JP2013245404A - Method for selectively separating and collecting manganese from cobalt and nickel using screening effect of mixed extracting agent - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method capable of selectively separating and recovering manganese using a mixed extracting agent in a pH range of 4-5.SOLUTION: An organic phase including manganese is obtained from solvent extraction of an aqueous solution including manganese using a mixed extracting agent including a solvent of phosphoric acid-based (phosphonic, phosphinic, phosphate and phosporicacid) series and alkyl monocarboxylic acid, and manganese is selectively separated and collected by specifically reducing an extraction ratio of cobalt. Manganese can be selectively collected from cobalt and nickel by the extraction suppression effect of valuable metal in a specified pH range without changing the extraction order of manganese, cobalt, and nickel.

Description

  The present invention relates to a method for selectively recovering only Mn from Co, Ni, Li using a mixed extractant.

  Separation and recovery of valuable metals using solvent extraction is a technique related to selective extraction of a desired metal at a specific pH portion with a solvent. That is, when the target metal M1 and the impurity M2 in the aqueous solution are present, if the target metal M1 is extracted in a low pH portion and the impurity M2 is extracted in a high pH range, It means that separation and recovery of M1 from M2 are easy.

  However, extracting only Mn using solvent extraction is an extremely difficult task. This is because manganese, cobalt, and nickel have similar physical properties and thus the extracted pH ranges are very close to each other. In particular, the extraction behavior of Mn and Co is similar. Therefore, it is not easy to separate and recover Mn from Co. Accordingly, the present invention seeks to provide a technique for separating and recovering manganese from cobalt.

  As a technique for solvent extraction method for valuable metals, WO 2005/073415 is a method for recovering Co and Ni from an aqueous solution of 1-50 g / L Mn, 0.1-5 g / L Co, 0-0.1 g / L Ni. Presented. However, as in the above-mentioned document, it is easy to recover Co and Ni present at relatively low concentrations from Mn, which has a concentration difference about 10 times higher. In addition, in the above document, by using a mixed solvent (commercial name: mixed with LIX63 and Versatic 10 acid), by moving the extraction curve of Co and Ni extracted from a higher pH than the original manganese to the left side, from Mn Extraction was performed in a low pH range (pH is 3.5 to 4.5). This is due to the general metal extraction order, the rising effect of changing manganese> cobalt> nickel in the order of cobalt> nickel> manganese.

  In the present invention, a method capable of selectively separating and recovering only manganese from a solution containing a valuable metal at a concentration in the same or similar range is presented as a method that differs from the above-mentioned literature.

  An object of the present invention is to provide a method for selectively separating and recovering only Mn in a specific pH region using a mixed extractant.

  Another object of the present invention is to provide a mixed extractant having a high recovery rate for manganese as an extractant used in a solvent extraction method for valuable metals.

  The present invention relates to an aqueous solution containing manganese with respect to bis-2-ethylhexyl phosphoric acid, 2-ethylhexyl phosphonic acid, bis- (2,4,4). -From trimethylpentyl) hypophosphorous acid (bis- (2,4,4-trimethylpentyl) phosphinic acid), tributyl phosphate, trialkylphosphine oxide, and alkyl monocarboxylic acid Provided is a method for selective separation and recovery of manganese, characterized in that an organic phase containing manganese is obtained by solvent extraction using a mixed extractant containing two or more selected from the group consisting of:

  Preferably, the organic phase obtained from the solvent extraction is washed with EDTA (Ethylenediaminetetraacetic acid).

  Preferably, the organic phase after the washing step is subjected to an acid removal step.

  Moreover, this invention provides the organic phase containing manganese characterized by being obtained by the said solvent extraction.

  Moreover, this invention provides the organic phase containing manganese obtained after the said washing | cleaning process.

  Further, the present invention is characterized in that the concentration ratio of bis-2-ethylhexyl phosphoric acid / alkyl monocarboxylic acid is 0.4 to 0.6, A mixed extractant for selective separation and recovery of manganese is provided.

  According to the present invention, manganese can be selectively separated and recovered, in particular, by reducing the extraction rate of cobalt while not changing the extraction sequence of valuable metals using the mixed extractant. That is, while valuable metals were extracted in the order of manganese> cobalt> nickel, manganese was selectively recovered by suppressing the extraction rate of cobalt and nickel in the acidity range of pH 4-5.

It is a figure which shows the extraction behavior of a valuable metal with respect to D2EHPA and Versatic 10 acid single use. It is a figure which shows the extraction behavior of Co according to Versatic 10 acid density | concentration addition to 0.43M D2EHPA. It is a figure which shows the extraction behavior of Mn according to Versatic 10 acid density | concentration addition to 0.43M D2EHPA. It is a figure which shows the extraction behavior of Ni according to Versatic 10 acid density | concentration addition to 0.43M D2EHPA. It is a figure which shows the extraction behavior of Li according to Versatic 10 acid density | concentration addition to 0.43M D2EHPA. It is a pH-isotherm experiment result using 1M D2EHPA / 0.134M Versatic 10 acid system. It is a pH-isotherm experiment result using a 0.8M D2EHPA / 0.334M Versatic 10 acid system. It is a pH-isotherm experiment result using a 0.434M D2EHPA / 0.7M Versatic 10 acid system. It is a pH-isotherm experiment result using a 0.134M D2EHPA / 1M Versatic 10 acid system. It is an example of the countercurrent multistage extraction method using the mixed extractant of D2EHPA and Versatic 10 acid. It is a result of the washing | cleaning process according to EDTA density | concentration. It is the result of the H ₂ SO ₄ concentration according Dakkyo process. It is a schematic diagram of a Mn solution removal flow in a countercurrent two-stage simulated removal process.

  The present invention provides a selective separation and recovery method for manganese, characterized in that an organic phase containing manganese is obtained by solvent extraction of an aqueous solution containing manganese using a mixed extractant.

  It is an organic solvent to be used for the mixed extractant in the present invention. Examples of the organic solvent include 2-ethylhexyl phosphonic acid, bis-2-ethylhexyl phosphoric acid, mono-2-ethylhexyl ester ), Di-2,4,4-trimethylpentyl phosphinic acid, bis- (2,4,4-trimethylpentyl) hypophosphorous acid (bis- (2, 4,4-trimethylpentyl) phosphinic acid), alkyl monocarboxylic acid, tributyl phosphate, trialkylphosphine oxide can be used.

  Preferably, two or more of these solvents are selected and mixed for use. In the present invention, preferably, as a phosphoric acid (phosphonic, phosphinic, phosphate, phosporic acid) series solvent, 2-ethyl hexyl phosphonic acid, bis- (2,4,4-trimethylpentyl) Hypophosphorous acid (bis- (2,4,4-trimethylpentyl) phosphinic acid), tributyl phosphate, trialkylphosphine oxide is used. More preferably, in the present invention, manganese and methane are extracted by solvent extraction using a mixed extractant containing bis-2-ethylhexyl phosphoric acid and alkyl monocarboxylic acid. Manganese is selectively separated and recovered from aqueous solutions containing other valuable metals.

  The concentration ratio of the bis-2-ethylhexyl phosphoric acid / alkyl monocarboxylic acid contained in the mixed extractant in the present invention is preferably 0.4 to 0.6. It is. This is because the selective extraction of manganese that the present invention intends to achieve can be achieved with optimum efficiency within the range of the concentration ratio between the organic solvents in the mixed extractant. That is, the present invention improves the extraction rate of manganese contained in an aqueous solution containing manganese by adjusting the concentration ratio of the organic solvent contained in the mixed extractant, while reducing the extraction rate of other valuable metals described later. The present invention relates to a method for selectively recovering manganese.

  The concentration range of preferred bis-2-ethylhexyl phosphoric acid and alkyl monocarboxylic acid provided in the present invention is 0.1M-1M. In the above concentration range, a mixed extractant in which the concentration ratio of bis-2-ethylhexyl phosphoric acid / alkyl monocarboxylic acid is adjusted to 0.4 to 0.6 is used. Then, manganese is selectively recovered.

  Meanwhile, the mixed extract may further include kerosene as a diluent.

  In the present invention, the aqueous solution containing manganese may include one or more selected from the group consisting of cobalt, nickel, and lithium. That is, the present invention selectively recovers manganese from an aqueous solution containing cobalt, nickel, or lithium as impurities in addition to manganese. In this case, preferably, the aqueous solution may contain manganese and cobalt, nickel, or lithium in the same or similar range. More preferably, the concentration is 1-20 g / L.

  Moreover, the pH (acidity) of the aqueous solution to be subjected to solvent extraction in the present invention is preferably 4-5. In the solvent extraction, the extraction rate appears to be different depending on the pH of the aqueous solution, thereby obtaining an extraction curve for each valuable metal. The present invention reduces the extraction rate of metals other than manganese in a specific pH region without changing the extraction curve of such valuable metals, that is, without changing the extraction sequence of valuable metals, thereby improving the recovery rate of manganese. Increase. In particular, the present invention provides a mixed extractant capable of selectively extracting manganese by lowering the cobalt extraction rate in the pH 4-5 region.

  The solvent extraction process in the present invention may consist of multiple stages. Preferably, the multistage extraction is a countercurrent multistage extraction method. FIG. 10 is a diagram showing an example of a countercurrent multistage extraction method using a mixed extractant of D2EHPA and Versatic 10 acid. The first stage of extraction is the stage where the aqueous solution is charged, the third stage of extraction is the stage where the aqueous solution finally comes out, R1 is the raffinate (extraction residue) concentration that exits the first stage, and R2 is the raffinate that exits the second stage. (Extraction residue) concentration, R3 is the raffinate (extraction residue) concentration leaving the third stage. When mixed extractant of 0.43M D2EHPA / 0.7M Versatic 10 acid is used, 98.62% Mn, 4.12% Co, 1.09% Ni, 0.24% Li are extracted. The However, Mn is not completely separated from Co, Ni, and Li.

  Accordingly, in the present invention, a cleaning process is subsequently performed to remove a small amount of cobalt and nickel co-extracted with manganese from the organic phase obtained in the solvent extraction process. In the cleaning step, EDTA is used to selectively remove cobalt and nickel so that only pure manganese is present in the organic phase. As the EDTA concentration increases, the impurity cleaning rate increases, but the Mn loss rate also increases. Therefore, the concentration of EDTA for effective cleaning can be presented. The present invention preferably provides a cleaning step with 0.07M-2M EDTA, more preferably with 0.095M-0.115M EDTA.

A removal step can be performed to recover manganese from the organic phase containing manganese obtained after the washing step. The removal step is generally a removal step with an acid typified by sulfuric acid (H ₂ SO ₄ ), but is not limited thereto. The removal rate depends on the concentration of sulfuric acid, and complete removal can be achieved preferably by performing the removal in multiple stages.

  The present invention further provides an organic phase containing manganese obtained in each step together with the method for selectively separating and recovering manganese. That is, it should be understood that after the solvent extraction step, the organic phase containing manganese and after the washing step, impurities are removed and the organic phase containing manganese with a higher purity is still within the scope of the present invention.

  Hereinafter, the present invention will be described in more detail through embodiments. However, this is to help understanding of the invention and should not be understood as limiting the invention.

Embodiment 1. FIG . Preparation of aqueous phase (A) and organic phase (O) As aqueous phases, aqueous solutions of 1-20 g / L Co, 1-20 g / L Mn, 1-20 g / L Ni, and 1-10 g / L Li concentrations were prepared. The initial pH was adjusted to 4-6. NH ₄ OH solution was used as the pH adjuster.

  Next, bis-2-ethylhexyl phosphoric acid (trade name: D2EHPA) and alkyl monocarboxylic acid (trade name: Versatic 10 acid) were used as the organic phase. The mixed extractant was prepared by adjusting to a concentration range of 0.1M-1M D2EHPA and 0.1M-1M Versatic 10 acid. Kerosene was used as the diluent.

2. 200 ml each of the prepared aqueous phase and organic phase was put into a 1 L Pyrex (registered trademark) container for pH-isotherm experiment and countercurrent multistage extraction. At this time, the ratio of O (organic phase) / A (aqueous phase) was adjusted to the condition of 1-2. The pH of the aqueous phase was measured at 1-7.5, and stirred at the target pH value at pH 0.5 intervals for 30 minutes, and then the aqueous phase was collected after the aqueous phase and the organic phase were completely separated. Next, in countercurrent multistage extraction, 20 ml each of the aqueous phase and the organic phase were put into a 125 ml separation funnel, and then stirred for 30 minutes. The aqueous phase collected in all experiments was analyzed with an atomic absorption analyzer (Perkin Elmer AAnalyst 400: AAS).

3. Evaluation of extraction behavior (1) Extraction behavior of valuable metals according to single use of 0.43M D2EHP and 0.7M Versatic 10 acid FIG. 1 shows the results when Versatic 10 acid and D2EHPA were used alone as the organic phase. In FIG. 1a, when 0.43M D2EHPA was used alone, the extraction behavior of valuable metals was in the order of Mn>Co>Ni> Li. The extraction curve of Mn has a general form, while the extraction curve of Co is almost close to a linear form. From this, it can be confirmed that D2EHPA is an extractant that selectively extracts Mn from Co. At pH 5, Mn was 88%, Co was 34%, Ni was 9%, and little lithium was extracted. Next, in FIG. 1b, when Versatic 10 acid is used alone, not all metal ions are extracted at pH 1 to 5.5, while Ni>Co> Mn is extracted from pH 6 or higher, and Li is not extracted. It was. From the above results, D2EHPA is selective to Mn, and Versatic 10 acid does not affect the extraction of valuable metals at pH 1-5.5, but does affect the extraction of valuable metals from pH 6 or higher, and Ni at pH 6 or higher. It can be seen that this is a selective organic solvent.

(2) Concentration effect of Verssatic 10 acid on D2EHPA 0.43M In order to investigate the extraction behavior of valuable metals according to Versatic 10 acid concentration addition to D2EHPA, Versatic10 was added to 0.43M D2EHPA in the 0M-0.9M concentration range. A pH isotherm experiment was performed. The results are shown in FIGS.

  In FIG. 2, in the case of Co, when 0.1M Versatic 10 acid is added at pH 2-6, the extraction behavior is similar to that when D2EHPA is used alone, and then 0.3M-0.9M Versatic 10 When acid was added, the extraction rate decreased. Moreover, the extraction behavior of Co increased rapidly from pH 6 or higher. It can be seen that among the mixed extractants, increasing Versatic 10 acid concentration has a decreasing effect on Co extraction behavior at pH 2-5, and has an effect on increasing Co extraction from pH 6 and above. In particular, when 0.9M of Versatic 10 acid was added compared to 0.43M D2EHPA alone, 34% to 14% of Co was reduced in the pH 5 region, contributing to a reduction of about 20%.

In FIG. 3, in the case of Mn, compared with Co, there is not much feature to be noted, but the increase in the concentration of Versatic 10 acid slightly reduced the extraction rate of Mn. In particular, 0.9M Versatic 10 acid moves the pH ₅₀ value of Mn from 2.6 to 3.2, which means that the Mn extraction curve moves to the right. That is, when the concentration of Versatic 10 acid was 0.9 M or more, the extraction behavior began to decrease so that Mn was also similar to Co.

  In FIG. 4, in the case of Ni, the extraction rate of Ni increased as the concentration of Versatic 10 acid increased. That is, in the extraction of Ni, it can be seen that the influence of Versatic 10 acid is larger than that of D2EHPA, and the action of Versatic 10 acid starts from pH 5 or higher. That is, since it was not affected by D2EHPA between pH 2-5, only a small amount was extracted, and the extraction rate increased rapidly from 5 or more due to the influence of Versatic 10 acid.

  In FIG. 5, in the case of Li, it was not extracted in the whole pH range, and it can be seen that neither D2EHPA nor Versatic 10 acid has an effect on Li.

(3) Extraction behavior of valuable metals in equimolar experiment of mixed extractant The total concentration of mixed extractant was fixed at 1.134M, and the extraction behavior was evaluated while changing the concentrations of D2EHPA and Versatic 10 acid. Equimolar experiments were performed at 25 ° C., O / A = 1, using ammonia number as pH adjuster, stirring rate was 250 RPM, mixed extractant was 0.1M-1M D2EHPA, and 0.1M The total concentration of the extractant was adjusted to 1.134M by mixing in the -1M Versatic 10 acid range.

FIG. 6 is a diagram showing the results of a pH-isotherm experiment using 1M D2EHPA / 0.134M Versatic 10 acid system. △ _{pH 50} value of Co is about pH 4.5, △ _{pH 50} value of Mn is △ _{pH 50} value of about pH 2, Ni was pH 6.5. Co was extracted up to 80.92%, Mn up to 96.77%, and Ni up to 67.98%.

FIG. 7 is a diagram showing the results of a pH-isotherm experiment using a 0.8M D2EHPA / 0.334M Versatic 10 acid system. △ _{pH 50} value of Co is about pH5.35, △ _{pH 50} value of Mn is about pH 2.25, △ _{pH 50} value of Ni it is about pH 6. When compared with FIG. 6, the ΔpH ₅₀ value of Co is 0.515 shifted from pH 4.5 to 5.15. Through this, it can be seen that the extraction behavior of Co decreases as the concentration of Versatic 10 acid increases. Further, Co was extracted up to 75.64%, Mn up to 96.49%, and Ni up to 66.14%. However, when compared with FIG. 6, in the case of Co, the maximum extraction rate is Versatic 10 acid. It showed a tendency to decrease gradually as the concentration increased.

FIG. 8 is a diagram showing the results of a pH-isotherm experiment using a 0.434M D2EHPA / 0.7M Versatic 10 acid system. △ _{pH 50} value of Co is about pH 7.25, △ _{pH 50} value of Mn is about pH 2.5, △ _{pH 50} value of Ni was about pH 6.75. When comparing FIGS. 6 to 8, the ΔpH ₅₀ value of Co increases to 4.5, 5.15, and 7.25 as the Versatic 10 acid concentration increases, which indicates that the extraction rate of Co decreases. .

FIG. 9 is a diagram showing the results of a pH-isotherm experiment using a 0.134M D2EHPA / 1M Versatic 10 acid system. △ _{pH 50} value of Co is about pH 6.75, △ _{pH 50} value of Mn is about pH 7.2, △ _{pH 50} value of Ni was about pH 7. The phenomenon in which the extraction rate of Mn clearly decreases and then increases again from pH 7, Co and Ni are also not extracted within the pH 1.5-5 range, while the phenomenon in which the extraction rate increases from 5.5 clearly Can see. In FIGS. 1a and 1b, Mn is selectively influenced by D2EHPA over Co, Ni, and Li while Co and Ni are selectively affected by Versatic 10 acid when compared to the case of using each solvent alone. I understand that.

The following <Table 1> represents the _{ΔpH 50 (M-Mm)} value at pH 5 in each of the above mixed extractant systems.

From the above table, pH _{50 (Co-Mn)} is the highest at 4.75 at a concentration of 0.7 M Versatic 10 acid and 0.434 M D2EHPA, and at this time, pH _{50 (Ni-Mn)} is 4.25. Therefore, it can be seen that 0.7M Versatic 10 acid / 0.434M D2EHPA is the optimum mixed extractant concentration for selectively separating Mn from Co, Ni and Li.

4). Washing 0.07-2M EDTA to selectively remove co-extracted Co, Ni, and Li in the organic phase, O (organic phase) / A (aqueous phase) = 4, 25 Washing was performed under the condition of ° C. The result is shown in FIG. Although the loss rate of Mn was also increased by increasing the concentration of EDTA, the cleaning rate of impurities Co, Ni, and Li reached 99.9%. In particular, when 0.1M DETA is used, the loss rate of manganese is 1.7%, and at this time, 99.9% Co, Ni, Li cleaning rate is achieved, A good Mn solution was obtained.

5. Removal 1-20 g / L Mn, 1-20 g / L Co, 1-20 g / L Ni, 1-10 g / L From an aqueous solution of Li, countercurrent 3 using 0.43M D2EHPA and 0.7M Versatic 10 acid mixed solvent After the stage extraction, the organic phase that had undergone the EDTA washing process had an almost pure Mn solution composition. For this organic phase, removal by acid concentration, removal according to the ratio of O (organic phase) / A (aqueous phase), and a countercurrent two-stage simulated removal experiment were carried out.

(1) acid concentration and O / A ratio according Dakkyo H ₂ SO ₄ concentration 0.05M, 0.1M, 0.25M, 0.5M, 1M, 1.5M, different from to O / A ratio in 2M In an experiment in which was adjusted to 1-2, the organic phase containing Mn was removed. The result by O / A ratio 2 is shown in FIG. About 76% at 0.5M acid concentration, 83% at 1M, 88% at 1.5M, 88% at 2M, and M2 removal as the concentration of H ₂ SO ₄ increases. Since the rate increased, the removal rate did not increase any more at a concentration of 1.5M or more and was constant. Therefore, it can be seen that complete removal is difficult in only one step.

(2) Counterflow two-stage simulated removal From the above results, countercurrent two-stage simulated removal was performed under the conditions of 0.5 MH ₂ SO ₄ and O / A = 2. The results are shown in FIG. The overall removal rate was 99.99%, and the concentration of Mn contained in the organic phase when exiting the second stage was as small as 15 mg / L. Therefore, it can be seen that a pure Mn solution is obtained by two-stage countercurrent escape.

Claims (17)

  For aqueous solutions containing manganese, bis-2-ethylhexyl phosphoric acid, 2-ethylhexyl phosphonic acid, bis- (2,4,4-trimethylpentyl) Selected from the group consisting of hypophosphorous acid (bis- (2,4,4-trimethylpentyl) phosphinic acid), tributyl phosphate, trialkylphosphine oxide, and alkyl monocarboxylic acid A method for selective separation and recovery of manganese, wherein the organic phase containing manganese is obtained by solvent extraction using a mixed extractant containing two or more of the above.   The method for selectively separating and recovering manganese according to claim 1, wherein the aqueous solution contains one or more selected from the group consisting of cobalt, nickel, and lithium.   The method for selectively separating and recovering manganese according to claim 2, wherein the aqueous solution contains at least one selected from the group consisting of manganese and cobalt, nickel and lithium at the same concentration.   The selective for manganese according to claim 2, wherein the concentration of one or more selected from the group consisting of manganese and cobalt, nickel and lithium contained in the aqueous solution is 1 to 20 g / L. Separation and recovery methods.   The concentration ratio of bis-2-ethylhexyl phosphoric acid / alkyl monocarboxylic acid contained in the mixed extractant is 0.4 to 0.6. The selective separation and recovery method for manganese according to claim 1.   The concentration of bis-2-ethylhexyl phosphoric acid and alkyl monocarboxylic acid contained in the mixed extractant is 0.1M-1M, The selective separation and recovery method for manganese according to claim 1.   The selective separation and recovery method for manganese according to claim 1, wherein the pH (acidity) of the aqueous solution is 4-5.   The method for selectively separating and recovering manganese according to claim 1, wherein a washing step with EDTA (Ethylenediaminetetraacetic acid) is performed on the organic phase obtained from the solvent extraction.   The method for selective separation and recovery of manganese according to claim 8, wherein the concentration of EDTA (Ethylenediaminetetraacetic acid) is 0.07M-2M.   The method for selective separation and recovery of manganese according to claim 8, wherein the concentration of EDTA (Ethylenediaminetetraacetic acid) is 0.095M-0.115M.   The method for selectively separating and recovering manganese according to claim 8, wherein the organic phase after the washing step is subjected to an acid removal step.   [12] The selective separation and recovery method for manganese according to claim 11, wherein the acid concentration is 0.5M-2M.   The method for selective separation and recovery of manganese according to claim 1, wherein the solvent extraction step comprises multiple stages.   The selective separation and recovery method for manganese according to claim 11, wherein the removal step comprises multiple stages.   An organic phase comprising manganese, obtained by the method of claim 1.   Organic phase comprising manganese, obtained by the method of claim 8.   Selective separation of manganese, characterized in that the concentration ratio of bis-2-ethylhexyl phosphoric acid / alkyl monocarboxylic acid is 0.4 to 0.6 And a mixed extractant for recovery.

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