Stage Counter Current Extraction Research Articles

Extraction and recovery of zinc from spent pickling solution: Experimental design and mechanism analysis

Solvent extraction of zinc with N, N-di(1-methylheptyl) acetamide (N503) from hot-dip galvanizing spent pickling solution is studied. The interaction between N503 concentration, extraction time, and phase ratio (O/A) is investigated using response surface methodology (RSM), and the experimental parameters are optimized as follows: the concentration of N503 is 50 % (v/v), the extraction time is 12 min, and the O/A is 16:5. The extraction efficiency of zinc is 82.12 %, and the separation coefficient (βZn/Fe) is 278.92 under the condition of single stage extraction. After four stages of countercurrent extraction, zinc is almost completely extracted from the aqueous phase. Additionally, it is found that zinc can be stripped effectively under the conditions of 0.4 mol/L HCl, stripping time of 10 min and O/A of 4:1. Also, the extraction mechanism of N503 is determined by electrostatic potential, FT-IR, and 1H-NMR spectroscopy, and the extraction complex is [CH3CONR2H]ZnCl3. In summary, a method for separating zinc from spent pickling solution has been developed, and it has a certain industrial application prospect.

Negligible emissions and highly efficient recovery of Mo, V, and Al from spent hydroprocessing catalysts through alkaline leaching and solvent extraction

Spent petroleum hydroprocessing catalysts (HPCs) are considered hazardous waste due to their high content of heavy metals and organic pollutants, posing a risk of environmental pollution and significant loss of valuable metals if not properly disposed. This study aimed to characterize the spent HPCs using optical microscopy, SEM-EDS, XRF, C & S analyzer, XRD, and XPS. Additionally, the effectiveness of six organic solvents in removing the black oil covering the surface of spent HPCs was investigated. Furthermore, the recovery of Mo, V, and Al from the spent HPCs was examined through stepwise leaching using NaOH + NaClO2 and NaOH, followed by the separation of Mo, V, and Al via selective precipitation of Al and solvent extraction using Aliquat 336. The results indicated that toluene and tetrahydrofuran exhibited the highest efficiency in removing the black oil. Under the optimized oxidizing alkaline leaching conditions (0.09 g/mL NaOH + 0.05 g/mL NaClO2, 90 °C, 1 h), Mo, V, and Al achieved leaching efficiencies of 99.9 %, 99.9 %, and 20.1 %, respectively. Subsequently, Al in the residue was recovered through leaching with NaOH, resulting in a total leaching efficiency of 95 % under the optimized alkaline leaching conditions (0.12 g/mL NaOH, 180 °C, 3 h). The Al in both leaching solutions was precipitated by adjusting the pH to 8.60. For the subsequent Mo/V separation, the best conditions involved either four stages of counter-current extraction or two stages of cross-current extraction using a solution of 21 wt% Aliquat 336 dissolved in a mixture of kerosene and isooctanol (volume ratio 9:1) at a pH of 8.60. Finally, a hydrometallurgical flowchart for the recovery of Mo, V, and Al from spent HPCs was proposed.

Combined hydrometallurgical route for recovery of metals from spent LIB using hydrochloric acid and phosphonium ionic liquid

ABSTRACT This research explored the significance of Cyphos IL 101 in recovering metal values from waste LiMn2O4 batteries. Several leaching parameters were investigated to recover metals from the leach liquor of the battery material. The maximum leaching efficiency of Li (100%) and Mn (99.6%) was attained with 3.0 mol/L hydrochloric acid, 30°C, S/L ratio of 10 g/L, and 60 min leaching duration. The leaching process was diffusion-controlled. At pH 5.5, the separation of manganese and lithium exhibited excellent selectivity towards manganese over lithium using 0.1 mol/L Cyphos IL 101. 99.6% manganese extraction and negligible lithium extraction were obtained with two stages of counter-current extraction at A/O 1:1 predicted by the McCabe-Thiele plot. Using 0.1 mol/L hydrochloric acid, a stripping efficiency of 99.4% was attained for manganese.

Complete recycling of valuable metals from electroplating sludge: Green and selective recovery of chromium

The recovery of chromium (III) is a key step for complete recycling of heavy metals from electroplating sludge. Therefore, thermodynamic equilibrium diagrams of Me-PO43--H2O[Me: Cr (III), Zn (II), Cu (II), Fe (II), Fe (III), Ni (II)] systems at 298 K have been established, the thermodynamic analysis for the precipitation of chromium (III) using phosphates and the conversion of CrPO4 to Cr(OH)3 using caustic soda were conducted. The results showed that phosphate seemed preferentially combined with Cr (III) rather than other metal cations in order of Cr (III) > Fe (III) > Fe (II) > Zn (II) at the pH range of 1.0 ∼ 5.0. The verification experiment results indicated that about 94.1% Cr (III), 5.51 %Fe (II), and 0.33% Zn (II) reached were precipitated by adding 110% theoretical amount of Na3PO4·12H2O at equilibrium pH equal to 2.0. As consistent with the thermodynamic analysis, alkali conversion of CrPO4 with NaOH achieved a leaching efficiencies of Cr (III) and phosphorus were 5.1% and 90.6%, which realized phosphate recycling and the recovery of leached Cr (III). 99.7% Zn was deeply separated and recovered from Fe (II/III) by D2EHPA by two stages of counter current extraction with an O/A ratio of 1:2, 5 min stirring at 20 °C. And the optimal conditions for Zn stripping were considered as mixing 1 mol/L H2SO4 and loaded D2EHPA with O/A ratio of 5:1 at room temperature for 5 min. The proposed process shows a promising industrial application in view of its low cost, complete recycling, and wide adaptability. SynopsisElectroplating sludge will cause serious pollution to the environment if not properly treated. This study reports a new treatment method of electroplating sludge to achieve comprehensive recovery of all valuable metals. Compared with traditional process, this process exhibits a promising industrial application due to its no emissions, lower cost, complete reagent cycle, purer product, higher quality, broader adaptability, and greener production.

Tailored hydrophobic deep eutectic solvent for removing trace aluminum impurity to produce high-purity GdCl3

In the current industrial production of high-purity gadolinium (Gd) products, aluminum (Al) is enriched into GdCl3 solution as the main impurity element. It is urgent to develop a new process to effectively remove Al3+ from GdCl3 solution. In this paper, a novel strategy for separating Al3+ and Gd3+ based on hydrophobic deep eutectic solvent (HDES) is reported. The main physical properties of HDESs were characterized, including density (<0.90 g/cm3), viscosity (<30 mPa·s), water content (<3.5 %) and water solubility (TOC < 300 mg/L). The extraction performances of HDESs for separating of Al3+ from GdCl3 solution were systemically investigated. Compared with other HDESs, N,N-diethyldodecanamide (DM):ibuprofen (BF) (3:1) HDES has a better separation performance, with the maximum separation factor of Al/Gd (βAl/Gd) being greater than 400. It was found that DM:BF (3:1) HDES could quantitatively remove Al3+ (E% > 99 %) from the original GdCl3 solution (853.9 mg/L Al3+ and 5466.2 mg/L Gd3+) in three continuous counter-current extraction stages. The co-extraction rate of Gd3+ was only 2.43 %, and the purity of GdCl3 in the raffinate was 99.9 %. After the loaded HDES was scrubbed one more time, the comprehensive yield of Gd exceeded 99 %. The loaded HDES could be easily stripped, regenerated and sustained stability over five regeneration cycles. The HDES studied in this paper has the advantages of simple preparation, low toxicity, low viscosity, good hydrophobicity and excellent separation effect, which is conducive to the sustainable preparation of high-purity GdCl3.

Recovery of pure MnSO4 by crystallization after separation of Fe(III) and Zn(II) from the reductive leaching solution of manganese dust containing Mn3O4

Manganese dust generated during the production of ferroalloys contains iron and zinc oxides together with other minor oxides. Pure manganese compounds can be recovered from the leaching solution of the manganese dust by removing the impure ions. In this work, sulfuric acid and ferrous sulfate were employed as leaching and reducing agents for the manganese oxides in the dust. First, the leaching conditions for complete dissolution of the manganese oxides were investigated by varying the concentration of sulfuric acid and ferrous sulfate, and pulp density. Second, after oxidizing Fe(II) to Fe(III) by hydrogen peroxide, Fe(III) was removed from the solution by three stages of counter current extraction with D2EHPA. Third, Zn(II) was removed by two stages of cross current extraction with Cyanex 272. Stripping conditions for Fe(III) and Zn(II) were determined from the respective loaded organics. Fourth, Mn(OH)2 was precipitated from the raffinate by adjusting the pH of the solution to 10 with NaOH solution. The MnSO4 crystals with 99.5% purity were recovered by crystallization from the sulfuric acid solutions after the precipitates of Mn(OH)2 were dissolved. A comparison of the cost of the chemicals used to recover MnO2 and MnSO4 indicated that the current process was much more economical.

ЭКСТРАКЦИОННАЯ ОЧИСТКА ТЯЖЁЛОЙ ФРАКЦИИ ГАЗОЙЛЯ ВИСБРЕКИНГА СМЕСЯМИ N,N-ДИМЕТИЛФОРМАМИДА С N-МЕТИЛМОРФОЛИНОНОМ-3 И ЛЁГКОЙ ФРАКЦИИ N,N-ДИМЕТИЛФОРМАМИДОМ

The results of extraction purification of visbreaking gas oil by Kirishinefteorgsintez LLC, divided into a light fraction of 204-264oC and a heavy fraction of 257-343oC by vacuum distillation, are presented. By four–stage countercurrent extraction of the light fraction with N, N - dimethylformamide at a mass ratio of 1.5:1 to raw materials and a temperature of 40 °C, the sulfur content was reduced from 1.911% by weight to 0.240% by weight in the raffinate. The results of a single-stage extraction of the heavy fraction of visbreaking gas oil with the sulfur content of 2.406% by weight are presented. The extraction was performed by mixtures of N, N – dimethylformamide with N – methylmorpholinone – 3 of the composition 50/50% by weight with mass ratios to raw materials of 0.5:1, 0.6:1 and 0.75:1. The extraction was also performed by mixtures of these solvents with the content of N – methylmorpholinone – 3 in the mixed extractant of 30 and 70% by weight and the mass ratio to raw materials 0.6:1. The results of two–stage extraction purification in cross–current with a mixture of N, N – dimethylformamide – N - methylmorpholinone - 3 of the composition 50/50% by weight with a mass ratio to the heavy fraction of 0.6:1 are presented. By four–stage countercurrent extraction purification with the mixed extractant containing N – methylmorpholinone - 3 30% by weight at a mass ratio of 1.5:1 to raw materials and a temperature of 40 oC, the raffinate was obtained with a yield of 51.6% by weight with the sulfur content of 0.952% by weight. During the process the degrees of extraction were, % by weight: organosulfur components – 79.6, nitrogen–containing compounds – 93.4, polyaromatic hydrocarbons – 88.6 and alkenes – 60.9. By mixing the extracted refined products, marine fuel can be obtained that meets the requirements for sulfur content - no more than 0.5% by weight

Selective Extraction of Cu(II) from the Hydrochloric Acid Leaching Solution of Spent Lithium-Ion Batteries by a Mixture of Aliquat 336 and LIX 63

The smelting reduction of spent LIBs produces metallic alloys containing Co, Cu, Fe, Mn, and Ni. These metallic alloys can be completely dissolved by 2 M HCl solution containing H2O2 as an oxidizing agent. Extraction of the leaching solution with D2EHPA results in a Fe(III) free raffinate. In this work, solvent extraction experiments were performed with a mixture of Aliquat 336 and LIX 63 to separate Cu(II) from the Fe(III) free raffinate. This mixture showed selectivity for Cu(II) over Co(II), Mn(II), Ni(II), and Si(IV). The mixture of 0.3 M Aliquat 336 and 0.2 M LIX 63 had the highest synergistic coefficient for the extraction of Cu(II) from the solution. The Cu(II) in the loaded mixture was easily stripped by weak sulfuric acid solution, which facilitates the recovery of copper sulfate from the stripping solution. McCabe-Thiele diagrams for the extraction of Cu(II) by the mixture and for the stripping with sulfuric acid solution were constructed. Three stages of counter-current extraction and stripping experiments verified that only Cu(II) was completely extracted, and the purity of Cu(II) in the stripping solution was higher than 99.9%. Considering the selectivity and easy stripping of Cu(II) from the loaded organic, this mixture can be employed in real operation for the recovery of valuable metals from the leaching solutions of spent LIBs.

Recovery of lithium from high Mg/Li ratio salt-lake brines using ion-exchange with NaNTf2 and TBP

In view of the complex problems for the ionic liquids (ILs) recovery with the system containing ILs and TBP, this work proposed a NaNTf2-based synergistic extraction system, NaNTf2 + TBP, which could realize the effective reutilization of the extraction system without reducing the lithium separation ability. Under the optimal extraction parameters, the extraction efficiency of Li+ exceeded 98%, while that of Mg2+ was only ~1%. The results of mass spectrometry (ESI-MS) and slope analysis showed that two TBP molecules involved in the extraction process of Li+, and the Li+ extraction mechanism obeyed the cation-exchange process. According to the red shift of the FT − IR peak of PO in TBP and the chemical shift changes of P in 31P NMR, the interaction strength between TBP and different metal ion followed the sequence: ETBP−H >> ETBP−Li > ETBP−Mg > ETBP−K > ETBP−Na. It was also found that after a three−stage countercurrent extraction process, [Li+]org was 0.42 g L−1, and the total recovery efficiency of Li+ was about 98%. The saturated extraction capacity for Li+ could be as high as 5.4 g L−1, and Li+ could be stripped with the aqueous solution containing 0.2 mol L-1 HCl. In addition, the extraction efficiency of Li+ was almost not attenuated after 6 extraction cycles. This new extraction system shows a certain industrial application prospect for Li+ separation from the salt lake bine with high Mg/Li ratio.

Separation of Pd(II) and Zn(II) by Solvent Extraction using Commercial Extractants from Hydrochloric Acid Leaching Solution of Cemented Pd from Spent Electroplating Solutions

The demand for palladium (Pd) has increased and this has made it necessary to recover pure Pd from diverse secondary resources. To recover the small amount of Pd(II) present in spent electroplating solutions, Pd(II) is concentrated by cementation with zinc metal. In this work, a hydrometallurgical process consisting of leaching and solvent extraction was developed to recover Pd from the cemented Pd. The extraction behavior of Pd(II) and Zn(II) from synthetic HCl solution by commercial extractants such as LIX 63, Cyanex301, DOS, TBP, Alamin 308, Alamine 336 and Aliquat 336 was investigated by varying HCl concentration. The results showed that LIX 63, Cyanex 301 and DOS selectively extracted Pd(II) over Zn(II). These three extractants were employed to separate Pd(II) and Zn(II) from actual leaching solutions with cemented Pd using a mixture of 7.0 M HCl and 0.5% M H2O2 with 2 g/L pulp density at 60oC for 120 min. Cyanex 301 and DOS selectively extracted Pd(II) over Zn(II) from the leaching solution, while a small amount of Zn(II) was co-extracted with Pd(II) by LIX 63. A two stage counter-current extraction of actual leaching solution with LIX 63 resulted in the co-extraction of Zn(II) with Pd(II). The complete stripping of Pd(II) from the loaded Cyanex301 was achieved using either diluted aqua regia or a mixed solution of 5 M HCl and 0.5% NaClO at an A/O ratio of ten. The hydrometallurgical process is proposed to recover a pure Pd(II) solution from cemented Pd.

Recovery of Rare Earth Metals (REMs) from Nickel Metal Hydride Batteries of Electric Vehicles

Nickel metal hydride (NiMH) batteries are extensively used in the manufacturing of portable electronic devices as well as electric vehicles due to their specific properties including high energy density, precise volume, resistance to overcharge, etc. These NiMH batteries contain significant amounts of rare earth metals (REMs) along with Co and Ni which are discarded due to illegal dumping and improper recycling practices. In view of their strategic, economic, and industrial importance, and to mitigate the demand and supply gap of REMs and the limited availability of natural resources, it is necessary to explore secondary resources of REMs. Therefore, the present paper reports a feasible hydrometallurgical process flowsheet for the recovery of REMs and valuable metals from spent NiMH batteries. More than 90% dissolution of REMs (Nd, Ce and La) was achieved using 2 M H2SO4 at 75 °C in 60 min in the presence of 10% H2O2 (v/v). From the obtained leach liquor, the REMs, such as Nd and Ce, were recovered using 10% PC88A diluted in kerosene at eq. pH 1.5 and O/A ratio 1/1 in two stages of counter current extraction. La of 99% purity was selectively precipitated from the leach liquor in the pH range of 1.5 to 2.0, leaving Cu, Ni and Co in the filtrate. Further, Cu and Ni were extracted with LIX 84 at equilibrium pH 2.5 and 5, leaving Co in the raffinate. The developed process flow sheet is feasible and has potential for industrial exploitation after scale-up/pilot trails.

Separation of Gallium(III) and Indium(III) by Solvent Extraction with Ionic Liquids from Hydrochloric Acid Solution

The manufacture of semiconductor materials containing gallium and indium requires the separation of these metals owing to their coexistence in the resources of these materials. In this work, solvent extraction of In(III) and Ga(III) from a hydrochloric acid solution by ionic liquids (ILs) was investigated to separate them. The ILs were synthesized by reacting organophosphorus acids (Cyanex 272, PC88A and D2EHPA) and Aliquat 336 (ALi-CY, ALi-PC, and ALi-D2). In(III) was selectively extracted over Ga(III) by the ILs in the range of initial pH from 0.1 to 2.0. The equilibrium pH was always higher than the initial pH because of the coextraction of hydrogen ions. The highest separation factor between In(III) and Ga(III) was 87, which was obtained by ALi-PC at an initial pH of 1.0. Stripping of the loaded ALi-PC with hydrochloric and sulfuric acid led to selective stripping of In(III) over Ga(III). Scrubbing of the loaded ALi-PC with pure In(III) solution was not effective in removing the small amount of Ga(III) present in the loaded ALi-PC. Batch simulation experiments for the three counter-current extraction stages indicated that the complete separation of both metal ions was possible by extracting In(III) using ALi-PC, with remaining Ga(III) in the raffinate.

Cleaner production of rare earth elements from phosphorus-bearing sulfuric acid solution of vein deposit monazite

In the present study, the recovery of rare earth elements (REEs; viz. cerium, lanthanum, and yttrium) from sulfate leach liquor of vein deposit Korean monazite has been investigated using the solvo-chemical techniques. The dissolved phosphorus (373 mg L−1), which may significantly affect the products’ purity, was selectively removed using the benzyl-di-methyl amine (BDMA). The logarithmic distribution vs. BDMA concentration along with spectral analysis of the organic phases revealed the formation of extracted species 3[BDMA].[H3PO4]¯. The quantitative removal of phosphorus was achieved in three stages of counter-current extraction (CCE) under the organic-to-aqueous (O:A) ratio of 1.0:1.5, leaving REEs’ into the raffinate. Subsequently, Cyanex 923 was employed to selectively extract cerium(IV) from P-depleted solution under the varying parameters of extractant and sulfuric acid concentration, temperature, and O:A ratio. The quantitative extraction of cerium (∼99% from 864 mg L−1 feed concentration) showing exothermic nature was achieved at an O:A of 1:2 under three stages of CCE while using 0.15 mg L−1 extractant into organic phase and 1.12 mol L−1 H2SO4 into aqueous phase. Further, the experimental results and spectral analysis of the organic phases could reveal that cerium solvates as [Ce(SO4)2].2[Cyanex 923].[HSO4−]¯ species. Cerium was successfully stripped from loaded organic by contacting with a higher concentration of H2SO4 solution (≥4.0 mol L−1) in presence of 0.1 mol L−1 H2O2, yielding an enriched high-purity solution of 2.54 g L−1 cerium. Lanthanum and yttrium were recovered from the Ce-depleted raffinate by co-precipitation with oxalic acid, forming a mixture of C6La2O12.10H2O and C6Y2O12.4H2O. The study approaches a cleaner production of high-purity REEs for clean energy programs under Sustainable Development Goals.

The Influence of Continuous Multi Stage Countercurrent Extraction Process (CMCE) Propolis Extract Administration on Superoxide Dismutase Activity and Hepatocytes Fibrosis Degree (An Experimental Study on Male Wistar Rats Induced with Carbon Tetrachloride (CCl4))

Introduction: Continuous Multi Stage Countercurrent Extraction Process (CMCE) propolis extract containing Caffeic Acid Phenethyl Ester (CAPE) may inhibit the formation of lipid peroxidation. However, it is still unclear whether or not CMCE propolis is able to increase SOD activity and reduce acute hepatocytes damages induced by CCl4. Objective: To evaluate the influence of CMCE propolis extract administration in increasing the SOD activity and reducing the hepatocytes fibrosis of male Wistar rats induced with CCl4. Method: an experimental research with a post-test only control group design. Twenty eight male Wistar rats were divided into four groups. Group C-N was only induced with CCl4, while group CM-3, CM-7, and CM-14 were induced with CCl4 and received CMCE propolis extract respectively with 3.6 mg/200 g BW, 7.2 mg/200 g BW, and 14.4 mg/200 g BW. CMCE propolis was administered for 14 days and then CCl4 was administered on the last day. SOD activity was measured using the colorimetric method, while the hepatocytes fibrosis degree was assessed using Image J Software method with NASH score modification. Results: Post Hoc LSD analysis indicated that SOD activity in group CM-3 (51.67 ± 4.20), CM-7 (70.21 ± 6.26), CM-14 (80.85 ± 4.59) was lower than that in group C-N (23.70 ± 5.12) with P <0.05. Meanwhile, the Mann-Whitney U test showed that the hepatocytes fibrosis degree in group CM-3 (0.85 ± 0.69), CM-7 (1.14 ± 0.37), and CM-14 (0.71 ± 0.48) was significantly lower than that in group C-N (2.28 ± 1.25) with p<0.05. Conclusion: The CMCE propolis extract administration was able to increase the SOD activity and reduce the hepatocytes fibrosis degree of male Wistar rats induced with CCl4

Optimization of nanofiltration for treatment of acid mine drainage and copper recovery by solvent extraction

The high levels of metals and sulfate ions in acid mine drainage (AMD) constitutes a severe risk to the environment. Our study evaluated at pilot-scale the operational conditions of actual AMD nanofiltration (NF) to recover water and subsequent recovery of copper from the concentrated retentate solution by a solvent extraction (SX) process. NF showed a high copper concentration capacity (0.6 to 2.4 g/L) and good total rejection of species (~82%). While NF treatment allowed a high water recovery of 80%, the polarization resistance could limit its performance. A 1.1 g/L copper retentate solution was selected for use in the SX study to prevent membrane fouling in a possible in-series process (NF-SX). Equilibrium isotherms and McCabe-Thiele diagrams obtained using LIX 84-IC as the extractant indicated that using two countercurrent extraction stages and one stripping stage, it could be recovered 97% of the copper. The use of antiscalants and CaSO4 precipitates formed during NF had a negligible effect on the copper extraction yield by SX. The combined NF-SX results showed that a high recovery of water and copper from AMD is possible. This technology can have an impact on the reduction of freshwater consumption and wastewater treatment costs of mining, and its development is the subject of further research work.

Recovery of neodymium, dysprosium, and cobalt from NdFeB magnet leachate using an unsymmetrical dialkylphosphinic acid extractant, INET-3

Rare earths (REs) and Co are critical strategic resources. Their recovery is crucial for ensuring that their supplies are adequate and for reducing environmental pollution. End-of-life NdFeB magnets are important secondary RE sources. The separation of Dy, Nd, and Co from NdFeB leachate using a relatively new extractant (2,3-dimethylbutyl) (2,4,4′-trimethylpentyl)phosphinic acid (INET-3), was investigated in this study. The separation parameters, such as equilibrium pH, phase ratio, INET-3 concentration, and number of counter-current extraction stages, were optimised. The results show that INET-3 can separate Dy, Nd, and Co efficiently. For the preferential extraction of Dy from synthetic iron-free NdFeB leachate, the optimum equilibrium pH is 2.60. Under this condition, separation of Dy from the leachate requires four counter-current extraction stages at A/O (volume ratio of aqueous to organic) = 1:2. This is demonstrated by a simulated four-stage counter-current extraction process. At equilibrium pH = 2.52 and A/O = 1:2, 98% of Dy is recovered with 95% purity. As to the subsequent separation of Nd from the leachate, nearly 100% is recovered with 99% purity through a simulated three-stage counter-current extraction process at equilibrium pH = 5.33 and A/O = 1:1. Approximately 95% of Co remains in the raffinate with 99.98% purity.

A sustainable process for recovery of potash fertilizer from glauconite through simultaneous production of pigment grade red oxide

A sustainable process is proposed and developed for the recovery of potash fertilizer from glauconitic clay with simultaneous production of pigment grade iron oxide. Potassium is a part of stable structure (dioctahedral T-O-T) in glauconite and locked in alumino-silicate matrix. In order to break this matrix and maximize potassium dissolution, the glauconite sample containing 5.6% K2O and 31.9% Fe2O3 was subjected to reduction with coke followed by oxidation cooling (redox roasting). The process simultaneously releases potash and convert iron in the matrix to ferric state. The redox roasted sample was leached in hydrochloric acid and the leach liquor containing 6.1 g/L of potassium and 30.2 g/L of iron was subjected to solvent extraction using mixed solvent system (20% Aliquat 336 and 15% TBP) to separate iron prior to recovery of potash. Based on McCabe–Thiele plot, two stage counter current extraction at O:A ratio of 1:0.75 and three stage stripping at O:A ratio of 0.4:1 are sufficient to remove >99% of iron from the leach solution. The strip solution was hydrothermally treated to produce red iron oxide suitable for pigment application and iron free raffinate was treated to produce fertilizer grade potassium chloride.

Partition studies on cobalt and recycling of valuable metals from waste Li-ion batteries via solvent extraction and chemical precipitation

Present work addresses Co(II) extraction from chloride medium using toluene diluted Cyphos IL 102 as an innovative extractant for the recovery of cobalt. Effect of various parameters has been examined. Co(II) is transferred into the organic phase as [P66614+]2[CoCl42−] which can be efficiently stripped by 0.05 mol L−1 HCl. Loading capacity and recyclability have been assessed. Temperature effect confirmed that the extraction of Co(II) is endothermic in nature. Studies were further extended to recover cobalt, manganese and lithium from waste Li-ion batteries containing 2.915 g L−1, 0.576 g L−1, 3.370 g L−1, 0.407 g L−1, 0.014 g L−1, 0.033 g L−1, 0.019 g L−1 of cobalt, lithium, manganese, nickel, aluminium, iron and copper, respectively. The influence of the concentration of Cyphos IL 102 to extract cobalt from leach liquor has been investigated. The McCabe-Thiele plot suggested two theoretical stages of counter current extraction at A/O 1/1 with Cyphos IL 102 (0.2 mol L−1) for the quantitative extraction of Co(II) with negligible extraction of nickel and lithium. A stripping efficiency of around 99.9% for Co(II) was obtained using 0.05 mol L−1 HCl in a single stage at O/A 1/1. Cobalt is recovered as cobalt oxide from the loaded organic phase. Manganese and lithium were also recovered from leach liquor as MnO2 and Li2CO3 using the precipitation method. All the recovered products were identified using XRD, EDX as well as FE-SEM techniques.

Yttrium and europium separation by solvent extraction with undiluted thiocyanate ionic liquids.

An yttrium/europium oxide obtained by the processing of fluorescent lamp waste powder was separated into its individual elements by solvent extraction with two undiluted ionic liquids, trihexyl(tetradecyl)phosphonium thiocyanate, [C101][SCN], and tricaprylmethylammonium thiocyanate, [A336][SCN]. The best extraction performances were observed for [C101][SCN], by using an organic-to-aqueous volume ratio of 1/10 and four counter-current extraction stages. The loaded organic phase was afterwards subjected to scrubbing with a solution of 3 mol L−1 CaCl2 + 0.8 mol L−1 NH4SCN to remove the co-extracted europium. Yttrium was quantitatively stripped from the scrubbed organic phase by deionized water. Yttrium and europium were finally recovered as hydroxides by precipitation with ammonia and then calcined to the corresponding oxides. The conditions thus defined for an efficient yttrium/europium separation from synthetic chloride solutions were afterwards tested on a leachate obtained from the dissolution of a real mixed oxide. The purity of Y2O3 with respect to the rare-earth content was 98.2%; the purity of Eu2O3 with respect to calcium was 98.7%.

Extraction Separation of Sc(III) and Fe(III) from a Strongly Acidic and Highly Concentrated Ferric Solution by D2EHPA/TBP

The solvent extraction and separation process of Sc(III) and Fe(III) from a strongly acidic and highly concentrated ferric solution using mixtures of di(2-ethylhexyl) phosphate (D2EHPA) and tri-n-butyl phosphate (TBP) in sulfonated kerosene was studied. The effects of various parameters, including D2EHPA concentration, dosage of TBP, and phase ratio, were investigated for the extraction process. The results indicated that the extraction rate of Sc(III) was 99.72% with 1.09% Fe(III) co-extracted after two stages of counter-current extraction under optimal conditions. Moreover, saturation capacity and slope analysis were used to determine the reaction mechanism. Sc(III) is extracted in the form of HSc(SO4)2·4HL. Further separation of Sc(III) and Fe(III) was realized in a scrubbing and stripping process. First, 98.67% of the co-extracted iron in the loaded organic phase was scrubbed with a dilute HCl solution by a three-stage counter-current scrubbing. Then, 85.00% of Sc(III) can be stripped efficiently with a 2-mol/L NaOH solution saturated in 1-mol/L NaCl by three-stage cross-current stripping.