KR101842092B1 - Direct Reduced Copper Apparatus and Method therefor - Google Patents

Abstract

The present invention relates to an apparatus and a method for directly reducing copper. More particularly, the present invention relates to an apparatus and a method for directly reducing copper by reducing copper ash from copper byproducts generated during copper and copper alloy smelting to a high purity copper using a fluidized bed reduction reaction.
The apparatus for directly reducing copper according to the present invention comprises: a reactor formed to supply copper by-products and a reducing gas, respectively, the copper by-products being reduced by the reducing gas to produce copper in a solid state; A metal recovery unit connected to a lower end of the reactor so as to discharge copper generated in the reactor from the reactor; A gas burning device for discharging unreacted reducing gas from the reactor; And a baffle installed at an upper portion of the reactor to prevent the copper by-product from being discharged to the gas burning apparatus.

Description

TECHNICAL FIELD [0001] The present invention relates to a direct reduction copper apparatus and method therefor,

The present invention relates to an apparatus and a method for directly reducing copper. More particularly, the present invention relates to an apparatus and a method for directly reducing copper by reducing copper ash from copper byproducts generated during copper and copper alloy smelting to a high purity copper using a fluidized bed reduction reaction.

Copper and copper alloys are widely used throughout the industry and their demand is increasing day by day, but most of the raw materials are imported due to the weakness of domestic mineral resources. Due to resource depletion, price fluctuations, export control by resource-rich countries, and environmental regulations, it is becoming difficult to secure stable supply of resources. Recycling of waste and securing necessary resources, technology for manufacturing copper and copper alloy In particular, dross and dust generated during the copper and copper alloy smelting process contain trace amounts of rare metals and precious metals, which have a copper content 10 times or more higher than copper ores and have very high recycling value. At present, copper and copper alloy smelting debris generates 120,000 tons per year and worth 480 billion won. Waste generated by dust is 40,000 tons per year, worth 64 billion won. In the case of recycling of such dross and dust, 10,000 tons, and resource recovery value of 544 billion won.

Development of economical recycling technology for such oil resources can contribute not only to import substitution but also to resource securing and environmental preservation.

Techniques for recovery and recycling of copper and zinc from copper and copper alloy smelting byproducts are divided into a dry method and a wet method. To recover copper and zinc from copper smelting by-products through the wet process, techniques such as precipitation, substitution, ion exchange, solvent extraction and electrolytic refining are used in combination.

The dry process is mainly used for mass-processing the copper smelting by-products, and the dry process is divided into the TSL process and the PRIMUS process. The TSL process is suitable for treating non-ferrous smelting by-products and is widely used. The TSL method consists of a melting furnace and a volatilization furnace. The liquefied gas is injected into the molten metal in the furnace at different ratios of high-pressure combustion gases through the lance provided at the top of the furnace. It is possible to recover. The residue is a technique for stabilizing and disposing of insoluble slag.

The PRIMUS method uses iron oxide raw pellets and waste raw pellets. This method is characterized in that raw pellets are charged into a multi-stage furnace and powdered coal and combustion air are blown to produce directly reduced iron through direct reduction process.

In the dry smelting method of smelting by-products, when the copper content is low, there is a problem in economical efficiency, so that it is difficult to apply the method, and other oxides other than the target metal are reduced together due to reaction time and high temperature, There is a disadvantage in that the object metal is recovered using layer separation. Especially, in case of TSL method, it is necessary to improve the gas handling facility. In case that the smelting byproduct to be charged is differential, it is necessary not only to prevent scattering but also to reduce recovery and throughput due to scattering. In the PRIMUS method, the efficiency is known to be less than 70% due to the short life span of the refractory. In the case of wet smelting, the components of the raw material are important, and impurities other than the target metal may be recovered together with the recovered material, which makes it difficult to obtain the recovery rate and high purity. In order to solve such a dry / wet problem, it is urgently required to create a new market based on the manufacture of Direct Reduction Copper (DRC) through introduction of a new process which has low process difficulty and low maintenance cost.

Direct Reduced Copper (DRC) is an overall technology for copper and copper alloy smelting by-products which are continuously reduced copper and copper alloy by using a fluidized bed reduction reactor and recovered in high purity copper.

Korean Patent No. 10-1494256 filed by the same applicant as the prior art has an effect of minimizing the loss rate occurring in the separation of valuable metals and improving the recovery efficiency, but has the following problems.

First, the dispersion plate is formed into a disk type, and the metal powder reduced in the reactor is compacted and falls down to the reactor, or the reduced metal is fused around the dispersion plate to block the dispersion plate, The supply of gas is not smooth and the flow of the normal particles is inhibited. As the phenomenon continues, the dispersion plate is completely clogged. In this case, there is a problem in that all of the reactors must be separated / disassembled in order to clean or repair the dispersing plate.

Second, the reactors used in the above patent have a straight shape with the same upper and lower diameters. When the gas flow rate supplied to the reactor is increased, the light raw material powder is accumulated on the buffer chamber through the primary separator. The raw powder accumulated in the buffer chamber is fed to the reactor by a separate carrier gas. At this time, the raw material powder recovery carrier gas is mixed with the reducing gas supplied into the reactor, and the flow rate in the entire reactor is increased. This increased flow rate affects the fluidity of the powder, which makes it difficult to control the flow.

Third, the first metal recovery part provided for recovering the reduced metal powder is connected to the lower part of the reactor by a small-diameter pipe which is inclined. This transfer pipe is only 1/4 of the diameter of the reactor, and the powder is clogged so that the recovery of the reduced metal is not smooth. In addition, it is inclined 30 to 45 ° from the non-perpendicular ground, so that the emission of the reduced metal is likewise limited. This disadvantage has a problem that the amount of recovered metal is limited and the throughput per unit process is small and the production efficiency is lowered.

(Document 1) Korean Patent Publication No. 10-1494256 (Feb.

The present invention has been made to solve the problems of the prior art, and it is an object of the present invention to provide a method for recovering copper contained in copper by-products generated during copper and copper alloy smelting, And to recover high quality copper.

In addition, the present invention aims at minimizing the loss rate in the separation of valuable metals by using a process using an electric induction furnace and a melting furnace, and improving the recovery efficiency through an economical method.

The present invention also provides a tube-shaped dispersion tube, which can be detached from the outside, and minimizes clogging of the dispersion tube due to fusion of the reducing metal.

In addition, the present invention aims at providing a baffle inside the reactor to prevent loss due to scattering of dust having a low density, and to improve the shape of the reactor to minimize the loss of raw materials.

According to an aspect of the present invention, there is provided a reactor including: a reactor configured to supply a copper by-product and a reducing gas, respectively, so that the copper by-product is reduced by the reducing gas to generate solid copper; A metal recovery unit connected to a lower end of the reactor so as to discharge copper generated in the reactor from the reactor; A gas burning device for discharging unreacted reducing gas from the reactor; And a baffle disposed above the reactor so that the copper byproduct is not discharged to the gas burning apparatus.

A plurality of dispersion tubes for dispersing the reducing gas; And a gas preheater connected to the dispersion pipe to preheat the reducing gas.

And a briquetting machine for feeding the copper recovered in the metal recovery part to the melting and smelting process.

In the gas burning apparatus, CO, CO 2, or unreacted reducing gas generated in the reactor is preferably completely burned by a burner or a catalytic system and discharged to the atmosphere.

The reactor comprises an upper reactor; And a lower reactor, wherein the upper reactor is formed in the form of a funnel, and the upper diameter of the upper reactor is preferably at least twice the diameter of the lower reactor.

And a powder storage device for storing the copper by-product before the copper byproduct is introduced into the reactor, wherein the powder storage device stores the copper by-product in a reducing reaction to remove residual water and organic matter, It is preferable to perform inert gas atmosphere control such as Ar and N2.

And a powder injector for transferring the by-products from the powder storage device to the reactor, wherein the powder injector is a screw feeder or a bucket elevator for conveying fine particles of 50 microns or less.

And a gate valve disposed between the reactor and the metal recovery unit.

It is preferable that the dispersion tube is in the form of a tube and can be mounted and removed from the outside of the reactor.

According to another aspect of the present invention, there is provided a process for producing copper, comprising: a copper generation step in which copper by-products are reduced by a reducing gas to produce high purity copper; Immediately recovering the generated copper without exposure to the atmosphere; And burning the unreacted reducing gas and discharging the unreacted reducing gas in the copper generating step.

The copper generation step may include heating the copper by-product to remove moisture and organic matter, and storing the copper by-product in an inert gas atmosphere.

According to the present invention, copper byproducts can be recovered by reducing a reducing gas to recover copper of high purity, whereby copper of high purity can be continuously recovered, and a separate pelletizing step for the pulp sludge is not required. The copper can be recovered in a simple and economical manner, the loss rate occurring when copper is recovered can be minimized, and the recovery efficiency can be increased.

In addition, the baffle is installed in the reactor to prevent the loss due to the scattering of dust having a low density, which occurs during the process of flowing the copper byproduct into the reactor.

In addition, since the dispersion tube for uniformly dispersing the mixed gas flowing into the reactor is provided in the form of a tube, fusion of the reducing metal is not caused due to the dispersion tube, and desorption is possible outside the reactor.

1 is a conceptual diagram illustrating an apparatus for recovering copper from copper by-products according to an embodiment of the present invention.
FIG. 2 is a graph of an SEM image and an XRD analysis result of a reduction reaction by-product according to an embodiment of the present invention. FIG.
3 is a graph of an SEM image and an XRD analysis result after a reduction reaction according to an embodiment of the present invention.
4 is a graph showing a result of a differential pressure change and a flow rate control during a reduction reaction according to an embodiment of the present invention.
5 is a magnified photograph of the recovered direct reduced copper according to an embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the drawings, the same reference numerals are used to designate the same or similar components throughout the drawings. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

1 is a conceptual diagram illustrating an apparatus for recovering copper from copper by-products according to an embodiment of the present invention.

As shown in FIG. 1, an apparatus 100 for recovering copper from copper by-products according to an embodiment of the present invention is formed to supply copper by-products and a reducing gas, respectively, so that the copper by- A metal recovery unit 130 connected to the lower end of the reactor 110 so as to discharge the copper produced in the reactor 110 from the reactor 110 and a reactor 110 connected to the reactor 110, And a baffle 115 installed on the reactor 110 so that the by-products are scattered and not introduced into the gas burning apparatus 160.

The copper by-products may be copper, brass, copper oxide, silicon oxide, aluminum oxide and the like as copper and copper alloy smelting by-products, and the copper oxide may be CuO and Cu2O.

The copper by-products may be stored in the powder storage device 120 in the form of powder before being input to the reactor 110. The powder storage device 120 is for storing copper by-products which are copper and copper alloy smelting byproducts, and the copper by-product powder is stored by heating for the reduction reaction to remove residual water and organic substances first.

In addition, the powder storage device 120 is operated in a temperature range of less than 600 ° C to minimize the heat loss of the reactor 110 when the byproduct powder is introduced into the reactor 110, and to prevent further oxidation of the by- The inert gas atmosphere such as argon (Ar) or nitrogen (N2) can be controlled.

The byproducts stored in the powder storage device 120 flow into the reactor 110 through the powder feeder 125 and the powder feeder 125 can be adapted to various techniques depending on the position and size of the powder storage device 120 And fine particles having a size of 50 microns or less can be stably transported to the reactor 110 due to the powder characteristics of copper by-products in a screw feeder or a bucket elevator system.

The reactor 110 may be operated at a temperature of less than 800 ° C as a device for directly generating reducing copper (DRC) through a reduction reaction of copper by-products, copper and copper alloy smelting byproducts. The flow rate of the copper by-products in the reactor 110 may vary depending on the density and particle size of the copper byproduct, and the length (a) of the reactor 110 and the length (a) of the reactor 110 (b) is 1: 2 or more, and the longitudinal length of the reactor 110 is long. Particularly, when the longitudinal length of the reactor 110 is smaller than the transverse length, the by-product is piled up at an angle of repose and the reduction is not smoothly performed, so that the shape minimizing the angle of repose is preferable.

Further, in the case where the diameter of the reactor is the same as the diameter of the reactor, the increase of the flow rate of the reducing gas increases the flowability of the copper byproduct powder, which makes it difficult to control the flow. The upper reactor 111 has a funnel shape and the upper diameter of the upper reactor 111 is larger than the diameter of the lower reactor 112 2 < / RTI >

In the reactor 110, the reduction reaction proceeds in the range of 500 to 1300 ° C., and the reduction reaction is preferably performed at 500 to 800 ° C. in order to recover the copper. When LNG is used as the reducing gas, As a result, CH4, which is a main component of LNG, is decomposed into C and H2 to perform a reduction reaction.

The dispersion tube 140 is installed for the purpose of introducing the inert gas and the reducing gas into the reactor 110, and the by-product causes the fluidizing reaction by the reducing gas dispersed by the dispersion tube 140. The dispersion tubes 140 can be arranged in parallel within a maximum of three to facilitate fluidity of the by-products. Active byproducts with vigorous fluidity can induce a reducing gas and gas-solid reaction to a higher opportunity in the reactor 110.

The dispersion holes of the dispersion tube 140 may be formed to have a uniform size of 5 mm or less.

A reducing gas and an inert gas can be simultaneously injected into the reactor 110 through the dispersion tube 140. The ratio of the reducing gas to the inert gas may be 0 to 50% of the inert gas.

The gas preheater 150 preheats the gas to a temperature of 500 to 700 ° C. to control the inert atmosphere and the reducing atmosphere of the reactor 110, and the preheated gas is supplied to the reactor through the dispersion tube 140. If the temperature of the gas preheater is low or the gas residence time is short, the reactor temperature may be lowered to lower the reaction efficiency, so that the gas residence time can be sufficiently secured. The dispersion tube 140 may further include a gas mixer (not shown) to maximize the mixing effect of the inert gas and the reducing gas.

The gas preheater 150 may be constructed to supply inert gas to the powder storage unit 120 and the metal recovery unit 130 as well as the reactor 110.

The metal recovery unit 130 is formed to communicate with the lower end of the reactor 110 and can be opened and closed, and the reduction reaction is completed and the reduction copper is recovered. The metal recovery unit 130 can be controlled in an atmosphere of argon (Ar) or nitrogen (N2) to prevent reoxidation of the reduced copper metal.

A gate valve 135 is provided between the metal recovery unit 130 and the reactor 110. When the reduction reaction is completed, the gate valve 135 is opened to drop the reduced copper vertically downward from the bottom of the reactor 110 The reduced copper powder can be discharged from the reactor 110 all at once. When all of the copper powder is discharged, the gate valve 135 is closed and the copper byproduct is further supplied from the powder storage device 120 to the reactor 110 so that a semi-continuous process is performed.

The metal recovering portion is connected to the lower portion of the reactor by a small diameter tube which is inclined to the lower portion of the reactor, and the recovered metal recovered amount is limited and the throughput per unit process is small and the production efficiency is lowered. However, That is, the diameter of the metal recovery part 130 formed at the lower end of the reactor is substantially the same as the diameter of the reactor 110, so that the bottle neck phenomenon does not occur and it is discharged in the vertical direction, .

At the bottom of the metal recovery unit 130, a briquette machine 170 can be connected to the melting and smelting process.

The briquetting machine 170 is a device for producing fine powders in a form of a glaze. In the case of the reduced metal, since re-oxidation occurs due to fine particles, the briquetting machine 170 reduces the specific surface area to prevent further oxidation, And the powder is compacted easily to be put into the apparatus during the refining process in order to produce high purity copper. This makes it possible to minimize the direct contact area of the reduced copper during storage, which is advantageous for storage and transportation.

The gas burning system 160 is for treating a reducing reaction flue gas and is used to treat carbon monoxide (CO) or carbon dioxide (CO 2) or unreacted reducing gas (CH 4, C, and H 2) generated during the reduction reaction using a burner Or completely burned using a catalytic method and then released into the atmosphere.

Of the copper by-products generated during copper and copper alloy smelting, copper by-product samples used for direct reduction copper production are copper samples. 500 kg of a copper sample is prepared and a reduction reaction is carried out.

FIG. 2 is a graph of an SEM image and an XRD analysis result of a reduction reaction by-product according to an embodiment of the present invention. FIG.

As shown in FIG. 2, the copper sample was analyzed by X-ray diffraction (XRD), LabX XRD-6100, Shimadzu, and the main peak of the copper sample was matched with copper dioxide (Cu 2 O). As a result of observing SEM (Scanning Electron Microscopy, Nova NanoSEM 200, FEI) for microstructural analysis, it was composed of atypical particles and EDX (Energy-dispersive X-ray spectroscopy) (ZnO) is present in an amount of 20% or more.

First, 500 kg of a copper sample to be reduced is prepared and a reduction reaction is performed. The copper sample is heated to 700 ° C using a reactor and maintained at a heating rate of 8 ° C per minute. N2 gas is injected through the gas preheater 150 and the gas preheater 150 maintains a temperature of 600 < 0 > C. 50 LPM (l / min) is injected to form a fluidized bed of the initial copper by-product, and the fluidization of the powder is observed through the differential pressure sensor. The LNG gas is supplied from the point of time when the target temperature is reached. LNG gas (CH4) flow rate is 120 LPM, inert gas N2 is 20 LPM, and total 140 LPM is input.

In the fluidized bed reduction reaction, the phase change to the metal particles occurs during the reduction reaction of the oxide, the flow phenomenon is remarkably reduced, and the pressure of the reactor is rapidly increased such as CO, CO2 and H2O. Therefore, the section where the differential pressure becomes zero is selected as the reduction reaction termination section. In order to induce a stable reduction reaction, a 60-minute reduction reaction is performed. When the actual differential pressure decreases to 0, it is confirmed that 500 kg reduction reaction is completed within 20 minutes after supplying the reducing gas. After the reduction, the internal pressure difference becomes zero without changing the flow rate.

FIG. 3 is a graph of an SEM image and an XRD analysis result after a reduction reaction according to an embodiment of the present invention, FIG. 4 is a graph illustrating a result of a differential pressure change and a flow rate control during a reduction reaction according to an embodiment of the present invention, Is a magnified photograph of the recovered direct reduced copper according to an embodiment of the present invention.

As shown in FIGS. 3 to 5, SEM analysis and XRD analysis were performed to confirm the reduction result. As a result, atypical fine dusts were observed in spherical form and EDX analysis showed copper powder. As a result of the XRD analysis, the initial Cu2O was completely reduced to Cu and the ZnO peak mixed with impurities was remarkably observed.

FIG. 4 is a graph showing differential pressure results obtained when the pressure is changed through a differential pressure sensor to detect a change in pressure in the reactor, and black, blue, and red are results of differential pressure of dust fluidized in the reactor, respectively. The value expressed in the sea color near the X-axis is the amount of LNG input during the reduction reaction. When CH4 is injected into the reactor near the right side of the X axis, a severe reduction reaction occurs, and the results of the differential pressures 1, 2, and 3 converge to zero. When the time is zero, it takes about 20 minutes . However, in order to induce the reduction reaction of the unreacted reducing dust, the actual CH4 injection time is 60 minutes.

5 is a photograph after briquetting the directly recovered copper powder recovered as described above. The conditions necessary for briquetting are a direct reduction copper film obtained by adding 5% of water without using a binder, stirring through a mixer, and recovering through a briquetting machine 170.

The apparatus for recovering copper from copper byproducts according to the present invention can recover copper of high purity by recovering copper of high purity by a reduction reaction using a reducing gas, It is possible to recover the copper in a simpler and more economical manner and to minimize the loss rate occurring during copper recovery and improve the recovery efficiency.

In addition, a baffle can be installed in the reactor to prevent loss due to scattering of dust having a low density, which occurs in the process of flowing copper by-product into the reactor.

In addition, since the dispersion tube for uniformly dispersing the mixed gas introduced into the reactor is provided in the form of a tube, fusion of the reducing metal does not occur due to the dispersion tube, and it is possible to desorb from the outside of the reactor.

The foregoing description is merely illustrative of the technical idea of the present invention, and various changes and modifications may be made by those skilled in the art without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are intended to illustrate rather than limit the scope of the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. The scope of protection of the present invention should be construed according to the following claims, and all technical ideas within the scope of equivalents should be construed as falling within the scope of the present invention.

110: reactor 111: upper reactor
112: Lower reactor 115: Baffle
120: Powder storage device 125: Powder injector
130: metal recovery unit 135: gate valve
140: dispersion pipe 150; Gas preheater
160: Gas burning device 170: Briquetting machine

Claims (11)

The copper by-product and the reducing gas, respectively, and the copper by-product is reduced by the reducing gas to form a solid state copper;
A metal recovery unit connected to a lower end of the reactor so as to discharge copper generated in the reactor from the reactor;
A gas burning device for discharging unreacted reducing gas from the reactor;
A baffle installed at an upper portion of the reactor to prevent the by-product from being discharged to the gas burning apparatus;
A plurality of dispersion tubes for dispersing the reducing gas;
A gas preheater connected to the dispersion pipe to preheat the reducing gas; And
And a gas mixer for mixing a reducing gas and an inert gas introduced into the dispersion tube,
The dispersion tubes are in the shape of a tube and are arranged in parallel within a maximum of three for smooth flow, and can be mounted and dismounted from the outside of the reactor,
The dispersion holes of the dispersion tube are formed in a size of 5 mm or less,
The reactor comprises:
An upper reactor; And
A lower reactor,
The upper reactor is formed in the form of a funnel,
Wherein the upper diameter of the upper reactor is at least twice the diameter of the lower reactor.
delete The method according to claim 1,
And a briquetting machine for feeding the copper recovered in the metal recovery part to the melting and smelting process.
The method according to claim 1,
The gas burning apparatus includes:
Wherein the CO, CO 2, or unreacted reducing gas generated in the reactor is completely burned by a burner or a catalytic system and discharged to the atmosphere.
delete The method according to claim 1,
And a powder storage device for storing the copper by-product before the copper byproduct is introduced into the reactor,
Wherein the powder storage device performs control of an inert gas atmosphere such as Ar and N2 in order to remove residual water and organic substances by heating and storing the by-products for reduction reaction, and to prevent oxidation.
The method of claim 6,
And a powder injector for transferring the by-product from the powder storage device to the reactor,
Wherein the powder injector is a screw feeder or a bucket elevator for delivering fine particles of 50 microns or less.
The method according to claim 1,
And a gate valve installed between the reactor and the metal recovery unit.
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