Solvent extraction with LIX 973N for the selective separation of copper and nickel

LIX 973N diluted with Iberfluid was used to co‐extract copper and nickel from ammoniacal/ammonium carbonate aqueous media. The influence of equilibration time, temperature, equilibrium pH and extractant concentration on the extraction of both metals has been studied. It was observed that neither copper nor nickel extraction is sensitive to temperature and equilibrium pH, however nickel extraction equilibrium is reached at a longer contact time (20 min) than that of copper (5 min), in addition nickel extraction depends greatly on the extractant concentration in the organic phase. For a solution containing 3 g dm⁻³ each of copper and nickel and 60 g dm⁻³ ammonium carbonate, conditions were established for the co‐extraction of both metals, ammonia scrubbing and selective stripping (with H₂SO₄) of nickel and copper. Using the appropriate extractant concentration the yield (extraction stage) for both metals is near 100%, whereas the percentage of nickel and copper stripping is also almost quantitative. © 1999 Society of Chemical Industry     

Recovery of copper from sulphate medium by Lix-84 in kerosene

The extraction–stripping reaction of Cu(II) by Lix-84 in kerosene from aqueous sulphate medium of pH 2·5 has been investigated. The effects of pH, metal ion, extractant and strip solution concentrations as well as the loading capacity of the extractant were investigated. The number of stages required for the extraction and stripping of copper was also evaluated. The results are used to assess the conditions for purification of industrial waste solutions containing copper through counter-current extraction in a horizontal mixer-settler.     

Solvent Extraction Studies for Separation of Zn(II) and Mn(II) from Spent Batteries Leach Solutions

This study aims at assessing the possibility of using solvent extraction processes for separating Zn(II) and Mn(II) dissolved in aqueous solutions obtained by acid bioleaching of spent alkaline and Zn-C batteries. In this context, Cyanex 272 and DEHPA were tested as extractant agents, and the former was shown to have better performance. Hence, the effect of four factors (equilibrium pH, extractant concentration, A/O ratio, and temperature) into three response variables (extraction efficiency of Zn, Y_Zn; extraction efficiency of Mn, Y_Mn; separation factor, β) were tested according to a full factorial design (2⁴) with two replicated center points. Our study revealed that Y_Zn depends mainly on the extractant concentration, Y_Mn on the equilibrium pH and β on the equilibrium pH, extractant concentration, and A/O ratio as well as on second and third order interactions. One extraction step is sufficient to reach high extraction of zinc in synthetic solutions, but two stages were required for real leaching liquor. The extraction kinetics is fast (less than 15 min) for both metals, even when real liquor was tested. The organic solvent can be efficiently recovered using a stripping solution of H₂SO₄ 1 M and thus the process can be considered environmentally sustainable.     

Extraction of vanadium(V) from sulfate solutions by ACORGA M5640

ACORGA M5640 (hydroxy‐oxime derivative) has been applied as an extraction reagent for vanadium(V) from sulfate media. The extraction system was studied as a function of contact time, temperature, aqueous pH, diluent of the organic phase, and metal and extractant concentrations. The extraction reaction is endothermic and it is dependent on the organic diluent, aqueous pH and extractant concentration. The data have been analysed numerically to determine the stoichiometry of extracted species and their equilibrium constants. It was found that vanadium was extracted into the organic phase by a complex mechanism which involves the formation of two species (VO₂R and VO₂R. HR, where R represents the extractant). Vanadium stripping by acidic and ammonium hydroxide solutions was also studied. Copyright © 2003 Society of Chemical Industry     

Extraction of molybdenum(VI) from sulfate solutions by LIX 622

The application of LIX 622 (oxime derivative) as an extraction reagent of molybdenum (VI) from sulfate media was studied. The extraction system was studied as a function of contact time, temperature, aqueous pH, diluent of the organic phase and metal and extractant concentrations. The extraction is exothermic and it is dependent on the organic diluent, aqueous pH and reagent concentration. The data have been analysed numerically to determine the stoichiometry of extracted species and their equilibrium constants. It was found that molybdenum was extracted into the organic phase by a complex mechanism which involves the formation of three species (MoO₂L₂, MoO₄H₃HL⁺HSO₄⁻ and MoO₄H₂HL, where L represents the extractant). Molybdenum stripping by acidic and ammonium hydroxide solutions was also studied. © 2000 Society of Chemical Industry     

Kinetics and mechanism of extraction of Cu(II) by CYANEX 302 from nitrate medium and oxidative stripping of Cu(I) using Lewis cell technique

The extraction of Cu(II) from nitrate medium using CYANEX 302 (bis(2,4,4-trimethylpentyl) monothiophosphinic acid) in kerosene under equilibrium conditions showed that copper is first extracted as Cu²⁺ followed by reduction of CuA₂ (HA)₂ to Cu⁺ while the CYANEX 302 extractant is correspondingly oxidized. The stripping of Cu(II) from loaded organic solutions by using different stripping agents showed that effective stripping is obtained upon using high concentration of nitric acid which oxidizes the extracted Cu(I) to Cu(II).     

Co-extraction and selective stripping of copper (II) and molybdenum (VI) using LIX 622

LIX 622 diluted with kerosene was used to co-extract copper (II) and molybdenum (VI) from acidic sulphate solutions. The influence of equilibrium pH and extractant concentration on metal co-extraction has been studied. The extraction of both metals is sensitive to equilibrium pH; however, molybdenum is extracted preferably to copper at acidic pH values. For aqueous phases containing both metals, conditions were established for the co-extraction, selective stripping of copper and molybdenum and NH₃ removal from the stripped organic solution.     

Removal of Copper(II) from a Concentrated Sulphate Medium by Cloud Point Extraction Using an N,N′-Bis(salicylaldehyde)Ethylenediimine Di-Schiff Base Chelating Ligand

Various chelating ligands have been investigated for the cloud point extraction of several metal ions. However, limited studies on the use of the Schiff base ligands have been reported. In this work, cloud point extraction behavior of copper(II) with N,N′‐bis(salicylaldehyde)Ethylenediimine Schiff base chelating ligand, (H₂SALEN), was investigated in aqueous concentrated sulphate medium. The extraction process used is based on the formation of hydrophobic H₂SALEN–copper(II) complexes that are solubilized in the micellar phase of a non‐ionic surfactant, i.e. ethoxylated (9.5EO) tert‐butylphenol. The copper(II) complexes are then extracted into the surfactant‐rich phase above cloud point temperature. Different parameters affecting the extraction process of Cu(II), such as equilibrium pH, extractant concentration, and non‐ionic surfactant concentration were explored. The extraction of Cu(II) was studied in the pH range of 2–11. The results obtained showed that it was profoundly influenced by the pH of the aqueous medium. The concentration factor, C_f, of about 17 with extraction efficiency of E % ≈100 was achieved. The stoichiometry of the extracted complex of copper(II) was ascertained by the Yoe–Jones method to give a composition of 1:1 (Cu:H₂L). The optimum conditions of the extraction‐removal have been established as the following: (1) 1.86 × 10^?3 mol/L ligand; (2) 3 wt% surfactant; (3) pH of 8 (4) 0.5 mol/L Na₂SO₄ and (5) temperature of 60 °C.     

Separation and recovery of copper from waste printed circuit boards leach solution using solvent extraction with Acorga M5640 as extractant

Waste printed circuit boards (WPCBs) have received extensive attention in recent years because of its harmfulness and resource. In this work, two-step leaching process was carried out by using steel pickling waste liquor (SPWL) as the leaching agent. The leaching solution contains a variety of metals, especially iron, which will have an effect on the recovery of copper. Acorga M5640 (M5640) extractant with a kerosene diluent was used to recover copper from WPCBs leach solution, and the separation factor is adopted to analyze the effects of these metal ions. The effect of different parameters such as pH of aqueous phase, phase ratio (O/A), M5640 concentration, contact time as well as the concentration of H₂SO₄ as stripping reagent were investigated. Over 90.0% copper was extracted with pH 1.1, phase ratio (O/A) 1/1, M5640 concentration 16%, contact time 3 min at room temperature. For the stripping process, the 60 s contact time and 2.5 mol/L H₂SO₄ concentration are suitable with 90.0% stripping percentage of copper. Copper extraction isotherm accords with Langmuir isotherm equation and the results show that iron is the most influential metal ion for copper extraction, which will reduce the theoretical saturation of the extractant. The extractant M5640 has excellent reuse performance and can be recycled more than 10 times, which demonstrated M5640 has the industrial application value in the extraction of copper from WPCBs leach solution.     

Recovery of Fumaric Acid from Industrial Wastewater by Chemical Extraction and Stripping

Abstract

The study on chemical extraction and stripping for the recovery of fumaric acid from low concentration organic acid wastewater has been carried out. The parameters influencing the extraction efficiency were investigated, including extractant concentration, the initial pH, the volume ratio of water to oil (W/O), the extraction temperature, and the concentration of n‐octanol. The heat effect of the extraction process, the formation of acid‐amine complexes, and the corresponding equilibrium constant were determined. In the optimum condition that kerosene/N₇₃₀₁/n‐octanol was 2:2:1, pH was 0.5, W/O was 1:1, and the temperature was 303K, through chemical extraction and stripping, the COD_cr value of fumaric acid wastewater decreased from 71040 mg/l to 8411 mg/l, and the overall COD_cr removal rate reached 88.16%, and the extraction efficiency of fumaric acid was 70.67%. The extractant was regenerated by a stripping process with 2% NaOH, and the stripping rate almost arrived at 100%. The regenerated extractant was cycled seven times without decreasing extraction efficiency and the stripping rate. And fumaric acid was obtained by adjusting the pH of the salt from stripping. After extraction, the fumaric acid wastewater can be further treated by oxidation or biodegradation to environmentally acceptable levels.     

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     

Extraction of gold from cyanide or chloride media by Cyanex 923

A new phosphine oxide extractant, commercially known as Cyanex 923, has been studied in order to be applied in the recovery of gold from either cyanide or chloride aqueous media. Au(CN)₂⁻ is extracted by this reagent throughout the whole pH range. The presence of lithium salts in the media improves the extraction. The extraction mechanism proposed can be explained in terms of a solvating reaction, the species formed in the organic phase being the following: Li⁺Au(CN)₂⁻3(R₃PO). The stripping can be performed by low ionic strength solutions such as dilute KCN solutions, and the reaction is enhanced by an increase in temperature. In chloride media, the extractant is able to extract gold (III) in the entire range of acid concentrations. The amount of extraction agent required, to achieve the same level of extraction, in this medium is much lower than in the cyanide media. The temperature has a negative effect on the extraction. Another difference observed between the two media, is that the presence of ionic salts in chloride media has no influence on the extraction, which may be attributed to the fact that the extracted species, HAuCl₄, is a protonated instead of an ionic species. © 1998 SCI     

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.     

Purification of nickel sulphate solutions containing iron,copper, cobalt,zinc and manganese

Acidic nickel-bearing solution containing iron, cobalt, manganese, zinc and copper was processed through a solvent extraction and precipitation technique to obtain a pure nickel sulphate solution. Iron was extracted using 0.2M Cyanex-272 (partially neutralised) as the extractant. Stripping of iron from the loaded organic has also been studied. After iron recovery through solvent extraction the raffinate still contained 0·25 g dm^?3 of iron which was quantitatively separated by a lime precipitation technique. During this iron precipitation there was no loss of cobalt and nickel but copper, manganese and zinc were coprecipitated to some extent. From the iron-free nickel sulphate solution the other impurities were extracted using the same extractant (Cyanex-272) in a single stage. The metal ions from the loaded organic were stripped using a 0·5% (v/v) H₂SO₄ solution in a single stage. The entire operation needs only seven stages: two stages for iron extraction, three stages for iron stripping from the loaded organic, and one stage each for extraction and stripping of other impurities. In the entire operation the loss of nickel was less than 0·5%.     

The extraction of lactic acid by emulsion type of liquid membranes using alamine 336 in escaid 100

The extraction of lactic acid from aqueous solutions through an emulsion liquid membrane containing Alamine 336 as carrier was investigated. The influence of mixing speed, diluent type, surfactant concentration, extractant concentration, feed solution pH, stripping concentration, phase ratio, and feed concentration were examined. Liquid membrane consists of a diluent (n‐heptane, toluene, kerosene, Escaid 100, and Escaid 200), a surfactant (Span 80) and an extractant (Alamine 336), and Na₂CO₃ were used as a stripping solution. It is possible to extract 91% of lactic acid from aqueous solutions using Alamine 336 in Escaid 100, as an extractant and a diluent respectively.     

Separation of Copper and Nickel from Ammoniacal/Ammonium Carbonate Solutions Using ACORGA PT5050

ABSTRACT

ACORGA PT5050 diluted with iberfluid (kerosene-type diluent, mostly aliphatic) was used to coextract copper and nickel from ammoniacal carbonate solutions. The influence of kinetics, temperature, equilibrium pH, and extractant concentration on the extraction of both metals has been studied. It was observed that nickel extraction is very sensitive to aqueous pH and that the extraction falls beyond an equilibrium pH of 9. For a typical solution containing near 3 g/L each of copper and nickel and 60 g/L ammonium carbonate, conditions were established for the coextraction and selective stripping of nickel and copper.     

Recovery of Copper from a Waste Heat Boiler Dust Leach Liquor using LIX 84I and LIX 622N

The dust collected from the waste heat boiler of a copper plant was leached with sulfuric acid and the leach liquor contained 31.63 kg/m³ Cu, 14.78 kg/m³ Fe, 2.21 kg/m³ Zn, 0.26 kg/m³ Co, 0.09 kg/m³ Ni, and 0.23 kg/m³ Cd. The iron content in the leach liquor was precipitated out using Ca(OH)₂ and from the filtrate copper was extracted with the extractants LIX 84I and LIX 622N in kerosene. Extraction of copper with either extractant increased with increasing equilibrium pH and extractant concentration. The McCabe-Thiele plots for quantitative extraction of copper indicated 3-stages at O:A ratio of 3:2 with 30% extractants. The counter-current extraction study showed 0.21 kg/m³ and 6.77 g/m³ copper in the third stage raffinates of LIX 84I and LIX 622N indicating 98.64% and 99.95% extraction, respectively. For extraction of a mole of copper ion, two moles of the extractant was required to release two moles of hydrogen ion to the aqueous phase. The quantitative stripping of copper from the loaded organic phases of LIX 84I and LIX 622N with 180 kg/m³ H₂SO₄ was possible in 3-stages at O:A ratio of 3:1 and 3:2, respectively. The thermodynamic parameters such as ΔH, ΔG, and ΔS were calculated for both the systems. The enthalpy change (ΔH) values were positive for extraction of Cu with either extractant indicating the processes to be endothermic. The IR spectra indicated the association of phenolic-OH group of oxime molecules in the formation of copper complexes.     

Cobalt removal from waste‐water by means of supported liquid membranes

BACKGROUND: Supported liquid membranes (SLM) are an alternative technique to remove and recover metals from diluted process solutions and waste‐water. In the present work, the removal of Co(II) from a synthetic CoSO₄ solution containing initial amounts of cobalt(II) in the range 100–200 ppm (0.1–0.2 g dm^?3) has been studied on a pilot scale. By performing batch equilibrium experiments, the optimal settings, i.e. the composition of the organic phase, the pH of the feed, the type and concentration of the stripping agent were determined. RESULTS: It is shown that the equilibrium characteristics of a synergistic extractant mixture containing di‐2‐ethyl‐hexylphosphoric acid (D2EHPA) and 5‐dodecylsalicylaldoxime (LIX 860‐I) are superior to D2EHPA. Both hydrochloric acid and sulfuric acid have been evaluated as stripping solutions in liquid–liquid extraction tests and as the receiving phase in a SLM configuration. Although equilibrium tests showed no difference in stripping characteristics between both chemicals, it was observed that in a SLM configuration the stability of the system when hydrochloric acid is used is poor. With a commercially available SLM module (Liqui‐Cel Extra‐Flow 4 × 28) having a surface area of 19 m², a steady Co(II) flux of 0.140 gm^?2h^?1 has been obtained at influent concentrations of cobalt between 100 and 200 ppm with 3 mol dm^?3 sulfuric acid as stripping phase. CONCLUSIONS: The results obtained show that a supported liquid membrane containing a synergistic mixture of LIX 860‐I and D2EHPA gives the possibility of recovering cobalt from dilute solutions. Copyright © 2008 Society of Chemical Industry     

Liquid-Liquid Extraction Studies of Trivalent Yttrium from Phosphoric Acid Solutions Using TOPS 99 as an Extractant

Liquid-liquid extraction studies of trivalent yttrium (Y) from phosphoric acid solutions have been carried out with commercial organophosphoric acid based extractant TOPS 99 (Talcher Organo phosphorus solvent, an equivalent of di-2-ethylhexyl phosphoric acid). The parameters studied include equilibration time, acid concentration, extractant concentration, diluent, metal concentration, temperature, stripping, and regeneration of the extractant. Increase of phosphoric acid concentration in the range from 0.01 to 0.5 M on the extraction of trivalent Y with 6 × 10^?3 M TOPS 99 (Talcher Organo phosphorus solvent) decreases the percentage extraction, indicating the transfer of metal follows ion exchange type reaction. The plot of log D vs. equilibrium pH gave a straight line with a slope of 3.1 indicating the exchange of three moles of hydrogen ions for every mole of trivalent Y extracted into the organic phase. Stripping of metal from the loaded organic with mineral acids indicate sulphuric acid as the best stripping agent. The extraction behavior of associated elements clearly follows their ionic radii with a maximum separation factor of 414 for Lu-Tb.     

Continuous Laboratory Gold Solvent Extraction from Cyanide Solutions using LIX 79 Reagent

Continuous laboratory solvent extraction of gold from cyanide solutions has been investigated by using LIX 79 guanidine‐based extractant. Different variables that affected the extraction included aqueous pH, extractant concentration and modifier concentration. Extraction isotherms of the aurocyanide complex with respect to the other cyanoanions were compared, and the following order of selectivity was observed: Au > Ag > Cu > Zn > Fe. According to the pH isotherms, aurocyanide can be extracted in alkaline media, and a better separation with respect to other cyano anions was obtained in the pH range 10.5–11.2. From the McCabe‐Thiele diagrams, better recovery was observed when using LIX 79 and tridecanol at 10 vol.‐%. Stripping gold from the loaded organic was carried out at pH > 12 by using NaOH and NaCN solutions. The pilot plant tests indicate that a two‐stage extraction followed by one strip step are more than adequate to obtain an overall process efficiency of 92 %. However, for those cases where copper is present significantly, a copper wash stage is recommended before gold stripping. In this case, stripping of copper is accomplished at a pH 10.8, whereas the gold stripping was done at a pH of 12.0.