JP3151182B2 - Copper electrolyte cleaning method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention removes metals such as copper, arsenic, antimony, bismuth and nickel which increase in a circulating copper electrolytic solution when electrolytically refining crude copper to produce high-purity electrolytic copper. The present invention relates to a method for purifying a copper electrolyte solution, and in particular, a hydrogen sulfide gas can be generated in a required amount by adding sodium hydrogen sulfide on site, which is very convenient in handling, and nickel is used as nickel sulfate and nickel sulfide.
The present invention relates to a method for purifying a copper electrolyte which enables impurities such as arsenic, antimony, and bismuth to be separated and recovered as sulfide.

[0002]

2. Description of the Related Art In a copper electrolytic refining system for producing high-purity electrolytic copper by electrolytically refining crude copper, copper, arsenic, antimony, bismuth, nickel and the like in a copper anode elute and circulate as the electrolysis proceeds. Gradually accumulates in the copper electrolyte.
An increase in the concentration of an impurity metal such as arsenic, antimony, and bismuth not only deteriorates the quality of electrolytic copper, but also adversely affects the properties of electrolytic copper due to the excessive presence of copper. Therefore, in the copper electrolytic refining system, the cleaning of the electrolytic solution is usually performed periodically.

[0003] As a method of purifying a solution, a copper electrolyte solution is heated and concentrated to separate and remove copper as copper sulfate using a difference in solubility, and then copper, arsenic, antimony, and bismuth remaining in the solution by electrolytic sampling are removed. 2. Description of the Related Art A method of electrodepositing and finally cooling a liquid to separate and remove nickel as nickel sulfate by utilizing a difference in solubility has been widely practiced. However, since this liquid purification method uses an electrowinning method for removing arsenic, antimony, and bismuth, it has a drawback that highly toxic arsine gas (AsH ₃ ) is generated during electrolysis. Furthermore, it has the disadvantage that the power consumption during electrowinning is extremely high.

[0004] As a method of solving these drawbacks,
There is a method proposed in JP-A-9-78284.
This method is illustrated schematically in FIG.
Then, sodium, hydrogen sulfide is added to liquid I to separate and remove copper, arsenic, antimony, and bismuth from liquid I as sulfides. Hydrogen sulfide gas is generated by reacting with the remaining sulfuric acid, and the generated gas is brought into contact with liquid II to separate and remove copper, arsenic, antimony, and bismuth as sulfide from liquid II. This is an excellent method for purifying a copper electrolyte. Further, in the neutralization facility, an alkaline agent such as slaked lime or calcium carbonate or caustic soda is added to one of the divided electrolytes to which sodium hydrosulfide has been added to adjust the pH to 8 to 12 so that nickel or nickel which cannot be sufficiently removed as sulfide is added. It is beneficial to separate and remove impurities such as iron as a neutralized precipitate. The precipitate is sent to the smelting process as filter cake, and the filtrate is discharged as wastewater.

[0005] This proposed method (referred to as the electrolytic solution splitting method)
Is a useful method that can be used industrially as a method for purifying the copper electrolysis circulating fluid, instead of electrowinning arsenic or the like that generates harmful arsine. It is produced by reacting inexpensive industrial sodium hydrogen sulfide with sulfuric acid remaining in the liquid in a soda addition tank, and the required amount is passed directly to the reaction tank, so it is easy to process and a large amount of highly toxic and expensive hydrogen sulfide gas is used. This is a very excellent method in that it eliminates the need to transport and store it in a safe place and allows safe operation.

[0006]

However, according to the electrolytic solution splitting method, when impurities such as nickel and iron are separated and removed from one of the split electrolytes to which sodium hydrosulfide is added, the sulfuric acid concentration in the solution is reduced. It is expensive and requires a large amount of neutralizing agent due to its large throughput. Therefore, the present invention provides nickel sulfate and sulfide from a circulating copper electrolytic solution in a copper electrolytic refining system for producing high-purity electrolytic copper by electrolytically refining crude copper while making the most of the advantage of the electrolytic solution splitting method. It is an object of the present invention to provide a method of recovering nickel and separating and recovering impurities such as arsenic, antimony, and bismuth as sulfide.

[0007]

Means for Solving the Problems The present inventors contacted a hydrogen sulfide gas with a copper electrolyte to separate and remove copper, arsenic, antimony and bismuth in the copper electrolyte as sulfide, and to recover copper and the like. Thereafter, the copper electrolyte was divided into two parts, one of which was returned to the circulating copper electrolyte of the copper electrorefining system, and the other copper electrolyte was heated and concentrated, then cooled, and utilizing the difference in solubility of nickel sulfate, A part of nickel is removed as nickel sulfate, and this copper electrolyte is again divided into two parts, one of which is returned to the circulating copper electrolyte of the copper electrolytic refining system, and the other copper electrolyte is
Hydrogen sulfide is generated by adding sodium hydrogen sulfide, and this gas is brought into contact with the copper electrolyte to be processed next, and copper, arsenic, antimony and bismuth in the copper electrolyte are separated and removed as sulfide. Was found to be very practical.

When hydrogen sulfide is generated, nickel sulfide is generated from nickel in the copper electrolyte as a side reaction, and can be separated and removed as sulfide. Before contacting the copper electrolyte with hydrogen sulfide gas and separating and removing copper, arsenic, antimony and bismuth in the copper electrolyte as sulfides,
If a part of copper is separated and recovered in advance by the electrowinning method or the heating and concentration method of the electrolytic solution, the required amount of sodium hydrosulfide and hydrogen sulfide gas is reduced, and the amount of sulfide containing copper etc. is reduced. Have the advantage.

[0009] Based on these findings, the present invention is, after solution purification by extracting a part of the electrolyte from the electrolytic cell to prevent deposition of impurities in the circulating electrolyte in (1) copper electrorefining, electropolishing In the method for purifying a copper electrolyte circulating in a tank, a hydrogen sulfide gas is brought into contact with the extracted copper electrolyte to separate and remove copper, arsenic, antimony, and bismuth in the copper electrolyte as sulfides. The copper electrolyte filtrate from which is separated and removed is divided into two, one is returned to the circulating copper electrolyte, the other copper electrolyte is heated and concentrated, and then cooled to remove a part of nickel as nickel sulfate. The copper electrolyte filtrate from which nickel has been removed is again divided into two parts, one is returned to the circulating copper electrolyte, and sodium hydrosulfide is added to the other copper electrolyte filtrate to generate hydrogen sulfide. Next to the copper electrolyte to be treated Provided is a method for purifying a copper electrolyte, which is used for contacting. The present invention also provides (2) an electrolytic extraction method or an electrolytic solution before contacting hydrogen sulfide gas with the extracted copper electrolytic solution to separate and remove copper, arsenic, antimony, and bismuth in the copper electrolytic solution as sulfides. (1) a method for purifying a copper electrolyte solution according to the above (1), wherein a part of copper is separated and recovered in advance by a heat concentration method; Before recovering most of the above, the copper electrolyte is passed through an ion exchange resin, and a part of antimony and / or bismuth in the copper electrolyte is adsorbed and removed by the ion exchange resin (2).
And a method for purifying a copper electrolyte.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In copper electrolytic refining, the amount of copper eluted from an anode is generally larger than the amount of copper deposited on a cathode, so that the concentration of copper in an electrolytic solution gradually increases. Increase of a predetermined or more copper concentration interfere with optimal electrorefining. On the other hand, arsenic, antimony, bismuth, nickel, iron and the like contained in the copper anode elute in the electrolyte. When these impurity ions reach a certain degree or more, they deposit on the cathode and lower the quality of electrolytic copper. Nickel also has the detrimental effect of raising the electrolysis voltage and antimony being suspended by hydrolysis. Therefore, it is important to remove the electrolytic solution from the electrolytic cell and purify the circulating copper electrolytic solution after the purification and return to the electrolytic cell.

One embodiment utilizing the method of the present invention is a method for treating a copper electrolyte by removing metals such as copper, arsenic, antimony, bismuth and nickel from the copper electrolyte to purify the solution. FIG. 1 is a process sheet specifically described below in detail, but it should be understood that the scope of the present invention is not limited thereto.

1. Preliminary recovery of copper by copper electrowinning Part of copper is separated and recovered in advance by electrowinning from copper electrolyte. According to this method, electrolytic copper having a purity of 99% or more can be obtained. Since the copper electrolyte contains the largest amount of copper as a metal component, a large amount of copper sulfide is generated together with other sulfides when the solution is brought into contact with hydrogen sulfide gas as it is.
In this case, the consumption of the hydrogen sulfide gas increases and the amount of the sulfide also increases. Therefore, if copper is separated and recovered by electrowinning in advance, the necessity is eliminated, which is advantageous. In the case of electrowinning, when the copper electrolytic solution is first pretreated with an ion exchange resin, impurities such as antimony and bismuth are not mixed, and the purity of electrolytic copper is increased, which is more advantageous. After the above treatment, the electrolyte typically contains about 5 to 20 g / copper / copper.
L, arsenic is about 1-10 g / L, antimony is about 0.1-
1 g / L, bismuth about 0.05-1.0 g / L, nickel about 5-20 g / L, free sulfuric acid about 150-300
g / L. Alternatively, copper sulfate may be heated and concentrated to separate and recover copper sulfate in advance.

2. Removal of copper, arsenic, antimony and bismuth In step 1, hydrogen sulfide gas is brought into contact with the electrolyzed solution from which a part of copper has been separated and removed to cause a reaction with copper, arsenic, antimony and bismuth in the copper electrolyte. After they are formed and precipitated as sulfides, they are separated and removed from the liquid by a conventional filtration method. The required amount of hydrogen sulfide gas is determined according to the amount of arsenic and the like described above. Usually, an amount of about 5 to 10% above the theoretical amount required for sulfide formation is used. The nickel content of the separated sulphides is zero or infinitely close.

3. Separation of Copper Electrolyte (Part 1) The filtrate obtained after separating copper or the like as sulfide is divided into a first liquid (filtrate 1) and a second liquid (filtrate 2). The first liquid (filtrate 1) is subjected to steps 1 and 2 to remove components such as copper, arsenic, and antimony, and the components are adjusted so as to be suitable for electrolytic refining of copper. Forward.
Actually, the concentrations of copper, arsenic and antimony in the obtained purified solution are all 0.1 g / L or less. The second liquid (filtrate 2) is subjected to a nickel recovery step. First liquid (filtrate 1)
The ratio of the first liquid (filtrate 1) to the second liquid (filtrate 2) will be described later in detail, but the first liquid (filtrate 1) is about 2: 1 to 5: 1 since the amount required for nickel recovery is practically desired. It is preferred that

4. Generation and recovery of nickel sulfate The second liquid (filtrate 2) is heated and concentrated, and then cooled,
After crystallizing nickel as nickel sulfate, it is separated and recovered from the liquid by a conventional filtration method. In this process,
About 40 to 70% by weight of nickel is recovered from the liquid.
Since the recovered nickel sulfate contains almost no impurities, it has utility as a product as it is.

5. Division of Copper Electrolyte (Part 2) The filtrate obtained after separating nickel as nickel sulfate is divided into a third liquid (filtrate 3) and a fourth liquid (filtrate 4).
The third liquid (filtrate 3) has been subjected to step 4 to remove some of the nickel components, and the components have been adjusted so as to be suitable for the electrolytic refining of copper. The fourth liquid (filtrate 4) is used for generating hydrogen sulfide gas and recovering nickel. The ratio of the third liquid (filtrate 3) to the fourth liquid (filtrate 4) will be described later in detail, but since it is practically desired to generate a required amount of hydrogen sulfide gas, about 2: 1 to 1 Preferably it is 4: 1.

6. Generation and utilization of hydrogen sulfide gas Sodium hydrosulfide is added to the fourth liquid (filtrate 4) and reacted with sulfuric acid in the liquid to generate hydrogen sulfide gas. If this gas is recovered and used in step 2, a large amount of highly toxic gas can be generated on site, which is very convenient in handling. The necessary amount of hydrogen sulfide gas is determined in advance, and sodium hydrosulfide is added to the fourth liquid (filtrate 4) in an amount necessary for generation of the gas. Since the fourth liquid (filtrate 4) is concentrated in step 4, the sulfuric acid concentration is high (350 g / l to 600 g / l), the required amount of liquid is small, and the size of the reaction tank can be reduced.

[7] Generation and Recovery of Nickel Sulfide When hydrogen sulfide is generated in step 6, nickel remaining in the liquid reacts with sodium bisulfide to form and precipitate as nickel sulfide. The nickel sulfide is recovered and separated from the liquid by a conventional filtration method. In this step, about 90% by weight of nickel is recovered from the liquid. Thereafter, the liquid is drained.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG.
The copper electrolyte was treated according to the method proposed in JP-A-9-78284. (Example 1) 1. Preliminary recovery by copper electrowinning A copper electrolyte (30 m ³ ) containing 45 g / L of copper was treated by a known electrowinning method to obtain 45% of electrolytic copper 1 having a purity of 99.9%.
0 kg and 606 kg of electrolytic copper 2 having a purity of 99% were separated and recovered. The solution after electrolysis contains 10 g / L of copper and 5 g of arsenic.
g / L, antimony 0.5 g / L, bismuth 0.2
g / L, nickel 18 g / L, free sulfuric acid 244 g / L
L was included. 2. Removal of copper, arsenic, antimony, and bismuth 225 m ³ of hydrogen sulfide gas was introduced into the solution after the electrolysis, and a contact reaction was caused between the solution and the gas to generate and precipitate sulfide 1. From the liquid, by a conventional filtration method,
Separated and removed. Nickel was not practically contained in Sulfide 1. The obtained filtrate contained copper, arsenic, antimony, and bismuth only at a concentration of 0.1 g / L or less, and was clean. 3. Division of Copper Electrolyte (Part 1) From the filtrate, 20 m ³ was separated as a pure liquid (filtrate 1). 4. Production and Recovery of Nickel Sulfate The remaining 10 m ³ of the filtrate was concentrated by heating, and then cooled to produce and precipitate nickel in the solution as nickel sulfate. The produced nickel sulfate was collected by filtration and separation by a conventional method. The amount of nickel sulfate is 594kg
Met. 5. Separation of Copper Electrolyte (Part 2) From the filtrate, 3.3 m ³ was separated as a pure liquid (filtrate 3). 6. Generation and Use of Hydrogen Sulfide Gas To the remaining 1.5 m ³ of the filtrate, 2540 kg of industrial sodium hydrogen sulfide containing about 25% of NaSH is added at a rate of about 10 kg per minute, and reacted with sulfuric acid in the liquid. 255 m ^{3 of} hydrogen sulfide gas was generated. 7. Generation and recovery of nickel sulfide When hydrogen sulfide was generated, nickel remaining in the liquid reacted with sodium bisulfide to form and precipitate as nickel sulfide. The produced nickel sulfide is produced in a conventional manner,
Filtered and separated. The amount of nickel sulfide after drying was 76 kg.

In this method, the amounts of the processing liquid, the products in each step and the amount of the liquid after the processing are as shown in Table 1.

[0021]

[Table 1]

(Comparative Example) As shown in FIG.
/ L electrolyte solution 30 m ³ containing treated by a known electrowinning method (decoppered electrolysis) was separated and recovered copper purity of 99.99% copper to 450Kg and 99.9% of the copper to 600Kg destination . In the solution after the electrolysis, copper was 10 g /
1, 5 g / l of arsenic, 0.4 g / l of antimony, 0.1 g / l of bismuth, 15 g / l of nickel and 244 g / l of free sulfuric acid. About 1 / of this solution
5 in 6.7 m ³ of one of the divided electrolytes (liquid I)
500 kg of industrial sodium hydrogen sulfide containing about 25% SH was added to precipitate copper, arsenic, antimony and bismuth (sulfide I). In addition, excess industrial sodium hydrosulfide 1
740 Kg was added at a rate of about 10 Kg per minute and reacted with sulfuric acid in the solution to generate hydrogen sulfide gas. This hydrogen sulfide gas was supplied to the remaining divided electrolyte (second solution) 23.3 m.
^The reaction was led to ³ , and the remaining split electrolyte solution (second solution II) was brought into contact with hydrogen sulfide gas to precipitate copper, arsenic, antimony and bismuth (sulfide II). The precipitate was separated by filtration, and the obtained filtrate was clean and had a concentration of copper, arsenic antimony and bismuth of 0.1 g / l or less. Since the solution to which industrial sodium bisulfide is added contains substances such as sulfuric acid, nickel and iron, slaked lime 905K
g was added to adjust the pH of the solution to 10 to neutralize and precipitate heavy metals, followed by filtration, and the filter cake was repeatedly subjected to a smelting process. Although it is excellent as a method for purifying a copper electrolytic solution, in this electrolytic solution splitting method, when impurities such as nickel and iron are separated and removed from one of the split electrolytic solutions to which sodium hydrosulfide is added, the electrolytic solution in the liquid is separated. Since the sulfuric acid concentration was high and the amount of treatment was large, a large amount of neutralizing agent was required.

(Example 2) Copper 45 g / l, arsenic 5 g / l
l, antimony 0.4 g / l, bismuth 0.1 g /
1, nickel 15g / l and free sulfuric acid 160g / l
Was extracted and passed through an ion exchange resin (EPROUS MX-2 manufactured by Miyoshi Resin Co., Ltd.) to adsorb some of antimony and bismuth. The solution passed through the resin contained 45 g / l copper, 5 g / l arsenic, 0.1 g / l antimony, 0.05 g / l bismuth, 15 g / l nickel and 160 g / l free sulfuric acid. This solution was treated by a known method to remove copper by electrolytic sampling. However, since antimony and bismuth in the solution were low, 600 kg of 99.99% pure copper and 450 kg of 99.9% pure copper were used. Obtained. The solution after the electrolysis was treated in the same manner as in Example 1.

[0024]

According to the method of the present invention, from a copper electrolyte,
Nickel can be recovered as nickel sulfate and nickel sulfide, and arsenic, antimony, and bismuth can be recovered as sulfide. According to the method of the present invention, sodium bisulfide is added to the fourth liquid (filtrate 4) and reacted with sulfuric acid in the liquid to generate hydrogen sulfide gas. This gas is recovered and used in step 2. As a result, a large amount of highly toxic gas can be generated on site, which is very convenient in handling. The required amount of hydrogen sulfide gas is determined in advance, and sodium hydrosulfide is added to the fourth liquid (filtrate 4) in an amount required for generation of the gas, so that the copper electrolyte can be purified. The advantages of the electrolytic solution splitting method can be utilized.

[Brief description of the drawings]

FIG. 1 is a flow sheet of a method for purifying a copper electrolyte according to one embodiment of the present invention.

FIG. 2 is a flow sheet of a conventional method for purifying a copper electrolyte.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-9-78284 (JP, A) JP-A-7-188963 (JP, A) JP-A-6-116775 (JP, A) JP-A-10-108 147823 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) C25C 1/00-7/08 C22B 15/14

Claims (3)

(57) [Claims] 1. A method for purifying a copper electrolytic solution circulating in an electrolytic cell after extracting a part of the electrolytic solution from the electrolytic cell to purify the electrolytic solution in order to prevent accumulation of impurities in the circulating electrolytic solution in copper electrolytic refining. , A hydrogen sulfide gas is brought into contact with the extracted copper electrolyte to separate and remove copper, arsenic, antimony and bismuth in the copper electrolyte as sulfides, and the copper electrolyte filtrate from which the sulfides are separated and removed is divided into two parts One was returned to the circulating copper electrolyte, the other was concentrated by heating, and then cooled to remove a part of nickel as nickel sulfate, and the copper electrolyte filtrate from which nickel sulfate had been removed was recycled again. Divide, return one to the circulating copper electrolyte, add sodium bisulfide to the other copper electrolyte filtrate to generate hydrogen sulfide, and contact the generated hydrogen sulfide with the copper electrolyte to be processed next Copper electricity characterized by using Liquid purification method of lysis. 2. A method in which a hydrogen sulfide gas is brought into contact with the extracted copper electrolytic solution to separate copper, arsenic, antimony, and bismuth in the copper electrolytic solution as sulfides. 2. The method for purifying a copper electrolyte according to claim 1, wherein a part of copper is separated and recovered in advance by a method. 3. Prior to recovering most of the copper in the extracted copper electrolytic solution by an electrowinning method, the copper electrolytic solution is passed through an ion exchange resin, and the antimony and / or
3. The method for purifying a copper electrolyte according to claim 2, wherein a part of bismuth is adsorbed and removed by the ion exchange resin.