JP2000239885A - Anode for electrolytic refining of copper and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce an anode for the electrolytic refining of copper capable of reliably preventing the inclusion of Bi into electrolytic copper though Bi is contained in the anode by a simple method and apparatus excellent in economical efficiency. SOLUTION: The anode for the electrolytic refining of copper has a lead content satisfying the conditions (1) 260 (mass-ppm)<=hPb <=600 (mass-ppm) in the case of Bi<40 (mass-ppm), (2) 260 (mass-ppm)<=Pb<=[50.0×Bi-1,400] (mass-ppm) in the case of 40 (mass-ppm)<=Bi<46 (mass-ppm), (3) [50.4×Bi-2,058] (mass-ppm)<=Pb<=[50.0×Bi-1,400] (mass-ppm) in the case of 46 (mass-ppm)<=Bi<71 (mass-ppm) and (4) 1,520 (mass-ppm)<=Pb<=2,150 (mass-ppm) in the case of Bi >=71 (mass-ppm). Metal lead is added to a refining furnace in the dry refining of copper and/or metal lead is added to crude copper aftermelt refining in an anode casting step to produce the objective anode for the electrolytic refining of copper.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an anode for electrolytic copper refining used in electrolytic refining in copper smelting and a method for producing the same. The present invention relates to a copper electrolytic refining anode capable of preventing contamination with copper and a method for producing the same.

[0002]

2. Description of the Related Art Electrolytic copper in copper smelting is manufactured by the following steps. That is, first, crude copper obtained by dissolving and oxidizing copper ore is purified in a purification furnace, and the obtained purity is obtained.
98-99wt% refined crude copper is converted to an anode plate for copper electrolytic refining (hereinafter referred to as
(Referred to as copper electrolytic refining anode or anode).

Next, an anode and a cathode plate (hereinafter, referred to as a cathode) for copper electrorefining obtained by casting are alternately arranged at regular intervals in an electrolytic tank containing an electrolytic solution which is a copper sulfate solution. , Current density: under conditions where a current of 200 to 270 A / m ² or more is applied, copper ions eluted from the anode, which is purified crude copper, into the electrolytic solution are electrodeposited on the cathode, and extremely high-purity copper ( Electrolytic copper) is manufactured.

[0004] On the other hand, the anode, which is purified crude copper, contains a small amount of impurities.
Impurity metal ions such as i, Sb, As, and Fe elute into the electrolyte. If the concentration of these impurity metal ions in the electrolyte exceeds a certain value, the purity of the electrodeposited copper decreases, the current efficiency decreases, and the conductivity decreases. Is needed.

[0005] In particular, Bi forms floating slime in the electrolytic solution and adheres to the surface of the cathode to lower the quality of the product (electrolytic copper), and tends to cause bumps on the surface of the electrodeposited copper. , Bi present in the grain boundaries has an adverse effect such as melting at the time of hot working in wire processing of electrolytic copper and cutting or breaking the processed product. For this reason,
It is usually necessary to limit the Bi content to 1 mass-ppm or less.

In order to minimize the influence of Bi on the above copper products, the concentration of Bi suspended in the electrolyte must be reduced.
It must be kept below 100mg / l. As a method for removing Bi from the electrolyte, JP-A-55-154595 and JP-B-58-154595 have been disclosed.
No. 10995 discloses a method of adding a drug to an electrolytic solution. However, these methods described above,
A method of co-precipitating Bi, Sb with barium sulfate generated by adding barium carbonate to the electrolyte, or a method of co-precipitating Bi by adding carbonate of barium, strontium or lead in the electrolyte, There was a problem.

[0007] That is, the above-mentioned methods for removing Bi all involve adding a chemical such as barium carbonate, strontium carbonate, or lead carbonate to the electrolytic solution, which requires an expensive chemical and a predetermined amount of the chemical. However, there is a problem in that Bi cannot be prevented from being mixed into the electrolytic copper even if is added. Also, in the electrolyte
As another method of removing Bi, JP-A-60-211091 discloses a method of removing impurities such as Bi and Sb in an electrolytic solution by bringing the electrolytic solution into contact with a specific chelating resin.

[0008] However, the above-mentioned method at least involves adsorption,
A two-column adsorption tower is required for desorption, and handling of the deteriorated chelate resin becomes a problem.

[0009]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of the prior art, and to add a chemical addition step or a liquid purification step using an adsorbent to the electrolytic refining step,
It is an object of the present invention to provide a copper electrolytic refining anode capable of reliably preventing Bi in a copper electrolytic refining anode from being mixed into electrolytic copper by a simple and economical method and apparatus, and a method for producing the same. And

[0010]

The present inventors have conducted intensive studies to solve the above-mentioned problems of the prior art, and
The present inventors have found that it is possible to reliably prevent Bi in an electrolytic solution from being mixed into electrolytic copper by adding metal lead to a copper electrolytic refining anode in advance, and have arrived at the present invention.

That is, a first invention is an anode for copper electrolytic refining used for electrolytic refining in copper smelting,
An anode for copper electrolytic refining, characterized in that the lead content in the anode satisfies the following conditions (1) to (4). (1) When Bi <40 (mass-ppm): 260 (mass-ppm) ≦ Pb ≦ 600 (mass-ppm) (2) When 40 (mass-ppm) ≦ Bi <46 (mass-ppm): 260 (mass-ppm) ≤ Pb ≤ [50.0 x Bi-1400] (mass-ppm) (3) When 46 (mass-ppm) ≤ Bi <71 (mass-ppm): (50.4 x Bi-2058) ( mass-ppm) ≦ Pb ≦ (50.0 × Bi-140
0] (mass-ppm) (4) When 71 (mass-ppm) ≤ Bi: 1520 (mass-ppm) ≤ Pb ≤ 2150 (mass-ppm) In the above formulas (1) to (4), , Bi, and Pb all indicate mass-ppm.

A second invention is a method for producing an anode for electrolytic copper refining used for electrolytic refining in copper smelting,
A method for producing an anode for electrolytic copper refining, comprising adding metal lead to molten refined crude copper in a refining furnace and / or a casting step of the anode in copper dry smelting.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail. As described above, the electrolytic refining as the final stage of copper smelting is performed by electrodepositing a plate-shaped anode, which is purified crude copper serving as a copper source of electrolytic copper, and copper ions eluted from the anode into the electrolytic solution as metallic copper. The cathodes are alternately arranged.

As the above-mentioned anode, one obtained by casting purified crude copper obtained in a refining furnace and shaping it into an anode shape for electrolytic refining is used. The anode for copper electrolytic refining in the present invention corresponds to the Bi content in the purified crude copper,
This is an anode obtained by adding metallic lead to purified crude copper. The addition of metallic lead to purified blister copper is carried out in a refining furnace in the dry smelting of copper,
Alternatively, it can be carried out at the time of casting an anode for copper electrolytic refining, that is, at the time of pouring molten copper into a mold, or at both.

In the present invention, it is preferable to add metallic lead to molten copper which is being refined in a refining furnace, and moreover, metallic lead (hereinafter also referred to as Pb) is added to the molten copper after completion of the reduction treatment in the refining furnace. Is more preferably added. This is because the following effects (1) to (3) can be obtained by using the above method.

(1) Predetermined amount of P by simple method and high yield
b can be added to the copper electrorefining anode. (2) Pb can be uniformly distributed in the anode. (3) According to the above (1) and (2), at the time of electrolytic purification, Bi eluted from the anode and Pb generated from the eluted Pb
Coprecipitation with SO ₄ can be performed quickly and sufficiently.

It is preferable to adjust the amount of metallic lead to be added in accordance with the Bi content in the purified crude copper, ie, the Bi quality. FIG. 1 shows a preferred relationship between the Bi content and the Pb content in the anode for copper electrolytic refining discovered by the present inventors. As shown in FIG. 1, the Pb content in the anode for copper electrolytic refining in the present invention corresponds to the Bi content in the anode,
It is preferable to satisfy the following conditions (1) to (4).

(1) When Bi <40 (mass-ppm): 260 (mass-pp)
m) ≤ Pb ≤ 600 (mass-ppm) (2) When 40 (mass-ppm) ≤ Bi <46 (mass-ppm): 260 (mass-p
pm) ≤ Pb ≤ [50.0 x Bi-1400] (mass-ppm) (3) When 46 (mass-ppm) ≤ Bi <71 (mass-ppm): (50.4 x Bi
−2058) (mass-ppm) ≦ Pb ≦ (50.0 × Bi-1400) (mass-pp
m) (4) When 71 (mass-ppm) ≤ Bi: 1520 (mass-ppm) ≤ Pb ≤ 2150
(mass-ppm) In the above conditions (1) to (4), the unit of Bi and Pb indicates mass-ppm.

The Pb content in the copper electrolytic refining anode is adjusted according to the above-mentioned conditions (1) to (iv) in accordance with the Bi content in the anode.
If it is not less than the lower limit of (4),
Bi contamination can be prevented. Further, when the Pb content exceeds the upper limit of the above-mentioned conditions (1) to (3) in the range of Bi <71 (mass-ppm), the effect of preventing the incorporation of Bi is substantially saturated, and economical and economical. When the Pb content exceeds the upper limit of the above condition (4) in the range of 71 (mass-ppm) ≦ Bi, Pb is mixed into the electrolytic copper, and the current efficiency also decreases.

Further, in the present invention, the content of Pb in the anode for electrolytic copper refining corresponds to the content of Bi in the anode in order to prevent Bi from being mixed into the electrolytic copper product. It is more preferable to satisfy the following conditions (5) to (8). (5) When Bi <40 (mass-ppm): 300 (mass-ppm) ≤ Pb ≤ 600
(mass-ppm) (6) When 40 (mass-ppm) ≤ Bi <45 (mass-ppm): 300 (mass-p
pm) ≦ Pb ≦ [52.0 × Bi-2040] (mass-ppm) (7) When 45 (mass-ppm) ≦ Bi <71 (mass-ppm): [52.0 × Bi
−2040) (mass-ppm) ≦ Pb ≦ (50.0 × Bi-1400) (mass-pp
m) (8) When 71 (mass-ppm) ≤ Bi: 1600 (mass-ppm) ≤ Pb ≤ 2150
(mass-ppm) In the above conditions (5) to (8), the unit of Bi and Pb indicates mass-ppm.

According to the present invention described above, by adjusting the Pb content in accordance with the Bi content in the purified crude copper in the anode production stage, Bi can be stably and reliably incorporated into electrolytic copper. It became possible to prevent. This is considered to be due to the following reason. That is, in the electrolytic refining of copper, usually about 20 to 50 anodes are arranged in the electrolytic cell, respectively, in opposition to the cathode for electrolytic copper electrodeposition.

Further, the stirring of the liquid in the electrolytic cell is naturally limited since it causes dispersion of the slime and entrainment in the electrodeposited copper. As a result, when Bi is prevented from being mixed into electrolytic copper by adding a chemical as in the related art, formation of a concentration distribution of the chemical in the electrolytic solution cannot be avoided even under the circulating condition of the electrolytic solution.

On the other hand, according to the present invention, a predetermined amount of Pb is added to and contained in each anode, so that Bi eluted from the anode is replaced with a predetermined amount of PbSO ₄ generated by Pb eluted from the same anode. And quickly co-precipitate.
As a result, it is possible to stably prevent Bi from being mixed into the electrolytic copper. Also, according to the present invention, Bi in the anode
By adjusting the content of Pb according to the content,
Bi can be extremely effectively prevented from being mixed into the electrolytic copper for all of the electrolytic copper in the electrolytic cell.

Further, according to the present invention, it is only necessary to add metallic lead to molten copper in a refining furnace, and when metallic lead is added in the anode casting step, an apparatus for adding metallic lead is provided. Only with simple, economical methods and equipment,
It has become possible to prevent Bi in the anode for copper electrolytic refining from being mixed into electrolytic copper.

[0025]

The present invention will be described more specifically below with reference to examples. (Example) The contents of Bi and Pb in refined crude copper being refined in a refining furnace in dry smelting of copper were analyzed.

Next, based on the obtained analysis results, the melting after the oxidation / reduction treatment is completed so that the Pb content of the purified crude copper satisfies the Pb content of the above-mentioned conditions (1) to (4). Metal lead is added to purified blister copper, and the obtained molten purified blister copper is poured into a mold, and an anode plate for copper electrolytic refining: anode A (Example 1 of the present invention);
Anode B (Inventive Example 2) was produced. Table 1 shows the Pb content and Bi content in the purified crude copper before the addition of metal lead and the Pb content and Bi content in the anode after the addition of metal lead for each anode.

The Pb content in the anode A and the anode B obtained by adding the metal lead coincides with the content calculated from the addition amount of the metal lead. The addition yield of metal lead was able to be improved.

[0028]

[Table 1]

Next, each of the produced anodes and cathodes was
An electrolytic refining experiment of purified crude copper was performed under the following conditions by alternately arranging the same in the same electrolytic cell. [Electrolysis refining conditions] Electrolyte: Copper sulfate aqueous solution (Cu: 45 g / l, H ₂ SO ₄ : 200 g / l) Cathode current density: 250 A / m ² Bath temperature: 60 ° C Electrodeposition time: 24 h After electrolytic refining, cathode The electrodeposited copper is peeled off and collected, and the Bi in each copper corresponding to the anode A and the anode B is removed.
As a result of analyzing the content, the Bi content was 0.1 mas, respectively.
Less than s-ppm and less than 0.2 mass-ppm, high purity copper with low Bi content could be produced.

No bump was observed on the surface of any electrolytic copper, and no cutting occurred during the processing of the electrolytic copper wire. (Comparative Example) An anode C was manufactured in the same manner as in the above-described Example except that no metallic lead was added to the refined crude copper after the completion of the oxidation / reduction treatment.

Table 1 shows the Pb content and Bi content in the purified crude copper. Next, an electrolytic refining experiment of the purified crude copper was performed under the same conditions as in the above-described example. After the electrolytic refining, the copper electrodeposited on the cathode was peeled off and collected, and the surface was observed and the Bi content in the copper was analyzed.As a result, the occurrence of bumps on the surface of the copper was observed. The amount was 1.2 mass-ppm, which was outside the allowable range.

[0032]

According to the present invention, it is possible to reliably prevent Bi from being mixed into electrolytic copper by an extremely simple method and apparatus.

[Brief description of the drawings]

FIG. 1 is a graph showing a preferable relationship between a Bi content and a Pb content in an anode for copper electrolytic refining.

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Gunshi Ishii 6-1-1 Hibi, Tamano-shi, Okayama Mitsui Mining & Smelting Co., Ltd.Hibi Smelter Co., Ltd. (72) Inventor Kazuyuki Kawabata Hino, Tamano-shi, Okayama 6-1-1 Mitsui Kinzoku Mining Co., Ltd. Hibiki Smelter F-term (reference) 4K001 AA09 BA23 DA05 GA13 4K058 AA11 BA21 BB03 EC04

Claims (2)

[Claims] An anode for copper electrorefining used in electrolytic refining in copper smelting, wherein the content of lead in the anode satisfies the following conditions (1) to (4): Anode for electrolytic refining. (1) When Bi <40 (mass-ppm): 260 (mass-ppm) ≦ Pb ≦ 600 (mass-ppm) (2) When 40 (mass-ppm) ≦ Bi <46 (mass-ppm): 260 (mass-ppm) ≤ Pb ≤ [50.0 x Bi-1400] (mass-ppm) (3) When 46 (mass-ppm) ≤ Bi <71 (mass-ppm): (50.4 x Bi-2058) ( mass-ppm) ≦ Pb ≦ (50.0 × Bi-140
0] (mass-ppm) (4) When 71 (mass-ppm) ≤ Bi: 1520 (mass-ppm) ≤ Pb ≤ 2150 (mass-ppm) In the above formulas (1) to (4), , Bi, and Pb all indicate mass-ppm. 2. A method for producing an anode for copper electrorefining used in electrolytic refining in copper smelting, wherein metal lead is contained in molten refined crude copper in a refining furnace and / or a casting step of the anode in dry smelting of copper. A method for producing an anode for electrolytic refining of copper, characterized by adding: