JPH0625765A - Method for removing and recovering copper in ferroscrap - Google Patents

Abstract

(57) [Summary] [Objective] To develop an efficient process for decopperizing ferro-scrap containing copper in the presence of oxygen with an ammoniacal aqueous solution containing ammonia and ammonium carbonate. [Structure] One of a plurality of reactors connected by a solution transfer means
In the second step, decopperization of scrap is performed by a batch operation, and after the completion of the treatment, all the leachate in the reactor is withdrawn,
A part of it is transferred to another reactor by the solution transfer means and used for the next scrap treatment, and the remaining leachate is temporarily stored in a storage tank and then used for continuous operation to recover copper oxide or metallic copper. To do.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for removing and recovering copper from ferro scrap containing copper for recycling ferro scrap as a raw material for steel melting. More specifically, the present invention uses an ammoniacal aqueous solution containing ammonia and an ammonium salt to selectively dissolve and remove copper from ferro scrap containing copper, thereby obtaining a product having a purity suitable for recycling. The present invention relates to a method for removing and recovering copper in ferro scrap by recovering and utilizing a high ferro scrap as copper oxide or copper metal.

[0002]

2. Description of the Related Art Ferro-scrap often has a high copper content mainly due to the inclusion of copper wires used as electric wires or conductors and other parts made of copper or copper alloys. For example, abandoned automobiles, waste electrical products, machine waste, and the like.

Copper is an element which adversely affects the performance such as mechanical properties and workability of steel products, and when ferro scrap mixed with copper is used as a raw material for steel melting, only low quality steel can be produced. . Therefore, it is desirable to remove copper from ferro scrap, and various decoppering methods have been studied in the past. The following is a typical decopperization method for removing copper from ferro scrap.

A method for selectively extracting copper from molten iron into a flux containing sodium sulfide or sodium sulfate as a main component (122, 123rd Nishiyama Memorial Technical Course, pp. 112-118,
(The Iron and Steel Institute of Japan), a method of melting scrap at high temperature and evaporating lower melting copper under vacuum (CAMP-ISIJ, Vol. 1 (1988), pp.116.
9-1172), after sulphurizing copper in scrap, then compressing or crushing scrap and mechanically separating and recovering embrittled copper sulfide (JP-A-2-285035), aluminum, magnesium or alloys thereof Method for selectively extracting copper into the melt of a mixture (JP-A-3-199314)
.

However, the method (1) requires a considerably large amount of flux in order to obtain a high decoppering rate, and it is difficult to handle this flux at high temperatures, and the flux cost is high. The method of increasing the evaporation rate of copper is
High-temperature and high-vacuum conditions that require a large amount of energy are required, and it is difficult to recover copper. In the method of 1, the treatment of the waste gas containing sulfur oxides generated in the sulfurization step becomes a heavy burden, and in the separation of sulfided copper by mechanical means, copper can be removed at a sufficiently high decoppering rate. Have difficulty.
The method is based on the expensive metal Al, Mg, or Al
-Mg alloy is required.

[0006]

In order to overcome the drawbacks of the conventional decoppering method, the present inventor first used a ferro scrap by using an ammoniacal aqueous solution containing ammonia and an ammonium salt (eg, ammonium carbonate). Removes copper from
Proposed a method of collecting (Japanese Patent Application No. 3-297375) (hereinafter,
This method is called the prior invention).

In an ammoniacal aqueous solution in the presence of oxygen, copper forms an ammonia and an ammine complex and is easily dissolved, whereas iron is passivated in spite of its greater ionization tendency than copper. Because it does not dissolve at all. The prior invention utilizes such properties of copper and iron. That is, when ferro scrap containing copper is treated with an aqueous ammonia solution in the presence of oxygen,
According to the formula (1), copper in scrap can be selectively dissolved as an ammine copper (II) complex, and decopperized high quality ferro scrap can be obtained. At the same time, the ammoniacal aqueous solution in which copper separated from the scrap is heated to decompose the ammine copper (II) complex, recover the copper content as copper oxide or metallic copper, and regenerate ammonia and ammonium salts. be able to.

As a method for recovering copper, when the ammonium salt used in the aqueous ammoniacal solution is, for example, ammonium carbonate which forms an unstable salt with copper, the solution is heated to decompose the complex. As shown in the formula (2), ammonia and carbon dioxide gas are generated and copper is precipitated as copper oxide, which is recovered. The generated ammonia and carbon dioxide gas can be used to regenerate an ammoniacal aqueous solution containing ammonia and ammonium carbonate. When ammonium forms a stable water-soluble salt with copper like ammonium sulfate, heating the solution to decompose the complex produces an aqueous solution of copper sulfate as shown in equation (3). The copper sulfate aqueous solution may be electrolyzed to recover copper as metallic copper. By absorbing the ammonia evaporated during the heating of the solution into the electrolytic waste solution containing sulfate ions, the ammoniacal aqueous solution containing ammonia and ammonium sulfate is regenerated.

Cu + 2NH ₃ + 2NH ₄ ⁺ + 1 / 2O ₂ = Cu (NH ₃ ) ₄ ²⁺ + H ₂ O (1) Cu (NH ₃ ) ₄ CO ₃ = CuO ↓ + 4NH ₃ ↑ + CO ₂ ↑ (2) Cu (NH ₃ ) ₄ SO ₄ = CuSO ₄ + 4NH ₃ ↑ (3) The dissolution reaction of copper represented by the above formula (1) is a dissolution product, contrary to general common sense. When the ammine copper (II) complex is present in the solution at a certain concentration or more, the reaction rate is remarkably accelerated to several times to several tens of times. Therefore, a part of the leachate containing the ammine copper (II) complex generated by the dissolution of copper is returned to the dissolution step so that the solution during the dissolution treatment always contains the ammine copper (II) complex at a certain concentration or more. Is advantageous.

As can be seen from the above equations (1) to (3), the method for removing and recovering copper of the invention of the prior application is that, in principle, ammonia and ammonium salts necessary for the reaction are completely recovered, and a treatment aqueous solution is obtained. Since it can be recycled and reused, the cost of chemicals and wastewater treatment is low and it is economical. The removal and recovery rate of copper from ferro scrap is also high.

When this method of decopperizing ferro scrap is industrially carried out, it is difficult to continuously charge and discharge the scrap with the ammoniacal aqueous solution because of the shape of the scrap, and therefore batch (batch) operation is appropriate. Therefore, it is desirable to develop an efficient process. In addition, it is desirable to recycle ammonia in order to use it effectively, and to avoid the escape of ammonia to the outside of the treatment system as much as possible in order to prevent deterioration of the working environment due to ammonia. The present invention has been achieved with the aim of solving the above problems.

[0012]

The method for removing and recovering copper in ferro scrap according to the present invention comprises treating ferro scrap containing copper with an ammoniacal aqueous solution containing ammonia and an ammonium salt in the presence of oxygen. Copper in the scrap is selectively dissolved as an ammine copper (II) complex to obtain decoppered scrap, and copper oxide or metallic copper is decomposed from the leachate in which copper is dissolved through decomposition of the ammine copper (II) complex. And recovering the scrap by treating one of a plurality of reactors connected by solution transfer means.
In one batch operation, the total amount of the leachate in the reactor is withdrawn after the treatment, and a part of the leachate is transferred to another reactor by the solution transfer means and used for the next scrap treatment, and the remaining leachate is used. Is characterized by being stored in a storage tank and then used for recovery of copper oxide or metallic copper by continuous operation.

In a preferred embodiment, the ammonium salt is ammonium carbonate. In this case, the above method comprises the steps of preparing an ammoniacal aqueous solution containing ammonia and ammonium carbonate, and treating ferro-scrap containing copper with the ammoniacal aqueous solution in the presence of oxygen to obtain copper in the scrap. Is selectively dissolved as an ammine copper (II) complex to obtain a leachate in which decoppered scrap and copper are dissolved, and ammonia and carbon dioxide gas are evaporated from the leachate to form an ammine copper (II) complex. It can be carried out by a method comprising a step of decomposing and crystallizing copper oxide, and a step of filtering and drying the crystallized copper oxide to recover, and according to the present invention, in the dissolving step, the treatment is carried out by a solution transfer means. It is carried out by batch operation in one of a plurality of connected reactors, and after the treatment is completed, all the leachate in the reactor is withdrawn, and a part of the leachate is removed by the solution transfer means. Was next used to scrap and transferred to another reactor, after the rest of the leachate which is once stored in a storage tank, to crystallization treatment by continuous operation in the crystallization step.

It is preferable that the decoppered scrap remaining in the reactor after the entire amount of the leachate is extracted is subjected to a cleaning treatment for removing ammonia in the reactor and then taken out. In addition, by recovering the ammonia generated by the decomposition of the ammine copper (II) complex and recycling it to prepare an ammoniacal aqueous solution, it can be recycled.

[0015]

FIG. 1 shows an example of a process diagram of the treatment method of the present invention when the ammonium salt is ammonium carbonate. Figure 1
As shown in Fig. 1, this ferro-scrap treatment method comprises a step of preparing an ammoniacal aqueous solution used as a treatment solution,
Dissolving copper in the scrap by immersing the scrap in the treatment solution in the reactor, decoppered scrap, a dissolution step of obtaining a leachate in which copper is dissolved, a crystallization step of crystallizing copper oxide from the leachate, and The process consists of filtration and drying of copper oxide.

In the solution preparation step, water (in the illustrated example, scrap cleaning water is used) absorbs ammonia and carbon dioxide gas in a suitable container to prepare an ammoniacal aqueous solution containing ammonia and ammonium carbonate. .
In the preferred embodiment, most of the raw material ammonia and carbon dioxide gas are supplied by recycling the ammonia and carbon dioxide gas generated in the crystallization step, so that ammonia and carbon dioxide gas to be newly replenished are not necessary, or only a small amount. Good.

In the dissolving step, a ferro scrap containing copper is treated in the presence of oxygen by using a mixed solution of the prepared ammoniacal aqueous solution and the returned leachate as a treating solution to selectively dissolve the copper. , Decoppered scrap and leachate containing copper. A part of the leachate is returned because, as described above, an ammine copper (II) complex having a remarkable effect of promoting copper dissolution is added to the treatment solution. For this purpose, it is generally preferred to return at least 70% of the leachate.

In the melting step, scrap is charged into a reactor, then the above mixed solution is injected, and an oxygen-containing gas (pure oxygen gas, air, etc.) as an oxidant is blown into the solution while stirring the solution. It is preferable to carry out. Since the gas discharged from the upper part of the reactor contains ammonia and unreacted oxygen, it is preferable to circulate and use the gas for gas injection to suppress the discharge of ammonia out of the system. Oxygen is consumed in the reaction, and oxygen is supplemented if necessary.
The processing temperature is usually room temperature to 70 ° C. By this process,
Copper in the scrap reacts with the aqueous ammonia solution and oxygen to selectively dissolve as an ammine copper (II) complex, as shown in the above formula (1). On the other hand, since iron, which is the main component of scrap, is passivated, virtually no melting of iron occurs.

The dissolution step is carried out by a batch operation using a plurality of reactors as shown in the figure, and the crystallization step is carried out by a continuous operation. In the dissolution process, after the completion of copper dissolution, the whole amount of the leachate produced was withdrawn from the reactor, a part of it was returned to the dissolution process by supplying it to another reactor, and the rest was temporarily stored in a storage tank. Then, it undergoes continuous crystallization in the crystallization process. The reason why the operation of this type is adopted in the present invention will be described below.

Leaching treatment in the conventional metal and chemical industry,
For example, in the leaching of valuable metals from ores, most of the leaching raw material (ore) is processed in powder form, so the raw material is continuously fed to the reactor (leaching tank) by means of powder conveyance or slurry conveyance. Easy to supply and withdraw.
However, it is difficult to grind the scrap, which is the processing raw material of the present invention, into a particle size suitable for continuous supply. It is not impossible to continuously load and unload scrap of irregular shape and large size into and out of the reactor, but this leads to enlargement of the equipment and significantly increases equipment costs. Therefore, in the method of the present invention, the melting step for treating scrap is a batch operation.

However, when the crystallization step is carried out in a batch operation, the leachate is charged into a crystallizer, heated to evaporate ammonia, and the slurry produced after crystallization is cooled to form a slurry. The operation of removing from the crystallizer must be repeated for each crystallization. This not only makes the operation complicated and unstable, but also requires repeated heating and cooling, resulting in a large energy loss. Further, if the number of times of this operation is reduced, a large crystallizer is required, which increases equipment cost. Therefore, in the method of the present invention, the crystallization step employs a continuous operation in which crystallization can be carried out stably and efficiently, and energy loss is small.

In order to reconcile the difference in operation method between the melting step and the crystallization step, the leachate separated from the scrap in the melting step is temporarily stored in a storage tank and then continuously sent to the crystallization step little by little. And continuously crystallize. In this way, both the steps of dissolution and crystallization can be efficiently carried out by the optimum method. In this case, after the copper removal treatment of the scrap is completed in the melting step, when the scrap is first taken out of the reactor, the scrap with a large amount of ammoniacal aqueous solution is exposed to the work environment, and toxic ammonia volatilizes around. , The working environment deteriorates significantly. Therefore, first remove all the leachate from the reactor, then wash the remaining scrap with water in the reactor, and if necessary, remove the adhering ammonia by another cleaning process, and then remove the scrap from the reactor. Is desirable.

In this case, if there is only one reactor in the melting step, the entire amount of the leachate is transferred to the storage tank for each decoppering treatment of one batch of scrap, the scrap cleaning treatment is completed, and the scrap is removed. After removal, some of the leachate in the storage tank will be returned to the reactor. The return amount of the leachate is preferably 70% or more in order to obtain a sufficient reaction accelerating effect, so it takes a very long time to transfer the liquid in the reciprocating direction between the reactor and the storage tank, and the scrap cleaning The dissolution treatment cannot be performed during the period. That is, the time required to transfer the liquid in the reciprocating direction and to wash the scrap is a standby time during which the copper removal processing of the scrap is impossible, and the processing efficiency is very poor.

According to the present invention, two or more reactors connected by the solution transfer means are prepared, the copper dissolution reaction of scrap is carried out in a batch operation in one of the reactors, and after the reaction, the reactors are dissolved. The whole amount of the leachate inside is withdrawn, a part (preferably 70% or more) thereof is transferred to another reactor by the solution transfer means, and the rest is transferred to the leachate storage tank. Before the solution is transferred, a scrap containing copper is charged into another reactor in advance, and then the leachate transferred from the solution transfer pipe is injected into the reactor. The shortage solution is replenished by simultaneously injecting the ammoniacal aqueous solution prepared in the solution preparation step to adjust the treatment solution to a predetermined concentration. On the other hand, in the reactor from which the whole leachate has been extracted, the remaining decoppered scrap is washed to remove the ammonia adhering to the scrap, and then the scrap is taken out. In this manner, the copper dissolution reaction is carried out by batch operation in each reactor while sequentially transferring the leachate from the reactor 1 to the reactor n.

Since ammonia gas is toxic and has a strong odor, it is preferable to remove ammonia from scrap as completely as possible in order to maintain a good working environment.
The washing treatment can be carried out by washing the scrap in the reactor with water supplied from the washing water storage tank, as shown in FIG. In the example shown in the figure, the wash water after washing is returned to the wash water storage tank, a part of this water is withdrawn in the solution preparation step, and new water is replenished to recycle ammonia in the wash water to the dissolution step, which is effective. In addition to being utilized, it prevents the increase of ammonia concentration in the wash water.

If residual ammonia is still present after washing with water, the ammonia can be completely removed from the scrap by another deammonia treatment (eg, spraying steam or gas at 100 ° C. or higher as shown). . When the steam or gas containing ammonia discharged from the reactor is used as a heat source in the crystallization process, the ammonia content can be recovered. In this way, the ammonia adhering to the scrap is removed in the reactor, so that the volatilization loss of ammonia due to the taking in and out of the scrap is almost eliminated. Then, the scrap is taken out of the reactor. This scrap has a significantly reduced copper content and becomes a high-quality raw material for steel melting.

In the present invention, by supplying a part of the leachate to the next reactor, ammine copper (II) as a reaction accelerator
The decopperization treatment of scrap can be performed in a short reaction time by using an ammoniacal aqueous solution containing a complex in a sufficient amount as a treatment solution. Furthermore, since the liquid withdrawal and the liquid injection into the next reactor proceed at the same time, the liquid transfer time, which is the waiting time, is shortened to almost half. Further, the cleaning process of scrap is carried out in parallel with the copper removal reaction of the next scrap, so it does not become the waiting time. Therefore, the waiting time is reduced to less than half. As described above, although the melting step for decoppering scrap is performed by the batch operation, the decoppering treatment can be performed very efficiently with the minimum waiting time.

The number (n) of reactors may be determined so as to be in harmony with the treatment capacity in the crystallization step, but normally 2 to 5 units will be sufficient. Further, it is preferable to connect the reactors with a solution transfer pipe so that the plurality of reactors form a loop. In order to prevent ammonia from escaping into the working environment, it is preferable that the reactor, the leachate storage tank, and the solution transfer pipe connecting these are all shielded from the outside air.

A part (preferably 30% or less) of the leachate extracted from the reactor is temporarily stored in a leachate storage tank and then supplied at a constant flow rate to the next crystallization step to undergo continuous crystallization. . In the crystallization step, the leachate is heated and / or decompressed in a suitable continuous crystallizer,
Ammonia and carbon dioxide are evaporated to decompose the ammine copper (II) complex and precipitate copper oxide crystals, as shown in the above formula (2). The slurry thus produced is continuously withdrawn from the crystallizer and sent to the next step of filtering and drying copper oxide.

Continuous crystallization is generally carried out by heating,
It is also possible to use a method utilizing reduced pressure such as flash distillation, which has the advantage that crystallization is completed in a short time. Crystallization by heating can be carried out using various known crystallizers, but a large amount of ammonia and carbon dioxide gas evaporate, so it is necessary to use a device capable of discharging and recovering the generated gas. As shown in the figure, it is economical to use steam available in the steel mill as the heat source. A preferable continuous crystallization apparatus suitable for use in this crystallization step is the apparatus described in JP-A-1-38045 to 1-38049. In these apparatuses, a plate distillation column (eg, a perforated plate distillation column) for directly injecting heated steam into a solution for crystallization and, if necessary, one or more crystallization tanks are provided in front of the distillation column. Take composition.

In the crystallization step, a large amount of ammonia and carbon dioxide gas are generated. In order to save resources in the method of the present invention, the vapor containing ammonia and carbon dioxide gas generated in the crystallization step is recycled to the treatment solution preparation step,
It is preferable to make effective use in the dissolution step.

The slurry containing the copper oxide crystals obtained from the crystallization step is filtered by a suitable device in the filtration / drying step to recover the copper oxide crystals. The recovered copper oxide crystals are usually washed with water and then dried to obtain a product. The water separated from the crystals by filtration is treated as wastewater.

The above description is for the case where the ammonium salt is ammonium carbonate. When forming a stable water-soluble salt with copper, such as ammonium sulfate, copper oxide does not crystallize even when the leachate is heated to evaporate ammonia, and copper sulfate does not crystallize as shown in equation (3). An aqueous solution is produced. In this case, recovery of copper from the leachate supplied from the leachate storage tank can be continuously performed by decomposition of the complex by heating the leachate and electrolysis of an aqueous solution (eg, copper sulfate aqueous solution) generated by the complex decomposition. . In the electrolysis step, the metal copper deposited on the cathode is recovered. On the other hand, the solution preparation step in this case can be carried out by recycling and absorbing the ammonia generated in the complex decomposition step into the electrolytic waste solution containing sulfate ions, and the ammoniacal aqueous solution containing ammonia and ammonium sulfate is regenerated. .

Examples of the copper-containing fest scrap to be treated by the method of the present invention include the above-mentioned waste automobiles, waste electrical products, and mechanical scraps. If desired, it is desirable to cut the scrap into suitable dimensions for processing before processing by the method of the present invention. Further, when the copper in the scrap is coated with an organic coating (eg, enamel coating) like the conductor wire of a motor coil, it is preferable to remove the organic coating and then perform the copper removal treatment. The removal of this organic coating removes scrap from 400-1000 ° C.
It can be carried out by incineration of the organic coating by heating to.

[0035]

[Example] Example 1 A scrap car was shredded with a shredder, and the copper content was 0.5.
Wt% ferro scrap (shredder scrap)
Was processed by the process shown in FIG.

A stainless steel container having an internal volume of 3 m ³ was used in the solution preparing step, and ^three stainless steel reactors having an internal volume of 1.5 m ³ were used in the dissolving step. Each of the wash water and leachate storage tanks was a stainless steel container having an internal volume of 3 m ³ . Diameter 150 mm, height 4500 m for crystallization process
An m 2 perforated plate type tray distillation column was used.

Each of the three reactors was charged with 500 kg of shredder scrap. First, reactor 1
NH ₃ 1.0 M, (NH ₄ ) ₂ CO ₃ 0.5 M, Cu (NH ₃ ) ₄ CO ₃ about 1.5
Inject 1000 liters of ammoniacal aqueous solution containing M concentration of ammine copper (II) complex and boil oxygen gas into the solution for 1.2 hours under the condition of solution temperature 50 ° C and circulating oxygen flow rate 1 m ³ / min. Copper removal treatment was performed.

Then, 30 liters of leachate from the reactor 1 was transferred to the leachate storage tank, and the remaining 970 liters of leachate was transferred to the reactor 2. The decoppered scrap remaining in the reactor is washed with water spray, and then deammonified by spraying steam, and the decoppered scrap from which ammonia has been completely removed is taken out of the reactor and a new shredder scrap 500 Charged kg. The copper content in the decoppered scrap had dropped to 0.07% by weight or less.
86% or more).

On the other hand, in the reactor 2, at the same time when the leachate from the reactor 1 was transferred, NH ₃ 4M,
(NH ₄ ) ₂ CO ₃ 2 M high-concentration ammoniacal aqueous solution (30 liters) was replenished to make the solution concentration in the reactor approximately the same as the solution used in reactor 1, and scrap treatment in reactor 1 In parallel with this, the scrap was decopperized under the same conditions as in reactor 1. In this way, the treatment of scrap is carried out by treating the leachate from the reactor 1 to the reactor 2 → the reactor 2 to the reactor 3 →
While sequentially transferring from the reactor 3 to the reactor 1, the batch operation was repeated. From the start of decoppering treatment in reactor 1,
The interval before the next decoppering process in reactor 2 is about 1.5.
It was time. Of these, 1.2 hours is the reaction time and the remaining
0.3 hours is the waiting time based on solution transfer.

About 150 leachate was transferred to the leachate storage tank.
After storing up to 1 liter, 50 leachate from this storage tank
It was continuously sent to the crystallization process at a flow rate of l / hr. In the crystallization step, using the above-mentioned plate distillation column, steam was blown into the column bottom as a heat source to heat the column bottom to evaporate ammonia and carbon dioxide gas and crystallize copper oxide. The vapor containing ammonia and carbon dioxide gas distilled from the top of the distillation column was recycled to the dissolution step via the solution preparation step. From the bottom of the distillation column, a slurry containing copper oxide crystals is continuously withdrawn at a flow rate such that the liquid level in the distillation column is kept constant and transferred to a filter, where the copper oxide separated by filtration is Was collected after washing with water and drying.

For comparison, using only one reactor, after the dissolution treatment, the total amount of the leachate was once transferred to a storage tank,
After the decoppered scrap was washed with water and deammonified with steam and taken out, a new shredder scrap was charged, and 970 liters of the leachate was returned from the storage tank, and the batch operation was repeated twice. In this case, the interval between the first copper removal start and the second copper removal start was about 2.1 hours. Of these, 1.2 hours was the reaction time, so the waiting time was 0.9 hours. That is, the waiting time was about three times longer than that of the method of the present invention.

[0042]

As described above, according to the method of the present invention, the melting step is carried out by a batch operation suitable for scrap processing, and the obtained leachate is once stored in a storage tank and then crystallized or otherwise. Since the copper recovery treatment is carried out by a continuous operation, both the steps of dissolution and copper recovery (crystallization) can be carried out efficiently. In addition, the dissolution process is streamlined between reactors using multiple reactors, streamlining the solution transfer, and cleaning the scrap in parallel with the next scrap process. Is possible.
As a result, the waiting time until the next reaction is significantly shortened, and the dissolution step can be performed very efficiently despite the batch operation.

Further, by extracting the leachate from the reactor after the dissolution treatment of copper and washing the decoppered scrap in the reactor to remove ammonia, the volatilization loss of ammonia accompanying the putting in and out of scrap is eliminated, and the ammonia odor is removed. Not scrap can be collected. Furthermore, by recycling the anions of ammonia and ammonium salts generated by the decomposition of the ammine copper (II) complex in the copper recovery step, the scrap treatment can be continued with almost no need to supplement the reaction components.

Therefore, the method of the present invention is very efficient, economical and practical, and it is expected that the decoppering treatment of scrap with an ammoniacal aqueous solution will be promoted toward practical use. As a result, scrap recycling is promoted, and at the same time copper resources are effectively used,
The present invention greatly contributes to resource saving.

[Brief description of drawings]

FIG. 1 is a process chart showing an example of a decoppering process of the present invention.

Claims (4)

[Claims] 1. A ferro scrap containing copper is treated with an ammoniacal aqueous solution containing ammonia and an ammonium salt in the presence of oxygen to selectively dissolve the copper in the scrap as an ammine copper (II) complex. A method for recovering copper oxide or metallic copper from a leachate in which copper is dissolved through decomposition of an ammine copper (II) complex together with obtaining decopperized scrap, wherein the scrap treatment is linked by a solution transfer means. Performed by batch operation in one of the plurality of reactors, and after the completion of the treatment, the whole amount of the leachate in the reactor is withdrawn, and a part of the leachate is transferred to another reactor by the solution transfer means to remove the next scrap. It is used for treatment, and the remaining leachate is stored in a storage tank once and then used for recovery of copper oxide or metallic copper by continuous operation. Copper removal and recovery method. 2. A step of preparing an ammoniacal aqueous solution containing ammonia and ammonium carbonate, and treating ferro-scrap containing copper with the ammoniacal aqueous solution in the presence of oxygen to convert the copper in the scrap into ammine copper ( II) a dissolution step of selectively dissolving as a complex to obtain a leachate in which decoppered scrap and copper are dissolved, and ammonia and carbon dioxide gas are evaporated from the leachate to decompose the ammine copper (II) complex and oxidize it. A method for removing and recovering copper in a ferro scrap containing copper, which comprises a step of crystallizing copper and a step of filtering and drying the crystallized copper oxide to recover the copper oxide. In a batch operation in one of the plurality of reactors connected by a solution transfer means,
After the treatment was completed, the whole amount of the leachate in the reactor was extracted, a part of the leachate was transferred to another reactor by the solution transfer means and used for the next scrap treatment, and the remaining leachate was temporarily stored in a storage tank. Then, a method for removing and recovering copper in the ferro scrap, characterized by performing a crystallization treatment by a continuous operation in a crystallization step. 3. The decoppered scrap remaining in the reactor after the entire amount of the leachate has been extracted is subjected to a cleaning treatment for removing ammonia in the reactor, and then taken out. The method according to 1 or 2. 4. The method according to claim 1, wherein ammonia generated by the decomposition of the ammine copper (II) complex is recovered and recycled to prepare an ammoniacal aqueous solution.