step is zinc,
Characterized in that the zinc is obtained in powder form,
Metal recovery method from steelmaking dust. According to paragraph 3,
In the fourth step, the flux includes calcium oxide (CaO) and silicon oxide (SiO ₂ ),
The temperature of the fourth step is 1,600 ℃ to 1,700 ℃,
Characterized in that the impurities containing aluminum (Al) are removed in the form of slag by the fourth step.
Metal recovery method from steelmaking dust. According to clause 9,
In the fourth step, a reducing agent is added,
The reducing agent is carbon powder,
Characterized in that the ratio of the steelmaking dust and the reducing agent is 5:1 to 20:1,
Metal recovery method from steelmaking dust. According to paragraph 3,
Characterized in recovering iron from the fifth step,
Metal recovery method from steelmaking dust. According to paragraph 1,
The first, second and third steps are characterized in that roasting and zinc reduction distillation process equipment are used.
Metal recovery method from steelmaking dust. According to paragraph 1,
The fourth and fifth steps are characterized in that a crucible device for recovering pig iron is used.
Metal recovery method from steelmaking dust. Conveyor belt consisting of a plurality of unit belts arranged in one direction; and
It includes a reactor through which the conveyor belt passes,
The reactor is installed with a first gas out line having a first valve and a second gas outline having a second valve,
The reactor is installed with a heater that can control the temperature inside the reactor,
A gate is formed between the unit belts at the start and end of the reactor so that the inside of the reactor can be sealed.
Zinc metal recovery unit. According to clause 14,
A hopper is installed at the starting end of the conveyor belt to input the raw materials,
Characterized in that a residue recovery area is formed at the end of the conveyor belt to recover residues from which the reaction has been completed in the reactor.
Zinc metal recovery unit. According to clause 14,
The reactor is divided into a first zone and a second zone,
Moved from the first area to the second area by the conveyor belt,
A first heater and a first valve of a first gas outline are formed in the first area,
A second heater and a second valve of the second gas outline are formed in the second area,
The first heater and the second heater are heated separately,
Characterized in that the first valve and the second valve operate separately,
Zinc metal recovery unit. According to clause 16,
A gate is formed to separate and seal the first region and the second region of the reactor,
Characterized in that the gate is formed between the unit belts,
Zinc metal recovery unit. According to clause 14,
The second gas outline is connected to a zinc condensing means,
Characterized in that the zinc condensing means includes an exterior and an inner tube located inside the exterior.
Zinc metal recovery unit. According to clause 18,
The inner tube is removable from the outer tube,
Characterized in that a sliding rail is formed on the exterior so that the inner tube can be slid and detached.
Zinc metal recovery unit. According to clause 18,
Characterized in that at least one partition wall that can be attached by condensing the zinc vapor is formed in the inner tube,
Zinc metal recovery unit. According to clause 18,
The at least one partition wall is plural,
Characterized in that the plurality of partition walls are formed in a zigzag pattern on the upper and lower sides of the inner tube,
Zinc metal recovery unit. Injecting steelmaking dust and reducing agent into the reactor through a conveyor belt;
Closing the gate of the reactor to seal the interior of the reactor;
performing a roasting process by raising the interior of the reactor to a first temperature using the heater of the reactor;
Discharging impurities and vapor of low melting point metal elements generated in the roasting process through a first gas out line;
generating zinc vapor by closing the first gas outlet line and raising the interior of the reactor to a second temperature; and
Comprising: discharging the zinc vapor through a second gas out line and recovering it in the form of zinc powder in a zinc condensing means,
The second temperature is higher than the first temperature,
Method for recovering zinc from steelmaking dust using a zinc metal recovery device.