Valuable metal recovery method

Abstract

In this valuable-metal-recovery method, a valuable metal composed of cobalt and / or nickel is recovered from a raw solution that contains cobalt and / or nickel and also contains copper, wherein an ion adsorption step S01 for bringing the raw solution into contact with a chelate resin having a bispicolylamine group to adsorb metals in the raw solution onto the chelate resin, and a cobalt and nickel elution step S02 for eluting the cobalt andand / or nickel adsorbed onto the chelate resin by using a sulfuric acid solution, said method further comprising a copper elution step S04 for eluting the copper adsorbed onto the chelate resin by using an aqueous ammonia solution according to the amount of copper adsorbed onto the chelate resin.

Description

Valuable metal recovery methods

[0001] The present invention relates to a method for recovering valuable metals comprising at least one of cobalt and nickel from a raw solution containing at least one of cobalt and nickel and also containing copper. This application claims priority to Japanese Patent Application No. 2024-035546, filed on March 8, 2024, the contents of which are incorporated herein by reference.

[0002] Valuable metals such as cobalt and nickel are contained in the leachate of nickel laterite ore, the raffinate obtained after copper extraction from the leachate of copper ore, and waste liquids generated during the treatment of printed circuit boards and waste batteries. These leachates, raffinates, and waste liquids contain impurities such as iron, copper, and zinc in addition to cobalt and nickel. Ion adsorption using a chelating resin is used as a method for recovering cobalt and nickel from the above-mentioned leachates and waste liquids.

[0003] In the ion adsorption method, as described in, for example, Patent Document 1 and Non-Patent Documents 1 and 2, a solution containing the metal is brought into contact with a chelating resin to adsorb the metal onto the chelating resin, and then an eluent such as an acid is passed through the chelating resin to elute the adsorbed metal. Here, the chelating resin from which the adsorbed metal has been eluted is reused to treat the solution.

[0004] Patent Document 1 describes a method for recovering cobalt and nickel by subjecting a raffinate solution obtained after leaching copper ore and extracting copper ions with a solvent to a pretreatment of pH adjustment and iron (III) ion reduction, selectively extracting copper using a chelating resin (ion exchange resin) and then selectively extracting cobalt and nickel, and then eluting the cobalt and nickel from the chelating resin with sulfuric acid.

[0005] Non-Patent Document 1 describes a method for separating and recovering copper from a printed circuit board leachate containing a large amount of copper by adsorbing copper ions using a chelating resin having bispicolylamine groups and eluting them with sulfuric acid. Non-Patent Document 2 describes the relationship between the elution rates of the metals and the concentrations of the eluates obtained by eluting nickel with sulfuric acid and copper with an aqueous ammonia solution using a chelating resin having bispicolylamine groups to which nickel and copper have been adsorbed.

[0006] International Publication No. 2011 / 100442

[0007] Neto, IFF, et al., “A simple and nearly-closed cycle process for recycling copper with high purity from end life printed circuit boards” (Separation and Purification Technology, 2016), Vol. 164, 19-27. Ulloa, L., et al., “Split regeneration of chelating resins for the selective recovery of nickel and copper” (Separation and Purification Technology, 2020), Vol. 253, 117516.

[0008] In Patent Document 1, the cobalt and nickel are adsorbed onto a chelating resin after an appropriate pretreatment of the element mixture solution. The cobalt is eluted by eluting the chelating resin with low-concentration sulfuric acid, and the nickel is eluted by eluting with high-concentration sulfuric acid. However, with this method, the copper adsorbed within the chelating resin is not completely eluted and accumulates and concentrates, which may result in a decrease in the performance of the chelating resin due to the occupancy of the ion adsorption capacity.

[0009] In Non-Patent Document 1, the chelating resin is regenerated using sulfuric acid, but since the target is a printed circuit board leachate containing a high concentration of copper, a high concentration (32 mass%) of sulfuric acid is required as an eluent for copper ions, and the amount of sulfuric acid used per amount of resin is also large, which increases the processing cost.

[0010] Non-Patent Document 2 reports that, after examining the concentration conditions of the eluent, the highest elution rate was obtained when 18% by mass of sulfuric acid and 3.4% by mass of aqueous ammonia were used in combination, but even under those conditions, the elution rates of nickel and copper were less than 66%. Furthermore, it reports that the nickel adsorption rate decreases when adsorption and resin regeneration are repeated, and it is presumed that the performance of the chelating resin decreases due to the occupation of the ion adsorption capacity caused by the accumulation and concentration of copper ions within the resin.

[0011] As described above, the solution treatment method using a chelating resin having bispicolylamine groups is suitable for recovering cobalt and nickel, but when copper is present in the solution, copper ions are preferentially adsorbed onto the resin and are not efficiently eluted by passing sulfuric acid through the resin. As a result, there is a problem that the ion adsorption capacity of the resin loaded into the column decreases, as shown in Patent Document 1 and Non-Patent Document 2.

[0012] The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to provide a method for recovering valuable metals that can efficiently and stably recover valuable metals consisting of cobalt and nickel from a raw solution that contains at least one of cobalt and nickel and also contains copper.

[0013] In order to solve the above-mentioned problems, a method for recovering valuable metals according to a first aspect of the present invention is a method for recovering valuable metals comprising at least one of cobalt and nickel from a raw solution containing at least one of cobalt and nickel and also containing copper, the method comprising: an ion adsorption step in which the raw solution is brought into contact with a chelating resin having bispicolylamine groups to adsorb the metals in the raw solution onto the chelating resin; and a cobalt and nickel elution step in which at least one of cobalt and nickel adsorbed onto the chelating resin is eluted and recovered with a sulfuric acid solution to regenerate the chelating resin; and a copper elution step in which, depending on the amount of copper adsorbed onto the chelating resin, copper adsorbed onto the chelating resin is eluted with an aqueous ammonia solution to regenerate the chelating resin, and the ion adsorption step is carried out using the chelating resin regenerated in the copper elution step.

[0014] According to the method for recovering valuable metals of aspect 1 of the present invention, an ion adsorption step in which metals in a raw solution are adsorbed onto a chelating resin and a cobalt and nickel elution step in which at least one of cobalt and nickel adsorbed onto the chelating resin is eluted with a sulfuric acid solution are repeatedly performed. The method also includes a copper elution step in which copper adsorbed onto the chelating resin is eluted with an aqueous ammonia solution according to the amount of copper adsorbed onto the chelating resin to regenerate the chelating resin. This prevents performance degradation caused by copper adsorption onto the chelating resin. Furthermore, the use of an aqueous ammonia solution in the copper elution step allows efficient elution of copper ions from the chelating resin. Furthermore, because the copper elution step is performed according to the amount of copper adsorbed onto the chelating resin, the amount of aqueous ammonia used can be reduced, and deterioration of the chelating resin due to repeated adsorption and elution procedures can be suppressed, thereby extending its lifespan.

[0015] A second aspect of the present invention provides a method for recovering valuable metals, which recovers valuable metals consisting of at least one of cobalt and nickel from a raw solution containing at least one of cobalt and nickel and also copper, by repeatedly carrying out an ion adsorption step of bringing the raw solution into contact with a chelating resin having bispicolylamine groups to adsorb the metals in the raw solution onto the chelating resin, and a cobalt and nickel elution step of eluting and recovering at least one of cobalt and nickel adsorbed onto the chelating resin with a sulfuric acid solution to regenerate the chelating resin, and further comprising a copper elution step of eluting the copper adsorbed onto the chelating resin with an aqueous ammonia solution after carrying out the ion adsorption step and the cobalt and nickel elution step a predetermined number of times or more, thereby regenerating the chelating resin, and wherein the ion adsorption step is carried out using the chelating resin regenerated in the copper elution step.

[0016] According to the method for recovering valuable metals of aspect 2 of the present invention, an ion adsorption step in which metals in a raw solution are adsorbed onto a chelating resin and a cobalt and nickel elution step in which at least one of cobalt and nickel adsorbed onto the chelating resin is eluted with a sulfuric acid solution are repeatedly performed. Furthermore, after the ion adsorption step and the cobalt and nickel elution step are performed a predetermined number of times or more, a copper elution step is performed in which copper adsorbed onto the chelating resin is eluted with an aqueous ammonia solution to regenerate the chelating resin. This suppresses performance degradation caused by copper adsorption onto the chelating resin. Furthermore, the use of an aqueous ammonia solution in the copper elution step allows efficient elution of copper ions from the chelating resin. Furthermore, since the copper elution step is performed after the ion adsorption step and the cobalt and nickel elution step are performed a predetermined number of times or more, the amount of aqueous ammonia used can be reduced and the life of the chelating resin can be extended.

[0017] A valuable metal recovery method according to Aspect 3 of the present invention is characterized in that, in the valuable metal recovery method according to Aspect 1, the copper elution step is carried out when the amount of copper adsorbed on the chelating resin is 1.25 g / L-R or more. According to the valuable metal recovery method according to Aspect 3 of the present invention, the copper elution step is carried out when the amount of copper adsorbed on the chelating resin is 1.25 g / L-R or more, thereby reliably suppressing performance degradation caused by copper adsorption on the chelating resin. Furthermore, by appropriately carrying out the copper elution step, the amount of aqueous ammonia used can be reduced and the life of the chelating resin can be extended.

[0018] A method for recovering valuable metals according to Aspect 4 of the present invention is characterized in that, in the method for recovering valuable metals according to Aspect 2, the ion adsorption step and the cobalt and nickel elution steps are each carried out at least twice, followed by the copper elution step. According to the method for recovering valuable metals according to Aspect 4 of the present invention, the ion adsorption step and the cobalt and nickel elution steps are each carried out at least twice, followed by the copper elution step. This reliably suppresses performance degradation caused by copper adsorption to the chelating resin. Furthermore, by appropriately carrying out the copper elution step, the amount of aqueous ammonia used can be reduced and the life of the chelating resin can be extended.

[0019] A method for recovering valuable metals according to Aspect 5 of the present invention is the method for recovering valuable metals according to any one of Aspects 1 to 4, characterized in that the copper content in the raw solution is in the range of 0.0001% by mass to 1% by mass, the cobalt content is in the range of 0.001% by mass to 1% by mass, and the nickel content is in the range of 0.001% by mass to 1% by mass. According to the method for recovering valuable metals according to Aspect 5 of the present invention, since the raw solution to be treated contains copper as described above, by carrying out the copper elution step at an appropriate time, it is possible to reliably suppress the performance degradation caused by copper adsorption to the chelating resin and to reduce the amount of aqueous ammonia used.

[0020] A method for recovering valuable metals according to a sixth aspect of the present invention is the method for recovering valuable metals according to any one of the first to fifth aspects, wherein the raw solution contains cobalt and nickel, and the cobalt and nickel elution step comprises a cobalt elution step of eluting and recovering cobalt with a sulfuric acid solution having a sulfuric acid concentration of less than 4% by mass, and a nickel elution step of subsequently eluting and recovering nickel with a sulfuric acid solution having a sulfuric acid concentration of 5% by mass or more. According to the method for recovering valuable metals according to the sixth aspect of the present invention, the cobalt and nickel elution step comprises a cobalt elution step of eluting and recovering cobalt with a sulfuric acid solution having a sulfuric acid concentration of less than 4% by mass, and a nickel elution step of eluting and recovering nickel with a sulfuric acid solution having a sulfuric acid concentration of 5% by mass or more, thereby enabling cobalt and nickel to be separated and recovered.

[0021] A method for recovering valuable metals according to Aspect 7 of the present invention is the method for recovering valuable metals according to any one of Aspects 1 to 6, characterized in that the raw solution is a post-copper extraction solution discharged in the ore leaching step. According to the method for recovering valuable metals according to Aspect 7 of the present invention, since the raw solution is a post-copper extraction solution discharged in the ore leaching step, the valuable metals cobalt and nickel can be efficiently recovered from this post-copper extraction solution.

[0022] A valuable metal recovery method according to Aspect 8 of the present invention is the valuable metal recovery method according to any one of Aspects 1 to 6, characterized in that the raw solution is waste liquid from an acid leaching process of printed circuit boards. According to the valuable metal recovery method according to Aspect 8 of the present invention, since the raw solution is waste liquid from an acid leaching process of printed circuit boards, the valuable metals cobalt and nickel can be efficiently recovered from this waste liquid.

[0023] A valuable metal recovery method according to Aspect 9 of the present invention is the valuable metal recovery method according to any one of Aspects 1 to 8, characterized in that it further comprises a copper reduction step of reducing the amount of copper in the raw solution before the ion adsorption step. According to the valuable metal recovery method according to Aspect 9 of the present invention, the copper reduction step of reducing the amount of copper in the raw solution before the ion adsorption step is further included. This prevents excessive adsorption of copper ions onto the chelating resin in the ion adsorption step, thereby preventing a rapid deterioration in the performance of the chelating resin. Furthermore, it is possible to reduce the amount of aqueous ammonia used in the copper elution step, and to prevent deterioration of the chelating resin due to repeated adsorption and elution operations, thereby extending its lifespan.

[0024] A valuable metal recovery method according to Aspect 10 of the present invention is the valuable metal recovery method according to Aspect 9, characterized in that the copper reduction step is a cementation step in which a metal less noble than copper is added to the raw solution and copper ions contained in the raw solution are precipitated as metallic copper. According to the valuable metal recovery method according to Aspect 10 of the present invention, the above-described cementation step is carried out as the copper reduction step, so that the amount of copper in the raw solution can be reliably and efficiently reduced.

[0025] A valuable metal recovery method according to Aspect 11 of the present invention is the valuable metal recovery method according to any one of Aspects 1 to 10, characterized in that the pH of the raw solution is adjusted to within a range of 1.5 to 5.0 before the ion adsorption step. According to the valuable metal recovery method according to Aspect 11 of the present invention, the pH of the raw solution is adjusted to within a range of 1.5 to 5.0 before the ion adsorption step, so that cobalt and nickel in the raw solution can be efficiently adsorbed onto the chelating resin.

[0026] A method for recovering valuable metals according to Aspect 12 of the present invention is the method for recovering valuable metals according to any one of Aspects 1 to 11, characterized in that the ammonia concentration in the aqueous ammonia solution used in the copper elution step is within the range of 1.7% by mass or more and 3.4% by mass or less. According to the method for recovering valuable metals according to Aspect 12 of the present invention, the ammonia concentration in the aqueous ammonia solution used in the copper elution step is within the range of 1.7% by mass or more and 3.4% by mass or less, making it possible to reliably and efficiently elute copper ions from the chelating resin.

[0027] A method for recovering valuable metals according to Aspect 13 of the present invention is the method for recovering valuable metals according to any one of Aspects 1 to 12, characterized in that the sulfuric acid concentration in the sulfuric acid solution used in the cobalt and nickel elution step is within the range of 5.0 mass% or more and 50.0 mass% or less. According to the method for recovering valuable metals according to Aspect 13 of the present invention, the sulfuric acid concentration in the sulfuric acid solution used in the cobalt and nickel elution step is within the range of 5.0 mass% or more and 50.0 mass% or less, so that cobalt and nickel can be reliably and efficiently eluted from the chelating resin.

[0028] According to the present invention, it is possible to provide a method for recovering valuable metals that can efficiently and stably recover valuable metals consisting of cobalt and nickel from a raw solution that contains at least one of cobalt and nickel and also contains copper.

[0029] 1 is a flow chart showing a valuable metal recovery method according to a first embodiment of the present invention; 2 is a flow chart showing a valuable metal recovery method according to a second embodiment of the present invention; 3 is a graph showing the relationship between sulfuric acid concentration and the elution rate of cobalt and nickel in examples; and 4 is a graph showing the relationship between cumulative amount of liquid passed and adsorption efficiency of cobalt in examples.

[0030] An example of a valuable metal recovery method according to an embodiment of the present invention will be described below with reference to the drawings. The valuable metal recovery method according to this embodiment recovers valuable metals consisting of at least one of cobalt and nickel from a raw solution containing at least one of cobalt and nickel and also containing copper, such as a nickel laterite ore leachate, a raffinate solution obtained after copper extraction from a copper ore leachate, or a waste solution generated during the treatment of printed circuit boards, waste batteries, etc. It is preferable that the copper content in the raw solution be in the range of 0.0001% by mass to 1% by mass, the cobalt content be in the range of 0.001% by mass to 1% by mass, and the nickel content be in the range of 0.001% by mass to 1% by mass.

[0031] First Embodiment Here, a valuable metal recovery method according to a first embodiment of the present invention will be described with reference to the flow diagram of Figure 1. As shown in Figure 1, the valuable metal recovery method according to this embodiment includes an ion adsorption step S01, a cobalt and nickel elution step S02, an adsorbed copper amount determination step S03, and a copper elution step S04.

[0032] (Ion Adsorption Step S01) A raw solution containing at least one of cobalt and nickel and also containing copper is brought into contact with a chelating resin having bispicolylamine groups, and the metals (copper, cobalt, and nickel) in the raw solution are adsorbed onto the chelating resin. Here, the chelating resin having bispicolylamine groups has high selectivity for copper, cobalt, and nickel. Furthermore, since the chelating resin having bispicolylamine groups has a wide applicable pH range, it can directly treat strongly acidic solutions that would require pH manipulation in conventional methods, thereby significantly reducing equipment and reagent costs.

[0033] The flow rate (BV) of the raw solution supplied to the ion adsorption step S01 is preferably in the range of BV 30 to 100, and for cobalt adsorption, it is even more preferable that it be in the range of BV 30 to 50. The flow rate is preferably in the range of SV 1.5 to 18.0. An SV of 1.5 or higher allows efficient treatment of the raw solution, and an SV of 18.0 or lower prevents a significant decrease in the amount of metal adsorption per BV. The space velocity (SV) is the fluid flow rate per hour relative to the amount of resin. The flow rate (BV) is the volumetric equivalent of the amount of liquid passed through relative to the amount of resin, and is expressed as BV = flow rate (L) / resin volume (L).

[0034] (Cobalt and Nickel Elution Step S02) Next, at least one of the cobalt and nickel adsorbed on the chelating resin is eluted and recovered using a sulfuric acid solution, and the chelating resin is regenerated. Here, the sulfuric acid concentration in the sulfuric acid solution used in the cobalt and nickel elution step S02 is preferably in the range of 5.0 mass% or more and 50.0 mass% or less. If the sulfuric acid concentration is 5.0 mass% or more, cobalt and nickel can be efficiently eluted. Furthermore, if the sulfuric acid concentration is 50.0 mass% or less, the reaction between the sulfuric acid solution and the chelating resin can be suppressed, thereby extending the life of the chelating resin.

[0035] The sulfuric acid concentration of the sulfuric acid solution is more preferably 10.0% by mass or more, and even more preferably 20.0% by mass or more. A sulfuric acid concentration of 10.0% by mass or more allows for more efficient elution of cobalt and nickel. A sulfuric acid concentration of 20.0% by mass or more provides a higher elution rate for cobalt and nickel. The sulfuric acid concentration of the sulfuric acid solution is more preferably 40.0% by mass or less, and even more preferably 30.0% by mass or less. A sulfuric acid concentration of 40.0% by mass or less reduces the cost of the sulfuric acid reagent and facilitates handling. A sulfuric acid concentration of 30.0% by mass or less is expected to further reduce reagent costs and improve handling. The flow rate is preferably in the range of BV 10 to 20, and even more preferably BV 12 or more. The flow rate is preferably SV 1.5 to 18.0.

[0036] The cobalt and nickel elution step S02 may include a cobalt elution step in which cobalt is eluted and recovered using a sulfuric acid solution having a sulfuric acid concentration of less than 4.0% by mass, followed by a nickel elution step in which nickel is eluted and recovered using a sulfuric acid solution having a sulfuric acid concentration of 5.0% by mass or more. The use of a sulfuric acid solution having a sulfuric acid concentration of less than 4.0% by mass allows for selective elution of cobalt. The use of a sulfuric acid solution having a sulfuric acid concentration of 5.0% by mass or more then allows for elution of nickel.

[0037] The sulfuric acid concentration of the sulfuric acid solution in the cobalt elution step is more preferably 0.5% by mass or more, and even more preferably 1.0% by mass or more. The sulfuric acid concentration of the sulfuric acid solution in the cobalt elution step is more preferably 3.0% by mass or less, and even more preferably 2.0% by mass or less. The sulfuric acid concentration of the sulfuric acid solution in the nickel elution step is more preferably 10.0% by mass or more, and even more preferably 20.0% by mass or more. The sulfuric acid concentration of the sulfuric acid solution in the nickel elution step is more preferably 50.0% by mass or less, and even more preferably 40.0% by mass or less.

[0038] (Step S03 for Determining the Amount of Adsorbed Copper) Next, in the cobalt and nickel elution step S02, the adsorbed cobalt and nickel are eluted to determine the amount of copper (amount of adsorbed copper) adsorbed on the regenerated chelating resin. Note that the above-mentioned amount of adsorbed copper can be calculated in the ion adsorption step S01 using the following formula from the amount of copper contained in the feed solution, the amount of copper contained in the discharged solution, the amount of liquid passed, and the amount of resin. Note that LR below represents the volume (L) of the resin: (amount of adsorbed copper (g / L-R)) = (amount of copper contained in the discharged solution (g / L) - amount of copper contained in the feed solution (g / L)) × amount of liquid passed (L) ÷ amount of resin (L-R).

[0039] If the amount of copper adsorbed on the regenerated chelating resin (adsorbed copper amount) is less than a predetermined amount, the ion adsorption step S01 and the cobalt and nickel elution step S02 are repeatedly performed using the regenerated chelating resin. On the other hand, if the amount of copper adsorbed on the regenerated chelating resin (adsorbed copper amount) is equal to or greater than a predetermined amount, the copper elution step S04 described below is performed. Note that the repetition of the ion adsorption step S01 and the cobalt and nickel elution step S02 and the copper elution step S04 may be performed simultaneously, or either may be performed first.

[0040] In this embodiment, when the amount of copper adsorbed on the regenerated chelating resin (adsorbed copper amount) is less than 1.25 g / L-R, it is preferable to repeatedly perform the ion adsorption step S01 and the cobalt and nickel elution step S02, and when it is 1.25 g / L-R or more, to perform the copper elution step S04.

[0041] (Copper elution step S04) If the amount of copper adsorbed on the regenerated chelating resin (adsorbed copper amount) is equal to or greater than a predetermined amount, the copper adsorbed on the chelating resin is eluted with an aqueous ammonia solution to regenerate the chelating resin. The ion adsorption step S01 is then carried out again using the chelating resin regenerated by eluting the copper. The amount of copper adsorbed on the chelating resin is calculated by monitoring the copper concentration in the raw solution supplied and the copper concentration in the discharged liquid, and using the above-mentioned adsorbed copper amount calculation formula from the difference between the two.

[0042] Here, the ammonia concentration in the ammonia aqueous solution used in the copper elution step S04 is preferably in the range of 0.9 mass% or more and 6.8 mass% or less. If the ammonia concentration is 0.9 mass% or more, copper can be eluted. Furthermore, if the ammonia concentration is 6.8 mass% or less, the ammonia aqueous solution can be easily handled. Furthermore, the ammonia aqueous solution can be reused, although this depends on the amount of copper eluted.

[0043] The ammonia concentration in the aqueous ammonia solution is more preferably 1.3% by mass or more, and even more preferably 1.7% by mass or more. The ammonia concentration in the aqueous ammonia solution is more preferably 5.1% by mass or less, and even more preferably 3.4% by mass or less. The flow rate is preferably in the range of BV 10 to 48, and more preferably in the range of BV 12 to 24. The flow rate is preferably SV 1.5 to 24.0.

[0044] In this embodiment, as shown in Fig. 1, a copper content determination step S06 for determining the amount of copper in the raw solution and a copper reduction step S07 may be provided. In addition, as shown in Fig. 1, this embodiment may also include a pH determination step S08 for determining the pH of the raw solution supplied to the ion adsorption step S01 and a pH adjustment step S09.

[0045] (Copper content determination step S06) The amount of copper contained in the raw solution supplied to the ion adsorption step S01 is determined. There are no particular limitations on the method for determining the amount of copper; a measurement sample may be taken from the raw solution and the amount of copper may be measured using an existing component analysis means. If the amount of copper contained in the raw solution is less than a predetermined amount, the raw solution is supplied to the ion adsorption step S01. If the amount of copper contained in the raw solution is equal to or greater than the predetermined amount, the copper reduction step S07, which will be described later, is carried out. In this embodiment, it is preferable to perform the copper reduction step S07 when the amount of copper contained in the raw solution is 0.005% by mass or greater.

[0046] (Copper Reduction Step S07) In this copper reduction step S07, the amount of copper contained in the raw solution is reduced. There are no particular limitations on the means for reducing copper, and various existing methods may be applied. In this embodiment, a cementation step is preferably performed in which a metal less noble than copper is added to the raw solution, and copper ions contained in the raw solution are precipitated as metallic copper.

[0047] Here, examples of the metal that is more base than copper to be added include iron, aluminum, etc. When iron is added as a metal that is more base than copper, the amount of iron added is preferably within a range of 4 g / L to 230 g / L, and when aluminum is added as a metal that is more base than copper, the amount of aluminum added is preferably within a range of 2 g / L to 110 g / L.

[0048] (pH Determination Step S08) The pH of the stock solution to be supplied to the ion adsorption step S01 is determined. If the pH of the stock solution is 1.5 or more and 5.0 or less, the stock solution is supplied to the ion adsorption step S01. On the other hand, if the pH of the stock solution is less than 1.5 or more than 5.0, the pH adjustment step S09 described below is carried out.

[0049] Here, if the pH of the raw solution is 5.0 or less, precipitation of cobalt and nickel together with impurities can be suppressed. On the other hand, if the pH of the raw solution is 1.5 or more, cobalt and nickel can be efficiently adsorbed onto the chelating resin in the ion adsorption step S01. The pH of the raw solution is preferably 1.5 or more, and more preferably 2.5 or more. On the other hand, the pH of the raw solution is preferably 5.0 or less, and more preferably 3.5 or less.

[0050] (pH Adjustment Step 09) The pH of the raw solution is adjusted to a range of 1.5 to 5.0 using an acid or a base. Examples of the acid that can be used include sulfuric acid and nitric acid. Examples of the base that can be used include caustic soda, calcium hydroxide, and magnesium hydroxide.

[0051] The above-described process makes it possible to efficiently and stably recover valuable metals such as cobalt and nickel from a raw solution containing at least one of cobalt and nickel and also copper.

[0052] The valuable metal recovery method of this embodiment, configured as described above, repeatedly performs an ion adsorption step S01 in which metals in a raw solution are adsorbed onto a chelating resin, and a cobalt and nickel elution step S02 in which at least one of cobalt and nickel adsorbed onto the chelating resin is eluted using a sulfuric acid solution. It also includes an adsorbed copper amount determination step S03 in which the amount of copper adsorbed onto the chelating resin is determined, and a copper elution step S04 in which the copper adsorbed onto the chelating resin is eluted using an aqueous ammonia solution according to the amount of copper adsorbed onto the chelating resin to regenerate the chelating resin. This suppresses performance degradation caused by copper adsorption onto the chelating resin. Furthermore, the use of an aqueous ammonia solution in the copper elution step S04 allows for efficient elution of copper ions from the chelating resin. Furthermore, because the copper elution step S04 is performed according to the amount of copper adsorbed onto the chelating resin, the amount of aqueous ammonia used can be reduced and the life of the chelating resin can be extended.

[0053] In this embodiment, when the amount of copper adsorbed to the chelating resin in the adsorbed copper amount determination step S03 is 1.25 g / L-R or more, the copper elution step S04 is performed, which reliably suppresses performance degradation caused by copper adsorption to the chelating resin. Furthermore, by appropriately performing the copper elution step S04, the amount of aqueous ammonia used can be reduced and the life of the chelating resin can be extended.

[0054] Furthermore, in the present embodiment, when the cobalt and nickel elution step S02 includes a cobalt elution step of eluting and recovering cobalt with a sulfuric acid solution having a sulfuric acid concentration of less than 4 mass %, and thereafter a nickel elution step of eluting and recovering nickel with a sulfuric acid solution having a sulfuric acid concentration of 5 mass % or more, cobalt and nickel can be separated and recovered.

[0055] Furthermore, in this embodiment, if a copper content determination step S06 for determining the amount of copper contained in the raw solution and a copper reduction step S07 for reducing the amount of copper in the raw solution are provided before the ion adsorption step S01, by sufficiently reducing the amount of copper in the raw solution supplied to the ion adsorption step S01, it is possible to prevent excessive adsorption of copper ions onto the chelating resin in the ion adsorption step S01, and to prevent a sudden decrease in the performance of the chelating resin.

[0056] Furthermore, in this embodiment, when the copper reduction step S07 is a cementation step in which a metal less noble than copper is added to the raw solution and copper ions contained in the raw solution are precipitated as metallic copper, the amount of copper in the raw solution can be reliably and efficiently reduced.

[0057] Furthermore, in this embodiment, when the method includes a pH determination step S08 for determining the pH of the raw solution supplied to the ion adsorption step S01 and a pH adjustment step S09 for adjusting the pH of the raw solution to within a range of 1.5 to 5.0 or less, the cobalt and nickel in the raw solution can be efficiently adsorbed onto the chelating resin.

[0058] Furthermore, in this embodiment, when the ammonia concentration in the aqueous ammonia solution used in the copper elution step S04 is within the range of 1.7 mass % or more and 3.4 mass % or less, copper can be reliably and efficiently eluted from the chelating resin.

[0059] In addition, in this embodiment, when the sulfuric acid concentration in the sulfuric acid solution used in the cobalt and nickel elution step S02 is within the range of 5.0 mass % or more and 50.0 mass % or less, it is possible to reliably and efficiently elute cobalt and nickel from the chelating resin.

[0060] Furthermore, in this embodiment, when the copper content in the raw solution is within the range of 0.0001% by mass or more and 1% by mass or less, the cobalt content is within the range of 0.001% by mass or more and 1% by mass or less, and the nickel content is within the range of 0.001% by mass or more and 1% by mass or less, by performing the copper elution step S04 at an appropriate timing, it is possible to reliably suppress the performance degradation caused by copper adsorption to the chelating resin.

[0061] In this embodiment, when the raw solution is a post-copper extraction solution discharged in an ore leaching process, the valuable metals cobalt and nickel can be efficiently recovered from the above-mentioned post-copper extraction solution. Also, in this embodiment, when the raw solution is a waste liquid from an acid leaching process of a printed circuit board, the valuable metals cobalt and nickel can be efficiently recovered from the above-mentioned waste liquid.

[0062] Second Embodiment Next, a valuable metal recovery method according to a second embodiment of the present invention will be described with reference to the flow chart of Fig. 2. Note that the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

[0063] 2, the method for recovering valuable metals according to this embodiment includes an ion adsorption step S01, a cobalt and nickel elution step S02, a repetition count determination step S13, and a copper elution step S04. That is, in the second embodiment, the repetition count determination step S13 is included instead of the adsorbed copper amount determination step S03.

[0064] 2, the second embodiment may also include a copper content determination step S06 for determining the amount of copper in the raw solution and a copper reduction step S07. Also, the second embodiment may include a pH determination step S08 for determining the pH of the raw solution supplied to the ion adsorption step S01 and a pH adjustment step S09.

[0065] (Repetition Number Determination Step S13) In this repetition number determination step S13, the number of times that the ion adsorption step S01 and the cobalt and nickel elution step S02 have been repeatedly performed is determined, and when the number of times reaches a predetermined number, the copper elution step S04 is performed. Note that in this embodiment, it is preferable to perform the copper elution step S04 when the number of times of repetition reaches two or more.

[0066] The method for recovering valuable metals according to the present embodiment, configured as described above, includes a repeated ion adsorption step S01 in which metals in a raw solution are adsorbed onto a chelating resin, and a cobalt and nickel elution step S02 in which at least one of the cobalt and nickel adsorbed onto the chelating resin is eluted with a sulfuric acid solution. The method also includes a repetition count determination step S13 in which the number of repetitions of the ion adsorption step S01 and the cobalt and nickel elution step S02 is determined. After the repetition count is reached, the copper elution step S04 is performed using an aqueous ammonia solution to elute the copper adsorbed onto the chelating resin and regenerate the chelating resin. This reduces the degradation of performance caused by copper adsorption onto the chelating resin. Furthermore, the copper elution step S04 is performed after the ion adsorption step S01 and the cobalt and nickel elution step S02 are performed a predetermined number of times, thereby reducing the amount of aqueous ammonia used and extending the life of the chelating resin.

[0067] In the valuable metal recovery method of this embodiment, when the ion adsorption step S01 and the cobalt and nickel elution steps S02 are each performed at least twice, and then the copper elution step S04 is performed, the performance degradation caused by copper adsorption to the chelating resin can be reliably suppressed. Furthermore, by appropriately performing the copper elution step S04, the amount of aqueous ammonia used can be reduced and the life of the chelating resin can be extended.

[0068] Although the embodiment of the present invention has been described above, the present invention is not limited to this and can be modified as appropriate within the scope of the technical idea of ​​the invention.

[0069] The results of experiments conducted to confirm the effectiveness of the present invention are described below. In the following examples, the concentration of the solution was measured using an inductively coupled plasma optical emission spectrometer (Hitachi PS3500 DDII).

[0070] Example 1: To simulate a state in which a large amount of copper is adsorbed onto a chelating resin, 150 mL of aqueous copper sulfate solution was passed through a column packed with 10 mL of a chelating resin having bispicolylamine groups (manufactured by Sunresin, product name SEPRITE LSC495) at a flow rate of 1 mL per minute, yielding a resin adsorbed with 1.50 g / L-R of copper. Subsequently, pure water was passed through the column to wash away any adhering liquid between the chelating resin particles. After washing, 120 mL of 20% by weight sulfuric acid (BV12) was passed through the column at a flow rate of 1 mL per minute (SV6.0), followed by 120 mL of 1.7% by weight (=1N) aqueous ammonia solution (BV12) at a flow rate of 1 mL per minute (SV6.0).

[0071] The cumulative eluted copper amount calculated from the column outlet concentration was 0.54 g / L-R when 20% by weight sulfuric acid was passed through, and 0.82 g / L-R when 1.7% by weight aqueous ammonia was passed through. The cumulative eluted copper amount for both steps was 1.36 g / L-R, which accounts for 90.6% of the initial adsorbed copper amount. The eluted copper amount can be calculated from the copper concentration of the solution discharged from the column outlet after fractionation at each interval, the interval time, the flow rate, and the amount of chelating resin. (Eluted copper amount (g / L-R)) = (Amount of copper contained in the discharged solution (g / L) × Flow rate (L / min) × Interval time (min)) ÷ Amount of resin (L-R). The cumulative eluted copper amount was calculated as the sum of the amounts of eluted copper from the start to the end of the passage of the sulfuric acid solution or aqueous ammonia solution.

[0072] Example 2 The effects of the copper reduction step (cementation step) and the pH adjustment step on the raw solution to be fed to the ion adsorption step were confirmed.

[0073] Test (1): 50 mL of raffinate solution obtained after copper extraction from copper ore leachate was added with 5 mL of chelating resin having bispicolylamine groups and stirred for 1 hour. Test (2): 0.3 g of iron powder was added to 100 mL of raffinate solution obtained after copper extraction from copper ore leachate, and the mixture was stirred for 1 hour. The precipitated copper was filtered by suction to separate the solid and liquid. 50 mL of the resulting liquid was then sampled, to which 5 mL of chelating resin was added and stirred for 1 hour. Test (3): 4.2 mL of 14% by mass caustic soda was added to 100 mL of raffinate solution obtained after copper extraction from copper ore leachate to adjust the pH from 1.2 to 2.5. 50 mL of the resulting liquid was then sampled, to which 5 mL of chelating resin was added and stirred for 1 hour. Test (4): 0.3 g of iron powder was added to 100 mL of a raffinate solution obtained after copper was extracted from a copper ore leachate, and the mixture was stirred for 1 hour. The precipitated copper was filtered by suction, and 3.3 mL of 14% by mass caustic soda was added to adjust the pH from 1.2 to 2.5. 50 mL of the resulting solution was taken, and 5 mL of a chelating resin was added and the mixture was stirred for 1 hour.

[0074] The amounts of cobalt, nickel, and copper adsorbed, determined from the compositions of the solutions before and after adsorption obtained in the above tests (1) to (4), are shown in Table 1.

[0075]

[0076] Comparing Tests (1) and (2) in Table 1, it can be seen that removing copper in advance by cementation reduces the amount of copper adsorption, while increasing the amounts of cobalt and nickel adsorption. Comparing Tests (1) and (3) in Table 1 reveals a significant difference in the amount of cobalt and nickel adsorption depending on whether or not pH adjustment is performed. Chelate resins containing bispicolylamine groups generally adsorb metals more easily at higher pH levels, so a pH adjustment step is necessary when using low-pH solutions. Comparing Tests (1) to (4) in Table 1, it can be seen that Test (4) showed the highest amount of cobalt and nickel adsorption, demonstrating that the two steps of cementation and pH adjustment maximize the amount of cobalt and nickel adsorption in the ion adsorption step.

[0077] Example 3 Next, the sulfuric acid concentration of the sulfuric acid solution used in the cobalt and nickel elution step was examined.

[0078] 10 mL of a chelating resin having bispicolylamine groups was added to 100 mL of a sulfuric acid solution containing 200 ppm by mass of cobalt, and the mixture was stirred for 30 minutes to obtain a resin with cobalt adsorbed thereon. The post-adsorption solution was separated from the cobalt-adsorbed resin, and then the adhering liquid was removed by washing with water. 50 mL of 0.5 to 5% by mass sulfuric acid was added to the washed resin, and the mixture was stirred for 30 minutes. The elution rate (elution rate = amount of eluted cobalt divided by the amount of cobalt adsorbed on the resin) was calculated from the concentration of cobalt dissolved in the solution. A similar test was also performed using a sulfuric acid solution containing 200 ppm by mass of nickel, and the nickel elution rate for 1 to 10% by mass sulfuric acid was calculated.

[0079] The results are summarized in Figure 3. As can be seen from Figure 3, cobalt can be eluted at a sulfuric acid concentration of 0.5% by mass or higher, but when the sulfuric acid concentration is greater than 5% by mass, nearly 60% of nickel is also eluted. Therefore, to efficiently elute both nickel and cobalt, it is desirable to use sulfuric acid of 5% by mass or higher. On the other hand, to separately elute cobalt and nickel, it is desirable to use 0.5 to 4.0% by mass of sulfuric acid in the first stage to elute cobalt while suppressing nickel elution, and to use 5.0 to 50.0% by mass of sulfuric acid in the second stage to efficiently elute nickel.

[0080] Example 4 Next, the ammonia concentration of the aqueous ammonia solution used in the copper elution step was examined.

[0081] A column packed with 10 mL of chelating resin having bispicolylamine groups was passed through at a flow rate of 1 mL per minute a 150 mL aqueous solution of copper sulfate with a concentration of 100 mg / L, yielding a resin adsorbed with 1.5 g / L-R of copper. Pure water was passed through the column to remove any adhering liquid between the chelating resin particles. After washing, 120 mL (BV 12) of 20% by weight sulfuric acid was passed through the washed chelating resin at a flow rate of 1 mL per minute (SV 6.0), and the elution rate (elution rate = amount of eluted copper divided by the amount of copper adsorbed on the resin) for 20% by weight sulfuric acid was calculated from the copper concentration of the solution discharged from the column outlet.

[0082] After passing sulfuric acid through the chelating resin, 120 mL (BV 12) of an aqueous ammonia solution having the concentration shown in Table 2 was passed through the resin at a flow rate of 1 mL per minute (SV 6.0). The cumulative copper elution rate after passing the aqueous ammonia solution is shown in Table 2. Comparing tests (5) to (8) in Table 2, it can be seen that the copper elution rate reaches approximately 90% when the concentration of the aqueous ammonia solution used for elution is 1.7% by mass or higher. On the other hand, when the concentration is 0.9% by mass or lower, the copper elution rate is low and the regeneration of the chelating resin is insufficient.

[0083]

[0084] Example 5 Next, the amount of copper adsorbed on the chelating resin was examined.

[0085] A column packed with 10 mL of bispicolylamine-containing chelating resin was passed through a column containing 10 mL of 100 mg / L copper sulfate solution at a flow rate of 1 mL per minute, yielding resins adsorbed with 1.0, 1.25, and 1.5 g / L-R copper. Pure water was passed through the resin to remove any adhering liquid between the chelating resin particles. After washing, the chelating resin and the same amount of chelating resin without adsorbed copper were passed through a sulfuric acid mixture (600 mL, BV 60) containing 200-300 ppm cobalt at a flow rate of 0.5 mL per minute (SV 3.0), and the cobalt concentration of the solution discharged from the column outlet was recorded over time.

[0086] The above results are summarized in Figure 4, where the vertical axis represents the cobalt adsorption efficiency (= ratio of outlet cobalt concentration / cobalt concentration in the feed solution) and the horizontal axis represents the flow rate (BV). As can be seen from Figure 4, when a resin with a copper adsorption capacity of 1.25 g / L-R or more is used, the cobalt adsorption efficiency begins to decrease at flow rates of BV10 and above. Therefore, if it is desired to efficiently adsorb cobalt, it is desirable to carry out a copper elution step using an aqueous ammonia solution once the copper adsorption capacity of the chelating resin reaches 1.25 g / L-R or more.

[0087] As a result of the above confirmatory experiments, it was confirmed that the present invention can provide a method for recovering valuable metals that can efficiently and stably recover valuable metals consisting of cobalt and nickel from a raw solution that contains at least one of cobalt and nickel and also contains copper.

Claims

1. A method for recovering valuable metals, comprising recovering valuable metals consisting of at least one of cobalt and nickel from a raw solution containing at least one of cobalt and nickel and also copper, the method comprising: an ion adsorption step in which the raw solution is brought into contact with a chelating resin having bispicolylamine groups to adsorb the metals in the raw solution onto the chelating resin; and a cobalt and nickel elution step in which at least one of cobalt and nickel adsorbed onto the chelating resin is eluted and recovered with a sulfuric acid solution, thereby regenerating the chelating resin; and a copper elution step in which copper adsorbed onto the chelating resin is eluted with an aqueous ammonia solution in accordance with the amount of copper adsorbed onto the chelating resin, thereby regenerating the chelating resin; wherein the ion adsorption step is carried out using the chelating resin regenerated in the copper elution step.

2. A method for recovering valuable metals, comprising recovering valuable metals consisting of at least one of cobalt and nickel from a raw solution containing at least one of cobalt and nickel and also containing copper, the method comprising: an ion adsorption step in which the raw solution is brought into contact with a chelating resin having bispicolylamine groups to adsorb the metals in the raw solution onto the chelating resin; and a cobalt and nickel elution step in which at least one of cobalt and nickel adsorbed onto the chelating resin is eluted and recovered with a sulfuric acid solution, thereby regenerating the chelating resin; and a copper elution step in which, after the ion adsorption step and the cobalt and nickel elution step have been performed a predetermined number of times or more, the copper adsorbed onto the chelating resin is eluted with an aqueous ammonia solution to regenerate the chelating resin, wherein the ion adsorption step is carried out using the chelating resin regenerated in the copper elution step.

3. The method for recovering valuable metals according to claim 1, wherein the copper elution step is carried out when the amount of copper adsorbed on the chelating resin is 1.25 g / L-R or more.

4. The method for recovering valuable metals according to claim 2, characterized in that the copper elution step is carried out after the ion adsorption step and the cobalt and nickel elution step are each carried out at least twice.

5. A method for recovering valuable metals as described in claim 1 or claim 2, characterized in that the copper content in the raw solution is in the range of 0.0001% by mass or more and 1% by mass or less, the cobalt content is in the range of 0.001% by mass or more and 1% by mass or less, and the nickel content is in the range of 0.001% by mass or more and 1% by mass or less.

6. A method for recovering valuable metals according to claim 1 or claim 2, characterized in that the raw solution contains cobalt and nickel, and the cobalt and nickel elution process comprises a cobalt elution process in which cobalt is eluted and recovered using a sulfuric acid solution having a sulfuric acid concentration of less than 4% by mass, and a nickel elution process in which nickel is eluted and recovered using a sulfuric acid solution having a sulfuric acid concentration of 5% by mass or more.

7. A method for recovering valuable metals according to claim 1 or 2, characterized in that the raw solution is a post-copper extraction solution discharged in the ore leaching process.

8. A method for recovering valuable metals according to claim 1 or 2, characterized in that the raw solution is waste liquid from an acid leaching process for printed circuit boards.

9. A method for recovering valuable metals according to claim 1 or claim 2, characterized in that a copper reduction step for reducing the amount of copper in the raw solution is provided before the ion adsorption step.

10. A method for recovering valuable metals as described in claim 9, characterized in that the copper reduction process is a cementation process in which a metal less noble than copper is added to the raw solution and copper ions contained in the raw solution are precipitated as metallic copper.

11. A method for recovering valuable metals according to claim 1 or 2, characterized in that the pH of the raw solution is adjusted to within the range of 1.5 to 5.0 before the ion adsorption step.

12. A method for recovering valuable metals as described in claim 1 or claim 2, characterized in that the ammonia concentration in the aqueous ammonia solution used in the copper elution step is within the range of 1.7 mass% or more and 3.4 mass% or less.

13. A method for recovering valuable metals as described in claim 1 or claim 2, characterized in that the sulfuric acid concentration in the sulfuric acid solution used in the cobalt and nickel elution process is within the range of 5.0 mass% or more and 50.0 mass% or less.

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