WO2023189211A1

WO2023189211A1 - Cobalt and nickel recovery method

Info

Publication number: WO2023189211A1
Application number: PCT/JP2023/008091
Authority: WO
Inventors: 晃一郎高次; 史人田中; 尚也佐藤
Original assignee: 三菱マテリアル株式会社
Priority date: 2022-03-28
Filing date: 2023-03-03
Publication date: 2023-10-05
Also published as: JP2023145408A

Abstract

This cobalt and nickel recovery method comprises: a pretreatment step for removing either/both copper ions or/and iron(III) ions contained in a raw solution containing either/both cobalt or/and nickel; and a xanthate treatment step for adding a xanthide to the pretreated solution to selectively precipitate a xanthate of either/both cobalt or/and nickel, and recovering the precipitate.

Description

How to recover cobalt and nickel

The present invention relates to a method for recovering cobalt and nickel contained in wastewater and the like. In particular, the present invention relates to a method for efficiently recovering cobalt-nickel from a solution containing high concentrations of impurities such as iron but low concentrations of cobalt and nickel.
This application claims priority based on Japanese Patent Application No. 2022-052432 filed in Japan on March 28, 2022, the contents of which are incorporated herein.

As a technology to recover cobalt leached into solution from waste batteries, nickel laterite ore, or copper-cobalt ore, etc., we are currently at the stage where recovery methods using cobalt extraction solvents and the differences in solubility products of various metal hydroxides are utilized. The sum recovery method is used.

For example, Patent Document 1 describes a method for recovering metal ions from a metal-containing solution obtained by wet-processing lithium ion battery waste. When the metal-containing solution contains magnesium ions and at least one of cobalt ions and nickel ions, a solvent containing a carboxylic acid-based extractant is used to remove the cobalt ions and the magnesium ions while leaving the magnesium ions in the metal-containing solution. Nickel ions are extracted into the solvent. Next, cobalt ions and nickel ions are back-extracted and recovered from the solvent.

Further, Patent Document 2 describes a method for recovering cobalt from acid leaching liquid obtained by acid leaching a lithium ion waste battery and containing cobalt and the like. Utilizing the difference in solubility products of metal hydroxides, impurities are removed through multi-stage neutralization and cobalt is recovered. Furthermore, the precipitate is redissolved and multistage neutralization is repeated. Through the above steps, high purity cobalt salt crystals are obtained.

Non-Patent Document 1 describes a method of recovering cobalt as a precipitate by neutralizing the liquid after copper extraction in hydrometallurgical copper smelting of copper-cobalt sulfide ore in stages. Furthermore, Non-Patent Document 2 describes the use of methyl xanthate or ethyl xanthate as a selective precipitant for cobalt or nickel.

In the step neutralization method described in Patent Document 2 and Non-Patent Document 1, cobalt is selected because cobalt co-precipitates with iron and aluminum as impurities for solutions containing high concentrations of iron and aluminum together with cobalt. There is a problem that it cannot be precipitated. Furthermore, if the cobalt concentration in the solution is low, the cobalt recovery rate will decrease, making it impossible to efficiently recover cobalt.

On the other hand, in the solvent extraction method described in Patent Document 1, iron and copper are extracted by the cobalt extraction solvent, so in order to avoid this, a multi-stage solvent extraction process is required and the process is complicated. Moreover, if the cobalt concentration in the solution is low, there is a problem that the solvent loss per amount of cobalt recovered increases and the processing cost increases.

Additionally, Non-Patent Document 2 describes the following matters. In the xanthate method, xanthate ions do not form precipitates with ferrous ions, manganese ions, chromium ions, etc., but xanthate ions react selectively with cobalt ions and nickel ions to form precipitates. generate. This precipitate can be separated by flotation using its hydrophobicity.

However, for example, wastewater from the hydrometallurgical process of copper ore contains many metal ions, and metal ions (hereinafter referred to as inhibiting metal ions) that form precipitates along with cobalt and nickel due to xanthate. If they are present, cobalt and nickel cannot be selectively precipitated by the xanthate method. Such inhibiting metal ions are not clear in the disclosure content of Non-Patent Document 2, and it is difficult to apply the xanthate method to actual operation based only on the disclosure content of Non-Patent Document 2.

Japanese Patent Application Publication No. 2021-172856 JP 2021-139030 Publication

An object of the present invention is to provide a cobalt-nickel recovery method that can be applied to actual operations.

The present inventors have clarified the inhibiting metal ions in the xanthate method. Cobalt and nickel can then be selectively recovered from various solutions, such as wastewater from the hydrometallurgical process of copper ore, by pre-treating them to remove the inhibiting metal ions. made it possible to do so. As a result of the above, it has become possible to apply the cobalt and nickel recovery method using the xanthate method to actual operations.

The present invention is a cobalt-nickel recovery method that solves the above problems with the following requirements.
[1] A pretreatment step of removing one or both of copper ions and iron (III) ions contained in the raw solution containing one or both of cobalt and nickel;
A xanthate treatment step of adding a xanthate to the solution after the pretreatment to selectively precipitate one or both of cobalt and nickel xanthate salts and recovering the precipitate. How to recover cobalt and nickel.
[2] In the pretreatment step, a reduction treatment is performed by a cementation reaction,
When the raw solution contains copper ions, adding metallic aluminum to the raw solution to precipitate the copper ions in the raw solution into metallic copper,
When the raw solution contains iron (III) ions, metal aluminum is added to the raw solution to reduce the iron (III) ions in the raw solution to iron (II) ions, as described in [1] above. Cobalt and nickel recovery method.
[3] In the xanthate treatment step, the xanthate salt is selectively precipitated by using a flotation equipment to add the xanthate salt to the solution after the pretreatment, and the precipitate is collected as froth. [1] or the cobalt-nickel recovery method described in [2] above.
[4] The method for recovering cobalt-nickel according to any one of [1] to [3] above, further comprising the step of thermally decomposing the xanthate salt of the recovered precipitate to obtain cobalt-nickel slag.
[5] The raw solution is a leachate noble liquid of a hydrometallurgical process of copper ore, a liquid after copper extraction, or a waste liquid after copper extraction treatment,
According to any one of [1] to [4] above, further comprising a step of recycling the liquid after the xanthate treatment after collecting the precipitate by returning it to the leachate used in the leaching step of the hydrometallurgical smelting step. Cobalt and nickel recovery method.

In the recovery method according to one embodiment of the present invention, it is only necessary to add xanthate in an amount necessary to form xanthate salts of cobalt and nickel, so even if the concentrations of cobalt and nickel in the raw solution are low, the recovery method can be efficiently carried out. Cobalt and nickel can be recovered.

The amount of metal ions that are more likely to precipitate than cobalt and nickel xanthate salts is smaller in the raw solution such as the wastewater from the hydrometallurgical process of copper ore, so it is practical to remove copper ions from the raw solution during pretreatment. What is necessary is to remove iron (III) ions. Using a cementation reaction as a pretreatment, copper ions are precipitated as metallic copper and iron(III) ions are reduced to iron(II) ions, so that the amount of substituted metal (e.g. aluminum) required for these reactions is It is efficient. Further, since the substitution metal aluminum does not coprecipitate with cobalt or nickel, pretreatment can be performed without adversely affecting the next step of xanthate treatment.

Furthermore, in the recovery method according to one embodiment of the present invention, impurities such as copper ions and iron (III) ions are removed without using a neutralization reaction, so liquid properties such as pH are hardly changed. Therefore, the liquid after xanthate treatment can be returned to the source and reused. For example, if the raw solution is the leached noble liquor of the hydrometallurgical process of copper ore, the liquor after copper extraction, or the waste liquor after copper extraction treatment, after the xanthate treatment obtained by the recovery method according to one embodiment of the present invention. The liquid can be recycled and reused by returning it to the leachate used in the leaching process of the copper ore hydrometallurgical smelting process, and wastewater treatment is not required. Furthermore, the recovery method according to one embodiment of the present invention can be performed using simpler steps and equipment compared to the neutralization method and the solvent extraction method.

A process diagram showing an example of the collection method of this embodiment

Hereinafter, details of the cobalt-nickel recovery method of this embodiment will be explained.
The recovery method of the present embodiment includes the steps of preparing a raw solution containing one or both of cobalt and nickel, and removing one or both of copper ions and iron (III) ions contained in the raw solution. a pretreatment step, and a xanthate treatment step of adding a xanthate to the solution after the pretreatment to selectively precipitate one or both of cobalt and nickel xanthate salts and recovering the precipitate. .
An example of the collection method of this embodiment is shown in FIG.

<Process of preparing stock solution>
In the recovery method of the present embodiment, the raw solution containing either one or both of cobalt and nickel is, for example, the leached precious liquid in the hydrometallurgical process of copper ore, the liquid after copper extraction, the acid leached precious liquid of lithium ion waste batteries, etc. This is a solution containing liquid or waste liquid after these treatments (copper extraction treatment, acid leaching treatment).
The raw solution contains one or both of cobalt and nickel, and one or both of copper ions and iron (III) ions. The solution is prepared as a stock solution.
In the hydrometallurgical smelting process for copper ore, first, the copper ore is brought into contact with a leachate to leach out the copper, thereby obtaining a leachate precious liquid (leaching process). Next, copper is extracted from the leached liquid by a solvent extraction method or a precipitation method (copper extraction step).
Hereinafter, the solution before copper is leached will be referred to as a "lixiviant" or "leach solution". The solution obtained by the leaching process and containing a high concentration of copper is called a "pregnant leach solution." The solution after copper has been selectively removed by the copper extraction process is called a "raffinate". Strictly speaking, the solution after copper has been selectively removed by the solvent extraction method is also called a "solvent extraction raffinate." The liquid after copper extraction can also be referred to as the waste liquid after the copper extraction process.
The solution remaining from a chemical or mechanical process after the desired chemical has been removed is also referred to as "process discharge."

<Pre-treatment process>
Pretreatment is performed to remove one or both of copper ions and iron (III) ions contained in the raw solution. Copper ions and iron(III) ions are impurities that form xanthate salts, which have a lower solubility product than the cobalt and nickel xanthate salts.
In the pretreatment, one or both of copper ions and iron (III) ions are removed. Specifically, when the raw solution contains copper ions, the copper ions are removed in the pretreatment. If the raw solution contains iron (III) ions, the iron (III) ions are removed in the pretreatment. When the raw solution contains copper ions and iron (III) ions, the copper ions and iron (III) ions are removed in the pretreatment. In this embodiment, removing iron(III) ions is to significantly reduce the concentration of iron(III) ions in the raw solution.
As a pretreatment, for example, metal aluminum is added to the raw solution and reduction treatment is performed by cementation reaction. Metal aluminum refers to metal aluminum plates, aluminum scraps such as aluminum scraps and aluminum cans, and other metal aluminum-containing materials. Note that aluminum, which is a substitution metal in the cementation reaction, does not co-precipitate with cobalt or nickel.
From the viewpoint of reaction rate, the amount (number of moles) of metallic aluminum added is preferably 60 times or more the total number of moles of copper ions and iron (III) ions in the raw solution.

If a metal that is electrically more expensive than the target metal is added to the raw solution, a cementation reaction will occur, so there is a possibility that zinc powder, which is more expensive than cobalt or nickel, may be used. However, in general, the liquid and wastewater after copper extraction in the hydrometallurgical process of copper ore is strongly acidic (pH around 1.5), and zinc powder is highly reactive under acidic conditions, and the zinc powder itself is Since it dissolves and increases the zinc concentration in the solution, it is not suitable for the cementation reaction in this embodiment.

When metallic aluminum is added to the raw solution, the copper ions in the raw solution are reduced to become metallic copper and precipitate, and the iron (III) ions are reduced to iron (II) ions. If the raw solution contains copper ions and iron (III) ions, these copper ions and iron (III) ions will precipitate together with cobalt and nickel when xanthate is added. cannot be selectively precipitated. Interference by copper ions and iron (III) ions in the raw solution can be prevented by removing them in advance.

Even if iron (II) ions are present in the solution, the solubility product of iron (II) xanthate salts is larger than the solubility product of cobalt or nickel xanthate salts, and in the next step, iron (II) ions are converted to cobalt. and nickel. Therefore, by reducing the iron (III) ions in the raw solution to iron (II) ions, cobalt and nickel can be selectively precipitated in the next step.

On the other hand, if iron(II) ions remain in the solution during the pretreatment, if the solution after the xanthate treatment described below is reused as the leachate used in the leaching process of the hydrometallurgical smelting process of copper ore, this iron (II) ion can be reused. II) Ions can act as oxidizing agents for copper ore and increase the leaching rate. Furthermore, iron (II) ions remain in the solution and do not precipitate together with copper ions, which prevents iron from being mixed into the metallic copper precipitate produced by the cementation reaction, allowing the recovered metallic copper to be reused as a product. be able to.

In general, metal ions whose solubility product of xanthate salt is smaller than that of cobalt or nickel are, for example, Au, Ag, Hg, Cd, Pb, Bi, Sb, Sn, etc. Since these become inhibitory metals, it is usually preferable to remove them from the solution by pretreatment. However, in solutions such as leached precious liquor, post-copper extraction liquor, and wastewater from the hydrometallurgical process of copper ore, the concentration of these is much lower than that of cobalt and nickel, while copper ions and iron(III) ions is contained in higher concentrations than cobalt and nickel. Therefore, if copper ions and iron (III) ions are removed, cobalt and nickel can be sufficiently precipitated by the xanthate treatment in the next step. Aluminum ions, magnesium ions, and chromium ions do not become inhibitory metals, so they may be included in the raw solution.

<Xanthate treatment process>
A xanthate salt is added to the pretreated solution to precipitate cobalt and nickel as xanthate salts. As the xanthate, for example, alkyl xanthates such as methyl xanthate and ethyl xanthate can be used. Specifically, potassium amyl xanthate (PAX), potassium ethyl xanthate (PEX), potassium isopropyl xanthate (PIPX), etc. can be used. Further, compounds in which potassium is replaced with sodium in the above compounds (SAX, SEX, SIPX), sodium isobutyl xanthate, potassium propyl xanthate, etc. can also be used.

If the amount of xanthate added is 1 to 3 equivalents relative to the amount of cobalt or nickel, a sufficient amount of precipitation can be obtained. When the solution contains cobalt and nickel, the amount of xanthate added may be 1 to 4.5 equivalents based on the total amount of cobalt and nickel in the solution after pretreatment. In addition, in order to increase the recovery rate of cobalt and nickel to 90% or more, the amount of xanthate compound added is preferably 2.5 equivalents or more. Further, the amount of the xanthate compound added is preferably 3 equivalents or less. If the amount of xanthate added exceeds 4.5 equivalents, the recovery rate of cobalt per amount of xanthate added will decrease, which is not preferable.
Note that the equivalent amount of the xanthate compound added to the total amount of cobalt and nickel is a value calculated by the following formula.
Equivalent amount of added amount of xanthate = number of moles of xanthate / total number of moles of cobalt and nickel

The larger the molecular weight of the precipitate of xanthate salts of cobalt or nickel, the more oily it becomes. Since these precipitates are fine particles, they are suspended in the solution. A polymer flocculant is added to this solution to flocculate and coarsen the precipitate, which can then be collected as froth. For example, using flotation equipment, air is blown into the solution while stirring the solution after xanthate treatment to generate froth. Next, a polymer flocculant is added to the solution to flocculate and coarsen the floating precipitate. Then, the aggregates of the precipitate are attached to the floss, and the aggregates that float and overflow from the solution are collected (recovered as overflow). When no flocs (agglomerates of precipitates) are observed to adhere to the floss, the air blowing is stopped to stop the generation of froth, and the flocs that have overflowed so far are collected. The cobalt-nickel xanthate salt is then recovered by filtering the aggregate froth.
Specific examples of polymer flocculants include nonionic polymer flocculants.

By roasting the recovered cobalt-nickel xanthate salt precipitate at a temperature of 150°C or higher and 400°C or lower, organic matter is removed and a roasted slag (cobalt-nickel slag) in which cobalt and nickel are concentrated can be obtained. Incidentally, roasted slag is also called sintered ore, and slag is a calcined product. On the other hand, the liquid after separating the xanthate salt aggregate froth can be reused by being returned to the leachate used in the leaching process of the hydrometallurgical process of copper ore.

Examples of this embodiment will be shown below. In Examples and the like, the metal concentration in the liquid and the slag was measured by ICP-AES (Inductively Coupled Plasma Atomic Emission Spectroscopy). The iron (II) ion concentration in the liquid was measured according to the JIS standard (JIS K 0400-57-10, "1,10-phenanthroline absorption spectrophotometry"). The iron (III) ion concentration in the solution was calculated by subtracting the iron (II) ion concentration from the total iron concentration in the original solution. The thermal decomposition behavior of the slag was measured by a thermogravimetric-differential thermal analyzer (TG-DTA).
In addition, the raw solution used in Examples and the like was a liquid (raffinate) after copper extraction in a hydrometallurgical process of copper ore. The components of this stock solution are shown in Table 1. Note that the pH of the original solution was 1.5.
In the following tables, the unit of concentration "%" is mass %, and the unit "ppm" is mass ppm.

[Example 1]
(Pretreatment: reduction treatment by cementation reaction)
The raw solution was stirred for 24 hours with 8 g of a metal aluminum plate immersed in 200 ml of the raw solution. The precipitate was then removed. After 24 hours, the copper ion concentration and Fe(II) ion concentration in the solution were measured. Table 2 shows the copper ion concentration and Fe(II) ion concentration. Test No. The copper removal rate in the raw solution of No. 1 was 99.8%, and the proportion of Fe(II) ions was 100%.
Instead of the metal aluminum plate, use aluminum can scraps obtained by crushing aluminum beverage cans into 3 mm pieces, or heated aluminum can scraps obtained by heating the aluminum can scraps at 500°C for 1 hour in an electric furnace to remove the surface coating. Test No. was used except that it was used. Reduction treatment by cementation reaction was performed in the same manner as in 1 (Test Nos. 2 and 3). The results are shown in Table 2. Test No. In both cases 2 and 3, most of the copper was removed and most of the Fe(III) ions were reduced to Fe(II) ions.
The proportion of Fe(II) in the solution is the ratio of the Fe(II) concentration to the total iron concentration in the solution [Fe(II) concentration + Fe(III) concentration], and was determined according to the following formula [1]. .
Fe(II) ratio = Fe(II) concentration/(Fe(II) concentration + Fe(III) concentration)×100...[1]

[Example 2]
(xanthate treatment)
Test No. 1 of Example 1, which was pretreated by cementation. 50 ml of the solution of No. 1 was taken, and an aqueous solution of xanthate drugs (PAX, PEX, PIPX, SIPX) shown in Tables 3 and 4 was added to 50 ml of this solution, and the mixture was stirred. The residual liquid after stirring for 30 minutes was filtered, and the concentrations of cobalt ions and nickel ions in the filtrate (rear liquid) were measured. Then, the distribution ratio of cobalt and nickel to the generated precipitate was calculated. The results are shown in Tables 3 and 4.
The "residual solution" is a solution after adding the xanthate drug but before filtration, and is a solution in which precipitates are suspended.
"After-liquid" is the filtrate after addition of xanthate drug and filtration. That is, the after-liquid is the filtrate obtained by filtering the residual liquid and removing the precipitate. The after-liquid is also called the filtrate of the residual liquid.
The equivalent amount of xanthate drug added is the equivalent of the amount of xanthate drug added to the total amount of cobalt and nickel in the solution.
The distribution ratio to the precipitate is the ratio (%) of the weight (g) of cobalt or nickel in the precipitate to the weight (g) of cobalt or nickel in the original solution, and was determined by the following formula [2].
Distribution rate to the precipitate (%) = 100 - [Concentration of Co or Ni in the filtrate of the residual solution (%) x Weight (g) of the filtrate of the residual solution (rear solution) / (in the raw solution Concentration of Co or Ni (%) x initial weight of stock solution] x 100...[2]

As shown in Table 3, in order to obtain a recovery rate of 90% or more for cobalt and nickel, the amount of xanthate agent added must be 2.5 equivalents or more based on the total amount of cobalt and nickel in the solution. be. In addition, there are differences in the stability of Ni xanthate in the liquid depending on the type of xanthate drug used, and when PIPX was used (Test Nos. 30 and 31), Ni xanthate was produced before Co xanthate. Which test no. Also in samples Nos. 10-12, 20-22, 30, and 31, the distribution ratio of Al, Mg, and Fe in the solution to the precipitate was 1% or less.

Table 4 shows the equivalent amount of SIPX added, the pH of the solution, and the distribution rate of Co to the precipitate when SIPX was used as the xanthate agent. The cobalt recovery rate is slightly affected by the pH of the solution, but from the results in Tables 3 and 4, the amount of xanthate agent added is 2.5 equivalents or more and 4.5 equivalents relative to the total amount of cobalt and nickel in the solution. It has been found that a recovery rate of 90% or more can be obtained in the following cases.

[Example 3]
Test No. of Example 1 Regarding 5 L of the solution of No. 1, a small flotation machine was used to generate a precipitate of xanthate salt and concentrate and recover it. PAX, PIPX, and PEX were used as xanthate agents, and 2.5 equivalents of xanthate agents were added to the total amount of cobalt and nickel in the solution. The solution was stirred for about 15 minutes to allow the metal ions and xanthate to react. Then, a polymer flocculant (Cliffrock PN161 manufactured by Kurita Industries, Ltd.) was added to perform flotation method. Flotation was carried out under the conditions of air blowing rate of 1 to 10 L/min and flotation time of 10 to 15 minutes. The condition of the froth was visually confirmed, and flotation was performed until no aggregates adhered to the froth, and this state was defined as the end point of flotation.
The overflowed aggregate froth was collected and then filtered to separate the precipitate aggregate and filtrate. The concentrations of cobalt and nickel in the filtrate of the aggregate froth were measured. The residual liquid in the flotation machine after collecting the aggregate froth was a suspension of fine precipitates. The concentrations of cobalt and nickel in the suspended liquid were measured. The residual liquid was then filtered and separated into a fine precipitate and a filtrate. The concentrations of cobalt and nickel in the residual filtrate (after-liquid) were measured. From the measured concentrations of cobalt and nickel, the distribution ratio of cobalt and nickel was calculated using the formula described below. The results are shown in Table 5.
When PAX was used, the precipitate of xanthate salt became oily and adhered to the inner wall of the flotation machine, so it was not possible to concentrate and recover it by flotation. On the other hand, when PEX and PIPX were used, concentrated recovery by flotation was possible. In addition, when PEX was used, the precipitate was easily aggregated, and the Co distribution rate of the precipitate aggregate in the floss was 89.9%.

The distribution ratio shown in Table 5 is determined by the following formula.
(A) Metal concentration in raw solution (%)
(B) Weight of stock solution (g)
(C) Weight of aggregate floc overflowed by flotation (g)
(D) Metal concentration (%) in the filtrate of aggregate froth
(E) Residual liquid weight (g)
(F) Metal concentration in suspension of residual liquid (%)
(G) Metal concentration (%) in the residual filtrate (after-liquid)
Assuming that (A) to (G) represent the respective parameters as described above, each distribution rate is calculated using the following formula.
(H) Distribution rate (%) to unreacted metal in the liquid = 100 - ((C) x (D) + (E) x (G)) ÷ ((A) x (B)) x 100
(I) Distribution rate to precipitate in residual liquid (%) = ((F) - (G)) x (E) ÷ ((A) x (B)) x 100
(J) Distribution rate (%) to precipitate in froth = 100-(H)-(I)
The distribution ratio to unreacted metal in the liquid indicates the proportion of cobalt or nickel that remains in the liquid as metal ions without forming a precipitate.
The distribution ratio to precipitates in the residual liquid indicates the proportion of cobalt or nickel that becomes fine precipitates suspended in the residual liquid.
The distribution ratio to the precipitate in the froth indicates the proportion of cobalt or nickel that becomes an aggregate of the precipitate attached to the floss.

[Example 4]
The weight change due to thermal decomposition of the solid precipitate collected in Example 2 was measured using TG-DTA. Regardless of which xanthate agent was used, most of the organic matter was thermally decomposed at 150°C to 250°C, and the sample weight decreased by 70% to 75%. That is, the weight after heating was 25 to 30% of the weight before heating. Table 6 shows an example of the composition of the cobalt-nickel slag after thermal decomposition. The elements other than those listed in Table 6 were mainly oxygen (O).

[Example 5]
(Leaching test of copper ore using liquid after recovering Co, Ni)
Test No. of Example 2. Sulfuric acid was added to the solution after recovering Co and Ni in No. 22 to adjust the pH to 1.5. The resulting solution was added as a leachate to a copper ore slurry with a pulp concentration of 10%, and was shaken (vigorously shaken) for 8 hours. Next, the leaching rate of copper in the ore was determined from the amount of copper leached into the solution (leaching solution). The pH was measured 1, 2, and 4 hours after the start of the test, and sulfuric acid was added to maintain the pH at 1.5.
As a control test, a similar test was conducted using a liquid after copper extraction (raffinate) from copper hydrometallurgy, which corresponds to the leachate in actual operation. These results are shown in Table 7.
The leaching rate from the copper ore was 90% or more for both the raffinate and the liquid after recovering Co and Ni. From this result, it was confirmed that the liquid after recovering Co and Ni can be used as a leachate for copper ore in the same way as normal raffinate.

[Reference example 1]
A simulated liquid having the same composition as in Table 1 was prepared. However, all Fe ions were Fe(III) ions. Calcium hydroxide powder was added to 150 ml of the simulated solution while stirring, and the pH was raised stepwise to form a precipitate. The distribution ratio of metal ions to the precipitate was determined from the metal ion concentration in the solution.
Iron hydroxide started to precipitate around pH 2.5, and aluminum hydroxide started to precipitate around pH 3.5. The Co concentration in the solution decreased in the same manner as the Fe and Al concentrations, and it was confirmed that Co was co-precipitated in the process of neutralizing and removing impurities. Although 99% or more of Fe and Al were removed from the solution at pH 4.2, the residual rate of Co in the solution at that time was 4.5%.

[Comparative example 1]
Regarding the copper extraction solution (raffinate) having the composition shown in Table 1, the xanthate drug PEX was added in an amount of 3 equivalents based on the total amount of Co and Ni in the raffinate without performing the pretreatment shown in Example 1. Added. Other than that, the same xanthate treatment as in Example 2 was performed. The results are shown in Table 8. The distribution ratio of Co and Ni to the precipitate of Comparative Example 1 is significantly lower than that of Co and Ni to the precipitate of Example 2, and the precipitate contains Cu and Fe(III). It seems that it is.

The recovery method of this embodiment collects cobalt from raw solutions such as the solution after copper extraction in the hydrometallurgical process of copper ore, the acid leaching noble solution of lithium ion waste batteries, and the waste solution after copper extraction treatment and acid leaching treatment. It can also be applied to the process of recovering nickel. The after-liquid after cobalt-nickel is recovered by the recovery method of the present embodiment has almost no change in liquid properties from the original solution, so the after-liquid can be reused as a leachate for copper ore. Therefore, the recovery method of this embodiment is highly useful in actual operations.

Claims

A pretreatment step of removing one or both of copper ions and iron (III) ions contained in the raw solution containing one or both of cobalt and nickel;
A xanthate treatment step of adding a xanthate to the solution after the pretreatment to selectively precipitate one or both of cobalt and nickel xanthate salts and recovering the precipitate. How to recover cobalt and nickel.
In the pretreatment step, reduction treatment is performed by cementation reaction,
When the raw solution contains copper ions, adding metallic aluminum to the raw solution to precipitate the copper ions in the raw solution into metallic copper,
When the raw solution contains iron (III) ions, metal aluminum is added to the raw solution to reduce the iron (III) ions in the raw solution to iron (II) ions. How to recover cobalt and nickel.
In the xanthate treatment step, the xanthate salt is selectively precipitated by using a flotation equipment to add the xanthate salt to the solution after the pretreatment, and the precipitate is collected as froth. The method for recovering cobalt-nickel according to claim 2.
The method for recovering cobalt-nickel according to claim 1 or 2, further comprising the step of thermally decomposing the xanthate salt of the recovered precipitate to obtain cobalt-nickel slag.
The raw solution is a leached noble liquid of a hydrometallurgical process of copper ore, a liquid after copper extraction, or a waste liquid after copper extraction treatment,
The method of cobalt-nickel according to claim 1 or 2, further comprising a step of recycling the solution after the xanthate treatment after collecting the precipitate by returning it to the leachate used in the leaching step of the hydrometallurgical smelting step. Collection method.