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The article presents studies on the extraction of iron from chloride solutions with aliphatic alcohols, ketones, and their mixtures. Dilution of 1-octanol with an inert aromatic diluent to a concentration of 80 vol.% led to an increase in its extraction capacity, while the extraction capacity of 2-octanone has decreased with dilution. A synergistic effect was found for a 1-octanol/2-octanone mixture, the maximum of extraction was observed at a ketone concentration of 80 vol.%. The effect of a mixture composition and chloride ion concentration on the iron extraction degree was studied. McCabe-Thiele results indicated that at Fe(III) concentration in the aqueous phase 9.32 g∙dm−3, it is possible to extract iron(III) quantitatively using a mixture of alcohols C8+C10 (70 vol.%) and 2-undecanone (30 vol.%) after three extraction stages. Stripping of Fe(III) from the mixture was done with distilled water. After the stripping, the loaded Fe(III) concentration in the organic phase was reduced from 27 g∙dm−3 to <0.001 g∙dm−3 for 3 stages. The conditions were tested in continuous mode at a cascade of laboratory extractors. During the tests on the cascade, the low solubility of the mixture of ketone with alcohol was established, and the concentrated solution of ferric chloride was obtained. [ABSTRACT FROM AUTHOR]

Base metal hydrometallurgy in a chloride medium has considerable advantages, as metals can be recovered by solvent extraction through a neutral complex mechanism without extra reagent addition, leading to ready lixiviant recycling and significantly reduced wastewater discharge. However, the recovery of Ni(II) using this hydrometallurgical method is challenging because of the unavailability of appropriate extraction reagents. In this study, a new reagent, N-2-ethylhexylpyridine-3-formamide (MEH3), was used to efficiently extract Ni(II) from weakly acidic (pH > 2.5) or neutral chloride solutions in the form of neutral complexes without pH adjustment. Some other metal ions can also be extracted; the selectivity of the reagent for each metal decreased in the following order: Cu(II) > Zn(II) > Ni(II) > Fe(III) > Co(II) > Mn(II). The reagent had weak ability to extract other metal ions such as Ca, Al, Cr(III), Mg, and Li. The extraction of Ni(II) was positively correlated with the Cl− concentration in the aqueous solution, indicating that Cl− is a driving force for Ni(II) extraction. The Ni(II) loaded organic phase was stripped with water, and approximately 50 g/L of Ni(II) in the loaded strip liquor was obtained at an O/A ratio of 15:1. The Ni(II) extraction mechanism was further studied using crystal structure analysis, FT-IR spectroscopy, and the maximum loading capacity. The results showed that a Ni(MEH3) 2 Cl 2 complex was formed via Ni(II) extraction. In conclusion, the MEH3 system can selectively extract Ni(II) from a chloride solution without consuming alkaline reagents, and no new substances are produced, which is beneficial for the realization of mother liquor recycling and has a positive impact on clean hydrometallurgy. • The reagent N-2-ethylhexylpyridine-3-formamide was prepared as a new extractant for metal ions. • Ni(II) can be extracted by MEH3 in the form of neutral complexes in weakly acidic (pH > 2.5) chloride solutions. • A complex of Ni(MEH3) 2 Cl 2 was formed via Ni(II) extraction. [ABSTRACT FROM AUTHOR]

Chloride is one of the effective medium in which platinum group metals (PGMs) can be brought into a solution, thus chlorocomplexes are particularly important in the process chemistry of PGMs separations. Rh (III) chlorocomplexes are poorly extracted into organic solvents, which is due to the charge of the complex as well as those inert character in a solution, that is, formation of RhCl6-n(H2O)n(3-n) - (n=1-6) . The problem of solvent extraction of Rh from chloride solutions has not yet been solved and there is no effective industrial extractant for Rh. PGMs are traditionally separated from one another and the other metals by a complex series of selective precipitation techniques. These are generally inefficient in terms of the degree of separation achieved. Solvent extraction applied to refining process for PGMs offers several advantages over the traditional precipitation methods. Adding Sn (II) to a Rh (III) feed is a good procedure which can be used to make Rh react more easily to extraction, however, stripping of Rh from the loaded organic pahse is very difficult. In the present study, the extraction of Rh from hydrochloric acid solutions with tri-n-octylamine (TOA) and tri-octyl methyl ammonium chloride (TOMAC) were tested to clarify the effect of addition of Sn (II) on the extraction of Rh and stripping of Rh.

The solvent extraction ability of 1,1′-dialkyl-2,2′-bibenzimidazoles (L) for the recovery of copper(II) ions from aqueous chloride solutions has been investigated. It was found that 1,1′-didecyl- 2,2′-bibenzimidazole is a useful extractant for the separation of copper(II) ions from both weakly and strongly acidic solutions. Copper(II) can be effectively stripped of organic solutions by a water or ammonia solution in a one-stage process. In low acidity media (pHfeed > 1), the extraction percentage of Cu(II) increases with an increase in metal ions and chloride concentrations. Copper(II) ions are extracted as binuclear complexes (CuCl2)2L2 (L = extractant). The constructed McCabe−Thiele diagram shows that the reduction of copper(II) ions concentration from 25 to approximately 5 g/dm³ in an aqueous feed is possible in two extraction stages. When [HCl]feed ≥ 1 M, (LH+)2(CuCl42-)L complex is formed. From the strongly acidic solutions ([HCl] = [LiCl] = 4 M), almost 100% of copper(II) ions can be removed by 1,1′-didecyl-2,2′-bibenzimidazole. Benzyl alcohol, used as an organic phase modifier, enables the selective extraction of copper(II) over zinc(II) ions from a weakly acidic chloride solution. [ABSTRACT FROM AUTHOR]

Research into the solvent extraction of iron(III) from a chloride solution after bauxite HCl leaching by neutral oxygen-containing extractants and their mixtures were studied and the iron(III) extraction degree from chloride solutions using alcohols is presented. The effect of dilution of alcohol with a ketone by an extraction mixture in relation to its effectiveness was investigated. The iron(III) was efficiently extracted by the mixture of 1-octanol and 1-decanol (70%) with 2-undecanone (30%) from hydrochloric bauxite leach liquor at an O:A ratio = 2-4:1 at an iron(III) concentration of 7.4 g/L and 6 M HCl. For the removal of iron-containing organic phase from impurities (Al, Ca, Cr) that are co-extracted with iron(III), we used two step scrubbing at O:A = 5:1 by 7 M HCl as a scrub solution. The iron(III) stripping at the O:A ratio is shown. Using counter-current cascade of extractors, it was possible to obtain an FeCl3 solution with the iron(III) content of 90.5 g/L and total impurities less than 50 mg/L.

In the present study, the copper anode slime was leached in chloride media. Then, pregnant leach solution (PLS) was purified using solvent extraction method and Octanol-kerosene solution. HAuCl4.2L was determined as the extracted macromolecule, and separation of impurities, such as copper, iron and selenium was done in the presence of gold. McCabe-Thiele diagram of Au–HCl (3 M)– Octanol (40% v/v) in O/A=3/4 showed that Au concentration in aqueous phase decreased from the initial value of 200 to 7 mg/L, after 5 stages. Ammonia solution was proposed as the stripper and McCabe-Thiele diagram was presented to obtain the number of gold stripping steps by ammonia solution

Abstract Four new 1,1′-dialkyl-2,2′-bibenzimidazoles were used to extract zinc(II) from acid chloride solutions at various concentrations of chloride and hydrogen ions. In low acidity media (pH > 2), the maximum zinc(II) extraction with the compounds is observed at chloride concentrations in the range 0.7–1.8 M. Zinc(II) ions are extracted as neutral (ZnCl 2) m L n complexes (L = extractant) in which the m:n ratio varies from 1:2 to 3:3, depending on the metal-to-extractant molar ratio in the extraction media. In strongly acidic systems, anionic zinc(II) chloro-complexes may be extracted from aqueous solutions by protonated bibenzimidazoles as (LH+) 2 (ZnCl 4 2−) or/and (LH+)(ZnCl 3 −) ion pairs. In weakly acidic media, at [Cl−] < 2 M, Zn(II) can be separated from Cd(II), Cu(II), and Ni(II) by 1,1′-didecyl-2,2′-bibenzimidazole, the best extractant from the tested dialkyl derivatives of 2,2′-bibenzimidazole. From the feed containing 26 g/L Zn(II), over 80% of zinc(II) ions is selectively separated after four extraction stages. 1,1′-Didecyl-2,2′-bibenzimidazole can be used for the selective separation of pure Fe(III) and Zn(II) from acidic chloride solutions. At a high chloride concentration (6 M) and at 0.5–0.8 M HCl in the aqueous feed, Fe(III) is efficiently transferred into the organic phase in the presence of Zn(II) and is then easily stripped off with water. Zn(II) can be completely removed from the iron-free raffinate after this aqueous solution is acidified to 1.5 M HCl. Highlights • 1,1′-Dialkyl-2,2′-bibenzimidazoles extract zinc(II) from acid chloride solutions. • Zn(II) extraction depends upon the acid, chloride, salt, and metal concentration. • In weakly acidic media, Zn(II) can be separated from Cd(II), Cu(II), and Ni(II). • Fe(III) and Zn(II) can be selectively extracted from acid chloride solutions. [ABSTRACT FROM AUTHOR]

The extraction of zinc in the presence of manganese and cadmium from chloride solution with di 2 ethyl hexyl phosphoric acid (D2EHPA) in kerosene diluent were comprehensively investigated. The extraction experiments were carried out in order to determine the influential parameters in the conditions of A:O ratio of 1:1, pH range of 1–6, temperatures of 30 °C, 40 °C and 50 °C in an aqueous solution with concentrations of 5 g/L of zinc, manganese and cadmium. The variety of influential parameters in the process such as equilibrium pH, concentration of D2EHPA, temperature, contact time, initial concentration of ions and also thermodynamic parameters of zinc extraction in chloride solution were precisely evaluated. The results showed that in the optimal condition of pH = 2.5–3, temperature 40 °C and [D2EHPA] = 10 v/v, the extraction of Zn, Mn and Cd were 97%, 14% and 3% respectively. ΔpH 0.5 Zn-Mn and ΔpH 0.5 Zn-Cd in this condition respectively equal to 2.5 and more than 5.25. Also, the study indicated that the predominant zinc species extracted by D2EHPA was ZnCl + . Based on thermodynamic studies, the values of ΔH o , ΔS o and ΔG o for zinc extraction in condition of temperature 40 °C and [D2EHPA] = 10 v/v are 25.65 kJ.mol −1 , 79.20 J·K −1 ·mol −1 and 0.86 kJ·mol −1 respectively. Furthermore, the results showed that under constant concentration of D2EHPA, changes in the initial concentrations of Zn, Mn and Cd in the chloride solution were most effective in their separation. [ABSTRACT FROM AUTHOR]

Highlights: [•] Recovery of V (IV) from chloride solution with high Fe (II) concentration. [•] Vanadium extraction of 99% using D2EHPA and vanadium stripping of 98%. [•] High overall separation coefficient of V and Fe (β =200). [•] Purity of V2O5 product is 99.2%. [Copyright &y& Elsevier]

Abstract: This study was conducted as part of the development of a novel process for copper recovery from copper sulfide concentrates by chloride leaching, simultaneous cuprous oxidation and cupric solvent extraction to transfer copper to a conventional sulfate electrowinning circuit, and hematite precipitation to reject iron. The kinetics of cuprous and ferrous oxidation by oxygen and cupric solvent extraction were studied as a function of reaction time, stirring rate, oxygen pressure and extractants. The concentration of Cu(I)+Fe(II) decreased linearly with reaction time while the copper extraction increased with reaction time. The rate of cuprous and ferrous oxidation increased with increasing stirring rate and it was proportional to the partial pressure of oxygen. The cuprous and ferrous oxidation by oxygen was enhanced with the addition of organic solution. During the simultaneous cuprous oxidation and cupric solvent extraction, the aqueous solution pH first decreased sharply with time, then remained constant and finally increased, which was determined by the generation of H+ ions (cupric and ferric solvent extraction) and consumption of H+ ions (cuprous and ferrous oxidation by oxygen). The iron extraction increased as the oxidation reaction generated more ferric ions and raised the pH to a higher value. Simultaneous cuprous oxidation and cupric solvent extraction is feasible to transfer copper to the conventional sulfate electrowinning circuit from a chloride leaching system. The optimum copper solvent extraction conditions in chloride solution were proposed. [Copyright &y& Elsevier]

Abstract: This study was conducted as part of the development of a novel process for copper recovery from chalcopyrite by chloride leaching, simultaneous cuprous oxidation and cupric solvent extraction to transfer copper to a conventional sulfate electrowinning circuit, and hematite precipitation to reject iron. Copper solvent extraction from chloride solution has been studied using four LIX® extractants (LIX84-I, LIX612N-LV, XI-04003 and LIX984N) from BASF with respect to copper extraction as a function of pH and A/O ratio, and behavior of the impurities. At a pH below 0.5, the copper extraction increased quickly with increasing pH while at a pH above 0.5, it increased only slightly with pH. The copper extraction in organic solution was virtually not affected by the impurities. The iron extraction in organic solution increased with decreasing A/O ratio from 2:1 to 1:8 as the copper extraction decreased. Conversely, the Cu/Fe ratio in organic solution increased as copper extraction increased. The extractions of silver and lead were 1mg/L or lower under all conditions tested. The other impurities (Zn, Ni, Cd, Cr, Hg, As and Sb) were virtually not loaded into the organic solution. The optimum copper solvent extraction conditions in chloride solution were proposed. [Copyright &y& Elsevier]

Abstract: In this paper, solvent extraction of mixture of rare-earths (Sm(III), Gd(III), Dy(III) and Y(III)) from chloride solutions using acidic, neutral and basic type extractants and their mixtures has been investigated. The main objective of the work was to select a suitable solvent extractant system for the separation of mixture of rare-earths using organophosphoric acid (TOPS 99), phosphonic acid (PC 88A), phosphinic acid (CYANEX® 272), monothiophosphinic acid (CYANEX® 302), phosphine oxide (CYANEX® 923, CYANEX® 921) and amine based (ALAMINE® 336, ALIQUAT™ 336) extractants. The composition of the synthetic mixture of rare-earths was Sm — 1.835g/L, Gd — 0.862g/L, Dy — 0.303g/L, Y — 0.589g/L which was prepared according to the leach liquor of the Korean domestic ore. From the effect of aqueous phase acidity and extractant concentration on the extraction efficiency of rare-earths, PC 88A (0.1mol/L) considered as better extractant with high separation factor for Dy–Y pair with Sm–Gd pair. Mixture of extractants has shown no significant effect on the separation factors of rare-earths than individual extractants. [Copyright &y& Elsevier]

Research into the solvent extraction of iron(III) from a chloride solution after bauxite HCl leaching by neutral oxygen-containing extractants and their mixtures were studied and the iron(III) extraction degree from chloride solutions using alcohols is presented. The effect of dilution of alcohol with a ketone by an extraction mixture in relation to its effectiveness was investigated. The iron(III) was efficiently extracted by the mixture of 1-octanol and 1-decanol (70%) with 2-undecanone (30%) from hydrochloric bauxite leach liquor at an O:A ratio = 2-4:1 at an iron(III) concentration of 7.4 g/L and 6 M HCl. For the removal of iron-containing organic phase from impurities (Al, Ca, Cr) that are co-extracted with iron(III), we used two step scrubbing at O:A = 5:1 by 7 M HCl as a scrub solution. The iron(III) stripping at the O:A ratio is shown. Using counter-current cascade of extractors, it was possible to obtain an FeCl3 solution with the iron(III) content of 90.5 g/L and total impurities less than 50 mg/L. [ABSTRACT FROM AUTHOR]