Solvent Extraction Of Copper Research Articles

Solvent Extraction and Electro-Wining from Copper Leaching Product of Mawat Sulfide Ore Using Taguchi Method

This study includes solvent extraction and electrowinning of copper from leaching process. The Taguchi method was used to determine the optimum conditions for solvent extraction process of copper ore in sulfuric acid solution. The experimental parameters of solvent extraction were: Extractant mass of sodium diethyldithiocarbamate (SDDT), agitation time, and pH value. While, the electrowinning parameters were constant at 25°C temperature, reaction voltage of 2 V, 200 A/dm2 current density, and 2.5 cm distance between electrodes. The following optimum solvent extraction parameters levels were found: Extractant mass of SDDT 100 mg, agitation time 30 min, pH = 8. Under these conditions, the extraction ratio was 97.15%. It was observed that the extraction ratio increases with the increase of SDDT mass. A contacting time of 30 min is considered for ensuring state of equilibrium, and the extraction ratio decreases in a more alkaline medium (pH >8) when the cation of hydrolysis at the aqueous phase was sufficiently disturbed from heating, allowing elements to return to the aqueous phase, thereby decreasing the extraction ratio. After electrowinning is carried out, the results for the experiments were taken to quantitative analysis using the X-ray fluorescence pectrophotometer, scanning electron microscopy, and X-ray diffraction patterns which showed the presence of pure copper at a purity level of 100%.

Characterisation and treatment of spent deposited sludge of transformer oil (DSTO) by acid leaching and solvent extraction

ABSTRACTThe characterisation of spent transformer oil to determine its fitness for re-refining as well as the recovery of metals by hydrometallurgical treatment in chloride medium has been investigated. The leaching experiments on the spent material showed that its dissolution increases with leachant concentration performed at 75°C. Leaching studies showed that at optimal conditions, the dissolution reached 93% by 1.0 mol L−1 HCl solution within 120 min at 75°C. The solvent extraction of copper by bis(2,2,4-trimethylpentyl) phosphinic acid (CYANEX®272) in kerosene from a pregnant solution of aqueous spent deposited sludge of transformer oil containing 1243.4 mg L−1 Cu++, 389.2 mg L−1 Fe++/+++, 110.7 mg L−1 Ca++ and 235 mg L−1 Al+++ was studied. The results for the solvent extraction give an extraction efficiency of 91.77% total copper acquired via 0.2 mol L−1 CYANEX®272 in kerosene at 27 ± 2°C within 25 min at pH 4.0. A 0.1 mol L−1 HCl solution was found to be sufficient for the stripping of about 94.77% copper from the loaded organic phase. The Fourier transform–infrared spectroscopic analysis of the loaded organic phase supports the stripping experiment as there was no Cu metal ion present in the separated organic phase.

Removal of iron ions from industrial copper raffinate and electrowinning electrolyte solutions by chemical precipitation and ion exchange

The reduction of iron ions concentration from copper electrowinning electrolyte solution in copper solvent extraction and electrowinning process, is important to maintain good current efficiency. In this study both chemical precipitation (hydroxide and jarosite) and ion exchange methods were investigated using industrial copper raffinate and electrowinning solutions from Sarcheshmeh copper complex, Iran. Batch precipitation and adsorption tests were initially performed before, a fixed bed column was investigated for iron removal by ion exchange. Batch results indicated that with increasing the pH and dilution, improved the iron removal by chemical precipitation methods. Hydroxide and jarosite precipitations were performed efficiently at pHs of 3 and 2 and temperatures of 70°C and 95°C respectively. The iron removal efficiency was greater with jarosite precipitation (∼70%) compared to hydroxide (∼20%) for a particular pH (2). Diluting by 50% increased the removal efficiency up to 150%. Ion exchange results indicated that pH and dilution did not have a significant effect on the efficiency with this method and it practically performed at ambient temperatures. The batch equilibrium and kinetics experiments were performed with Purolite S957 resin and the results showed that the Sips isotherm (the maximum adsorption capacity was 42mg/g) and both the pseudo-nth order (kad=0.00083mg1−n/g1−n·s and n=1.92) and Langmuir-Freundlich kinetics models (kaLF=0.08mLmin-1mg-1,kdLF=0.12min-1 and n=0.12) were able to predict the equilibrium and kinetics data. In the fixed bed column experiments, the effects of parameters such as the volumetric flow rate and bed height on the breakthrough curves were studied. The iron removal efficiency for the industrial solution which included impurities was less than for synthetic solutions. The results showed that the resin selectively removed the iron ions but did not decrease the copper concentration and used resin was completely regenerated by hydrochloric acid (the amount of 5mL/g of resin and concentration of 30wt%) over several regeneration did not significantly alter the sorption capacity. Finally, a mathematical model based on chemical sorption was used to predict the experimental breakthrough curves data and results showed this model accurately predicted the experimental breakthrough curves. Overall, ion exchange was more efficient at iron removal than chemical precipitation.

Attachment of <i>Acidithiobacillus</i> <i>ferrooxidans</i> and Bioleaching of Chalcopyrite under Influence of Organic Substances Associated with Copper Solvent Extraction

Small quantities of organic substances are inevitably entrained and dissolve in the aqueous raffinate during a copper solvent extraction (SX) operation. These organic substances contaminate the bioleaching environment through the loopback of the raffinate. The attachment of cells of Acidithiobacillus ferrooxidans (At. ferrooxidans) to the low grade chalcopyrite ores and the bioleaching of the ores under the influence of solvent extraction organic substances were investigated. The results showed that the cells of At. ferrooxidans were apt to attach on the SX organics-contaminated chalcopyrite ores with an adsorption ratio of about 83%, larger than that of 44% on the uncontaminated ores as a control. However, the bioleaching efficiency decreased from 25% to 15% under the influence of the SX organic substances. Obviously, an improvement of the cells attachment did not improve the bioleaching efficiency of the low grade chalcopyrite ores by At. ferrooxidans in the present of the SX organic substances. The SX organic substances impacted the metabolism of At.ferrooxidans and their bioleaching ability.

Recovery of copper from alkaline glycine leach solution using solvent extraction

Abstract Glycine solutions in an alkaline environment have been shown to be able to leach copper from its oxide, native and sulfide minerals as a copper glycinate complex. This paper explores the recovery of copper from its aqueous glycinate complexes at alkaline pH through solvent extraction. Solvent extraction of copper from synthetic glycinate liquor (with background sulfate anions) containing 2 g/L Cu has been studied using Mextral 84H (2-hydroxy-5-nonylacetophenone oxime) and Mextral 54–100 (1-benzoyl-2-nonyl ketone) extractants with a kerosene diluent. The effect of different parameters such as pH of aqueous phase, glycine and extractant concentrations, equilibrium time, temperature, extractant loading capacity as well as the concentration of sulphuric acid as stripping reagent were investigated. Over 99.9% Cu was extracted with 5% Mextral 84 H at room temperature at an Aqueous-to-Organic (A:O) ratio of 2:1. Under similar conditions, 95.87% Cu was extracted by 10% Mextral 54–100. HPLC analysis for free glycine indicated that neither extractants take up glycine during the extraction process. Stripping experiments with spent electrolyte solution showed that copper loaded on Mextral 54–100 can be completely stripped in single stage at an O:A ratio of 10:1 while only 79.95% Cu can be stripped from Mextral 84H with same conditions applied. Copper extraction from leachates of malachite and chalcopyrite ore samples was performed in order to validate extraction results from the synthetic solutions. Over 99% copper was extracted from the malachite leachate (containing 2620 mg/L Cu) in a single stage by both 10% Mextral 54–100 (raffinate pH of 9.76) and 5% Mextral 84H (raffinate pH of 10.0) at an O:A of 2:1; with no impurity elements picked up by either extractants. At an O:A ratio of 2:1, single stage copper extraction from chalcopyrite leachate by 10% Mextral 54–100 (raffinate pH of 9.87) was 93.20% and 95.57% by 5% Mextral 84H (raffinate pH of 9.91) with the rejection of all impurity elements other than Zn in the aqueous raffinate. From the chalcopyrite leachate containing 2288 mg/L Cu and 699 mg/L Zn, the Zn co-extraction into the organic phase at an O:A ratio of 1 was found to be 16.5% for Mextral 54–100 whilst Zn co-extraction was not noted with Mextral 84H under the alkaline conditions.

A kinetic study on solvent extraction of copper from sulfate solution with Cupromex-3302 using Lewis cell

The reactive extraction of Cu(II) from a sulfate aqueous solution using Cupromex-3302 as a new extractant was investigated using a Lewis cell to reveal the mechanism of extraction. Various affecting parameters such as stirring speed, temperature, interfacial area, extractant concentration, Cu(II) concentration and aqueous phase pH were studied. The rate of copper extraction was found to be directly proportional to the concentrations of Cu(II) and extractant and inversely proportional to the concentration of H+. The extraction rate of Cu(II) increased with an increase in specific interfacial area demonstrated that the rate determining step of Cu(II) extraction by Cupromex-3302 was reactive extraction at the interface. Also, extraction rate increased with increasing the temperature. The activation energy (E) was calculated to be 15.2kJ/mol. This value suggested that extraction of Cu(II) in this system is controlled by diffusion mechanism.

Impact of solvent extraction organics on adsorption and bioleaching of A. ferrooxidans and L. ferriphilum

Copper solvent extraction entrained and dissoluted organics (SX organics) in the raffinate during SX operation can contaminated chalcopyrite ores and influence bioleaching efficiency by raffinate recycling. The adsorption and bioleaching of A. ferrooxidans and L. ferriphilum with contaminated ores were investigated. The results showed that, A. ferrooxidans and L. ferriphilum cells could adsorb quickly on minerals, the adsorption rate on contaminated ores were 83% and 60%, respectively, larger than on uncontaminated ores. However, in the bioleaching by the two kinds of acid bacterias, contaminated ores presented a lower bioleaching efficiency.

Recovery of Copper Metal through Reprocessing of Residues from a Hydrometallurgical Plant

The Chemical of Africa (CHEMAF) is a hydrometallurgical plant operated in Katanga since 2001. It produces copper metal using a process comprising the sulphuric acid leaching of copper-cobalt oxide ores under reducing conditions (Na 2 S 2 O 5 or SO 2 ) followed by the leach liquor purification by solvent extraction (SX) and electrowinning of copper. The leach liquor is recovered during the thickening of pulps from the leaching section and the scavenging of residues by washing in the counter-current decanters (CCD). The process residues were anciently dumped near the plant. With the increase in the run of mine (ROM) ores sulphide minerals content related to changes in the Kalukuluku deposit mineralogy and considering that the storage of residues may result in toxic pollutants release to the environment, their reprocessing is gaining the ground as the best option. The present research aims at recovering copper metal from residues (2.01% Cu and 0.32% Co) through their reprocessing based on the sulphuric acid leaching prior to the recovery of copper metal through cementation with iron shavings. The results from the experiments have showed that the leaching of copper (≈ 90%) and cobalt (86%) was successful when conducted during 90 minutes at 75°C using 150 g of residues subjected to stirring (500 rpm) in 1 L of H 2 SO 4 (30 g/L) in the presence of Na 2 S 2 O 5 (330 mV). Consequently, one recovers satisfactorily copper metal (2.5 g of solids assaying 93% Cu recovered at 86%) when 1 g of iron shavings was stirred (400 rpm) during 60 minutes at constant speed and at the room temperature in 250 mL of the metalliferous solution (10.84 g/L Cu and 1.73 g/L Co) prepared by the leaching of residues.

CFD Simulation and Experimental Study of Impeller Speed and Clearance Effects in the Mixer of Copper Solvent Extraction Unit

Objectives: Impeller speed and clearance are factors that have major role in the efficiency of dynamic mixers. Investigating effective parameters are the main goal of this research. Methods/Statistical Analysis: A computational fluid dynamics simulation based on the Eulerian-Eulerian two-phase method has been applied to study the behavior of aqueous-organic dispersion in the copper solvent extraction mixer. Findings: The hydrodynamic behavior of organic phase is visualized by using an image analyzing method. The effect of impeller speed and clearance on the position of eddies and fluid hydrodynamics are investigated. According to the results, by increasing impeller speed, dead zones are decreased and at impeller speeds more than 200 rpm dead zones around the baffles are almost non-existent. Optimum clearances are determined 8.5 and 7 cm for 100 and 200 rpm, respectively. Application/Improvements: The results can be used in the industrial mixer of the solvent extraction unit for improving the efficiency of the mixing process.

CFD simulation and experimental investigation of the copper solvent extraction in a pilot plant pulsed packed column in Sarcheshmeh Copper Complex

Present work deals with the development of a computational fluid dynamics (CFD) model for investigate the extraction of copper from leach solution with the Lix84-I. The model is based on Eulerian–Eulerian two phase equations in conjunction with the realizable k-e model for turbulence. Population balance modeling (PBM) is used to describe the dynamics of the time and space variation of droplet sizes in the column. The PBM equation is solved using the class method. The mass transfer is the important parameters which can improve the performance of pulsed column and changes widely with the variation in the droplet number density. Valid empirical correlations were implemented to the CFD model for mass transfer coefficients by user defined functions. To validate the model, the results of CFD model and experimental measurements were compared and there was a good agreement between them. The effects of flow rates and intensity of pulsation on the yield of copper extraction and entrainment of the organic phase were studied. The results shown that increasing the phase ratio (the flow rate of organic phase/aqueous phase) from 0.5 to 1.75, caused yield of copper extraction from leach solution increased from 31 to 91%. The organic entrainment increased with increasing the pulse intensity and phase flow rates. Additionally, the results show that the performance of the pulsed packed column for copper extraction is reasonable.

Selective separation of copper over solder alloy from waste printed circuit boards leach solution

The printed circuit boards (PCBs) from electronic waste are important resource, since the PCBs contain precious metals such as gold, copper, tin, silver, platinum and so forth. In addition to the economic point of view, the presence of lead turns this scrap into dangerous to environment. This study was conducted as part of the development of a novel process for selective recovery of copper over tin and lead from printed circuit boards by HBF4 leaching. In previous study, Copper with solder alloy was associated, simultaneously were leached in HBF4 solution using hydrogen peroxide as an oxidant at room temperature. The objective of this study is the separation of copper from tin and lead from Fluoroborate media using CP-150 as an extractant. The influence of organic solvent’s concentration, pH, temperature and A/O phase ratio was investigated. The possible extraction mechanism and the composition of the extracted species have been determined. The separation factors for these metals using this agent are reported, while efficient methods for separation of Cu (II) from other metal ions are proposed. The treatment of leach liquor for solvent extraction of copper with CP-150 revealed that 20% CP-150 in kerosene, a 30min period of contact time, and a pH of 3 were sufficient for the extraction of Cu(II) and 99.99% copper was recovered from the leached solution.

Improved dynamic modeling and simulation of an industrial copper solvent extraction process

Existing dynamic models of the mixer–settler SX process assume that the mixing stage can be modeled as a single mixer, whereas in recently developed technology, there are two mixing chambers (a pump–mixer and a mixer). Moreover, existing dynamic models assume that the hydrodynamics of the aqueous and organic phases in the settler were the same, whereas they are not similar. In this study, the existing dynamic models are extended to more accurately represent the mixing and settling behavior. Firstly, the parameters of the pump–mixer model were estimated using CFD simulation for each mixer–settler unit. Then, the dynamic simulation was performed to test the simulator with practical parameters over a period of 30days of industrial operating data. Compared to existing dynamic models, better fitting was obtained due to the continual updating of parameters, the use of multiple mixer unit models (pump–mixer and mixer) as well as allowance for different hydrodynamics of organic and aqueous phases in the settler.

Recovery of copper(II) and chromium(III) from nitrate medium with salicylideneaniline dissolved in 1-octanol

The solvent extraction of copper(II) and chromium(III) from nitrate medium with salicylideneaniline (HL) is studied as a function of various parameters: pH, concentration of salicylideneaniline, contact time and the nature of anoin (nitrate and sulfate) in aqueous phase. Chromium(III) is not extracted by salicylideneaniline diluted in 1-octanol. Copper(II) is only extracted by salicylideneaniline and it was found that the highest extractability achieved to 95 % at pH 4.9, The stoichiometry of the extracted species was determined by using the method of slope analysis. Elemental analysis, UV–vis and IR-spectra were used to confirm the structure. It is found that the copper (II) is extracted as CuL 2 .2H 2 O Their equilibrium constant, distribution coefficient, percentage extraction ( %E ) and free energy are also calculated.

Solvent extraction and separation of copper from base metals using bifunctional ionic liquid from sulfate medium

A novel solvent extraction process for extraction and separation of copper from other base metal ions using a bifunctional ionic liquid (IL) (trioctylmethylammonium/2,4,4-trimethylpentyl phosphinate, [A336/Cy272]) in kerosene was reported. This IL was found to extract copper more efficiently than the individual extractants Aliquat 336 or Cyanex 272. Formation of an octahedral copper-IL complex was characterized by UV-Visible spectra and metal ligand interaction was confirmed by FTIR spectra. The loading capacity of 0.1 mol/L [A336/Cy272] was found to be 1.71 g/L. Stripping studies reported that 0.298 g/L copper ions were efficiently stripped using 0.1 mol/L sulfuric acid from 0.05 mol/L loaded IL. The selectivity of copper against nickel, cadmium and iron was investigated from their equimolar binary mixtures using 0.05 mol/L [A336/Cy272] in kerosene. The highest separation factor βCu/Cd=8.41 was obtained at pH 3.56. Copper can be effectively separated from nickel over the pH range studied. The IL extracts preferentially iron over copper and the highest separation factor βFe/Cu was 3246 at pH 2.4. The extraction rate of metal ions from a synthetic solution containing copper with other metal impurities was in the order of Fe>Zn>Cu>Cd>Co>Ni.

Copper solvent extraction: Status, operating practices, and challenges in the African Copperbelt

%?681+4+ Although the first large-scale application of copper recovery by solvent extraction took place in Zambia in the early 1970s, it is only in the last decade that this technology has become widely employed in this part of the world and is now a mainstay unit operation in copper hydrometallurgical flow sheets. The mineralogy of the ores of the African Copperbelt, and hence the characteristics of African leach liquors, differs significantly from those in Chile and the southwestern USA, where copper solvent extraction has had a long and successful history. These differences provide operators, metallurgists, reagent vendors, and engineers with many challenges: new approaches are needed to adapt solvent-extraction technology for successful implementation in this region. This paper examines typical operating practice in the African Copperbelt, discusses differences compared with other parts of the world, and looks at some of the challenges and opportunities presented by these flow sheets.

Solvent Extraction of Copper: An Extractive Metallurgy Exercise for Undergraduate Teaching Laboratories

A multidisciplinary experiment for advanced undergraduate students has been developed in the context of extractive metallurgy. The experiment serves as a model of an important modern industrial process that combines aspects of organic/inorganic synthesis and analysis. Students are tasked to prepare a salicylaldoxime ligand and samples of the corresponding copper and nickel complexes, before performing test extractions and UV–vis spectroscopic analysis. The oxime ligand demonstrates a clear preference for extraction of Cu2+ in the presence of Ni2+ from aqueous solution under the conditions described. It is also possible to demonstrate that the ligand can be recovered and reused. The experiment has successfully been employed in a final year project-based laboratory course involving small groups of students.

Density Functional Theory Computations for Design of Salicylaldoxime Derivatives as Selective Reagents in Solvent Extraction of Copper

We have performed density functional theory computations to study interactions of salicylaldoxime (SALO) and its derivatives possessing appropriate alkyl group substitution in the main chain (CM-SALO) or side chain (CS-SALO) with copper, zinc and lead divalent ions. The objective of this study was to understand the underlying interaction mechanisms so as to exploit this knowledge in the design and development of selective reagents for solvent extraction. All computations were performed using plane wave ultrasoft pseudopotentials and Perdew–Burke–Ernzerhof generalized gradient approximation as implemented in the Plane Wave Self consistent field code. The relative order of selectivity, as per the computed interaction energies, was found to be: Cu > Zn > Pb. CM-SALO derivatives exhibited stronger interactions as compared to the CS-SALO derivatives. Our findings were consistent with our experimental results reported earlier and were explained by highest occupied molecular orbital–lowest unoccupied molecular orbital and Lowdin charge analyses.

Diversity of Bioleaching Microorganisms in Interfacial Emulsion of Copper Solvent Extraction

In the bioleaching - solvent extraction - electrowinning practices for copper extraction, the solvent extraction process is used to enrich the copper in the leachate to a high lever to make the sequent electrowinning process possible. O/W type of interfacial emulsion always forms at the interface between organic phase and aqueous phase in the solvent extraction practices. Diversified microorganisms were discovered by microscope growing in the interface emulsion of copper solvent extraction. The diversity of them was analyzed by using 16s rRNA gene sequencing. It was indicated that there exist seven categories of bacteria in the interface emulsion, among which common bioleaching bacteria, such as Leptospirillum sp.,Acidithiobacillus ferrooxidans, Metallibacterium sp., are included. The dominant strains are Leptospirillum sp. E4-L9 and Acidithiobacillus ferrooxidans ATCC 23270, which account up to 40.48 % and 38.1 %, respectively. It was uncovered that bioleaching bacteria can be intercepted by interfacial emulsion of solvent extraction to make their population in the raffinate lower and the efficiency of bioleaching decrease consequently.

Extraction and separation of indium and copper from zinc residue leach liquor by solvent extraction

Abstract Solvent extraction and separation of indium and copper from zinc residue reductive leach liquor containing a high concentration of zinc (ca. 85 g/L) and iron (ca. 35 g/L) was studied. Di-(2-ethylhexyl) phosphoric acid (D2EHPA) and Acorga M5640 were used as extractants for indium and copper, respectively. Indium was preferentially extracted by 15%(v/v) D2EHPA with three-stage extraction using an aqueous/organic (A/O) phase ratio of 6/1. Indium was effectively stripped from the D2EHPA organic phase by 4 M HCl. Copper was subsequently extracted selectively from the indium-extracted solution using 15%(v/v) Acorga M5640 with three-stage extraction using an A/O phase ratio of 2/1. Copper in the loaded Acorga M5640 organic phase was stripped by a synthetic spent electrolyte solution containing 25 g/L Cu and 180 g/L H 2 SO 4 . Based on the experimental results, a flowsheet for the separation and recovery of indium and copper from the reductive leach solution was developed and tested. The results showed that 95.4% of indium and 95.5% of copper were extracted, and the measured separation factors β In/Zn , β In/Cu , β In/Fe , β CuZn , and β CuFe were 4979, 1975, 3719, 1719, and 2446, respectively.

Mixing performance comparison of milliscale continuous high‐shear mixers

Mixing performance of two continuous flow millilitre‐scale reactors (volumes 9.5 mL and 2.5 mL) equipped with rotor‐stator mixers was studied. Cumulative residence time distributions (RTD) were determined experimentally using a step response method. Distributions were measured for both reactors by varying impeller speed and feed flow rate. The mixing effect was determined by measured RTDs. Computational fluid dynamics (CFD) were used to verify that the residence time distribution in the measurement outlet agreed with the outlet flow. The mixing power of both reactors was determined using a calorimetric method. The reactor inlet flow rate was found to affect mixing performance at 1–13 s residence times but the effect of impeller speed could not be noted. Both milliscale reactors are close to an ideal continuous stirred‐tank reactor (CSTR) at the studied impeller speed and flow rate ranges. The specific interfacial area was found to depend on the reactor inlet flow rate at constant impeller speed for the case of copper solvent extraction.