KR100902521B1 - Electrolytic process for the production of metallic copper and apparatus therefor - Google Patents

Abstract

An electrolytic process for producing metal copper in an electrolytic cell comprising an anode chamber and a cathode chamber separated from each other by a porous member, an anode located in the anode chamber, and a cathode located in the cathode chamber. The electrolytic process comprises the steps of providing an ammoniacal alkaline electrolyte solution containing diamine cuprous ions in each of the anode and cathode chambers, and applying direct current to the anode and cathode to produce metal copper on the cathode and tetra Producing a cuprous ions. An electrolytic cell apparatus comprising an anode chamber and a cathode chamber separated from each other by a porous member, an anode located in the anode chamber, a cathode located in the cathode chamber, and a direct current power source connected to the anode and the cathode. Ammoniacal alkaline electrolyte solution containing diamine cupric ions.

Electrolysis Process

Description

ELECTROLYTIC PROCESS FOR THE PRODUCTION OF METALLIC COPPER AND APPARATUS THEREFOR

1 is a schematic view of one embodiment of an electrolyzer device according to the invention.

[Description of Major Symbols in Drawing]

1: electrolyzer 2: porous member

3: cathode chamber 4: anode chamber

5: cathode 6: anode

7: electrolyte 8: DC power

9: Regeneration chamber 10,11: line

12: Purifier

The present invention relates generally to a process and apparatus for producing metal copper, and more particularly to an electrolytic process and apparatus for producing metal copper from copper-containing waste in which copper is present in the form of a metal or copper compound.

The need for resource conservation and environmental protection has become an important and pressing issue. Copper is one of the most important metals and many studies have been done to recover copper from copper-containing waste. Conventionally, recovery of copper from copper-containing waste has been carried out in a process of producing copper from copper ore by smelting. However, it is not possible to increase the amount of copper-containing waste to be treated with copper ore. Another known method for recovering copper from copper-containing waste is a wet process, in which the waste is treated with an acid such as sulfuric acid or hydrochloric acid. In this process, not only copper but also various other metals are bleached in an acidic solution, it is necessary to separate the copper compound and other metal compounds in order to increase the purity of the copper.

The electrowinning process is an effective method for recovering high purity copper metals from copper-containing solutions. This process of activating the Cu (II) ion electrolyte solution to form metal copper on the negative electrode and oxygen on the positive electrode consumes a lot of electrical energy to conduct electrolysis.

It is therefore an object of the present invention to provide an economical process that can recover metal copper by electrolysis with reduced electrical energy.

It is another object of the present invention to provide an electrolytic process of the above-described form capable of recovering metal copper from waste such as a printed wiring board containing metal copper.

It is yet another object of the present invention to provide an electrolyzer device capable of effectively producing metal copper from a copper-containing solution.

In order to achieve the above object, an electrolytic process for producing metal copper in an electrolytic cell comprising an anode chamber and a cathode chamber separated from each other by a porous member, an anode located in the anode chamber, and a cathode located in the cathode chamber is according to the present invention. Provided. The process comprises the steps of providing an ammoniacal alkaline electrolyte solution containing diamine cuprous ions in each of the anode chamber and the cathode chamber, and preventing substantial migration of tetramine cupric ions from the anode chamber to the cathode chamber. And applying a direct current to the cathode to produce metal copper on the cathode and to produce tetramine cupric ions on the anode.

In another aspect, the present invention, the electrolytic cell device comprising a positive electrode chamber and a negative electrode chamber separated from each other by a porous member, an anode located in the anode chamber, a cathode located in the cathode chamber, and a direct current power source connected to the anode and the cathode The present invention provides an electrolyzer device, wherein each of the anode chamber and the cathode chamber comprises an ammoniacal alkaline electrolyte solution containing diamine cupric ions.

Referring to FIG. 1, reference numeral 1 denotes an electrolytic cell having a porous member such as a porous diaphragm or membrane 2 that divides the internal space of the housing 1 into a cathode chamber 3 and an anode chamber 4. Indicates. The negative electrode 5 and the positive electrode 6 are disposed in the negative electrode chamber 3 and the positive electrode chamber 4, respectively, and are electrically connected to the DC power source 8.

Electrolyte solution 7 The permeable porous member 2 can be, for example, a fabric or a porous ceramic. A filter fabric for the filtration process can be suitably used as the porous member 2. The porous ceramic member may be, for example, a porous sheet having a metal substrate in the form of a net such as a nickel net and supported with nickel carbonyl powder sintered thereon. Such a composite member can be obtained by roll-pressing a nickel carbonyl powder layer together with a metal net to fix the layer on the net, and then sintering at about 1000 ° C. under an oxidizing atmosphere.

Cathode 5 electrochemically deposits, for example, copper, platinum plated titanium, stainless steel, titanium, nickel, platinum, alloy 42 (alloy containing about 42% iron and 58% nickel) or metal copper thereon. It may be another metal capable of giving electrons to Cu (I) ions to form. The anode 6 can be, for example, platinum, nickel, titanium, platinum-plated titanium, iridium oxide, ferrite, stainless steel, graphite, carbon fiber, or a Dimension Stable Anode (DSA). . In FIG. 1, devices such as pumps, valves and the like commonly used in systems containing liquid flow are not shown.

Contained in each cathode chamber 3 and anode chamber 4 is an ammoniacal alkaline electrolyte solution 7, which contains Cu (I) containing diamine cupric ions ([Cu (NH ₃ ) ₂ ] ⁺ ). Contains ions.

When the negative electrode 5 and the positive electrode 6 are energized by the direct current power source 8, the following reaction takes place on the negative electrode 5:

[Cu (NH ₃ ) ₂ ] ⁺ + e = Cu + 2 NH ₃

In the meantime, the following reaction takes place on the anode (6):

[Cu (NH ₃ ) ₂ ] ⁺ + 2 NH ₃ = [Cu (NH ₃ ) ₄ ] ⁺⁺ + e

Where e represents the former.

The electrolysis is suitably carried out at a temperature of 15-80 ° C. and a current density of 200 to 2,000 A / m ² .

The electrolyte solution 7 contained in the cathode chamber 3 preferably contains as little Cu (II) ions as possible in order to reduce the consumption of electrical energy required for electrolysis. Thus, by allowing the electrolyte solution 7 to flow from the cathode chamber 3 to the anode chamber 4 through the porous member 2, tetramine cupric ions are transferred from the anode chamber 4 to the cathode chamber 3. It is preferable to conduct electrolysis while substantially preventing the movement. This can be done by continuously or intermittently releasing a part of the electrolyte solution 7 from the anode chamber 4 while continuously or intermittently supplying a solution containing Cu (I) ions to the cathode chamber 3. .

The ammoniacal alkaline electrolyte solution 7 contains diamine cupric ions ([Cu (NH ₃ ) ₂ ] ⁺ ) and, if necessary, other Cu (I) complex ions. Examples of Cu (I) complex ions other than the diamine cupric ions are, as ligands, represented by Cl, Br, I, acetonitrile, cyanide, phosphine (PRH ₂ , PR ₂ H or PR ₃ ), Wherein R represents an alkyl group such as methyl, ethyl or propyl or an aryl group such as phenyl, tolyl or naphthyl) or arsine (AsH ₃ , As ₂ H ₄ , AsR ₃ or As ₂ R ₄ , where R is Complexes) having an alkyl group such as methyl, ethyl or propyl or an aryl group such as phenyl, tolyl or naphthyl).

The electrolyte solution 7 is preferably produced by reacting a waste containing copper with an ammoniacal alkaline solution containing copper (II) ions and a complexing agent. Examples of complexing agents include ammonium sulfate and ammonium chloride.

In a preferred embodiment, the electrolyte solution 7 can be produced by reacting metal copper with an ammoniacal alkaline solution containing Cu (II) ions in the presence of a complexing agent such as ammonium sulfate or ammonium chloride. Thus, the electrolyte solution 7 releases an ammoniacal alkaline solution containing tetramine cupric ion ([Cu (NH ₃ ) ₄ ] ⁺⁺ ) from the anode chamber 4 via line 10 and It can preferably be produced by introducing the released solution into a regeneration chamber 9 containing metal copper. In the regeneration chamber 9, the metal copper is oxidized with tetramin cupric ions as follows to form a diamine cuprous ion-containing ammonia alkaline solution, which is passed through the line 11 to the cathode chamber 3. ) Is recycled.

Cu + [Cu (NH ₃ ) ₄ ] ⁺⁺ = 2 [Cu (NH ₃ ) ₂ ] ⁺

When the metal copper used in the regeneration chamber 9 is contained in a material in which at least one additional metal component selected from the group consisting of Ni, Co and Zn coexists, the diamine cuprous ion from the regeneration chamber 9- The containing solution may further contain additional metal ions. In such a case, the diamine cupric ion-containing solution discharged from the regeneration chamber 9 is subjected to an anion exchange resin-filling ion exchanger tube, an ion chelating agent, in order to remove additional metal components before being introduced into the cathode chamber 3. The treatment is preferably performed in a purifier 12 such as a packed tube or a solvent extraction tube containing the same.

It is preferable that the ammoniacal alkaline electrolyte solution 7 has a pH of 8 to 12 in order to prevent precipitation. Also, in order to prevent precipitation, the concentration of Cu (I) ions in the ammoniacal alkaline electrolyte solution 7 is preferably at least five times the NH ₃ concentration contained in the ammoniacal alkaline electrolyte solution 7. More preferably, the concentration of Cu (I) ions in the ammoniacal alkaline electrolyte solution 7 is at least 6.3 g / L to prevent hydrogen formation at the negative electrode 5.

As can be seen from the reactions occurring at the cathode 5 and anode 6, the concentration of proton ions or hydroxyl ions does not change during electrolysis. In other words, the process according to the invention does not require pH adjustment of the electrolyte solution during electrolysis. However, when oxygen is present in contact with the electrolyte solution, the following reaction occurs, causing the pH of the electrolyte solution to change.

_{2 [Cu (NH 3) 2} ] + + 4NH 3 + 0.5O 2 + 2H + = 2 [Cu (NH 3) 4] ++ + H 2 O

This entails the need for the addition of a pH adjuster to facilitate the electrolysis. Therefore, it is preferable that the electrolyte solution is substantially prevented from contacting with oxygen. This can be accomplished, for example, using an inert gas atmosphere, such as an airtight electrolyzer and / or a nitrogen atmosphere.

The following examples will further clarify the invention.

Example 1

An ammoniacal alkaline electrolyte solution containing 31.8 g / L Cu (I) ion (diamine cupric ion), 5.0 mol / L NH ₃ and 1 mol / L ammonium sulfate was charged into an airtight electrolytic cell, The interior of the vessel was separated by a filter fabric into a cathode chamber in which the copper cathode was located and an anode chamber in which the platinum anode was located. The inner space of the electrolyzer was degassed and kept in a nitrogen atmosphere. Electrolysis was performed at 25 ° C. by applying direct current (current density: 500 A / m ² ) to the cathode and the anode. Metal copper is formed on the anode with a current efficiency of 98% based on the theoretical yield, while copper (II) ions (tetramine cupric ion) are formed on the anode with a current efficiency of 99% based on the theoretical yield Was observed. The electrolyte in the cathode chamber was colorless and transparent, while the electrolyte in the anode chamber turned blue. The power consumed was 190 kWh / t, which was much less than the power needed to produce metal copper (2,000 to 2,500 kWh / t) by the electrowinning process using sulfuric acid electrolyte.

Example 2

Ammonia alkaline with 25.2 g / L Cu (I) ions, 6.3 g / L Cu (II) ions, 5.0 mol / L NH ₃ and 1 mol / L ammonium sulfate using 28% aqueous ammonia An electrolyte solution was prepared. The ammoniacal alkaline electrolyte solution was filled into an airtight electrolytic cell, and the inside of the vessel was separated by a filter fabric into a cathode chamber where a copper cathode was located and an anode chamber where a platinum anode was located. The inner space of the electrolyzer was degassed and kept in a nitrogen atmosphere. Electrolysis was performed at 25 ° C. by applying direct current (current density: 500 A / m ² ) to the cathode and the anode. Metal copper was formed on the cathode with a current efficiency of 78% based on the theoretical yield, while copper (II) ions were formed on the anode with a current efficiency of 96% based on the theoretical yield. When the process was repeated in the same manner as described above except that the process was carried out at a temperature of 60 ° C., it was observed that metal copper was formed on the cathode with a current efficiency of 48% based on the theoretical yield.

Example 3

Of 5.0 mol / L in an aqueous solution containing ammonium sulfate of NH _3, 0.25 mol / L of copper sulfate (Ⅱ) and 1 mol / L, it was immersed in a printed wiring board having a metal wiring of copper. The aqueous solution was stirred under nitrogen atmosphere for 8 hours to obtain a substantially colorless solution (ammonia alkaline solution containing diamine cupric ions) that was used as feedstock.

The airtight electrolyzer was separated into a cathode chamber and an anode chamber by a permeable filter fabric. The copper plate cathode (4 cm × 4 cm) and the platinum plate anode (4 cm × 4 cm) were located in the cathode chamber and the anode chamber, respectively, and one of the two surfaces of each of the cathode and anode plates was in contact with the inner wall of the electrolytic cell. Only surfaces can be used. The inner space of the electrolyzer was degassed and kept in a nitrogen atmosphere. Anode chamber (200 ml), an aqueous solution containing 5.0 mol / L NH ₃ , 0.1 mol / L Cu (I) ions, 0.4 mol / L Cu (II) ions, and 1 mol / L ammonium sulfate On the other hand, a negative electrode solution (200 ml), an aqueous solution containing 5.0 mol / L of NH ₃ , 0.5 mol / L of Cu (I) ion and 1 mol / L of ammonium sulfate, was charged to the negative electrode chamber. Stir the electrolyte in each chamber with a magnetic stirrer. Electrolysis was carried out by applying a direct current (current density: 500 A / m ² ) to the cathode and anode for 8 hours at 25 ° C. in a nitrogen atmosphere, while supplying feedstock to the cathode in an amount of 2 ml per minute, while maintaining the anode chamber. The same amount of positive electrode solution was released from the. The average bath voltage was 1.2 V and the current efficiency was 99% based on the theoretical yield. The energy consumption rate was 570 kWh / t.

According to the present invention described above, it is possible to provide an economical process capable of recovering metal copper by electrolysis with reduced electrical energy. In addition, it is possible to provide an electrolytic process of the above-described type that can recover metal copper from waste such as a printed wiring board containing metal copper, and to provide an electrolytic cell apparatus that can effectively produce metal copper from a copper-containing solution. have.

Claims (12)

An electrolytic process for producing metal copper in an electrolytic cell comprising an anode chamber and a cathode chamber separated from each other by a porous member, an anode located in the anode chamber, and a cathode located in the cathode chamber, Providing an ammoniacal alkaline electrolyte solution containing diamine cuprous ions in each of the anode chamber and the cathode chamber, and Applying a direct current to the anode and the cathode to produce metal copper at the cathode and tetramine cupric ions at the anode; The electrolytic process according to claim 1, further comprising causing the electrolyte solution to flow from the cathode chamber to the anode chamber through the porous member. 2. The electrolyte solution according to claim 1, wherein the electrolyte solution further contains copper (I) ions other than diamine cuprous ions so that Cu (II) ions other than tetramine cupric ions are additionally formed at the anode. Electrolysis process. The electrolytic process according to claim 1, wherein the electrolyte solution is produced by reacting a waste containing metal copper with an ammonia alkaline solution containing copper (II) ions and a complexing agent. The electrolytic process according to claim 1, wherein the electrolyte solution has a pH of 8 to 12. The electrolytic process according to claim 1, wherein the electrolyte solution is prevented from contacting with oxygen. The method according to claim 1, wherein the electrolyte solution is discharged from the anode chamber, the released electrolyte solution is reacted with copper in the presence of a complexing agent to obtain a diamine cuprous ion-containing solution, and the diamine first Recycling at least a portion of the copper ion-containing solution to the cathode chamber. 8. The method according to claim 7, wherein the copper is contained in a material in which at least one additional metal component selected from the group consisting of Ni, Co, and Zn coexists, so that a diamine cuprous ion-containing solution is used for ions of the additional metal component. Wherein said process further comprises, prior to said recycling step, treating the diamine cupric ion-containing solution to remove said additional metal component therefrom. delete An electrolytic cell apparatus comprising an anode chamber and a cathode chamber separated from each other by a porous member, an anode located in the anode chamber, a cathode located in the cathode chamber, and a direct current power source connected to the anode and the cathode. Each of the anode chamber and the cathode chamber includes an ammoniacal alkaline electrolyte solution containing diamine cuprous ions, A regeneration chamber comprising a metal copper containing material and a complexing agent; The electrolyte solution is supplied from the anode chamber to the regeneration chamber so that the electrolyte solution supplied to the regeneration chamber reacts with the copper in the presence of a complexing agent to obtain a diamine cuprous ion-containing solution. Supply passage connecting the; And a recycling passage connecting said regeneration chamber and said cathode chamber to recycle at least a portion of a diamine cupric ion-containing solution to said cathode chamber. The electrolytic cell apparatus according to claim 10, wherein each of the cathode chamber, the anode chamber, the regeneration chamber, the supply passage and the recirculation passage is sealed to prevent contact between the electrolyte solution flowing through them and the air. The electrolyzer apparatus according to claim 10, further comprising a purifier installed in said recirculation passage to remove metal ion contaminants selected from Ni, Co, and Zn ions from the diamine cupric ion-containing solution.

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