Separation and Recovery of Cadmium from Acidic Leach Liquors of Spent Ni-Cd Batteries using Molten Paraffin Wax Solvent Extraction

Separation and recovery of cadmium from sulphate leach liquors of spent Ni-Cd batteries using TBP, HDEHP (D2EHPA), EHEHPA (PC 88A or Ionquest 801 or P507) have been investigated in a laboratory scale. Cadmium can be extracted into paraffin waxes from acidic solutions in the temperature range of 55–75°C using different extractants. The influence of various parameters on extraction and stripping were studied in detail. The feasibility of separation of cadmium from nickel using these extractants and their combination was studied. The mixture extractant of EHEHPA and TBP was found to be the best for the separation of Cd and Ni. A three-stage counter-current extraction simulation test for cadmium extraction was carried out at an A/O phase ratio of 4:1 and pH 2.5. More than 99.97% Cd²⁺ was extracted with the organic phase containing 0.7 mol L^?1 EHEHPA and 0.5 mol L^?1 TBP, while more than 99.97% nickel was left in the raffinate. The cadmium loaded organic phase was stripped with 2 mol L^?1 hydrochloric acid in the stripping stage. The present method can be applied to the separation and recovery of cadmium from acidic leach liquor of spent Ni-Cd batteries or related waste liquor.     

Process for the Recovery of Cobalt and Nickel from Sulphate Leach Liquors with Saponified Cyanex 272 and D2EHPA

Abstract

In this paper, a process is reported for the recovery of cobalt and nickel from copper raffinate solutions using partially saponified Cyanex 272 and D2EHPA as the extractants. The aqueous feed contains 1.65 g/L cobalt and 16.42 g/L nickel. More than 99.9% cobalt separation was achieved with 0.13 M Cyanex 272 (60% neutralized with alkali) in two counter‐current stages at an aqueous to organic phase ratio of 1.1:1. Co‐extraction of nickel was 0.18% only. Stripping of cobalt from a loaded organic phase was carried out with synthetic spent electrolyte solution at an organic to aqueous phase ratio of 2.5 in two counter‐current stages to generate a pregnant electrolyte solution to produce cobalt metal by electrowinning. Similarly, optimum conditions for nickel extraction with 60% neutralized 1 M D2EHPA at O/A ratio of 1.4 in 2 two stages and stripping of metal with synthetic spent electrolyte at O/A ratio of 1.6 in two stages were standardized. Extraction and stripping efficiencies were >99% and the flowsheet of the process is demonstrated.     

Extraction and recovery of cadmium(Ⅱ) using phosphine-oxide,tris[(dibutylamino)methyl]-(7CI,8CI) from nitric acid solutions

In the present article, a new separation system was employed for the extraction of cadmium from nitric acid solutions for the first time. Phosphine oxide, tris[(dibutylamino)methyl]-(7CI,8CI),which contains nitrogen atoms and phosphorus atom in molecular, was used as extractant. The influence of the following parameters was investigated: the organic/aqueous phase ratio (O/A), pH, contact time, temperature, the concentration of extractant, cadmium (Ⅱ), sodium nitrate and sodium chloride. Results demonstrated that quantitative extraction of cadmium was feasible from 50 mg/L cadmium feed solution in a single stage at pH 3.0, 15 min and O/A phase ratio 1:5 with 20% extractant in cyclohexane diluent. The cadmium extraction isotherm under different cadmium ion concentrations was established. The loaded cadmium could be stripped by 4 mol/L ammonium chloride aqueous solutions. A contrast study was carried out, and the results indicated that phosphine oxide, tris[(dibutylamino)methyl] –(7CI,8CI), could take the place of commercial organo-phosphorous extractants in the process of cadmium(II) extractions for its effectivity, stability and low price.     

Separation and Recovery of Light Rare-Earths from Chloride Solutions using Organophosphorus based Extractants

In this paper, separation possibilities of light rare-earths (LREs), Ce, La, Nd, and Pr with three acidic organophosphorus extractants such as TOPS 99 (an equivalent of di-2-ethylhexyl phosphoric acid, D2EHPA), PC 88A(2-ethylhexylphosphonic acid mono-2-ethylhexyl ester), and Cyanex 272 (Bis(2,4,4-trimethylpentyl)phosphinic acid) from synthetic chloride solutions of monazite at three initial pH values has been investigated. The composition of synthetic leach liquor is Ce ? 5.4 g/L, La ? 3.12 g/L, Nd ?1.35 g/L, and Pr ? 0.475 g/L at pH 2.0. Using sodium hypochlorite and sodium hydroxide, cerium was precipitated as ceric hydroxide quantitatively. Among the three investigated extractants, TOPS 99 showed better separation factors towards LREs. Therefore, 0.7 mol/L TOPS 99 has been employed for the separation of Nd, and Pr from La in 3-stages at an aqueous to organic phase ratio of 4:1 and pH 2.0. Raffinate contains 2120 mg/L La, 41 mg/L of Nd, and 17 mg/L of Pr corresponding to an extraction efficiency of 32.1%, 96.4%, and 96.2%, respectively. La from loaded organic phase was scrubbed with 9182 mg/L Nd solution and achieved a scrubbing efficiency of 98.2%. 1 mol/L HCl is used for quantitative stripping. A process flowsheet for the separation and recovery of LREs was presented.     

Separation and recovery of heavy metals from concentrated smelting wastewater by synergistic solvent extraction using a mixture of 2-hydroxy-5-nonylacetophenone oxime and bis(2,4,4-trimethylpentyl) -phosphinic acid

Extraction and separation of copper, zinc, nickel, and cadmium from calcium and magnesium in concentrated smelting wastewater by synergistic solvent extraction using a mixture of 2-hydroxy-5-nonylacetophenone oxime (Mextral 84H) and bis(2,4,4 -trimethylpentyl)-phosphinic acid (Cyanex 272) in an aliphatic diluent (DT-100) was studied. The effects of extractant concentrations, equilibrium pH, organic-to-aqueous phase ratios, system temperature, and extraction and stripping efficiencies on the extraction performance of the heavy metals were investigated. Extraction of pH isotherms showed that addition of Cyanex 272 to Mextral 84H causes obvious synergistic shifts for zinc and cadmium and a slightly antagonistic shift for nickel. The separation factor of cadmium over magnesium was 155.7 and the ΔpH₅₀ values between the metals were over 1.00 pH units. Semi-continuous tests for the metals extraction, scrubbing, and stripping were conducted in a continuous extraction apparatus with conditions further optimized for separation of the metals. Nearly 100% of the copper and nickel and over 98% of the zinc and cadmium were recovered with less than 0.1 mg/L copper and nickel, 26 mg/L of zinc, and 10 mg/L of cadmium remaining in the raffinate. A process in which all valuable metals are extracted simultaneously and stripped selectively at optimal conditions is proposed that is entirely feasible for the separation of copper, zinc, nickel, and cadmium from calcium and magnesium in concentrated smelting wastewater. The study determines the fundamental parameters for the treatment of smelting wastewater by solvent extraction.     

Solvent Extraction of Weak Acids in Binary Extractant Systems

The interphase distribution of weak acids in systems involving salts of quaternary ammonium bases with organic acids (binary extractants) has been analyzed. Significant differences in the extraction depending on the composition of the aqueous and organic phases for weak acids compared with that for strong acids in binary extractant systems have been shown. The difference in the extraction of weak acids with binary extractants compared with neutral extractants has been also revealed. The experimental data were interpreted by two variants of distribution processes, when two extracted species are formed (R₄NX and HA) and for the case of forming extracted species with strong H-bonds (R₄NX · HA). The least square regression method showed that the proposed mechanisms well describe the extraction of monocarboxylic acids with the binary extractant (the smallest sum of squares of relative deviations was 0.025) at their low initial concentrations (<0.05 mol · L^?1). It was shown that the most effective extraction of monocarboxylic acids takes place from acidic solutions (at pH < 2) that indicates the possibility of their effective stripping from organic solutions with water.     

Nickel(II) Extraction from Sulphate Media with Bis (2,4,4‐Trimethylpentyl)Dithiophosphinic Acid Dissolved in Nonane

The paper presents data on nickel(II) extraction from sulphate solutions with nonane‐diluted bis(2,4,4‐trimethylpentyl)dithiophosphinic acid (HR). An IR spectroscopy method is used to examine the state of HR in nonane, and it was shown to exist as a monomer up to a concentration of 0.1 M. With a further increase in concentration, the acid forms associated species. The value of the concentration of the monomeric form is determined as a function of the total HR concentration in nonane in the range of 0.0–1.0 M. Based on the comparative analysis of the extraction equilibrium data together with information from the visible and IR absorption spectra of the nickel extract, the configuration of the nickel(II) complex in the organic phase was determined to be a low‐spin, square‐planar complex. The complex composition was found to correspond to the formula NiR₂. The complex is hydrated, with the water very likely being bonded in the outer coordination sphere.     

The Extraction of Nickel with Aliphatic Oximes

Abstract

U.S. Bureau of Mines researchers investigated the use of aliphatic oximes to extract nickel from acidic, nickelous-chromic-chloride solutions. Batch solvent extraction tests were conducted to characterize the nickel extraction and stripping properties of several oximes. Results indicated that the oximes selectively extracted nickel over chromium by an ion pair mechanism. Nickel was most effectively stripped from the loaded oxime extractants with dilute hydrochloric acid; however, these acidic strip solutions partially degraded the oximes to their parent aldehydes by hydrolysis. The oximes could, however, be regenerated by contacting the solvent phase with a neutralized hydroxylamine-hydrochloride solution. Decyl oxime was successfully used in a continuous counter-current solvent extraction circuit that incorporated loading, stripping, and regeneration stages. The decyl oxime degraded 12 pct per loading and stripping cycle, but was effectively regenerated prior to recycling to the head of the circuit.     

An Extraction Technology for Nickel Sulfate Production from Nickel Solutions Produced by the Kola MMC

Studies were carried out to extract nickel by liquid extraction from sulfate–chloride solutions of the Kola MMC with neodecanoic acid (Versatic10) in sodium form. The influence of the concentration and degree of conversion of acid to salt form on the viscosity of organic mixtures and their extraction capacity has been established. The results of enlarged laboratory tests of conversion of sulphate-chloride solution into pure nickel sulphate solution are presented, from which a reactive salt NiSO₄?7H₂O containing 21.8% Ni and less than 0.01% impurities was isolated during crystallization.

     

Investigation of electrospun and film‐cast PVC membranes incorporated with aliquat 336 for efficient Cd extraction: A comparative study

This article was aimed to investigate the cadmium extraction behaviors of the two different polyvinyl chloride membranes incorporating Aliquat 336—electrospinning and film‐casting. An optimal investigation condition for membranes used in the extraction process was produced at 25 kV with 10 cm tip‐to‐collector distance. Membranes were electrospun for 8 h at 200 μL/h. Membrane extraction studies were carried out using a 127 mg/L Cd(II) solution. Scanning electron microscope (SEM) images revealed differences in fiber diameters and membrane morphology. The addition of Aliquat produced very fine fibers (7–722 nm) resulting Brunauer‐Emmett‐Teller (BET) surface areas of 4.67–11.3 m²/g for electrospun membranes and 1.70–5.44 m²/g for film‐casted membranes. Extraction studies using membranes with different levels of Aliquat (0–40% w/w) revealed that the cadmium extraction performance of electrospun membranes was significantly better than conventional film‐cast membranes. For 40% Aliquat 336, with an initial concentration of 127 mg/L Cd, the cast membrane extracted down to concentration to 115 mg/L as compared to electrospun membrane, which extracted down to 88 mg/L within 40 h. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Copper and Iron Extraction from Nickel Sulfate Electrolytes Using Binary Extractants

The extraction of copper(II) and iron(III) from nickel sulfate electrolytes by means of solutions of binary extractants such as methyltrioctylammonium, tetraoctylammonium and trioctylammonium caprylates, 2-ethylheptylcarboxylates, and di(2-ethylhexyl)phosphates in toluene has been studied. It has been shown that an efficient copper extraction is observed in the systems with methyltrioctyl ammonium dialkyl carboxylate and caprylate, whereas methyltrioocylammonium, and tetraoctylammonium salts can be used to extract iron. The stripping of copper and iron can be carried out using dilute sulfuric acid solutions.     

Simultaneous solvent extraction of cobalt and magnesium in the presence of nickel from sulfate solutions by Ionquest 801

The simultaneous extraction of Co(II) and Mg(II) from nickel sulfate solutions has been carried out using the organophosphonic extractant Ionquest 801 diluted in Exxsol D‐80. Statistical design and analysis of experiments were used in order to determine the main effects and interactions of the solvent extraction parameters, which were the extraction pH at equilibrium, the temperature, the extractant concentration and the organic/aqueous phase ratio. A statistically designed experiment was also carried out to study the stripping of the Ionquest 801 organic phase loaded with cobalt and magnesium by sulfuric acid solution. The number of stages required for both extraction and stripping processes of cobalt and magnesium was evaluated. The results of continuous counter‐current mini‐plant tests demonstrated the simultaneous recovery of cobalt and magnesium from nickel sulfate solution. Copyright © 2005 Society of Chemical Industry     

Homogeneous Liquid–Liquid Extraction and Determination of Cobalt,Copper, and Nickel in Water Samples by Flame Atomic Absorption Spectrometry

Abstract

A simple and effective homogeneous liquid–liquid extraction method has been used for the simultaneous extraction and preconcentration of cobalt, copper, and nickel after the formation of complex with 4‐benzylpiperidinedithiocarbamate potassium salt (K‐4‐BPDC), and later they were determined by flame atomic absorption spectrometry (FAAS) using (water/tetrabutylammonium ion (TBA⁺)/chloroform) as a ternary component system. The phase separation phenomenon occurred by an ion‐pair formation of TBA⁺ and perchlorate ion. After the optimization of complexation and extraction conditions ([K‐4‐BPDC]=2.0×10^?4 mol l^?1, [TBA⁺]=2.0×10^?2 mol l^?1, [CHCl₃]=60.0 µl, [ClO₄ ^?]=2.0 ×10^?2 mol l ^?1 and pH=6.0), a preconcentration factor of 200 was obtained for only 10 ml of the sample.

The analytical curves were linear in the range of 20–1500, 15–2000, 35–1600 µg l^?1 and the limits of detection were 10, 5, and 15 µg l^?1 for Co²⁺, Cu²⁺, and Ni²⁺, respectively. The proposed method was applied for the extraction and determination of Co²⁺, Cu²⁺, and Ni²⁺ in natural water samples with satisfactory results.     

Recovery of Zinc by LIX 984N‐C from Electroplating Rinse Bath Solution

The development of a complete solvent extraction process at the laboratory scale for recovering zinc from the zinc electroplating first rinse bath solution (alkali solution) containing ～1.9 g/L zinc (ZEFRBS) by a solvent extraction route using LIX 984N‐C, which is a new SX reagent developed by Cognis, and dissolved in commercial kerosene was investigated. By using LIX 984N‐C, an electrolyte from ZEFRBS with ～12 g/L zinc content, which was addable to the alkali zinc electroplating bath, was generated by 10 vol.% LIX 984N‐C in commercial kerosene at the O/A ratio of 1/4 and equilibrium pH value of 8.00 ± 0.05 with a two‐stage countercurrent extraction, and stripping of the loaded organic by a strip solution with 150 g/L sulfuric acid and with the O/A ratio of 1.5 at a two‐stage countercurrent stripping process. A new complete flow sheet of 10 vol.% LIX 984N‐C process for the recovery of zinc from ZEFRBS has been demonstrated.     

Separation of cobalt and nickel from acidic sulfate solutions using mixtures of di(2‐ethylhexyl)phosphoric acid (DP‐8R) and hydroxyoxime (ACORGA M5640)

DP‐8R and ACORGA M5640 extractants diluted in Exxsol D100 were used to co‐extract cobalt and nickel from aqueous acidic sulfate media. The influences of equilibration time, temperature, equilibrium pH and reagent concentrations on the extraction of both metals have been studied. It was observed that both cobalt and nickel extraction are slightly sensitive to temperature but are pH dependent. Metal extraction equilibria are reached within about 5 min contact time. In addition, cobalt extraction depends on the extractant concentration in the organic phase. For a solution containing 0.5 g dm^?3 each of cobalt and nickel and an initial pH of 4.1, conditions were established for the co‐extraction of both metals and selective stripping (with H₂SO₄) of cobalt and nickel. Using the appropriate reagent concentrations the yield (extraction stage) for both metals exceeded 90%, and stripping of cobalt and nickel was almost quantitative. Copyright © 2004 Society of Chemical Industry     

Competitive Separation of Lead,Cadmium, and Nickel from Aqueous Solutions Using Activated Carbon: Response Surface Modeling,Equilibrium, and Thermodynamic Studies

In this study, the competitive separation of lead, cadmium, and nickel ions from aqueous solutions using a commercial activated carbon (AC) has been investigated and optimized using response surface methodology (RSM). The optimal conditions to reach the highest adsorption capacity for these metals were found as follows: initial pH = 6.3, temperature = 56.8°C, and shaking speed = 308 rpm. Under these conditions, the sequence of adsorption capacity toward the metal ions was as follows: Pb (II): 9.44 mg g^?1 > Cd (II): 9.37 mg g^?1 > Ni (II): 4.52 mg g^?1. The effect of shaking speed on the adsorption capacity of AC was higher than the effects of the initial pH and temperature, indicating the more important role of physisorption than chemisorption in the adsorption of these metal ions. This was confirmed by the results of thermodynamic studies. The equilibrium adsorption data were fitted to the Freundlich, Langmuir adsorption isotherm models and the Dubinin–Radushkevich model parameters were evaluated. All the models were tested and all were shown to represent the experimental data satisfactorily. The thermodynamic parameters such as ΔH, ΔS, and ΔG were computed from the experimental data. These values show that the adsorption is endothermic and spontaneous. The positive value of ΔS° indicates increasing of randomness at the solid/liquid interface during the adsorption of metal ions on AC.     

Simultaneous Recovery of Nickel and Cobalt from Aqueous Solutions using Complexation-Ultrafiltration Process

Simultaneous recovery of nickel and cobalt from aqueous solutions by complexation-ultrafiltration process with polyethylenimine (PEI) was studied. Experiments were performed as a function of polymer/metal ratio (P/M), solution pH, and ionic strength. Effects of concentration time on metal rejection and membrane flux were also studied. At optimum experimental conditions of pH 6.0 and P/M 5.0, the nickel removal efficiency reaches at 99.9% and cobalt removal efficiency goes to 96.4%. Both nickel and cobalt removal efficiencies decreased as the adding salt concentration increases. During 12 h of the ultrafiltration process, the decline of membrane flux was less than 16% and the removal efficiencies for both nickel and cobalt were kept almost constant. Diafiltration was further performed to regenerate PEI. The removal efficiencies for both metals using recycled PEI were found to be close to those with the original PEI. Results from the two-step process of complexation-UF and decomplexation-UF separation showed that it could be a promising method for simultaneous recovery of nickel and cobalt from aqueous solutions.     

Solvent Extraction of Au(I) from Auro‐Cyanide Solution with Cetyltrimethylammonium Bromide/Tri‐n‐Butyl Phosphate System using Column‐Shaped Extraction Equipment

Abstract

Solvent extraction of Au(I) from alkaline cyanide solution containing several milligram per liter of gold was investigated with column‐shaped extraction equipment using tri‐n‐butylphosphate (TBP) as extractant with addition of quaternary ammonium salt, cetyltrimethylammonium bromide (CTAB), directly into the aurous aqueous phase in advance. The influences of the volume of TBP and the NaCl concentration in the aurous aqueous phase on Au(I) extraction were investigated. The experimental results for treating 50 L of synthetic auro‐cyanide solution containing 10 mg/L Au(I) and for treating real auro‐cyanide leaching liquor by CTAB/TBP system were reported. The results obtained establish that the column‐shaped extraction equipment was suitable for extracting Au(I) from low content auro‐cyanide solution at high aqueous/organic phase ratio, and that more than 97% of gold(I) could be extracted while the Au(I) concentration in the raffinate was less than 0.3 mg/L. In addition, the stripping of Au(I) from the loaded organic phase and the recycle of the organic phase were also discussed.     

Purification and Concentration of Xylose and Glucose from Neutralized Bagasse Hydrolysates Using 3,5‐Dimethylphenylboronic Acid and Modified Aliquat 336 as Coextractants

Abstract

Experimental trials of the extraction of xylose, glucose, and fructose from aqueous solutions were conducted using 3,5‐dimethylphenylboronic acid (DMPBA) and modified Aliquat^® 336 (MA) as combined extractants dissolved in Exxal^®10 diluent. MA was produced by contacting an Aliquat 336/Exxal 10 solution with a concentrated caustic soda solution so that the quaternary ammonium ions of Aliquat 336 would ion pair with hydroxide ions. The DMPBA/MA/Exxal 10 organic solution containing equimolar amounts of MA and DMPBA was contacted with a neutral aqueous solution containing one of glucose, xylose, or fructose and the extraction isotherms were determined. The molar ratio of DMPBA:sugar in a fully loaded organic solution was 2:1. The use of the MA instead of Aliquat 336 enabled significant proportions of the sugars to be extracted from aqueous solutions over a wide pH range (～2–11). Loaded organic solutions were stripped using aqueous hydrochloric acid solutions. Complete recovery of the sugar was possible by ensuring sufficient acidity was available in the strip solution. Solutions of MA in Exxal 10 were also found to extract sugar, although to a lesser extent than when DMPBA was included. Extraction of xylose and glucose from solutions derived from the acid hydrolysis of bagasse was performed. By varying the volumetric ratio of strip to organic phases, strip solutions with xylose concentrations up to 4× that of the original hydrolysate were produced while reducing the concentration of the undesirable acid soluble lignin by up to 90%. Hence, this process has the potential to produce high concentration monosaccharide solutions suitable for direct fermentation.     

Solvent extraction of silver(I) from nitrate media using thiourea derivatives

Liquid–liquid extraction of Ag(I) from nitrate solutions using N‐(N′,N′‐diethyl thiocarbamoyl)‐N″‐phenylbenzamidine (TCBA) and 1‐6,‐diethylcarbamoyl imino‐1,6‐diphenyl‐2,5 dithiahexane (TCTH) dissolved in cumene has been studied. The extraction of Ag(I) from 1 mol dm⁻³ NO₃⁻ solutions by TCTH and TCBA was investigated as a function of several variables: equilibration time, organic phase diluent, pH of aqueous phase, Ag(I) and NO₃⁻ concentration in aqueous phase as well as TCBA and TCTH concentrations. Experimental equilibrium data were analysed numerically using the programs LETAGROP‐DISTR and LETAPL and the results showed that Ag(I) extraction could be explained assuming the formation of AgL and AgNO₃HL with TCBA (HL) and AgNO₃S with TCTH (S). The metal extraction was not influenced significantly by the structures of the thiourea derivatives used as extractants. The back extraction of Ag(I) from loaded organic phase was performed using different strippants and 0.5 mol dm⁻³ NaSCN was found to be efficient for this purpose. © 2000 Society of Chemical Industry