Solvent Extraction Experiments Research Articles

Simple separation method of Zn(II) and Cd(II) from brine solution of zinc plant residue and synthetic chloride media using solvent extraction

Abstract In this work, the possibility of separation of Zn2+ and Cd2+ metal ions from chloride (brine) solutions was examined. For this purpose, simple solvent extraction (SX) experiments by di-2-ethylhexyl phosphoric acid (D2EHPA) in kerosene as a diluent was performed on synthetic and industrial chloride solution obtained from brine leaching of zinc filter cakes (by-product of zinc hydrometallurgical processing). The optimal conditions for separation were determined. The zinc extraction efficiency was 99% with negligible co-extraction of cadmium. Therefore, a high ΔpH0.5 value for Zn(II) and Cd(II) was achieved. FT-IR and slope analysis indicated that ZnClA ∙ 3HA and CdClA ∙ 3HA species were probably extracted.

Insight into essential channel effect of pore structures and hydrogen bonds on the solvent extraction of oily sludge

In this study, solvent extraction experiments were conducted to investigate the channel effect of pore structures and hydrogen bonds by analyzing the desorption behavior of oil components. The highest oil recovery efficiency was 87.9 % under optimum conditions. Pore structure of oily sludge was analyzed by N2 adsorption-desorption analysis and scanning electron microscope (SEM) measurements. Mesopores of sludge inhibited the desorption of oil molecules by analyzing the pore width and cumulative pore volume of residual sludge in desorption process. In addition, saturates and aromatics were easily extracted from sludge, while the desorption rate and desorption efficiency of oily sludge were limited by resins and asphaltenes respectively through component analysis and kinetic analysis. Furthermore, channel effect of pore structures and hydrogen bonds was investigated in the desorption process of oily sludge, which also provided a guidance to selectively extract light components from oily sludge with high efficiency in industry processing.

Activation of the Aromatic Core of 3,3'-(Pyridine-2,6-diylbis(1H-1,2,3-triazole-4,1-diyl))bis(propan-1-ol)-Effects on Extraction Performance, Stability Constants, and Basicity.

The “CHON” compatible water-soluble ligand 3,3′-(pyridine-2,6-diylbis(1H-1,2,3-triazole-4,1-diyl))bis(propan-1-ol) (PTD) has shown promise for selectively stripping actinide ions from an organic phase containing both actinide and lanthanide ions, by preferential complexation of the former. Aiming at improving its complexation properties, PTD-OMe was synthesized, bearing a methoxy group on the central pyridine ring, thus increasing its basicity and hence complexation strength. Unfortunately, solvent extraction experiments in the range of 0.1–1 mol/L nitric acid proved PTD-OMe to be less efficient than PTD. This behavior is explained by its greater pKa value (pKa = 2.54) compared to PTD (pKa = 2.1). This counteracts its improved complexation properties for Cm(III) (log β3(PTD-OMe) = 10.8 ± 0.4 versus log β3(PTD) = 9.9 ± 0.5).

Synthesis and characterization of a novel, reactive, yellow fluorescent organosilicon dye and its polysiloxanes

A novel, reactive, yellow fluorescent organosilicon dye, N-propyl-(diethoxy)methyl-silane-4-dimethylamino-naphthalimide, is designed and synthesized and is used to fabricate a covalently yellow fluorescent silicone oil by polycondensation of hydroxy-terminated polydimethylsiloxane. The chemical structure and optical properties of the N-propyl-(diethoxy)methyl-silane-4-dimethylamino-naphthalimide and covalently yellow fluorescent silicone oil are characterized by 1H nuclear magnetic resonance, 13C nuclear magnetic resonance, mass spectrometry, Fourier transform infrared, UV–Vis, and fluorescence spectra. The results indicate that the fluorescence quantum yields of N-propyl-(diethoxy)methyl-silane-4-dimethylamino-naphthalimide and covalently yellow fluorescent silicone oil are 2.61% and 3.5%, respectively. The λmax values of their dichloromethane solutions are 416 nm, and their λex and λem are 430 and 509 nm, respectively. Furthermore, covalently yellow fluorescent silicone rubbers are prepared using tetraethoxysilane as a cross-linker, and some of their properties are investigated. Thermogravimetric analysis and dynamic mechanical analysis show that heat resistance and tan δ of the covalently yellow fluorescent silicone rubber are improved in comparison with silicone rubbers without N-propyl-(diethoxy)methyl-silane-4-dimethylamino-naphthalimide moieties. Solvent extraction experiments indicate that the solvent resistance of the covalently yellow fluorescent silicone rubber is much better than that of noncovalently yellow fluorescent silicone rubber.

Separation of Tb(III) and Dy(III) from Chloride Solution by Extraction and Scrubbing with Ionic Liquid Prepared with Cyanex 272 and Aliquat 336

Terbium and dysprosium are rare earth elements which are employed in the manufacture of advanced materials. Separating Tb(III) and Dy(III) is very complicated because their chemical properties are similar. In order to develop a separation process based on solvent extraction, extraction and scrubbing experiments were conducted using weak hydrochloric solutions containing Tb(III) and Dy(III). In this work, three kinds of Cyanex 272, namely, single Cyanex 272, a mixture with Alamine 336 and an ionic liquid prepared with Aliquat 336 were employed. In the initial pH range between 1.5 and 5, the extraction behavior of both Tb(III) and Dy(III) was very similar using these extractants, resulting in low separation factor. In terms of extraction percentage and separation factor, the ionic liquid showed better performance than both single Cyanex 272 and the mixture. Scrubbing experiments were conducted using the loaded ionic liquid, employing a Dy(III) scrubbing solution. The optimum concentration of Dy(III) in the scrubbing solution was determined. A McCabe-Thiele diagram for the scrubbing of Tb(III) in the loaded ionic liquid with Dy(III) solution was constructed. In order to verify the separation of both metal ions, batch simulation cross-current scrubbing experiments were performed. After 6 cross-current scrubbing stages, the purity of Dy(III) in the loaded ionic liquid increased from 50% to 99%. By utilizing the data reported in this work, a process can be developed for the separation of Tb(III) and Dy(III) by solvent extraction. Key words: terbium(III), dysprosium(III), solvent extraction, scrubbing, separation

Synthesis of organophosphorus ligands with a central oxygen atom and their applications in solvent extraction

Various structurally related glycolamide compounds were synthesised and evaluated by solvent extraction experiments for the separation of rare earth elements (REEs) from aqueous acid solutions using dodecane as the diluent. We describe herein the full synthesis of a family of bifunctional ligands with a central oxygen and focus our investigation on the effects of structural modification on the extraction efficiencies. The combination of an amide, a PO donor site, and a central oxygen in such a glycolamide ligand showed interesting extraction properties for heavy rare earth elements from phosphoric acid solutions.

Molecular modelling of tantalum fluoride in sulphuric acid medium: A DFT study

During the solvent extraction (SX) experiments of tantalum (Ta) and niobium (Nb), the aqueous phase consisted of tantalum- and niobium penta-fluoride (Ta(Nb)F5), water (H2O) and sulphuric acid (H2SO4), which was contacted with an organic phase. In this study the aqueous phase used during SX was modelled by studying the interactions and resulting reactions of specifically TaF5 when it is contacted with H2O and H2SO4. Different functional and basis set combinations within density functional theory (DFT) were investigated. From previous modelling it was seen that by increasing the number of water molecules, the reaction energy decreased due to molecule stabilisation (hydrogen bonding) and subsequently a 1:1:10 metal:acid:water ratio were used.Results showed that the deprotonation of H2SO4 was exothermic, leading to the formation of HSO4−. Furthermore, from the various reactions and geometries between TaF5, H2SO4 and H2O investigated, it was observed that only four species would be available in the aqueous phase during solvent extraction, namely TaF5·H2O in water or diluted acid medium, TaF4·HSO4 in a concentrated H2SO4 medium and TaF4OH or TaF3OH·HSO4 if the aqueous phase was aged. From the results obtained a reaction mechanism that might occur during SX of TaF5 was predicted.

Extraction and recovery of the strategic element gallium from an iron mine tailing

Strategic elements become essential in recent years due to the extensive technological development of electronics and energy industries. One of the elements of greatest demand is gallium, since its compounds are used as semiconductors mainly in the manufacture of solar panels and LED diodes. Gallium is relatively abundant in the world; however, only a small percentage of these sources can be used as a commercial resource. There are studies in which gallium is recovered from both electronic wastes and mining activities wastes. In this project, gallium was recovered from an iron non-oxidized mine tailing. The tailing has a total content of Ga of approximately 13 mg/kg. The iron tailing was leached with 8 M HCl for 48 h, achieving total dissolution of the Ga present. To separate and concentrate Ga, there were performed solvent extraction experiments with the extractants: tributylphosphate (TBP), trioctylphosphine oxide (TOPO), and a mixture of both, with 3 different diluents: benzene, toluene and hexane to study the effect of these parameters. The results indicate that it was possible to extract up to 100% of Ga with tributylphosphate (TBP) and less than 35% of the Fe present. In the stripping stage it was recovered up to 100% of the extracted Ga with 0.1 M H2SO4.

Recovery of vanadium from secondary tailing of iron ore by salt roasting-alkaline leaching and solvent extraction processes

In this paper, the recovery of vanadium from the secondary tail deposits of iron ore by salt roasting-alkaline leaching and solvent extraction has been investigated. To extract the vanadium, after the characterizations studies (XRF, SEM, and EPMA analyzes), preliminary leaching was performed using HCl to reduce lime. Subsequently, the solid that was gained from this stage was put in the oven for palletizing and salt roasting (sodium carbonate) at the temperature of 850°C. This sample was leached in the presence of sodium bicarbonate (NaHCO3), under certain conditions. Solvent extraction experiments were carried out on the solution of carbonated leaching under different conditions. According to SEM studies, the dominant are calcium, vanadium, and phosphorus in the sample. The percentage of Vanadium (V), according to EPMA results in the 20 selected points, was determined as 0.65%. XRF analysis showed that V2O5 and CaO contents of sample were 2.04% and 51.72%, respectively. Lime was reduced to 32.59% after initial leaching with HCl. The carbonate leaching resulted in a total recovery of 93.46% at 85 °C for 60 minutes and with 40 g /l of sodium bicarbonate. In addition, under the optimum conditions of pH=6, the ratio Vaq/Vorg=1 and the organic phase concentration of 0.5 M using the anionic Aliquat 336 extractant, Vanadium can be recovered effectively (extraction efficiency=97%) from alkaline leaching solution in the form of decavanadate or and the anions in the form of or in one stage.

Density functional theory study with and without COSMO of H2 SO4 reactions in an aqueous environment for metal extraction.

In a recent study investigating the suitability of solvent extraction (SX) for the separation of Ta and Nb, it was shown that speciation data would be required to help explain the data obtained. As traditional speciation techniques cannot be readily applied for Ta and Nb, it was decided to determine the suitability of molecular modeling for this purpose. During the SX experiments the aqueous phase consisted of sulfuric acid (H2 SO4 ), water, and metal species. In this study density functional theory (DFT) modeling was used to calculate the formation energy of five possible reactions of H2 SO4 and H2 O. Different functional and basis set combinations were compared as well as the effect of infinite dilution by using the conductor-like screening model (COSMO), which simulates infinite dilution of solvents of varying polarity and includes the short-range interactions of the solute particles. The results obtained were used to determine whether it is possible to predict the reactions and mechanism when H2 SO4 and H2 O interact during SX. According to the results, the deprotonation of H2 SO4 was endothermic in a 1:1 acid-water ratio, while being both exothermic in the 1:5 and 1:10 acid-water ratio forming HSO4 - and SO4 2- respectively. Furthermore, it was seen that the hydration and dehydration of H2 SO4 in a bulk H2 O solution was a continuous process. From the energy calculations it was determined that although the H2 SO4 ●H2 O, HSO4 - ●H2 O, and H2 SO4 ●2H2 O species could form, they would most likely react with H2 O molecules to form HSO4 - , H3 O+ , and H2 O. © 2018 Wiley Periodicals, Inc.

Structure and properties of ultrasonically extruded SBR/BR blends and prepared compounds and vulcanizates with various fillers

The ultrasonic treatment of styrene-butadiene rubber (SBR)/butadiene rubber (BR) 50/50 blend in single screw extruder was carried out at amplitudes up to 10 μm. The untreated and treated SBR/BR blends were mixed with carbon black (CB), silica, and silica/silane to prepare 50/50/60 compounds. It was found that ultrasonic power consumption increased and die pressure reduced with the increase of ultrasonic amplitude, indicating a potential to increase extrusion output rate with the aid of ultrasound. Molecular weight of blends treated at 3.5 μm increased, and high molecular weight tail was observed at 5, 7.5, and 10 μm. Solvent extraction experiments showed the formation of gel in blends treated at 7.5 and 10 μm. No gel was observed in blends untreated and treated at 3.5 and 5 μm. SBR/BR/silica vulcanizates prepared from the blend treated at 5 μm showed the reduced loss tangent at −30°C, 0°C, and 60°C, predicting a lower snow, wet traction, and rolling resistance. Reduced loss tangent after ultrasonic treatment was a result of reduced filler flocculation. The tensile strength and elongation at break of all treated SBR/BR and SBR/BR/CB vulcanizates treated at 3.5 and 5 μm increased. Modulus 100% elongation (M100) of vulcanizates prepared from SBR/BR/silica treated at 5 μm was also increased.

Solvent Extraction of Am(III), Cm(III), and Ln(III) Ions from Simulated Highly Active Raffinate Solutions by TODGA Diluted in Aliquat-336 Nitrate Ionic Liquid

ABSTRACTThe extraction behavior of americium(III), curium(III) (minor actinides, MA), fission products (lanthanides (Ln(III)), Mo, Ru, Pd, and Rh), and corrosion products (Zr and Fe) was studied in batch solvent extraction experiments using the room-temperature ionic liquid (IL) Aliquat-336 nitrate ([A336][NO3]) and a solvent composed of 0.05 M TODGA in [A336][NO3]. From acidic, dilute Ln(III) feed solutions, [A336][NO3] extracts nitric acid (D ≈ 0.5) and partially An(III) as well as Ln(III) (DAm = 0.02–0.1, DEu, and DCm = 0.01–0.04). The influence of the acid concentrations and kinetics on extraction and back-extraction of Ln(III) and An(III) by 0.05 M TODGA in [A336][NO3] was investigated using radiotracer-spiked dilute Ln(III) feed solutions. With the solvent composed of 0.05 M TODGA in [A336][NO3], DAn and DLn increase as a function of aqueous feed acidity. In the case of a spiked, simulated highly active raffinate (HAR) feed solution, [A336][NO3] extracts La(III) (DLa = 1.36), Ru (DRu = 1.64), and Pd (DPd = 38), while the distribution ratios of other Ln(III) and An(III) were lower than unity. The solvent composed of 0.05 M TODGA in [A336][NO3] co-extracted from HAR Zr(IV) (DZr> 300), Pd (DPd = 206), and Ln(III) (DLn> 1, except for Nd(III)), but An(III) were retained in the aqueous phase. The interference caused by the co-extraction of several fission (Zr, Pd, Ru, and Mo) and corrosion (Zr) products, which are present in the HAR at relatively high concentrations, was suppressed using masking agents (oxalic acid and trans-1,2-diaminocyclohexane-N,N,N’,N’-tetraacetic acid, CDTA). In the case of the actual HAR solution, the kinetics were found to be faster compared with the extraction from dilute Ln(III) feed solutions, possibly due to the different aqueous speciation of the Ln(III) and An(III).

Leaching and Recovery of Rare-Earth Elements from Neodymium Magnet Waste Using Organic Acids

Over the last decade, rare-earth elements (REEs) have become critical in the European Union (EU) in terms of supply risk, and they remain critical to this day. End-of-life electronic scrap (e-scrap) recycling can provide a partial solution to the supply of REEs in the EU. One such product is end-of-life neodymium (NdFeB) magnets, which can be a feasible source of Nd, Dy, and Pr. REEs are normally leached out of NdFeB magnet waste using strong mineral acids, which can have an adverse impact on the environment in case of accidental release. Organic acids can be a solution to this problem due to easier handling, degradability, and less poisonous gas evolution during leaching. However, the literature on leaching NdFeB magnets waste with organic acids is very scarce and poorly investigated. This paper investigates the recovery of Nd, Pr, and Dy from NdFeB magnets waste powder using leaching and solvent extraction. The goal was to determine potential selectivity between the recovery of REEs and other impurities in the material. Citric acid and acetic acid were used as leaching agents, while di-(2-ethylhexyl) phosphoric acid (D2EHPA) was used for preliminary solvent extraction tests. The highest leaching efficiencies were achieved with 1 mol/L citric acid (where almost 100% of the REEs were leached after 24 h) and 1 mol/L acetic acid (where >95% of the REEs were leached). Fe and Co—two major impurities—were co-leached into the solution, and no leaching selectivity was achieved between the impurities and the REEs. The solvent extraction experiments with D2EHPA in Solvent 70 on 1 mol/L leachates of both acetic acid and citric acid showed much higher affinity for Nd than Fe, with better extraction properties observed in acetic acid leachate. The results showed that acetic acid and citric acid are feasible for the recovery of REEs out of NdFeB waste under certain conditions.

SEPARATION OF COPPER FROM A LEACHING SOLUTION OF PRINTED CIRCUIT BOARDS BY USING SOLVENT EXTRACTION WITH D2EHPA

Abstract Global generation of waste electrical and electronic equipment (WEEE) is increasing quickly. Metals from WEEE can be recovered by using unit operations of chemical engineering. This paper describes a combined hydrometallurgical route (sulfuric oxidant leaching + solvent extraction) to recover copper from printed circuit boards (PCBs). A non-magnetic fraction from comminuted PCBs was used to perform leaching tests at 75oC for 6 hours in an oxidizing media (sulfuric acid + hydrogen peroxide). In order to separate zinc, aluminum, and copper from the leaching liquor, solvent extraction tests were carried out using D2EHPA. Parameters that influence the process, such as pH, extractant concentration, and the aqueous/organic (A/O) ratio were investigated. Solvent extraction experiments were carried out in two stages: i) separation of zinc, aluminum, and residual iron, and ii) copper separation. The results showed that the leaching obtained around 60% aluminum, 94% copper, 76% zinc, 50% nickel and residual iron from the non-magnetic fraction of PCBs. With the solvent experiments, in the first stage, 100 wt.% zinc, iron and aluminum were extracted at pH 3.5, 2:1 A/O, 10 % (v/v) D2EHPA, while, in the second stage 100% of the copper was extracted at pH 3.5, 1:1 A/O, 20 % (v/v) D2EHPA.

Inspection for desorption behavior and desorption mechanism of oily sludge by thermodynamics and kinetics analysis

Abstract In this study, the solvent extraction experiment was investigated to probe the desorption behaviors and desorption mechanism of oily sludge with n-heptane as solvent. Desorption isotherms were analyzed and fitted by Langmuir, Freundlich and Redlich-Peterson equations at different temperatures. Then, the thermodynamics parameters such as standard free energy (ΔG°), standard enthalpy (ΔH°) and standard entropy (ΔS°) were calculated. Based on thermodynamics analysis and calculation, oil was proved to exist in the form of the colloidal dispersion system. In addition, the kinetics was fitted by the pseudo-first-order kinetic model and the pseudo-second-order kinetic model. Kinetic studies showed that desorption process of asphaltenes was restrained severely due to strong interactions between sludge and asphaltenes, and resins played a crucial role in asphaltenes desorption. The desorption mechanism was discussed based on experimental results and further analysis. The solvent effect and carry-over effect were deemed to be crucial to oil desorption. The carry-over effect is generated from electrostatic interactions, hydrogen bonds, electron donor-acceptor and π-π interactions, which was also the essence of asphaltenes desorption.

Recovery of metals from chloride leach solutions of anode slimes by solvent extraction. Part II: Recovery of silver and copper with LIX 63 and Alamine 336

In Part 1 of this paper, gold(III) and Sn(II) were recovered from the chloride leach solution of anode slimes by extraction with Cyanex 272 and stripping with (NH4)2S2O3 and NaOH solutions for gold(III) and Sn(II), sequentially. In this work, solvent extraction experiments were conducted to recover Ag(I) and Cu(II) from the Au(III) free raffinate containing Ni(II), Sn(II) and Zn(II) using two systems. In the first system, Cu(II) and Ag(I) were sequentially separated using LIX 63 and Alamine 336, respectively. Dilute HCl and NH4SCN were used as the stripping agents for Cu(II) and Ag(I), respectively. In the second system, Cyanex 301 co-extracted Ag(I), Cu(II) and Sn(II) from the Au(III) free raffinate. Aqua regia at different dilutions stripped these three metal ions from the loaded Cyanex 301. First, Cu(II) was selectively stripped from the loaded Cyanex 301 by employing ten times diluted aqua regia. Second, most of Ag(I) was selectively stripped over Sn(II) by five times diluted aqua regia. A process flowsheet for the separation and recovery of noble and base metals from the chloride leach solution of anode slime using extraction and stripping has been proposed.

Determination of arsenic species in mainstream cigarette smoke based on inductively coupled plasma mass spectrometry

In this work, arsenic species in mainstream cigarette smoke condensates was systemically studied with inductively coupled plasma mass spectrometry. A single particle inductively coupled plasma mass spectrometry was utilized for analysis of the physical forms of arsenic, and no particle arsenic was observed in mainstream cigarette smoke condensates. The solvent extraction experiments proved that the water-soluble arsenic was the main species in mainstream cigarette smoke condensates, which was consistent with the result of single particle inductively coupled plasma mass spectrometry. Furthermore, speciation of arsenite, arsenate, monomethylarsonic acid, and dimethylarsinic acid was investigated using high performance weak anion exchange chromatography coupled with inductively coupled plasma mass spectrometry detection. The developed high performance liquid chromatography coupled inductively coupled plasma mass spectrometry method was successfully applied to the determination of arsenic species in mainstream cigarette smoke condensates with satisfactory recoveries. Four arsenic species were detected in the mainstream cigarette smoke condensates from four brands of commercial available cigarettes, and there was a great difference between the arsenic content and composition among the different brands of cigarettes. It is found that arsenate was the main species in all tested cigarette samples.

Reduced bioavailability and plant uptake of polycyclic aromatic hydrocarbons from soil slurry amended with biochars pyrolyzed under various temperatures

Biochar has high potential for organic pollutant immobilization due to its powerful sorption capacity. Nevertheless, potential risks may exist when biochar-sorbed organic pollutants are bioavailable. A direct plant exposure assay in combination with an organic solvent extraction experiment was carried out in this study to investigate the bioavailability of polycyclic aromatic hydrocarbons (PAHs) with the application of pine needle biochars pyrolyzed under different temperatures (100, 300, 400, and 700°C; referred as P100-P700 accordingly). Biochar reduced solvent extractability and plant uptake of PAHs including naphthalene (Naph), acenaphthene (Acen), phenanthrene (Phen), and pyrene (Pyr), especially for three- and four-ring PAHs (Phen and Pyr) with high-temperature biochar. Plant uptake assay validates with organic solvent extraction for bioavailability assessment. Sorption of PAHs to biochars reduced plant uptake of PAHs in roots and shoots by lowering freely dissolved PAHs. Aging process reduced the bioavailability of PAHs that were bound to biochar. High pyrolysis temperature can be recommended for biochar preparation for purpose of effectively immobilizing PAHs, whereas application of moderate-temperature biochar for PAH immobilization should concern the potential risks of desorption and bioavailability of PAHs.

Polymer inclusion membranes (PIMs) containing purified dinonylnaphthalene sulfonic acid (DNNS): Performance and selectivity

Abstract The use of purified dinonylnaphthalene sulfonic acid (DNNS) as extractant in polymer inclusion membranes (PIMs) was investigated for the first time. DNNS is commonly supplied in 50 wt% water soluble diluent, which when applied in PIMs is expected to affect their stability. Purified and commercial DNNS were characterised by gas chromatography with flame ionization detection and thermogravimetric analysis coupled with Fourier transform infrared spectrometric detection. PIMs prepared with the purified DNNS reagent containing the same amount of membrane liquid phase as the commercial DNNS-based PIMs were able to accommodate more DNNS than the PIMs incorporating the commercial product which contained a significant percentage of diluent. This resulted in better extraction efficiency and slightly lower mass loss. The affinity of a PIM containing 35 wt% purified DNNS, 10 wt% 1-tetradecanol and 55 wt% poly(vinyl chloride) towards a range of monovalent and divalent cations in 0.001 M HCl solutions, based on the percentage extracted metal ion, was found to follow the order: Fe3+ (1:1, 93.9) > Ca2+ (2:1, 63.4) > Pb2+ (2:1, 59.7) > Zn2+ (2:1, 48.5) > Cu2+ (2:1, 45.0) > Ni2+ (2:1, 40.6) > Mg2+ (2:1, 35.0) > Na+ (1:1, 20.9) ≈ K+ (1:1, 20.1), where the numerical data in the brackets correspond to the stoichiometric ratio (DNNS: ion) and the percentage of metal ion extracted from the source solution, respectively. This order can be explained by the Hard and Soft Acids and Bases Theory and the hydration energy of the metal cations. The stoichiometric composition of the corresponding metal – DNNS adducts was determined in solvent extraction experiments.

Separation of Pt(IV), Rh(III) and Fe(III) in acid chloride leach solutions of glass scraps by solvent extraction with various extractants

Solvent extraction experiments were conducted to recover pure Pt(IV) and Rh(III) from the chloride leach liquor of glass industry scraps containing a small amount of Fe(III) using Alamine 336, TOPO, TBP and Cyanex 923. The Pt(IV) and Fe(III) were selectively extracted by Cyanex 923 leaving Rh(III) in the raffinate, while only Fe(III) was extracted by TBP. The Pt(IV) in the loaded Cyanex 923 phase was first selectively stripped over Fe(III) by NaSCN and then the remaining Fe(III) was stripped by HCl solution. The Fe(III) in the loaded TBP phase was easily stripped by dilute HCl solution. The McCabe-Thiele diagrams for the extraction of Pt(IV) by Cyanex 923 and of Fe(III) by TBP were constructed. Based on the obtained results, a flowsheet for the separation of three metals from the real leaching solution of glass industry scraps was proposed.