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Article

Yttrium Separation from Phosphorite Extract Using Liquid Extraction with Room Temperature Ionic Liquids Followed by Electrochemical Reduction

by
Silvester Jürjo
,
Ove Oll
and
Enn Lust
*
Institute of Chemistry, University of Tartu, 50411 Tartu, Estonia
*
Author to whom correspondence should be addressed.
Metals 2024, 14(8), 927; https://doi.org/10.3390/met14080927
Submission received: 22 July 2024 / Revised: 10 August 2024 / Accepted: 12 August 2024 / Published: 15 August 2024
(This article belongs to the Special Issue Hydrometallurgical Processes for the Recovery of Critical Metals)
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Abstract

:
The combined chemical extraction of rare earth elements from acid solutions and electrochemical separation of yttrium by electrodeposition from Estonian phosphorite ore samples containing rare earth elements has been conducted using ionic liquids at room temperature. It is shown that bis(2-ethylhexyl) phosphate can be used to selectively extract yttrium from other low rare earth elements, constituting the basis for further extraction. Electrochemical deposition can then be applied to the concentrated extraction product to separate valuable Y from the more abundant elements, such as Ca, from the natural sample. The addition of Bi salt to the working solution significantly aids REE’s deposition. It is shown that this extraction method can be highly efficient as well as selective when well-controlled different electrodeposition conditions are applied.

Graphical Abstract

1. Introduction

Rare earth elements (REEs) are strategic critical materials [1,2] as the REEs and REE alloys and compounds possess important electrocatalytic [3], optoelectronic [4], permanent magnetic [5], and advanced energy storage [6,7] and therefore REEs are applicable in many areas of modern energy technology, including solid oxide-energy devices [8,9,10], information, transport, and chemical technology. The estimated consumption of REEs is about 250 million tons per year [1]. To overcome any supply risk, novel high-technology recovery methods [11,12,13,14], in addition to modern raw material processing methods [15,16,17,18,19], should be worked out and industrially applied [8,9,10].
An extensive literature analysis of REE processing and recovery shows that the first studies in phosphate rock processing were made in the Soviet Union around 90 years ago [20,21]. Since that time, acid leaching with sulfuric acid, nitric acid, hydrochloric acid, and phosphoric acid has been introduced, followed by different recovery routes.
The chemical composition of phosphorite is complex [22,23,24,25,26,27,28] since, along with REEs, significant numbers of calcium and phosphorus trace elements (d-metals, sp-metals, distributed rare metals) occur at various levels in phosphate rock. Some heavy REEs (HREEs) are highly desired. For the efficient separation of HREEs, light REE, along with Y and most other trace elements, should at first be separated during the phosphorite ore processing stage [29,30,31,32,33,34]. REEs’ influence on living organisms and plants is complex due to the slow dissolution kinetics of phosphorite fertilizers and not being cleaned by REEs and other toxic and radioactive metal cations [35,36,37,38].
A significant improvement in Y separation using novel methods was observed as a final result. Y, along with Bi, has been reduced on the Pt working electrode surface [27,28]. Most light REE elements were isolated during liquid extraction, while Y and heavier REEs were additionally separated, applying electrochemical reduction at the propylene carbonate electrolyte. Most of the Y deposited onto the working electrode surface formed a bi-metallic layer with Bi. Meanwhile, heavy REE elements were reduced, deposited, and thereafter, mostly partially delaminated from the working electrode surface after the cation reduction to a zero-valence metallic state.

2. Experimental Section

2.1. Raw Materials and Chemicals

Samples of Estonian-concentrated phosphorite ore from the Ülgase outcrop were obtained from geological collections at the Institute of Ecology and Earth Sciences, University of Tartu [21,27,28].
HNO3 was purchased from Sigma-Aldrich (Burlington, MA, USA), HCl from Honeywell (Charlotte, NC, USA), bis(2-ethylhexyl) phosphate (D2EHPA) from Merck, propylene carbonate (PC) (used as the organic solvent for electrolyte solution) from Sigma-Aldrich, bismuth(III) trifluoromethanesulfonate Bi(OTf)3, 99%) from Alfa Aesar (Alfa Aesar, MA, USA), and 1-Butyl-1-methylpyrrolidinium Bis(fluorosulfonyl)imide (BMPyrFSI; used as the electrolyte for deposition) from Solvionic (Toulouse, France), (99.95%, H2O < 50 ppm). All chemicals have the purity of analytical grade.

2.2. Feed Solution

A total of 0.12 g of dry evaporated sample, obtained from liquid extraction with D2EHPA, was dissolved in 3 ml of propylene carbonate. A total of 0.09 g (50 mM) Bi(OTf)3 was added thereafter and dissolved, and finally, 0.18 g (0.2 M) of BMPyrFSI was added to the solution and dissolved. The solution was prepared under an argon atmosphere in a glovebox at room temperature. This solution was used during the electrochemical deposition experiments. For the electrochemical reduction selectivity experiments, the extractant mass was lowered to 0.03 g while the Bi concentration was lowered to 10 mM.

2.3. Equipment

The quantitative analyses of the REEs and trace elements in an untreated solution and extracted solution samples have been established using the Agilent 8800 QQQ ICP-MS in the N2O mode.
Electrochemical measurements were carried out in a three-electrode electrochemical cell at room temperature. Chemically purified Pt (but modified in situ with the Bi electrodeposited layer from the Bi(OTf)3 solution) was used as the working electrode, while high surface area Pt net was used as the counter electrode, and carbon fiber as the pseudo reference electrode [27,28,38,39].
The cyclic voltammetry [40] method was used to investigate the electrochemical characteristics of the completed electrochemical system using the Autolab PGSTAT 320 with FRA II. All measurements were carried out inside the MBRAUN LabMaster 130 Glovebox (H2O < 1 ppm, O2 < 1 ppm) filled with Ar.

2.4. Experimental Conditions

The separation of Y and REEs from natural phosphorite ore samples, followed by Y separation from other REEs, has been the focus of this study. The sample of Estonian phosphorite ore [21,27,28] was dissolved in 3 M hydrochloric acid aqueous solution, followed by liquid extraction with bis(2-ethylhexyl) phosphate [30,31]. After stripping the sample with concentrated nitric acid, a mixture of calcium, Y, heavy REEs, and some other trace element nitrates was formed [40,41,42,43]. The material received was dissolved in propylene carbonate in an argon atmosphere inside a glovebox; bismuth (III) trifluoromethanesulfonate (Bi(OTf)3) was added for Bi(3+) cations introduction, and 1-Butyl-1-methylpyrrolidinium bis(fluorosulfonyl)imide (BMPyrFSI) ionic liquid was added to enhance the electric conductivity of the working solution. An electrochemical study was performed, followed by an electrochemical reduction experiment when the reduction potential of Y was reached.
The dry material was transferred to the glovebox under an argon atmosphere and heated additionally inside the glovebox at 70 °C for 24 h to remove the residual water as much as possible. After the heating material was cooled down to room temperature and dissolved in propylene carbonate inside the glass vial, this mixture was stirred with a magnetic stirring bar at 600 rpm for 1 h for the dissolution of solid material (REEs). After that, Bi(OTf)3 was added and stirred for 1 h. Finally, an ionic liquid (BMPyrFSI) was added and stirred for 15 min. After dissolution, the mixture was transferred into an electrochemical cell for the electrochemical experiments. The cyclic voltammetry CV experiments were conducted before the electroreduction of the Bi and Y cations in the chronoamperometric mode. The potential cycling CV curves at a potential scanning rate of 50 mV/s were measured. Cathodic potentials of −2.0, −2.3, and −2.6 V were applied during electroreduction using the chronoamperometric mode for 24 h. Samples of the solution were taken before and after the electrochemical experiments for detailed ICP-MS studies. The platinum working electrode was rinsed with propylene carbonate and brought out from the glovebox.

2.5. Quantitative Analysis of REEs Extraction

For the detailed quantitative analysis, the extraction efficiency was calculated using Equation (1):
E = C i n i t i a l − C   ( f i n a l ) C ( i n i t i a l ) 100 %
where E stands for the extraction efficiency and c stands for the concentration of REEs (or other metal cations) in the final and initial solutions, respectively.
The concentration of Y and REE in the organic phase (D2EHPA) after the extraction experiment was calculated using Equation (2):
Corg = Cw(initial) − Cw(final)
where Corg stands for the element concentration in the organic phase, Cw(initial) stands for the element concentration in the water phase before the extraction experiment, and Cw(final) stands for the element concentration in the water phase after the extraction experiment.

3. Results and Discussion

3.1. Results of Extraction and Stripping Experiment

3.1.1. Extraction and Stripping of Y and Rare Earth Elements

Figure 1 demonstrates all of the steps used for the extraction, cleaning, and characterization of the Y and REEs’ production routes. Thus, a 10.5 g sample of phosphorite ore was dissolved in 100 mL of 3 M hydrochloric acid for 5 min at room temperature and filtered thereafter to remove any undissolved substance to prepare an acidic feed solution. A total of 50 mL of acidic feed solution was extracted with 5 mL of D2EHPA using a plastic separation funnel. The mixture was shaken for 1 min and thereafter kept still for 15 min for equilibration. The D2EHPA solution of REEs and Y, obtained from the extraction stage, was transferred to the new separation funnel and stripped thereafter with 50 mL of concentrated nitric acid. The solution mixture was shaken for 1 min and kept silent for 15 min for equilibration. The water phase was separated, H2O was evaporated, and nitrates of different elements were obtained. Water phase samples were collected before and after the extraction as well as after the stripping experiment to conduct the ICP-MS measurements.
The results in Table 1 indicate that extraction in the 3 M hydrochloric acid solution using D2EHPA as an extractant separates Y from light rare earth elements (La-Gd) efficiently. Light REEs remain in the water phase, while Y is collected in the organic phase. It should be stressed that Y is one of the major elements in the initial solution, with a concentration comparable to Ce, Nd, and La. Based on the data in Figure 1, Y, in addition to the very heavy REEs, became a dominant element in the organic phase. Thus, a very good separation of Y from light REEs was achieved during the extraction.
Our study established that the molar concentration of hydrochloric acid influences the extraction profile and its efficiency significantly. Based on the ICP-MS analysis data, extraction from a more concentrated hydrochloric acid than 3 M would enhance the separation selectivity of Y from other REEs further. However, the extraction efficiency of Y diminishes significantly in more concentrated acids. Extraction in a HCl acid less concentrated (1 M and lower) than 3 M HCl would increase Y’s extraction efficiency while introducing lighter REEs into the organic phase. Thus, 3 M HCl seems to be a good compromise—leaving light REEs (La-Gd) in the water phase while maintaining an acceptable extraction efficiency of Y and HREEs. To increase the total efficiency, i.e., the amount of Y that is extracted, two or three extraction cycles can be applied.
Stripping Y from the organic phase with concentrated nitric acid is not very efficient—only 8.5% of Y transfers from the organic phase back to the water phase. Stripping was not selective, as well. Heavy REEs were transferred back to the water phase to some extent. Still, it is worth noting that most heavy REEs (such as Yb and Lu) remain in an organic phase, even if stripping is performed with concentrated nitric acid. Stripping with 7.5 M hydrochloric acid provides a much higher Y stripping efficiency. However, obtainment of Y(NO3)3 was preferred for the following stage of electrochemical electrodeposition of the Y metal; therefore, nitric acid stripping was performed next. To obtain improved stripping results, stripping should be repeated several times.

3.1.2. Extraction and Stripping of Other Elements than Y and REE

Due to the presence of numerous elements in the phosphorite ore powder sample, extraction and subsequent stripping will not be limited to Y and REEs alone. Calcium is the major constituent element in natural phosphorite powder, and it remains the major element after extraction and stripping. In addition to calcium, elements such as Mg, Al, Fe, and Mn are still more abundant in the phosphorite sample compared to Y. Regardless of significant enrichment of Y, other elements than REEs still need to be isolated from Y. Selective precipitation of Ca is not achievable, since REEs tend to precipitate along with Ca and other metals, and no separation occurs. Electrochemical separation, i.e., electroreduction/electrodeposition of Y from other elements, has been suggested and applied in this article.

3.2. Results of Electrochemical Experiments

3.2.1. Cyclic Voltammetry Results for Concentrated Y and REEs Solution

Figure 2a shows the cyclic voltammograms (CVs) of the electrochemical deposition solution H. It is shown that the electrodeposition of Bi starts at E = −0.8 V and is a reversible process with an oxidation peak at E = −0.6 V corresponding to the stripping of Bi. It is also seen that the electroreduction of Y and other metals starts at significantly lower potentials with an electroreduction peak at E = −2.6 V. Based on our preliminary unpublished results conducted with pure Y(NO3)3 salt, this results from the electrodeposition on the Y metal and is correlated with the oxidation peak seen at E = −0.3 V, corresponding to the electrostripping of deposited Y.
The electroreduction of HREEs started at E < −2.9V, but this process was not fully studied (the current peak was not fully developed) as the electroreduction process of Y was our main interest at this time. In the CV, the curve scanned toward less negative potentials, and the oxidation of metals started at E= −0.9 to −0.8 V. In addition, the quasi-reversible oxidation peaks between E = −0.9 V to −0.8 V for the oxidation of Bi to Bi3+ and at E = −0.4 V for Y to Y3+ are relevant to the oxidation of deposited Bi and Y. The data for Bi3+ show that there is a normal difference between Eox − Ered, = 180–200 mV potentials, and thus is characteristic of the 3-electron redox process.
The electro-oxidation process of Y demonstrates a very high difference between the Eox–Ered (i.e., very high overvoltage) characteristics of a nearly irreversible process, similar to the results discussed by Bagri et al. [44].
When the electroreduction of sample H is measured below the Bi redox process potential range (Figure 2a curve 2), significantly higher electrodeposition currents were observed for the electrodeposition of Y below E = −2.2 V. This shows that the electroreduction of Y and other metals from sample G is significantly enhanced without the disturbance of the redox deposition and stripping of the porous Bi adlayer.
Higher electroreduction currents for the Y3+ cations and, thus, a more efficient reduction of Y3+ was achieved when the electroreduction was conducted using a preliminary Bi-modified Pt electrode from the extracted Y-REEs nitrate solutions (data in Figure 3a). For a better result of Y reduction, a higher current can be applied if there is no Bi3+ in the electrodeposition solution.
For this goal, in order to increase the selectivity of Y’s electroreduction and efficiency of the electrochemical extraction procedure, we also conducted experiments with significantly lower Bi and REEs extraction product G concentrations, as shown in Figure 3a. By decreasing the Bi3+ concentration five times (to 10 mM) and REEs concentration four times (to 10 mg/mL), the initial deposition of the Bi-metal adlayer (Figure 3a, curve 1) was seen to be significantly wider, with an electrodeposition peak at E= −1.4 V. It was also observed that the electrodeposition peak for Y and other metals from sample G was now more clearly distinguishable, starting at E = −2.0V with a peak at E= −2.4V. When the potential range is limited to the REEs deposition range only (Figure 3a, curve 2), the peak is shifted to slightly more negative potentials at E= −2.6V. This shows that electrodeposition is most efficient with a low concentration of Bi3+ ions within the electrochemical deposition solution H.

3.2.2. Chronoamperometry (i vs. Time t) Results

As described in Section 3.1, although the phosphorite ore extraction sample G has a complicated chemical composition, the extraction and stripping procedures somewhat help to concentrate the Y content from the phosphorite natural sample. Thus, the final electrodeposition of Y was performed at a fixed constant potentials E = −2.0, −2.3, and −2.6 for 1 h. The currents of the i-t curve (Figure 3b) first decrease (0 ~ 2500 s) and then retain a steady range between −0.06 mA and −0.09 mA (2500~3600 s). The sharp current drop is related to the fast depletion of the Y and REEs cations’ concentrations near the electrode’s surface; this is due to the decrease in surface concentration due to electroreduction being quicker than the stationary mass-transfer rate of cations from the solution phase to the electrode surface, i.e., into the reaction zone. A noticeably faster decrease in the deposition current was observed using 10 times the diluted Y(NO3)3 and REE(3+) cation-containing mixtures, as demonstrated in Figure 2b. The increase in cathodic current at longer deposition times (t > 1600 s) for E = −2.3 V, compared with data at E = −2.0 V (Figure 3b), is connected with the deposition of Bi, Y, and other REEs having a more negative redox potential than that for Bi3+, Y3+, etc. Even though the Bi-coated working electrode surface already shows a dark color, a much darker color can be clearly differentiated at the first thousand seconds. The constant lower current range indicates a slow mass-transfer kinetic at the interface. Different from our previous article, where the Bi and Pr co-reduction occurs on the working electrode surface [28], in some experiments, a reduced amount of Y was deposited separately after the Bi reduction step was completed. It should be mentioned that most of the dark precipitate remains on the electrode’s surface (>70%), as well as some parts of the REEs in the electrolyte solution (10%); however, a noticeable amount of reduced metals deposit at the bottom of the electrochemical cell (<20%).

3.3. Post-Experiment: Dissolution of Deposited Metals from Pt(Bi) Electrode Surface with Acid Solution

A black-coated layer was formed on the Pt working electrode’s surface during the electrodeposition processes of Bi, Y, and REEs. Therefore, the working electrode surface was rinsed with propylene carbonate and introduced into a concentrated nitric acid. At the same time, black precipitated material was observed at the bottom of the electrochemical cell (less than 20% of total mass). As seen in Figure 4, the concentration of most elements in the initial solutions has decreased significantly. At the same time, not all materials have been obtained from the working electrode. It has been previously suggested by Jürjo et al. [28] that some elements electrochemically reduced at the working electrode surface (from metallic cations to 0-valence state metals) are delaminated from the working electrode’s surface and incorporated into the black precipitate found on the bottom of the electrochemical cell.
The data in Figure 4 show that nearly all Bi3+ and Y3+ have been deposited onto the Bi-modified Pt electrode; there is no noticeable deposition of the HREEs because more negative potentials are needed for the deposition of HREEs on the Bi-modified Pt electrode. Additional studies are ongoing to resolve the exact mechanism of the REEs’ deposition on different metallic electrode surfaces.
From the selectivity experiments, it was shown that E < −2.0 V is required for Y deposition. Thus, many additional elements, such as Fe (>90%), Cu (>85%), Mn (>90%), Zn (>80%), and, importantly, Sr (>95%), will be deposited prior to Y at E = −2.0 V during 4 h. This means that fewer chemical purification steps will be necessary when electrodeposition is conducted in multiple steps.
Our previous studies [28] indicate that bismuth plays an important role in the electrochemical reduction process of REEs electroreduction. Bismuth reduction from Bi3+ cation to a zero-valence metallic state occurs at a less negative potential, forming the first layer at the Pt electrode’s surface and acting as a binder for the other metals that are reduced and deposited onto the Bi-modified electrode surface. The experiment results with praseodymium trinitrate salt, along with Bi(OTf)3 in ionic liquid electrolyte, indicated that a reduction of the Pr3+ cation only occurs if the Bi3+ cation is present. Hence, the formation of a Bi-Pr bi-metallic layer was suggested [28]. But differently from Pr3+ reduction, when considering Y3+ reduction, the position Y(0) does not delaminate from the Bi-modified Pt electrode’s surface. However, after electroreduction, many other REEs delaminated from the Bi(0)-modified electrode’s surface, exhibiting a very high surface roughness [45] and porosity with a very amorphous and soft structure.

4. Conclusions

The chemical and electrochemical extraction routes of Y from the Estonian Ülgase phosphorite ore concentrate sample were demonstrated by applying ionic liquids for both steps of extraction, followed by the electroreduction (electrodeposition) process. Bis(2-ethylhexyl) phosphate was used selectively to extract Y from other light REEs. The sample was thereafter concentrated and used for further extraction in a mixture of PC and BMPyrFSI. In order to increase the efficiency of electrodeposition, Bi salt was added into the REEs mixture. The electrodeposition showed a high extraction efficiency at E = −2.6 V, where nearly all of the initial Y in the solution was extracted and electrodeposited onto a Bi-modified Pt electrode over 30 h. Selectivity was studied at millimolar concentrate solutions, which showed that the method is highly selective for Y and that the applied electrochemical potential at room temperature can tune the selectivity.

Author Contributions

S.J.: Investigation, Methodology, and Writing—original draft. O.O.: Conceptualization, Supervision, Data curation, Writing—original draft, and Writing—review and editing. E.L.: Conceptualization, Project administration, Funding acquisition, and Writing—review and editing. All authors have read and agreed to the published version of the manuscript.

Funding

This research was funded by the Estonian Ministry of Education and Research (projects no. PRG676, PSG249), the Education and Youth Board projects ÕÜF12 and ÕÜF13, and by the EU through the European Regional Development Fund Centers of Excellence, TK210 (01.01.2024–31.12.2030).

Data Availability Statement

The raw data supporting the conclusions of this article will be made available by the authors on request.

Acknowledgments

We also acknowledge support from Päärn Paiste for their ICP-MS measurements and Jinfeng Zhao for her work with data curation.

Conflicts of Interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

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Figure 1. Schematic of the processes used for chemical and electrochemical separation of REEs from phosphorite ore.
Figure 1. Schematic of the processes used for chemical and electrochemical separation of REEs from phosphorite ore.
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Figure 2. (a) Cyclic voltammograms for 0.2 M BMPyrFSI and 50 mM Bi(OTF)3 in PC with addition of REEs extraction product G electrolyte system at potential scanning rate 50 mVs−1. Curve 1 shows Bi redox processes, and 2 is measured below the Bi redox process range. (b) Chronoamperometry data at E = −2.6 V for 0.2 M BMPyrFSI + 50 mM Bi(OTF)3 +REE extraction solution H during 27 h electrodeposition.
Figure 2. (a) Cyclic voltammograms for 0.2 M BMPyrFSI and 50 mM Bi(OTF)3 in PC with addition of REEs extraction product G electrolyte system at potential scanning rate 50 mVs−1. Curve 1 shows Bi redox processes, and 2 is measured below the Bi redox process range. (b) Chronoamperometry data at E = −2.6 V for 0.2 M BMPyrFSI + 50 mM Bi(OTF)3 +REE extraction solution H during 27 h electrodeposition.
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Figure 3. (a) Cyclic voltammetry (i vs. E) curves for 10 mM Bi(OTF)3 + 0.2 M BMPyrFSI in PC with addition of REEs extract sample G at Pt electrode at 50 mVs−1 potential scanning rate. Curve 1 shows both the Bi and Y electrodeposition ranges, while curve 2 is limited to the Y electrodeposition only. (b) Chronoamperometry (i vs. time) curve at constant potentials −2.0 V and −2.3 V for 10 mM Bi(OTF)3+ 0.2 M BMPyrFSI + PC with addition of REEs extracted sample G.
Figure 3. (a) Cyclic voltammetry (i vs. E) curves for 10 mM Bi(OTF)3 + 0.2 M BMPyrFSI in PC with addition of REEs extract sample G at Pt electrode at 50 mVs−1 potential scanning rate. Curve 1 shows both the Bi and Y electrodeposition ranges, while curve 2 is limited to the Y electrodeposition only. (b) Chronoamperometry (i vs. time) curve at constant potentials −2.0 V and −2.3 V for 10 mM Bi(OTF)3+ 0.2 M BMPyrFSI + PC with addition of REEs extracted sample G.
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Figure 4. Changes in concentrations of initial solution during electrodeposition. The blue bar designates a percentage of concentration decrease in initial solution H. The orange bar designates the percentage of how much of that decreased material was obtained from the Pt working electrode during the electroreduction of solution H.
Figure 4. Changes in concentrations of initial solution during electrodeposition. The blue bar designates a percentage of concentration decrease in initial solution H. The orange bar designates the percentage of how much of that decreased material was obtained from the Pt working electrode during the electroreduction of solution H.
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Table 1. Concentrations of Y and REEs in the initial solution in the water phase and the D2EHPA phase after the extraction experiment. Y content in D2EHPA was calculated according to Equation (1). The extraction efficiency of Y and rare earth elements from phosphorite ore dissolved in 3 M hydrochloric acid using D2EHPA as an extractant.
Table 1. Concentrations of Y and REEs in the initial solution in the water phase and the D2EHPA phase after the extraction experiment. Y content in D2EHPA was calculated according to Equation (1). The extraction efficiency of Y and rare earth elements from phosphorite ore dissolved in 3 M hydrochloric acid using D2EHPA as an extractant.
ElementCw Initial, ppbCorg, ppbExtraction Efficiency
Y364712237161.3%
La1675100.0%
Ce3912800.0%
Pr491600.0%
Nd215182291.1%
Sm447900.0%
Eu1037363.5%
Gd584700.0%
Tb 85213616.0%
Dy5132164732.1%
Ho100848748.3%
Er2612175167.0%
Tm29626288.5%
Yb1441141097.8%
Lu17717699.4%
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Jürjo, S.; Oll, O.; Lust, E. Yttrium Separation from Phosphorite Extract Using Liquid Extraction with Room Temperature Ionic Liquids Followed by Electrochemical Reduction. Metals 2024, 14, 927. https://doi.org/10.3390/met14080927

AMA Style

Jürjo S, Oll O, Lust E. Yttrium Separation from Phosphorite Extract Using Liquid Extraction with Room Temperature Ionic Liquids Followed by Electrochemical Reduction. Metals. 2024; 14(8):927. https://doi.org/10.3390/met14080927

Chicago/Turabian Style

Jürjo, Silvester, Ove Oll, and Enn Lust. 2024. "Yttrium Separation from Phosphorite Extract Using Liquid Extraction with Room Temperature Ionic Liquids Followed by Electrochemical Reduction" Metals 14, no. 8: 927. https://doi.org/10.3390/met14080927

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