JPH10147823A - Method for recovering nickel from copper electrolytic solution and method for purifying the same copper electrolytic solution - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for recovering nickel from a copper electrolytic solution as nickel sulfide having a product value as it is. SOLUTION: This recovering method comprises: allowing a copper electrolytic solution to contact with gaseous hydrogen sulfide to separate and remove copper, arsenic, antimony and bismuth as sulfides of them from the solution; and then, adding an excess amount of sodium hydrosulfide to the resulting solution to separate nickel as nickel sulfide; wherein nickel remaining in the solution thus obtained can be separated and recovered from the solution as nickel carbonate or nickel hydroxide by adding slaked lime or calcium carbonate to the solution to allow the alkaline agent to react with sulfuric acid in the solution and to form gypsum, separating and removing the gypsum and then, adding sodium carbonate or caustic soda to the resulting solution. Further, the solution obtained after removal of sulfides of copper, etc., can be returned to the electrolysis stage as a purified solution and circulated to reuse it.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a copper electrorefining system for producing high-purity electrolytic copper by electrolytically refining crude copper, to remove metals, particularly nickel, gradually accumulated in a circulating copper electrolyte. It relates to a separation and recovery method.

[0002]

2. Description of the Related Art In a copper electrolytic refining system for producing high-purity electrolytic copper by electrolytically refining crude copper, as the electrolysis proceeds, copper, arsenic, antimony, bismuth, etc. in a copper anode are eluted and circulated copper electrolysis is performed. Accumulates gradually in the liquid. 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 presence of excess copper. Therefore, in the copper electrolytic refining system, the cleaning of the electrolytic solution is usually performed periodically.

[0003] As a purification method, copper electrolyte 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, this liquid purification method has a drawback that highly toxic arsine gas (As ₃ H) is generated during electrolysis because an electrowinning method is used to remove arsenic, antimony, and bismuth. Furthermore, it has the disadvantage that the power consumption during electrowinning is extremely high.

[0004] As a liquid purification method capable of solving these disadvantages, there is a method proposed in Japanese Patent Application No. 7-263639. This method is schematically shown in FIG. 2, but the electrolyte solution is divided into two parts, and sodium hydroxide is added to solution I to form copper, arsenic, anmonium and bismuth as sulfides.
Separated and removed from the liquid, furthermore, excess sodium hydrosulfide is added and reacted with sulfuric acid remaining in the liquid to generate hydrogen sulfide gas, and the generated gas is brought into contact with liquid II to produce copper, arsenic , And an ammonium and bismuth are separated and removed from the solution II as sulfides, which is an excellent method for purifying a copper electrolyte.

However, in this electrolytic solution splitting method,
When sodium hydrogen sulfide is added to the liquid I to separate and remove copper, arsenic, ammonium and bismuth from the liquid I as sulfide, part of nickel is also separated and removed as nickel sulfide. Nickel is an impurity from the viewpoint of purifying the copper electrolyte, but is a valuable metal, and it is desirable that nickel can be separated and recovered from the system as nickel sulfide at a high rate.

[0006]

SUMMARY OF THE INVENTION Therefore, the present invention provides a method for separating and recovering nickel from a circulating copper electrolyte in a copper electrolytic refining system for producing high purity electrolytic copper by electrolytically refining crude copper. The purpose is to provide.

[0007] The present invention also claims that the copper electrolyte can be purified and nickel can be separated and recovered from the solution at a high rate.
It is an object of the present invention to provide a method for purifying a copper electrolytic solution that can simultaneously achieve a combined effect.

[0008]

Means for Solving the Problems As a result of intensive research, the present inventors have found that when hydrogen sulfide gas is brought into contact with a copper electrolyte, copper, arsenic, antimony and bismuth in the copper electrolyte are separated and removed as sulfide. However, after the copper, arsenic, antimony, and bismuth in the copper electrolyte are separated and removed as sulfide, the percentage of nickel that can be separated and recovered as nickel sulfide even if sodium bisulfide is added is Although it cannot be said that there is much, since impurities other than sulfur are scarcely mixed, it has been found that the recovered nickel sulfide has such a grade that it can be provided as it is to the market as a product except for excess sulfur, and the copper electrolytic solution of the present invention. Has proposed a method for recovering nickel from coal.

That is, in the method of the present invention, a copper electrolyte is brought into contact with hydrogen sulfide gas to separate and remove copper, arsenic, antimony and bismuth in the copper electrolyte as sulfides. This method is characterized in that sodium bisulfide is added to an electrolytic solution, and nickel is separated and recovered as nickel sulfide. In addition, after adding sodium bisulfide and separating and recovering nickel as nickel sulfide, further, slaked lime or calcium carbonate is added to the copper electrolyte and reacted with sulfuric acid in the copper electrolyte to form gypsum. After separation and removal, sodium carbonate or caustic soda may be added to further separate and recover nickel remaining in the copper electrolyte as nickel carbonate or nickel hydroxide.

[0010] Preferably, sodium hydrogen sulfide is excessively added to the copper electrolyte to generate hydrogen sulfide gas, and this gas is brought into contact with a copper electrolyte to be treated next, and copper in the copper electrolyte is removed. Used to separate and remove arsenic, antimony and bismuth as sulfides. This is because hydrogen sulfide gas is very poisonous and difficult to handle.

By using the above-mentioned method, a copper electrolytic solution can be simultaneously purified. For example, a hydrogen sulfide gas is brought into contact with a copper electrolyte to separate and remove copper, arsenic, antimony, and bismuth in the copper electrolyte as sulfides, and then the liquid is divided. To the second liquid, sodium hydrogen sulfide is excessively added, and nickel is separated and recovered as nickel sulfide, and the generated hydrogen sulfide gas is used to contact the copper electrolyte to be processed next.

Before contacting a copper electrolyte with a hydrogen sulfide gas to separate and remove copper, arsenic, antimony and bismuth as sulfides in the copper electrolyte, the copper is previously removed by electrowinning or heating and concentrating the electrolyte. If a part of is separated and collected, the required amount of sodium hydrogen sulfide and hydrogen sulfide gas will be reduced,
This has the advantage of reducing the amount of sulfide containing copper and the like.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a method for treating a copper electrolytic solution, which is an embodiment utilizing the method of the present invention and which purifies the copper electrolytic solution while recovering nickel from the electrolytic solution. Although shown as a sheet and specifically described below, it should be understood that the scope of the present invention is not limited thereto.

Preliminary Recovery of Copper by Electrowinning Part of copper is previously separated and recovered from the copper electrolyte by electrowinning. 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 electrolyte 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
Copper is about 5-20 g / L, arsenic is about 1-10 g / L, antimony is about 0.1-1 g / L, bismuth is about 0.05-
It contains 1.0 g / L, about 5 to 20 g / L of nickel, and about 150 to 300 g / L of free sulfuric acid.

As another method, the copper electrolyte may be heated and concentrated to be separated and recovered in advance as copper sulfate.

[0017] The removal of copper, arsenic, antimony and bismuth in the step of removing copper by contacting hydrogen sulfide gas with the post-electrolysis solution from which a portion of the copper has been separated to remove copper, arsenic, antimony and bismuth in the copper electrolyte. Then, they are formed and precipitated as sulfides, and then separated and removed from the liquid by a conventional filtration method. The necessary amount of hydrogen sulfide gas is determined according to the amount of arsenic and the like described above. Usually, an amount of about 0.1 to 5% above the theoretical amount required for sulfide formation is used. The content of nickel in the separated sulfide is zero or infinitely close.

Division of Copper Electrolyte The filtrate obtained after separating and removing copper and the like as sulfides is divided into a first liquid (filtrate 1) and a second liquid (filtrate 2). The first liquid (filtrate 1) is subjected to a process to remove components such as copper, arsenic, and antimony, and the components are adjusted so as to be suitable for electrolytic refining of copper. . 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. The ratio between the first liquid (filtrate 1) and the second liquid (filtrate 2) will be described later in detail, but since it is practically desired to generate a required amount of hydrogen sulfide gas, about 2: 1.
５5: 1 is preferred.

Generation / Utilization of Hydrogen Sulfide Gas and Generation / Recovery of Nickel Sulfide Sodium hydrosulfide is added to the second liquid (filtrate 2) and reacted with the remaining sulfuric acid to generate hydrogen sulfide gas. If this gas is collected and used in the process, a large amount of highly toxic gas can be generated on site, which is very convenient for handling. The required amount of hydrogen sulfide gas is determined in advance, and sodium bisulfide is added to the second liquid (filtrate 2) in excess of the amount required to generate the gas.

When hydrogen sulfide gas is generated by the addition of sodium bisulfide, about 25 to 30% by weight of nickel is recovered as nickel sulfide. Nickel sulfide has almost no impurities except for S, and therefore has utility as it is as a nickel raw material.

[0022] Slaked lime or calcium carbonate is first added to the second liquid (filtrate 3) after the nickel is separated and recovered as nickel sulfide through the step of producing and recovering nickel carbonate or nickel hydroxide, and the pH is adjusted to about 1 Adjusted to 0.5 to 2.5 to react with free sulfuric acid remaining in the solution to produce gypsum.
Let it settle. The settled gypsum is separated and removed by a conventional method.

Liquid obtained after removing gypsum (filtrate 4)
Then, sodium carbonate or caustic soda is added to adjust the pH to about 8 to 10, and nickel remaining in the solution is generated and precipitated as nickel carbonate or nickel hydroxide.
Thereafter, the generated nickel carbonate or nickel hydroxide is separated and recovered by a conventional method. Nickel purity is about 3
5 to 45%. Thereafter, the liquid is drained.

[0024]

EXAMPLES The method of the present invention A copper electrolyte was treated according to the above embodiment of the present invention .

Example 1 Preliminary recovery of copper by electrowinning A copper electrolytic solution (30 m ³ ) containing 45 g / L of copper was treated by a known electrowinning method to obtain 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. After the electrolysis, the solution contained 10 g / L of copper and 5 g of arsenic.
g / L, antimony 0.4 g / L, bismuth 0.1
g / L, nickel 15 g / L, free sulfuric acid 244 g / L
L was included.

Removal of Copper, Arsenic, Antimony and Bismuth 225 m ³ of hydrogen sulfide gas is introduced into the solution after electrolysis, and a contact reaction is caused between the solution and the gas to produce sulfide 1.
Settled. This was separated and removed from the liquid by a conventional filtration method. Sulfide 1 contained substantially no nickel. The obtained filtrate contained copper, arsenic, antimony, and bismuth only at a concentration of 0.1 g / L or less and was clean.

Separation of Copper Electrolyte Solution From the filtrate, 23.3 m ³ was separated as a pure solution (filtrate 1).

Production and Recovery of Nickel Sulfide To the remaining 6.7 m ³ of the filtrate, 2470 kg of industrial sodium bisulfide containing about 25% of NaSH is added at a rate of about 10 kg per minute, and the remaining free liquid in the liquid is added. It was reacted with sulfuric acid to generate 225 m ³ of hydrogen sulfide gas, which was led to the process and used for the precipitation of copper, arsenic, antimony and bismuth. Since a part of nickel in the liquid was formed and precipitated as nickel sulfide by the addition of the sodium hydrogen sulfide, a trace amount of hydrogen sulfide gas remaining in the liquid was removed, and then separated and recovered by a conventional method. Nickel sulfide after drying is 80
kg.

Generation and Recovery of Nickel Carbonate or Nickel Hydroxide The liquid (filtrate 4) after hydrogen sulfide gas has been generated and recovered,
First, 1270 kg of calcium carbonate was added,
= 2, and reacted with free sulfuric acid remaining in the solution to form and settle gypsum. The settled gypsum was separated and removed by a conventional method. After drying, the amount of gypsum is 2
It was 180 kg. After removing the gypsum, 161 kg of sodium carbonate was added to the liquid, and the mixture was neutralized and adjusted to pH = 9.
Nickel remaining in the solution was generated and precipitated as nickel carbonate. Thereafter, the produced nickel carbonate was collected by filtration and separation by a conventional method. The amount of nickel carbonate after drying was 200 kg, and the purity of nickel was 40%.

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

[0031]

[Table 1]

Comparative Example (Method described in Japanese Patent Application No. 7-263639) A copper electrolytic solution (30 m ³ ) containing 45 g / L of copper was treated by a known electrowinning method, and electrolytic copper I having a purity of 99.9% was obtained. 45
0 kg and 606 kg of electrolytic copper II having a purity of 99% were separated and recovered. After the electrolysis, the solution contained 10 g / L of copper and 5 g of arsenic.
g / L, antimony 0.4 g / L, bismuth 0.1
g / L, nickel 15 g / L, free sulfuric acid 244 g / L
L was included.

The electrolytic solution was divided into solution I (6.7 m ³ ) and solution II (2
3.3 m ³ ). To the liquid I, 500 kg of industrial sodium hydrogen sulfide containing about 25% of NaSH was added, and the sulfide I was added.
Was generated and precipitated. This was collected by filtration and separation by a conventional method, and further dried. Next, 1740 kg of industrial sodium hydrogen sulfide was added at a rate of about 10 kg per minute, and reacted with sulfuric acid in the liquid to generate hydrogen sulfide gas. This hydrogen sulfide gas was led to the second liquid, and caused a contact reaction with the liquid to generate and precipitate sulfide II. This was collected by filtration and separation by a conventional method, and further dried. The remaining filtrate (that is, the electrolytic return liquid) contained only copper, arsenic, antimony, and bismuth at a concentration of 0.1 g / L or less, that is, was clean.

First, in the liquid I after the generation of the hydrogen sulfide gas,
1280 kg of calcium carbonate was added to neutralize and adjust to pH = 2, and reacted with free sulfuric acid remaining in the solution to form and settle gypsum. The settled gypsum was separated and removed by a conventional method. After drying, the amount of gypsum was 2210
kg. After removing the gypsum, 125 kg of sodium carbonate was added to the filtrate, neutralized and adjusted to pH = 9, and nickel remaining in the solution was generated and precipitated as nickel carbonate. Thereafter, the produced nickel carbonate was collected by filtration and separation by a conventional method, and further dried.

In this treatment method, the amounts of the treatment liquid, the products in each step and the amount of the liquid after treatment are as shown in Table 2.

[0036]

[Table 2]

Comparison between Tables 1 and 2 shows that, in the method of the comparative example, nickel precipitates as antimony and the like as sulfide, and the amount of nickel recovered as nickel carbonate is small. On the other hand, in the method of the present invention, And nickel can be recovered in high purity as nickel sulfide.

Example 2 (Pretreatment using ion exchange resin) Copper 45 g / L, arsenic 5 g / L, antimony 0.4 g / L
L, bismuth 0.1 g / L, nickel 15 g / L, and a copper electrolytic solution containing 190 g / L of free sulfuric acid are withdrawn,
Ion exchange resin (EPROUS manufactured by Miyoshi Resin Co., Ltd.)
MX-2), and some of antimony and bismuth were adsorbed. The liquid that passed through this resin contained 45 g of copper.
/ L, arsenic 5g / L, antimony 0.1g / L, bismuth 0.05g / L, nickel 15g / L and free sulfuric acid 1
90 g / L was contained. When this solution was subjected to electrowinning treatment in the same manner as in the treatment method 1, 600 kg of 99.9% pure copper and 450 kg of 99% pure copper were obtained because the concentrations of antimony and bismuth in the solution were low. Was.

[0039]

According to the method of the present invention, from a copper electrolyte,
Nickel can be recovered as nickel sulfide at a high rate. Further, the method of the present invention can be used as a method for purifying a copper electrolyte.

[Brief description of the drawings]

FIG. 1 is a flow sheet of a method for purifying a copper electrolytic solution according to an embodiment of the present invention.

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

Claims (5)

[Claims] Claims 1. A hydrogen sulfide gas is brought into contact with a copper electrolytic solution,
Copper, arsenic, antimony, and bismuth in the copper electrolyte are separated and removed as sulfides. After recovering copper, etc., sodium bisulfide is added to the copper electrolyte,
A method for recovering nickel from a copper electrolyte, wherein nickel is separated and recovered as nickel sulfide. 2. After excessive addition of sodium bisulfide to separate and recover nickel as nickel sulfide, the copper electrolyte is
Slaked lime or calcium carbonate is added and reacted with sulfuric acid in the copper electrolyte to form gypsum, which is separated and removed.Additionally, sodium carbonate or caustic soda is added to remove nickel remaining in the copper electrolyte. The method according to claim 1, wherein the method is separated and recovered as nickel or nickel hydroxide. 3. An excessive addition of sodium bisulfide to a copper electrolyte,
The hydrogen sulfide gas generated at that time is brought into contact with a copper electrolyte to separate and remove copper, arsenic, antimony and bismuth in the copper electrolyte as sulfides. Method. 4. A method comprising bringing hydrogen sulfide gas into contact with a copper electrolytic solution,
Copper, arsenic, antimony, and bismuth in the copper electrolyte are separated and removed as sulfides. After the removal of copper and the like, the copper electrolyte is divided, the first solution is sent to the electrolytic refining process, and the second solution is water. Add sodium sulfide to separate nickel as nickel sulfide and generate hydrogen sulfide gas,
A method for purifying a copper electrolyte, wherein the gas is forwarded for use in a contact step with copper or the like. 5. A method in which hydrogen sulfide gas is brought into contact with a copper electrolytic solution,
Before separating and removing copper, arsenic, antimony and bismuth in the copper electrolyte as sulfide, a part of copper is separated and recovered in advance by an electrolytic sampling method or a heat concentration method of the electrolyte. Item 5. The method according to Item 4.