JP5143495B2 - Method for producing copper solution and method for producing copper - Google Patents

Description

  The present invention relates to a method for producing a copper solution and a method for producing copper using the same, and more specifically, to produce a copper solution by efficiently dissolving a crude copper powder obtained by pulverizing crude copper in a short time. The manufacturing method of the copper solution which can be performed, and the manufacturing method of copper using the copper solution obtained by the manufacturing method of this copper solution.

Conventionally, as an electrolytic purification process for converting crude copper into purified copper (electrocopper), for example, as shown in FIG. 1, in a copper electrolyte solution 3 in an electrolytic cell 4, a high purity copper plate is obtained from an anode 1 made of crude copper. When a direct current is passed through the cathode 2 made of the material, the copper content in the anode 1 is dissolved and transferred to the cathode 2 and deposited as purified copper (pure copper) on the surface of the cathode plate.
The crude copper usually contains noble metals, and these noble metals settle and deposit on the bottom of the electrolytic cell as slime during the electrolytic purification process. Precious metals and impurities are recovered by separately treating the sedimented and accumulated slime.

  However, in the conventional method, the distance between the anode and the cathode is preferably short in order to improve the productivity per unit area. However, if the distance is too short, a short circuit is likely to occur. When a short circuit occurs, current efficiency is reduced, and generation of nodules or the like causes an increase in impurities due to deterioration of the external shape of the cathode, entrainment of slime, and the like.

  In contrast, in the electrolytic refining process, the bottom of the electrolytic cell is made of a material that can be an insoluble anode, electrolytic slime is deposited on the bottom plate, and the bottom plate is electrically used as the anode to promote dissolution of the slime. Has been proposed (see, for example, Patent Document 1).

JP 2000-309893 A

However, the amount of copper deposited by electrolysis is proportional to the magnitude of the current, so increasing the current density increases the production capacity, but the inclusion of slime and copper electrolyte increases the level of impurities in the electrolytic copper, and The quality sometimes deteriorated. In addition, Cu ions are saturated in the copper electrolyte solution adjacent to the anode, non-conductive CuSO ₄ · 5H ₂ O crystals are precipitated, and a passive state phenomenon in which Cu cannot be eluted occurs. Sometimes occurred. Furthermore, the noble metal contained in a trace amount in the crude copper cannot be recovered until the final process, and the recovery of the noble metal may be delayed.

  An object of the present invention is to solve various problems in the prior art and achieve the following objects. That is, the present invention is a method for producing a copper solution capable of recovering noble metals early and effectively using them, removing impurities before electrolysis, and improving copper dissolution efficiency by using crude copper powder, Another object of the present invention is to provide a method for producing copper, which can repeatedly use sulfuric acid by using the copper solution obtained by the method for producing the copper solution and can produce high-quality purified copper extremely efficiently.

Means for solving the problems are as follows. That is,
<1> A method for producing a copper solution in which crude copper powder obtained by pulverizing crude copper is dissolved in an acid solvent,
The crude copper powder is dissolved in the first tank, a liquid containing undissolved material is charged into the second tank to precipitate the crude copper powder, and the concentrated and concentrated copper powder slurry portion is returned to the first tank, and the second tank It is a manufacturing method of the copper solution characterized by making the supernatant slurry part of a tank into a copper solution via filtration.
<2> The method for producing a copper solution according to <1>, wherein stirring is not performed in the second tank.
<3> The method for producing a copper solution according to any one of <1> to <2>, wherein the crude copper powder slurry portion precipitated and concentrated in the second tank is returned from the vicinity of the bottom of the first tank.
<4> The method for producing a copper solution according to any one of <1> to <3>, wherein the copper concentration of the copper solution is 50 g / L to 150 g / L.
<5> The method for producing a copper solution according to any one of <1> to <4>, wherein sulfuric acid is used as the acid solvent.
<6> A copper production method including at least a pulverization step, a copper powder dissolution step, a filtration step, a liquid purification step, and an electrolysis step,
The method for producing copper, wherein the copper powder dissolving step is performed by the method for producing a copper solution according to any one of <1> to <5>.

According to the method for producing a copper solution of the present invention, when the crude copper powder is dissolved in an acid solvent, the liquid containing the undissolved material is charged into the second tank, the crude copper powder is precipitated, and the concentrated copper powder is precipitated and concentrated. Since the slurry portion is returned to the first tank, the efficiency of copper dissolution is significantly improved, and the copper dissolution time in the copper production method using the coarse copper powder can be greatly shortened.
In addition, according to the copper production method of the present invention, purified copper is obtained using the copper solution obtained by the above production method, so that sulfuric acid can be used repeatedly, and the production cost is greatly reduced by shortening the time. Is possible.

Hereinafter, the manufacturing method of the copper solution of this invention is demonstrated in detail.
In the method for producing a copper solution of the present invention, crude copper powder obtained by pulverizing crude copper is dissolved in a solution containing an acid solvent to prepare a copper solution.
Here, the copper solution is a solution in which copper before adjustment is dissolved in a copper electrolyte used for electrolytic purification of copper, such as removal of impurities, reduction of free sulfuric acid concentration, adjustment of copper concentration for electrolysis, etc. In the present invention, it is distinguished from the copper electrolyte used for the electrolytic purification of copper.

  There is no restriction | limiting in particular as rough copper powder used for the manufacturing method of the said copper solution, Although it can select suitably according to the objective, Typically, it obtains by pulverizing crude copper as follows. .

<Crude copper>
There is no restriction | limiting in particular as a raw material of crude copper, For example, using the copper concentrate which selected copper ore of 0.5%-2.0% of copper grade excavated from the mine, and raised it to 20%-40% of copper grade However, in the present invention, it is preferable to use a recycled raw material selected from a waste printed board, a waste electronic component, and a waste electrical component from the viewpoint of effective use of resources.

The recycled material is pulverized and sieved, and this is concentrated and recovered into copper concentrate by copper, precious metal, etc. by specific gravity difference, magnetic force, eddy current sorting and electrostatic sorting. Manufacture.
In addition to Cu, the crude copper usually contains trace amounts of As, Ni, Pb, Sn, Zn, Fe, Sb, Bi, S, Te, Se, Au, Ag, Pt, Pd and the like. Among these, those containing a large amount of noble metals such as Au, Ag, Pt, and Pd are particularly preferable.

  The copper concentration in the crude copper is preferably 93% by mass to 95% by mass. According to the copper production method using the copper solution obtained in the present invention described later, highly purified copper can be efficiently obtained even from crude copper having a low copper concentration.

<Powdering process>
There is no restriction | limiting in particular as said powdering process, According to the objective, it can select suitably, For example, a wet reduction method, a vapor phase reduction method, an atomization method etc. are mentioned. Among these, the atomizing method is particularly preferable because it can be produced in large quantities at a low cost.

The atomizing method is a method of producing a crude copper powder by injecting a high-pressure gas or water as a grinding medium into a molten metal stream, grinding the metal stream, cooling and solidifying it.
In the gas atomization method in which gas is applied to the grinding medium, the obtained crude copper powder has a spherical shape, and it is possible to produce crude copper powder with a low oxygen content by using an inert gas, but the particle size is compared. It becomes rough. This is because the cooling rate of molten copper is low in the gas atomization method.

  In contrast, the water atomization method using water as the pulverizing medium can produce a product having a large shear energy and a small particle size because the mass of water is heavier than the gas even when shearing at the same flow rate as the gas. . In addition, the cooling rate can be increased, and a powder having an irregular grain shape and many irregularities on the surface is often produced. Moreover, since it becomes a particle | grain with a large surface area for said reason, the powder with comparatively high oxygen content is manufactured under the influence of the water vapor | steam which generate | occur | produces at the time of molten metal cooling, and the oxygen in atmosphere.

  In the present invention, in the water atomization method, a molten metal flow is caused to flow substantially in the center, and a water jet is jetted from its periphery so as to have an inverted conical shape, or a V-shaped water jet is opposed to the molten metal flow. The molten metal is crushed at the point (line) where the water jet converges or in the vicinity thereof by injecting it into a shape. In atomization, the angle between the molten metal and the water jet greatly affects the crushing force and also greatly affects the rebound phenomenon of the molten metal (molten metal). It is more preferable to inject so that it may become a letter shape from the point of freedom, such as adjustment of an injection angle.

Here, as an example of the atomizing apparatus used for the atomizing process, as shown in FIG. 2, the molten copper flow is retained by holding a molten iron flow from a holding furnace capable of holding and tilting molten copper. The molten copper flow is made to flow down from the tundish 10 and the nozzle 11 at the bottom of the tundish 10, and the molten copper flow is pulverized by discharging high-pressure water or air to the flowing molten copper flow. The spraying part 12 to be used, and the storage part 13 which is below the spraying part 12 and cools, stores and carries out the powdered crude copper powder. In FIG. 2, 14 is a stopper, 15 is a burner for keeping the molten copper in the tundish 10 warm, and 17 is a baffle plate bar.
As another example of the apparatus, a molten metal nozzle hole may be formed at the bottom of the crucible in the furnace having the crucible, and the hot water may be discharged from the nozzle in the same manner as described above.

Further, the water atomization method will be described in detail. First, the crude copper is melted, and the molten crude copper is flowed down from the bottom nozzle 11 of the tundish 10 to form a molten copper flow, and a water jet is injected into the molten copper flow. The temperature of the molten copper is preferably 50 ° C. or higher and more preferably 150 ° C. or higher with respect to the copper melting temperature (about 1083 ° C.). When the melting temperature is less than 150 ° C., the viscosity of the molten copper stream containing many impurities may be too high to smoothly flow. In addition, when the molten copper flow is caused to flow down from the tundish 10, a nozzle 11 is generally provided at the bottom thereof, and the molten copper flow is caused to flow down from the nozzle 11, but the nozzle diameter is 0.5 mm in diameter. -30 mm is preferable, 0.5 mm to 20 mm is more preferable, 3 mm to 15 mm is still more preferable, and 3 mm to 10 mm is particularly preferable. Further, the nozzle shape may not be circular, but the area thereof is preferably in a range equivalent to the area in the case of the circular shape. Outside this range, it becomes difficult to adjust the flow rate of the molten copper flow, and the molten copper flow may be clogged. Further, if the nozzle diameter is too large, it is difficult to produce fine granular powder.
Moreover, there may be a plurality of nozzles, and the molten copper flow rate is preferably 10 kg / min to 60 kg / min, more preferably 20 kg / min to 50 kg / min per nozzle.
The molten copper injection flow rate (pressure) is a factor that determines the discharge water flow rate, and the flow rate of the discharge water flow is preferably 100 m / s or more, and more preferably 200 m / s or more.
The amount of water is preferably 2 or more, more preferably 3 or more, and still more preferably 4 or more in terms of water / solution ratio. If the water / solution ratio is insufficient, a sufficient pulverization effect cannot be obtained, and a coarse powder tends to be obtained. Moreover, the amount of water vapor | steam generated can be reduced by making water solution ratio high.
The total solution flow rate is not particularly limited as long as the above relationship is balanced, and can be appropriately selected according to the purpose, and is preferably about 60 kg / min to 80 kg / min, for example.

  As the injection conditions of the water jet, the water pressure is preferably 10 MPa to 100 MPa, more preferably 20 MPa to 50 MPa. If the water pressure is less than 10 MPa, the particle size of the coarse copper powder may not be refined, and if the water pressure is 10 MPa or more, the particle size can be refined and the surface smoothed. At a high pressure such that the water pressure exceeds 100 MPa, the spraying apparatus becomes large and unrealistic. Moreover, in addition to making the said water pressure into the said range, 50 L / min-1,000 L / min are preferable, and 300 L / min-600 L / min are more preferable. When the water flow rate is less than 50 L / min, the generated water vapor is wound up, and the oxidation of the crude copper powder is promoted to increase the oxygen content. Cooling occurs and the apparatus becomes difficult.

As the shape of the water jet flow ejected from the spray nozzle of the spraying section 12, it is sprayed in a fan shape and a planar shape, and as shown in FIG. As shown in FIG. 4, an inverted quadrangular pyramid shape using four injection nozzles 100, 100, 100, 100 is preferable.
In FIG. 3, water is sprayed in three directions from three spray nozzles 100, 100, 100 in a fan shape and in a planar shape, and an inverted trigonal pyramid shape is formed by the water spray. Flow down 101 and grind.
In FIG. 4, water is sprayed from four directions from four spray nozzles 100, 100, 100, 100 in a fan-like and flat shape, and an inverted quadrangular pyramid shape is formed by the water spray, and is melted at the substantially central portion thereof. The copper stream 101 flows down and is crushed.
As shown in FIG. 5, the fan-like apex angle θ of the water jet flow ejected from the ejection nozzle 100 is preferably 10 ° to 30 °, and more preferably 15 ° to 25 °. When the apex angle θ is less than 10 °, the molten copper flow may deviate from the water jet flow, and it is necessary to spread the molten copper flow at a certain angle so that the molten copper flow and the water jet collide with each other. Moreover, even if the angle is too wide, the water jet flow unnecessarily spreads, so that there is an ineffective water flow.

  In the particle size distribution of the crude copper powder obtained by the powdering treatment, the mass ratio of the coarse copper powder having a particle size of 250 μm or less is preferably 90% or more, and the mass ratio of the crude copper powder having a particle size of 106 μm or less is 90% or more. More preferred. If the particle size is too large, the dissolution rate of the coarse copper powder may be slowed in the copper powder dissolving step described later, resulting in poor efficiency.

-Copper powder dissolution process-
Next, the crude copper powder obtained by the pulverization treatment is dissolved using an acid solvent. As this acid solvent, for example, sulfuric acid, nitric acid and the like can be used as appropriate, but sulfuric acid is particularly preferable.
Specifically, the crude copper powder is dissolved in the first tank, a liquid containing undissolved material is charged into the second tank, the crude copper powder is precipitated, and the concentrated coarse copper powder slurry portion is added to the first tank. The supernatant slurry portion of the second tank is made into a copper solution via filtration.
In the dissolution treatment, an oxidizing agent such as oxygen gas, air, or hydrogen peroxide may be used together with the acid solvent.

  The copper concentration of the copper solution obtained in the copper powder dissolving step is preferably 50 g / L to 150 g / L, and more preferably 70 g / L to 140 g / L. When the copper concentration is less than 50 g / L, the concentration may be too low when the copper electrolyte is prepared in a later step, and when it exceeds 150 g / L, copper sulfate may be precipitated depending on the temperature. May occur.

Moreover, it is preferable not to stir in the said 2nd tank, ie, to have no stirrer. Thereby, residual coarse copper powder begins to settle immediately after liquid feeding, and can be deposited on the bottom part periphery of a 2nd tank.
Furthermore, it is preferable to return the precipitated coarse copper powder and liquid from the vicinity of the bottom of the first tank.

  Here, as shown in FIG. 7, a dissolution tank 30 as a first tank for producing a copper solution includes a dissolution tank body 31 that stores the copper solution, and a baffle plate 32 inside the dissolution tank body. A stirrer 33 is disposed for stirring the copper solution. The stirrer 33 can control the number of rotations, and four turbine blades are in one stage. In addition, the temperature of the stored liquid can be raised and lowered and controlled at a constant temperature. In the dissolution tank, there is a pipe 34 through which a part of the liquid flows out to the side wall and is sent to a precipitation tank 35 as a second tank. The settling tank 35 is provided with a pump 36 into which the remaining coarse copper powder that has been dissolved in the dissolving tank 30 flows in together with the liquid, precipitates the remaining coarse copper powder, and returns it to the dissolving tank 30. In FIG. 7, reference numeral 37 denotes a coarse copper powder supply hopper, and 38 denotes an air ejector as an oxidant supply.

  In addition, after several minutes from the start of dissolution, the remaining copper powder that is in the middle of dissolution floats, and is sent to the precipitation tank 35 together with the liquid. Therefore, the opening on the side of the dissolution tank 30 of the pipe 34 is preferably near the copper solution liquid surface. In the settling tank 35, since there is no stirrer, the remaining coarse copper powder starts to settle immediately after feeding, and accumulates around the bottom of the settling tank 30. This is extracted together with the liquid from the bottom, and the liquid and the remaining coarse copper powder are put into the dissolution tank 30 via the pump 36. At this time, it is preferable to return from the vicinity of the bottom of the dissolution tank 30 from the viewpoint that the dissolution efficiency of copper can be improved.

  As shown in FIG. 7, the precipitation tank 35 is arrange | positioned in the dissolution tank 30, and the coarse copper powder precipitated in this precipitation tank 35 is sent to the dissolution tank 30, and a dissolution reaction is performed again. When the crude copper powder is dissolved while circulating the undissolved crude copper powder in this manner, the copper dissolution efficiency is remarkably improved, the dissolution time can be shortened, and the manufacturing cost can be greatly reduced.

Next, the copper manufacturing method of the present invention will be described in detail.
The copper manufacturing method of this invention uses the copper solution manufactured by the manufacturing method of the above-mentioned copper solution in a copper melt | dissolution process. Hereinafter, one embodiment of the method for producing copper of the present invention will be described with reference to FIG.

As shown in FIG. 6, the method for producing copper of the present invention comprises a filtering step of dissolving a crude copper powder obtained by pulverizing crude copper with an acid solvent (copper dissolving step), and filtering the obtained copper solution, and An electrolytic process is performed to obtain purified copper.
The copper production method of the present invention includes at least a pulverization step, a copper powder dissolution step, a filtration step, and an electrolysis step, preferably a desilvering substitution step, a secondary leaching step, and a liquid purification step. , A precious metal recovery step can be included, and other steps can be included as required. In addition, a copper powder melt | dissolution process and a filtration process may be collectively called a primary leaching process.

  In the copper production method, precious metals can be recovered early and effectively used, impurities can be removed before electrolysis, the efficiency of copper dissolution can be improved by using crude copper powder, and sulfuric acid can be used repeatedly. High-quality purified copper can be obtained efficiently.

(1) Powdering process The said powdering process is the same as the powdering process in the manufacturing method of the copper solution of this invention mentioned above, A rough copper powder is obtained by this process.

(2) Primary leaching step The primary leaching step includes a copper powder dissolution step and a filtration step, and may include a desilvering substitution step as necessary.

-Copper powder dissolution process-
The said copper powder melt | dissolution process is the same as the copper melt | dissolution process in the manufacturing method of the copper solution of this invention mentioned above, and, thereby, a copper solution is obtained.

-Filtration process-
The said filtration process is a process of filtering the copper solution containing the copper powder melt | dissolution slurry of a copper powder melt | dissolution tank. Here, what is not dissolved in the copper solution in which copper is dissolved but remains as a precipitate is filtered to obtain a primary residue.

-Desilvering substitution process-
A desilvering substitution step may be included between the copper powder dissolution step and the filtration step. This desilvering and replacing step is a step in which a solution containing the copper powder dissolving slurry in the copper dissolving tank is fed from the copper powder dissolving tank to the desilvering and replacing tank and processed in the desilvering and replacing tank.
Here, in the copper solution in which copper is dissolved, silver dissolved in a trace amount and other noble metals are cemented with undissolved copper powder in the copper powder dissolution slurry, and the dissolved silver, This is a step of solidifying the noble metal. When oxidized by applying a temperature in a copper powder dissolution tank, silver and the like dissolve in a very small amount in addition to copper, and have the role of returning it. The desilvering / replacement tank performs cementation with a constant residence time without blowing oxygen with only low stirring. Thereafter, the precipitate resulting from the cementation is filtered to obtain a primary residue containing a noble metal.
The filtration method is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include a filter press and vacuum filtration.

  Since a large amount of silver is dissolved in the filtrate of the secondary leaching tank (residue dissolution tank) and the filtrate of the purification liquid dissolution tank, which will be described later, these filtrates are put in a desilvering and replacement tank, and the above copper powder Perform cementation with the dissolved slurry. In addition, since the dissolved silver is electrodeposited prior to copper in electrolysis and causes deterioration of the quality of electrolytic copper, it is taken out as a residue in the primary leaching process and the secondary leaching process, and collected in a noble metal recovery process described later.

(4) Secondary leaching process (residue dissolution process)
The secondary leaching step is a step of leaching the primary residue with a used copper electrolyte solution, adding an oxidizing agent to the leaching solution, and obtaining a secondary residue having a higher precious metal concentration than the primary residue. Performed to increase the concentration of noble metals.
That is, the primary residue of the primary leaching step is immersed and dissolved in the used copper solution, but a secondary residue (insoluble precipitate) remains. This is filtered to remove secondary residues (insoluble precipitate). At this time, the concentration of noble metal in the secondary residue (insoluble precipitate) is higher than that of the primary residue.
Examples of the oxidizing agent include oxygen gas, air, and hydrogen peroxide.

  In the secondary leaching step, the primary residue (dissolved residue) from the primary leaching step is preferably leached using a copper electrolyte solution (electrolytic tail solution) that has been used in an electrolysis step described later. This electrolytic tail solution is an acid having a high concentration of free sulfuric acid and a strong leachability since metal ions such as copper are collected from the solution during electrolysis. Most of the copper in the primary residue is leached into the liquid, but noble metals that are hardly soluble in sulfuric acid are transferred into the secondary residue. The secondary residue is obtained by filtration or the like and used as a raw material for the precious metal recovery step.

(5) Precious metal recovery step The precious metal recovery step is a step of recovering precious metal from the secondary residue.
Examples of the noble metal include silver, gold, platinum, palladium, rhodium, and ruthenium.
There is no restriction | limiting in particular as a method of collect | recovering noble metals from the said secondary residue, Although it can select suitably according to the objective, For example, electrolytic purification, electrowinning, etc. are mentioned.

(6) Liquid Purification Step The liquid purification step is a step of reducing the free sulfuric acid concentration of the copper solution that is the filtrate in the primary leaching step and removing impurities in the copper solution, and is performed before the electrolysis step. It is preferable to do.
In the liquid purification step, the copper solution was put into a liquid solution dissolution tank, the copper powder was dissolved, and the free sulfuric acid concentration was brought close to 0 (zero), so that impurities such as arsenic, antimony and tin exceeded the solubility. Falls as a minute precipitate. By separating this from solid and liquid, impurities in the solution can be efficiently removed.
Moreover, although what fell as this deposit is isolate | separated by filtration, since there exists a small amount of undissolved copper powder and a noble metal in it, it is preferable to collect | recover. In this process, after filtration with a filter press, backwashing is performed with a post-electrolysis solution, so that impurities can be redissolved and recovered while leaving undissolved copper powder and noble metal in the filter press. The solution in which the impurities are redissolved is copper removal electrolysis, and after copper is recovered, it is preferably treated as waste water as waste water.
In the liquid purification step, impurities (for example, As and Sb) in the copper solution are reduced. For example, crude copper powder was added to the copper solution, air was blown into the liquid, and the crude copper powder was dissolved in the copper solution while stirring to reduce the free sulfuric acid concentration. After the reaction, the solution is filtered, and the copper concentration of the filtrate is adjusted for electrolysis to obtain an electrolytic solution for copper electrolysis. By using the crude copper powder in this manner, it is possible to remove arsenic, which is an inhibitory element, particularly in copper electrolysis, and it is possible to suppress an increase in cost because a new chemical agent such as hydrogen sulfide is not used.

(7) Electrolytic step The electrolytic step is a step of obtaining electrolytic copper by electrolyzing the copper solution (filtrate) obtained in the primary leaching step or the liquid purification step with a copper electrolytic solution adjusted for electrolysis. is there.
The copper concentration in the primary leaching step or the liquid purification step is adjusted with, for example, a used copper electrolytic solution to obtain a copper electrolytic solution. The copper electrolytic solution is preferably a copper sulfate solution having a copper concentration of 70 g / L to 100 g / L and a free sulfuric acid concentration of 5 g / L or less, particularly 1 g / L or less, and the liquid temperature is adjusted to 10 ° C. to 40 ° C. ing.
There is no restriction | limiting in particular as electrolysis conditions in the said electrolysis process, Although it can select suitably according to the objective, It is preferable as follows.
[Electrolysis conditions]
Current ^density: Preferably ^{20A / m 2 ~700A / m 2} , 30A / m 2 ~400A / m 2 is more preferable.
・ Bath voltage: 0.5V-3V
-Bath temperature: 30 to 80 degreeC is preferable and 40 to 70 degreeC is more preferable.
As the anode, for example, Pb, Pb alloy or the like is used.
For example, copper or stainless steel is used as the cathode.

  In addition, the higher the liquid temperature, the lower the power intensity, which is preferable. However, the decomposition rate of glue added for the purpose of smoothing the surface increases, the temperature constraint on the equipment, working atmosphere, heating cost, etc. For this reason, it is preferable to set an upper limit.

Specifically, as shown in FIG. 8, in the electrolytic process, the electrolysis process is performed by applying a direct current from a lead-based anode 1 to a cathode 2 made of a high-purity copper plate through a rectifier in a copper electrolyte 3 in an electrolytic cell 4. By flowing, water is electrolyzed at the anode 1, electrons move to the cathode 2, and deposit as electrolytic copper (pure copper) on the surface of the cathode plate.
In the electrolysis step, the anode is not passivated as compared with the prior art, and is less susceptible to the slime generated from the anode, so that the quality of electrolytic copper is improved.

  The copper produced by the copper production method of the present invention has a high purity and high purity because it contains less impurities (including noble metals) in the copper electrolyte than in the past. It is suitably used in various fields such as equipment materials, LSI wiring, and electric wires.

  Examples of the present invention will be described below, but the present invention is not limited to these examples.

Example 1
<Powdering process>
-Preparation of crude copper-
As raw materials for crude copper, waste printed circuit boards, waste electronic components, and waste electrical components are collected, crushed and sieved, and sorted by specific gravity difference, magnetic force, eddy current sorting, and electrostatic sorting to concentrate copper. It collect | recovered and it was set as the copper concentrate, this was processed with the converter, and crude copper was obtained. The composition of this crude copper is shown in Table 1. In addition to the elements described in Table 1, the crude copper contained trace amounts of Bi, S, Te, Se, Au, Ag, Pt, and the like.

-Powdering treatment-
Next, the crude copper having the above composition was melted in a melting furnace, and an atomizing process for obtaining a coarse copper powder was performed.
As shown in FIG. 2, the atomizing apparatus used for this atomizing process holds the molten copper, receives the tundish 10 from the holding furnace capable of tilting and stores the molten copper, and the molten copper from the bottom of the tundish. A spraying part 12 for pulverizing molten copper by discharging high-pressure water into the flowing molten copper stream and cooling the pulverized coarse copper powder below the spraying part And a storage unit 13 for storing and unloading.
Using this atomizing device, 100 kg of the crude copper was received in a tundish from a holding furnace in which molten copper was stored at 1130 ° C., and while keeping the temperature, 10 kg / min to 13 kg / min from a downstream outlet having a diameter of 13 mm. Then, the molten copper flow was flown down and sprayed at a water pressure of 20 MPa and a flow rate of 68 L / min by three-way blowing on the flow of molten copper flow to obtain 50 kg of crude copper powder. At this time, an inverted triangular pyramid shape was formed by the water ejected from the nozzle, and the molten copper flow was allowed to flow down to its substantially central portion.

The obtained coarse copper powder was sieved with a sieve having an opening of 106 μm, and the fine particle side was obtained as 106 μm under powder. At this time, the mass of the coarse copper powder that passed through the sieve was divided by the total mass of the coarse copper powder that had been sieved, and the percentage was obtained as a percentage, and it was 98 mass%. Further, when the particle size distribution was measured by sieving, 60% by mass was less than 25 μm, 22% by mass was 25 μm or more and less than 45 μm, 16% by mass was 45 μm or more but less than 106 μm, and the remainder was 106 μm or more.
The composition of the obtained 106 μm under powder of Example 1 was as shown in Table 2 below.

<Primary leaching process>
-Copper powder dissolution process-
Using the crude copper powder under the sieve shown in Table 2 above, dissolution was performed as follows to prepare a copper solution.
As shown in FIG. 7, the dissolution tank 30 for producing the copper dissolution liquid includes a dissolution tank body 31 for storing the copper dissolution liquid, and a baffle plate 32 disposed inside the dissolution tank body, and stirring of the copper dissolution liquid. A stirrer 33 is arranged. The stirrer 33 can control the number of rotations, and four turbine blades are in one stage. In addition, the temperature of the stored liquid can be raised and lowered and controlled at a constant temperature. In the dissolution tank, there is a pipe 34 through which a part of the liquid flows out to the side wall and is sent to the precipitation tank 35. The settling tank 35 is provided with a pump 36 into which the remaining coarse copper powder that has been dissolved in the dissolving tank 30 flows in together with the liquid, precipitates the remaining coarse copper powder, and returns it to the dissolving tank 30. In FIG. 7, 37 represents a coarse copper powder supply hopper, and 38 represents an air jet.

In the dissolution tank 30, 100 L of a liquid having a copper concentration of 40 g / L and a free sulfuric acid concentration of 10 g / L in a copper sulfate solution is prepared. To this, 4.4 kg of crude copper powder is added, and the crude copper powder is stirred and stirred. Dissolved. The set liquid temperature of the dissolution tank was 60 ° C., and the dissolution reaction was performed for 1 hour.
After several minutes from the start of dissolution, the remaining copper powder that is in the middle of dissolution floats, and is sent to the precipitation tank 35 together with the liquid. Therefore, the opening on the side of the dissolution tank 30 of the pipe 34 is preferably near the copper solution liquid surface. In the settling tank 35, since there is no stirrer, the remaining coarse copper powder begins to settle immediately after the liquid is fed and is deposited around the bottom of the settling tank. This is extracted together with the liquid from the bottom, and the liquid and the remaining coarse copper powder are put into the dissolution tank 30 via the pump 36. At this time, it is returned to the bottom of the dissolution tank 30.
As shown in FIG. 7, the precipitation tank 35 is arrange | positioned in the dissolution tank 30, and the coarse copper powder settled in the precipitation tank is sent to a dissolution tank, and a dissolution reaction is made again. When the crude copper powder is dissolved while circulating the undissolved crude copper powder in this manner, the copper dissolution efficiency is remarkably improved, the dissolution time can be shortened, and the manufacturing cost can be greatly reduced.
And the melt | dissolution rate of the copper solution in a melt | dissolution tank at the time of 30 minutes from a melt | dissolution start was calculated | required as follows. The results are shown in Table 3.

<Evaluation of solubility of crude copper powder>
The copper solution in the dissolution tank at 30 minutes from the start of dissolution was sampled, and the copper concentration in the copper solution was analyzed by an ICP emission spectroscopic analyzer (manufactured by Shimadzu Corporation).
The dissolution rate (% by mass) is obtained by dividing the dissolved copper amount (g) obtained by calculation based on the copper concentration value obtained by ICP analysis as a numerator and the copper mass (g) in the added crude copper powder as the denominator. Expressed in

(Comparative Example 1)
For comparison, in Example 1, the crude copper powder was dissolved only in the dissolution tank without providing a precipitation tank. The dissolution rate at 30 minutes after the start of dissolution was determined in the same manner as in Example 1. The results are shown in Table 3.

From the results in Table 3, when a precipitation tank is placed in the dissolution tank as in Example 1, the crude copper powder precipitated in the precipitation tank is sent to the dissolution tank, dissolved again, and dissolved while circulating to dissolve copper efficiency. Was found to be significantly improved. As a result, the process time can be shortened, and the manufacturing cost can be greatly reduced. In addition, the copper concentration in the copper solution at this time was about 80 g / L.

In the method for producing a copper solution of the present invention, when the crude copper powder is dissolved in an acid solvent, a liquid containing undissolved material is added to the second tank to precipitate the crude copper powder, and the concentrated copper powder slurry portion is concentrated by precipitation. Therefore, the efficiency of copper dissolution is remarkably improved, and the produced copper solution is suitably used in a method for producing copper using crude copper powder.
The copper produced by the copper production method using the copper solution obtained by the copper solution production method of the present invention has less impurities (including noble metals) contained in the copper electrolyte than in the prior art. It is a high-purity copper grade and is suitably used in various fields such as electronic component materials, electronic equipment materials, LSI wiring, and electric wires.

FIG. 1 is a flow diagram illustrating an example of a conventional copper electrolysis process. FIG. 2 is a schematic cross-sectional view showing an example of an atomizing apparatus used for powdering treatment. FIG. 3 is a schematic view showing water injection in a three-way system (inverted triangular pyramid). FIG. 4 is a schematic view showing water injection in a four-way system (inverted quadrangular pyramid). FIG. 5 is a schematic view showing an example of a horizontal fan type injection nozzle. FIG. 6 is a flowchart showing a copper electrolysis process using the coarse copper powder produced by the method for producing a copper electrolyte raw material of the present invention. FIG. 7 is a schematic cross-sectional view showing an example of a dissolution tank and a precipitation tank used in the copper melting step. FIG. 8 is a schematic view showing an example of an electrolytic cell used in the electrolysis process.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Copper anode 2 Cathode 3 Copper electrolyte 4 Electrolysis tank 10 Tundish 11 Bottom nozzle 12 Spraying part 13 Storage part 30 Dissolution tank 31 Dissolution tank main body 32 Baffle plate 33 Stirrer 35 Precipitation tank 100 Injection nozzle 101 Molten copper flow

Claims (6)

A method for producing a copper solution in which crude copper powder obtained by pulverizing crude copper is dissolved in an acid solvent,
The crude copper powder is dissolved in the first tank, a liquid containing undissolved material is charged into the second tank to precipitate the crude copper powder, and the concentrated and concentrated copper powder slurry portion is returned to the first tank, and the second tank A method for producing a copper solution, wherein the supernatant slurry portion of the tank is made into a copper solution via filtration.   The manufacturing method of the copper solution of Claim 1 which does not stir in a 2nd tank.   The manufacturing method of the copper solution in any one of Claim 1 to 2 which returns the rough | crude copper powder slurry part settled and concentrated in the 2nd tank from the bottom part vicinity of a 1st tank.   The method for producing a copper solution according to any one of claims 1 to 3, wherein the copper concentration of the copper solution is 50 g / L to 150 g / L.   The method for producing a copper solution according to any one of claims 1 to 4, wherein sulfuric acid is used as the acid solvent. At least a method for producing copper including a pulverization step, a copper powder dissolution step, a filtration step, a liquid purification step, and an electrolysis step,
The said copper powder melt | dissolution process is performed by the manufacturing method of the copper solution in any one of Claim 1 to 5, The manufacturing method of copper characterized by the above-mentioned.