JPH05271799A - Method for recovering valuable metal in electric furnace dust and device therefor - Google Patents

Abstract

PURPOSE:To recover the valuable metals in electric furnace dust at a high grade and low cost. CONSTITUTION:The valuable metals are reduced by mixing 5 to 20% fluorite and 3 to 30% carbonaceous reducing agent with the electric furnace dust and indirectly heating the dust at 1400 to 1500 deg.C in a nonoxidative reduction treating furnace 20 in which hermeticity is maintained. After molten iron and slag are recovered, the evaporated metal vapor is introduced to a filter 30 where the iron and lead are recovered. Further the metal vapor is introduced to a condensor 34 and zinc is condensed and recovered at 490 to 520 deg.C; in succession, the metal vapor from this condenser 34 is introduced to a trap 60 and cadmium is condensed and recovered. The efficient reduction of the valuable metals by the indirect heating at 1400 to 1500 deg.C in the reduction treating furnace 20 is enabled by the combined addition of the fluorite with the graphite. The molten iron recovered in such a manner has the high grade. Since the iron and the lead are recovered from the metal vapor in the filter 30, the zinc having the excellent grade is recovered in the condenser 34.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention collects valuable metals such as iron and zinc in electric furnace dust generated in an electric furnace for steelmaking at a low heat recovery cost and high quality, and does not elute harmful metals. The present invention relates to a method and an apparatus for recovering valuable metals from electric furnace dust capable of obtaining secondary slag.

[0002]

Electric furnace dust generated in an electric furnace for steelmaking contains valuable metals such as about 30% iron, about 20% zinc, and about 5% lead. Various methods such as a wet method and a dry method have been tried to recover the valuable metal in the electric furnace dust, but a decisively advantageous method has not been found yet.

That is, in the wet method, even if a dissolving method in which an oxidizing agent is added with a strong acid is adopted, the electric furnace dust has a strong oxide property that is difficult to dissolve in an acid, and therefore about 20%.
In some cases, the acid-insoluble component may be produced, and in such a state, extraction of iron becomes insufficient. Moreover, it is difficult to extract harmful substances. Although a method such as alkali melting can be considered for completely dissolving the solution, even if it can be dissolved, it is difficult to process it in a large amount.

Further, even in the electrolytic treatment which is the mainstream of the wet treatment, the recovery yield is remarkably lowered at the leaching stage of the pretreatment due to the above-mentioned problems, and the cost is increased as compared with the dry method.

Even in the dry method, a process such as a rotary kiln has a low temperature and tends to be structurally non-uniform.
The quality of metal and slag cannot be expected. Furthermore, even for zinc, which is the centerpiece, since it is recovered with crude zinc oxide, the selling price is low and the operation is difficult.

Next, although many patents using sensible heat of steel slag have been filed, this method has an advantage that the heat cost can be reduced. However, variations in processing and problems in the working environment pose problems, and unless these problems are resolved, safe and stable quality cannot be expected. Further, as for zinc to be recovered, crude zinc oxide has a problem of operating cost as in the rotary kiln.

Further, a method has been proposed in which electric furnace dust is melted together with a reducing agent and a solvent in a plasma melting furnace, and the generated metal vapor is guided to a splash condenser and condensed to recover zinc together with lead and the like. The quality of zinc produced is as low as 95%, the un-liquefied zinc oxide is collected by a bag filter, and the recovery yield is poor. Moreover, the temperature of the melting furnace is about 1600 ° C, which is a heat cost point. There is a problem with the durability of the device.

Conventional zinc distillation refining methods include a vertical retort method, an electrothermal distillation method, an ISP method and the like. In these methods, they are recovered by a rotary kiln before melting and reducing. When the crude zinc oxide is solidified and dried, the two-step treatment is unavoidable, which further increases the heat cost.

[0009]

As described above, the method for recovering valuable metals in electric furnace dust is decisively advantageous in terms of recovery rate and quality of recovered metals, cost, especially thermal cost. Since no method can be found, as a result, these electric furnace dusts do not collect valuable metals but detoxify them and then landfill them for disposal. In this way, discarding valuable metals without recovering them wastes valuable resources, is not a good measure, and may lead to environmental pollution.

The present invention has been made to solve the above-mentioned problems related to the recovery of valuable metals in electric furnace dust, and iron in electric furnace dust generated in a steelmaking electric furnace,
An object of the present invention is to provide a method and an apparatus for recovering valuable metal of electric furnace dust, which can recover valuable metal such as zinc at low heat recovery cost and high quality, and can obtain secondary slag without elution of harmful metal. And

[0011]

When the electric furnace dust is treated at a high temperature by a dry method, the heat cost becomes a problem. Therefore, the inventor has conducted extensive studies on a method of reducing and separating metal, zinc and slag at the lowest temperature possible. As a result, the inventors have found a range of optimum addition amounts of fluorite and a carbonaceous reducing agent that can make the slag have a low melting point composition and facilitate the reduction of metal and zinc in a short time even when treated at 1400 to 1500 ° C.

Further, as a reduction treatment furnace, it has been found that it is advantageous to use an indirect heating with a non-oxidizing atmosphere that maintains airtightness, in order to improve the recovery rate of zinc, and improve the quality of recovered zinc. Further investigation on the method was continued. As a result, they have found that high-purity zinc can be recovered by collecting the fumes of iron and lead with a filter before the metal vapor from the reduction treatment furnace is sent to the zinc condenser and condensed.

The method for recovering valuable metals from electric furnace dust according to the present invention has been completed based on the above findings, and 5 to 20% by weight of fluorite and 3 carbonaceous reducing agents are contained in the electric furnace dust. -30% mixed mixture was charged into a reduction treatment furnace and indirectly heated to 1400 to 1500 ° C. in an airtight non-oxidizing atmosphere, and molten iron and slag were extracted from the reduction treatment furnace and the reduced metal The gist of the invention is to introduce steam into a filter to recover iron and lead at 550 to 650 ° C., and further introduce metal vapor passing through the filter to a condenser to condense and recover zinc at 490 to 520 ° C.

Further, the valuable metal recovery apparatus for electric furnace dust of the present invention is characterized by indirectly heating the charged electric furnace dust, the mixture of fluorite and the carbonaceous reducing agent in an airtight non-oxidizing atmosphere. Extraction of molten iron and slag from the bottom and reduction treatment furnace that guides the metal vapor reduced from the top to the filter, and iron and lead are recovered from the metal vapor introduced from the reduction treatment furnace and further the metal vapor is guided to the condenser. The gist is that it comprises a filter and a condenser for condensing the metal vapor introduced from the filter and recovering zinc.

Fluorite and the carbonaceous reducing agent used for the recovery treatment of valuable metals are preferably pulverized to 0.3 mm or less. This is because valuable metals are not sufficiently reduced when the particle size exceeds 0.3 mm. Mainly to lower the melting point of slag with fluorite, but the amount added is within the scope of the claims,
Silica powder (particle size: 0.3 mm or less) may be added separately in order to adjust the low melting point composition and to increase the strength of the slag for producing a high value-added product. As the carbonaceous reducing agent, for example, graphite, coke, and electrode scraps can be used.

The fluorite and the carbonaceous reducing agent mixed with the electric furnace dust are sufficiently reduced so that the valuable metal is sufficiently reduced and the reduced metal is completely separated depending on the components of the electric furnace dust. It is necessary to form a low melting point slag.
Therefore, the range of the fluorite and the carbonaceous reducing agent is appropriately selected depending on the composition of the electric furnace dust. That is, fluorite is in the range of 5 to 20%, and carbonaceous reducing agent is in the range of 3 to 3
The composition is appropriately selected within the range of 0%. The mixture is solidified by a granulator, dried and sintered in a preheating furnace, and then put in a reduction treatment furnace.

Any reduction treatment furnace may be used so long as it can be indirectly heated in a non-oxidizing atmosphere under vacuum. For example, a cylindrical container made of silicon carbide or a material similar to this is vertically placed and stacked in several stages to form the center of an induction heating coil. It has a structure that can be indirectly heated. These containers are designed to be easily replaced depending on the degree of durability. The reason for setting the non-oxidizing atmosphere between the induction heating coil and the reduction treatment furnace is to prevent fume such as zinc that may leak from the gap of the container described above from adhering to the coil and damaging it. This is to improve durability.

The filter is equipped with a cooler capable of adjusting the introduced metal vapor to a desired condensing temperature, and fumes lead in the metal vapor and collects fine iron particles and lead fumes by passing through the filter. To do. The temperature is adjusted so that the inlet side is higher and the outlet side is 560 ° C. with two divided coolers. Various filters can be used as long as they can collect iron and lead. For example, a filler such as graphite (particle diameter 5 to 10 mmφ) between silicon carbide mesh plates.
It is possible to use, for example, a sandwich made by sandwiching it and setting it diagonally around the part through which the fume passes from above, and making it easy to replace.

The condenser may be of any type as long as it can efficiently condense and recover zinc from metal vapor. For example, a splash condenser that splashes molten zinc into gas as fine particles with an impeller, a vacuum condenser that draws an exhaust end with a vacuum pump and passes metal vapor as small bubbles through molten zinc, or a tray with holes. It is possible to use various types such as a stack of several stages to allow metal vapor to pass from the bottom. Here, in order to improve the distillation efficiency, the single-hole distillation stand was switched to a porous distillation stand, and a device capable of collecting cadmium (described later) was installed in the upper stage so that continuous treatment was possible. In addition, these condensers are equipped with a temperature control device for heating or cooling as necessary so that the temperature does not fluctuate depending on the throughput. These devices have a structure in which half-open double-open type is stacked in three stages.
The temperature can be adjusted to 0 ° C.

The metal vapor from which zinc has been recovered by the condenser is guided to a trap to collect cadmium, and the metal vapor introduced into this trap is also a cooler capable of condensing and liquefying the metal vapor at about 400 ° C. (known condition). Any model may be used as long as it is capable of condensing and collecting cadmium in the metal vapor. The cooler is divided into upper and lower parts, and the lower part can be adjusted to about 400 ° C and the upper part to 200 ° C or less.

Exhaust gas from which cadmium is collected contains carbon monoxide and chlorine gas. Carbon monoxide is applied to a heat exchanger and exhaust heat is used in a preheating furnace or the like, and chlorine gas is dechlorinated. Purify through the device. (Part of device omitted)

[0022]

A mixture of 5 to 20% by weight of fluorspar and 3 to 30% by weight of carbonaceous reducing agent in a weight ratio depending on the chemical composition of the dust in the electric furnace is charged into the reduction treatment furnace and hermetically sealed. Indirect heating at 1400 to 1500 ° C. in a non-oxidizing atmosphere while maintaining the property, the valuable metal oxide in the electric furnace dust is reduced to a metal by the carbonaceous reducing agent.

Among the reduced metals, lead, zinc and cadmium become metal vapor, and some iron particles are mixed with this and sent to the filter from the upper part of the reduction treatment furnace. On the other hand, iron melts and drip in the furnace, and accumulates on the bottom of the furnace. Also,
Since this reduction furnace maintains airtightness and performs indirect heating in a non-oxidizing atmosphere, fumes, such as zinc, are prevented from adhering to and damaging heating devices such as induction heating coils, and are reduced to metal. It prevents the zinc etc. that have been oxidized from being oxidized.

On the other hand, the non-metal oxide in the electric furnace dust is melted together with the fluorite to form a slag with a low melting point, and the slag is accumulated at the bottom of the furnace. This fluorite is combined with a carbonaceous reducing agent (silica powder is added if necessary) to remove non-metallic inclusions outside the system, and to complete the reaction of electric furnace dust in a short time while recovering the recovered metal. We are trying to improve the quality of. In addition, since slag is formed after the harmful metals such as lead and cadmium are completely reduced, it is completely harmless and has a high solidification strength, so it can be used for ceramics, stone materials, building materials, etc. is there.

The metal and slag accumulated on the bottom of the furnace are properly taken out of the furnace. Since small iron particles that cannot be separated from the metal remain in the slag, magnetic separation is performed when it is desired to remove.

The metal vapor sent from the reduction treatment furnace to the filter is adjusted to a desired condensation temperature by a cooler provided therein, so that lead in the metal vapor is fumed. This metal vapor then passes through the filter, which collects iron particulates and lead fumes and recovers iron and lead.

The metal vapor from which iron and lead have been recovered by the filter is sent to a condenser and adjusted to a predetermined condensation temperature, so that zinc is condensed and recovered. Since it has been collected,
High quality zinc is recovered. Subsequently, the metal vapor is sent to a trap to recover the cadmium.

In the present invention, the amount of fluorite mixed in the electric furnace dust is set to 5 to 20% because if the fluorite content is less than 5%, non-metal oxides and slag are not formed. If the fluorite content exceeds 20%, the clay in the slag rises and the separation from the metal becomes insufficient.

The amount of the carbonaceous reducing agent mixed with the electric furnace dust is set to 3 to 30% because the amount of the carbonaceous reducing agent is 3%.
If it is less than%, the valuable metal oxide is not sufficiently reduced and the recovery rate is reduced, and the amount of carbonaceous reducing agent is 30%.
This is because the recovery rate of valuable metals is considered to be saturated due to the effects of silicon carbide and other influences even if the value exceeds the range. Further, the effects of these alone are insufficient, and a stable effect can be obtained by adding them in combination.

The reaction temperature of the reduction treatment furnace is set to 1400 to 150.
0 ° C. means that the treatment temperature is less than 1400 ° C.
This is because the reduction reaction of valuable metal oxide is insufficient and the separation of metal and slag becomes insufficient.
This is because if it exceeds, the heat cost increases and the durability of the furnace cannot be guaranteed.

The temperature of the metal vapor is set to 55 in the filter.
It is 550 to recover iron and lead at 0-650 ℃.
If the temperature is lower than ℃, the metal vapor of zinc cannot be sent to the condenser, and zinc fumes are partially generated to reduce the recovery rate of zinc. If the temperature exceeds 650 ℃, lead fumes are not sufficiently generated. This is because the lead collection rate decreases.

In the condenser, zinc is condensed and recovered by setting the temperature of the metal vapor to 490 to 520 ° C. When the temperature of the metal vapor is less than 490 ° C., the distillation time becomes longer and the quality of zinc is lowered. From 5
This is because if the temperature exceeds 20 ° C., zinc will not be sufficiently condensed, which will impair the function of the circulation system and will also affect the collection of cadmium.

[0033]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the device of the present invention will be described below with reference to the drawings, and an embodiment of the method of the present invention using this device will be described to clarify the features of the present invention. FIG. 1 is a schematic side view of an embodiment of the device of the present invention. Electric furnace dust 10
Is 5 to 20% of fluorspar and other 12 depending on the components contained.
And 3 to 30% of graphite coke 14 are mixed by a mixer 16, granulated by a granulator, dried and sintered in a preheating furnace 18, and sent to a reduction treatment furnace.

The reduction treatment furnace 20 is formed by stacking a plurality of cylindrical containers made of silicon carbide or a material similar thereto in a stack, and in order to maintain airtightness and maintain a non-oxidizing atmosphere, a furnace top and a preheating furnace. The passage with 18 is shielded by an appropriate shield device 22. Further, Ar gas 24 can be blown from the furnace top if necessary.

This reduction treatment furnace 20 is placed at the center of an induction heating coil (not shown), and the temperature inside the furnace is maintained at 1400 to 1500 ° C. by indirect heating by this induction heating coil. Further, a slag port 26 for taking out the slag and the molten iron is provided at the bottom of the reduction treatment furnace 20, and the slag and the molten iron accumulated at the bottom of the furnace are periodically taken out. Further, one end of a metal vapor lead-out pipe 28 for leading out metal vapor generated in the furnace is attached near the top of the furnace to feed the metal vapor to the filter 30. In addition, due to airtight leakage of the reduction treatment furnace and other influences, a non-oxidizing atmosphere is provided between the furnace and the induction heating coil. Since the amount of fumes obtained here is extremely small, it is collected by a cyclone and the other exhaust gas is sent to the same treatment device.

The filter 30 is provided with a cooler 32 capable of adjusting the introduced metal vapor to a desired condensing temperature, and fume the lead in the metal vapor and at the same time pass iron fine particles or lead fume through the filter. To collect.

The metal vapor that has passed through the filter 30 is then introduced into the condenser 34, and the condenser 3
As shown in FIGS. 2 and 3, the numeral 4 designates a condensing tower 40 in which two kinds of trays 38 having holes 36 are alternately stacked.
And a zinc circulating device 42 for circulating condensed zinc, and a temperature adjusting device 44 of the condensing tower 40.

The tray 38 constituting the condensing tower 40 is shown in FIG.
As shown in the plan views of (a) and (b), the tray 36 is composed of two types of trays 38a and 38b whose shapes and positions of the holes 36 are not the same. Two types of trays 38a and 38 of different types
b are alternately stacked and constructed. As described above, since the holes 36 provided in the tray 38 do not penetrate straightly between the upper and lower trays, the metal vapor diffuses and condenses while colliding with the bottom surface of the tray 38 every time the holes 36 pass. It is supposed to do.

At the center of the bottom of the condensing tower 40, there is a metal vapor introducing port 46, and while the metal vapor introduced rises through the condensing tower 40, zinc contained in the metal vapor condenses and zinc is provided at the bottom. Liquid zinc is taken out from the take-out port 48. In the meantime, the temperature adjusting device 44 keeps the metal vapor at a predetermined temperature according to the amount of the metal vapor to be processed, and therefore, the device for heating or cooling the condensing tower 40 is a stack of half cut open type.

The zinc circulating device 42 cools the zinc taken out from the condensing tower 40 by the cooler 50, then recovers the zinc and part of the zinc by the circulating pump 52 by the condensing tower 40.
Zinc is injected into the condensing tower 40 from the zinc inlet 54 provided at the shoulder of the. When the tray is 38a, the injected zinc is dropped from the zinc dropping holes 56 provided at three locations on the outer periphery, and when the tray is 38b, it is dropped from the irregular holes 36. The contact time with the dripping zinc becomes longer, and zinc is efficiently condensed.

Above the agglomeration tower 40 of the condenser 34,
A trap 60, which is made of corrosion-resistant stainless steel and coated with a silicon carbide based composite material, is attached through a cadmium recovery tray 58. A metal vapor introduction port 62 penetrates through the center of the cadmium recovery tray 58, and the metal vapor introduced from the condenser 34 rises from the introduction port 62 and contacts the trap 60. Since the trap 60 is cooled to a predetermined temperature by the cooler 64 provided outside, cadmium in the metal vapor is condensed in the trap 60,
It is dropped on the cadmium recovery tray 58, enters the outer container through the cadmium outlet 66, and is recovered as solid cadmium.

The exhaust gas from the trap 60 from which cadmium has been collected is sent to the exhaust gas purifying device 70 by the vacuum pump 68. In the exhaust gas that collected cadmium,
Although carbon monoxide, chlorine gas and the like are contained, chlorine gas is purified through an exhaust gas purifying device 70, and carbon monoxide is exhausted to a heat exchanger and used for exhaust heat in a preheating furnace or the like. (Part of device omitted)

The operation of the apparatus of this embodiment having the above construction will be described. 5-20% by weight of fluorite and 3-30 by weight of carbonaceous reducing agent are used in a weight ratio depending on the electric furnace dust and its chemical composition.
The mixture mixed in the range of 10% is solidified by a granulator, dried and sintered in the preheating furnace 18, and then charged into the reduction treatment furnace 20 through the shielding device 22 to maintain airtightness and in an non-oxidizing atmosphere. When indirectly heated at 1400 to 1500 ° C., the valuable metal oxide in the electric furnace dust is reduced to a metal by the carbonaceous reducing agent.

Among the reduced metals, lead, zinc and cadmium become metal vapor, and some iron particles are mixed with this and sent from the upper part of the reduction treatment furnace 20 to the filter 30 by the metal vapor outlet pipe 28. On the other hand, iron melts and drip in the furnace, and accumulates on the bottom of the furnace.

On the other hand, the non-metal oxide in the electric furnace dust is melted together with fluorite to form a low melting point slag, which is collected at the bottom of the furnace. The metal and slag accumulated on the bottom of the furnace are properly taken out of the furnace through the outlet 26. At that time, Ar gas 24 is blown into the furnace from the top of the furnace as needed to apply pressure to the furnace.

The metal vapor sent from the reduction treatment furnace 20 to the filter 30 is adjusted to a desired condensation temperature by the cooler 32 provided, so that lead in the metal vapor is fumed. This metal vapor then passes through the filter, which collects iron particulates and lead fumes and recovers iron and lead.

The metal vapor from which iron and lead have been recovered by the filter 30 is sent to the condenser 34. The condensing tower 40 of the condenser 34 is adjusted to a desired condensing temperature by the temperature adjusting device 44, and the metal vapor introduced from the metal vapor introducing port 46 passes through the holes 36 of the stacked trays 38. The holes 36 provided in the tray 38 do not penetrate straightly between the upper and lower trays, and the metal vapor rises while colliding with the bottom surface of the tray 38 every time it passes through the holes 36. Efficiently condense. Further, since liquid zinc is injected into the upper part of the condensing tower 40 by the zinc circulation device 42 and dropped in the tray 38 and circulated, the condensation of zinc in the condensing tower 40 is further promoted.

Next, the metal vapor from which zinc is recovered in the condenser 34 rises from the inlet 62 of the cadmium recovery tray 58 mounted on the condenser 34 and contacts the trap 60. Since the trap 60 is cooled to a predetermined temperature by the cooler 64 provided outside, the cadmium in the metal vapor is condensed in the trap 60 and dropped into the cadmium recovery tray 58, and the cadmium outlet 6
Liquid cadmium is discharged from 6 to an outer container so that it can be retained, and is recovered as a solid.

The exhaust gas from the trap 60 from which cadmium has been collected is sent to the exhaust gas purifying device 70 by the vacuum pump 68. In the exhaust gas that collected cadmium,
Although carbon monoxide, chlorine gas and the like are contained, chlorine gas is purified through an exhaust gas purifying device 70, and carbon monoxide is exhausted to a heat exchanger and used for exhaust heat in a preheating furnace or the like. (Part of device omitted)

Next, an example in which electric furnace dust is processed by using the apparatus of this example will be described. 10% of fluorite previously crushed to a particle size of 0.2 mm or less and 8% of graphite were added to and mixed with electric furnace dust having the chemical components shown in Table 1. The mixture of the electric furnace dust, fluorspar and graphite was charged into a reduction treatment furnace and indirectly heated at 1450 ° C. in an airtight atmosphere.

[0051]

[Table 1]

The reduced metal and slag are properly taken out of the furnace, and the metal vapor collects iron and zinc at 560 ° C. with a filter, and then the metal vapor passing through the filter diffuses zinc at 500 ° C. with a condenser. -It was condensed and collected, and after cadmium was liquefied at 400 ° C by a trap, it was collected as a solid. Chemical analysis of the recovered metal, slag and zinc gave the results shown in Table 1. The recovery rates of valuable metals were 95% for iron, 75% for zinc, and 90% for slag with respect to the electric furnace dust, which were high recovery rates.

As shown in Table 1, the metal contained a high concentration of iron, and the amounts of zinc, lead, cadmium, etc. were minute. Further, it was found that zinc can be recovered with a high purity of 99.0% or higher, and iron, zinc, cadmium, and the like are also present in the slag with a very small amount, and the quality of the slag was confirmed.

Then, a dissolution test was conducted on the obtained slag, and the results were compared with the results of the dissolution test before treatment. The measured values of the eluted ion concentration and the pH of the eluate obtained by the dissolution test are shown in Table 2 together with the allowable values.

[0055]

[Table 2]

As shown in Table 2, the Cd ion before treatment was 3.84 ppm and the Pb ion was 6.57 ppm. , Pb ion is not detected,
Further, it was confirmed that the pH was 8.10 and was completely harmless.

[0057]

INDUSTRIAL APPLICABILITY As described in detail above, the method and apparatus for recovering valuable metals from electric furnace dust of the present invention contain 5 to 20% fluorite and 3 to 30% carbonaceous reducing agent in electric furnace dust. 1 in a reduction treatment furnace in a non-oxidizing atmosphere that is mixed and airtight
Indirect heating to 400-1500 ℃ to reduce valuable metals,
Molten iron and slag are collected, evaporated metal vapor is guided to a filter, and iron and lead are collected at 550 to 650 ° C,
Further, the metal vapor that has passed through the filter is guided to a condenser to condense and recover zinc at 490 to 520 ° C, and subsequently the metal vapor from the condenser is guided to a trap to condense and recover cadmium. In the reduction furnace, 1400 to 15 due to the combined addition of fluorite and graphite
Indirect heating at 00 ° C enables efficient reduction of valuable metals, the recovered molten iron is of high quality and can be recycled into molten steel, and metal vapor has iron and lead recovered in the filter. Therefore, in the condenser, zinc of high quality is recovered. Moreover, since the treatment temperature is relatively low, the heat cost is low and the furnace durability is excellent, and the slag obtained is completely detoxified and has a high solidification strength. High-value-added products can be expected as a base material for supplying building materials.

[Brief description of drawings]

FIG. 1 is a schematic explanatory view of an embodiment of the device of the present invention.

FIG. 2 is a vertical cross-sectional view of a condenser tower of a condenser.

3 is a cross-sectional view of a tray that constitutes the condensing tower of FIG.

FIG. 4 is a vertical sectional view of a trap.

[Explanation of symbols]

10 Electric Furnace Dust 12 Fluorite / Others 14 Graphite / Coke 20 Reduction Treatment Furnace 22 Shielding Device 26 Outlet Port 30 Filter 34 Condenser 38 Tray 40 Condensing Tower 42 Zinc Circulation Device 60 Trap

Claims (2)

[Claims] 1. Fluorite in an electric furnace dust in a weight ratio of 5 to 20
% And a carbonaceous reducing agent in a proportion of 3 to 30% are charged into a reduction treatment furnace and heated in an airtight non-oxidizing atmosphere at 140%.
Indirect heating to 0 to 1500 ° C., extracting molten iron and slag from the reduction treatment furnace, introducing reduced metal vapor to a filter, recovering iron and lead at 550 to 650 ° C., and further passing metal through the filter. A method for recovering valuable metals from electric furnace dust, which comprises introducing steam to a condenser and condensing and recovering zinc at 490 to 520 ° C. 2. The molten iron and slag are extracted from the bottom and reduced from the top by indirectly heating the charged mixture of electric furnace dust, fluorspar and carbonaceous reducing agent in an airtight non-oxidizing atmosphere. A reduction treatment furnace that guides the metal vapor that has been collected to the filter, a filter that recovers iron and lead from the metal vapor that has been introduced from the reduction treatment furnace, and that further guides the metal vapor to a condenser, and a condensation of the metal vapor that has been introduced from the filter. A valuable metal recovery device for electric furnace dust, which comprises a condenser for recovering zinc.