Kinetics Of Copper Extraction Research Articles

Kinetic modelling of chalcopyrite leaching assisted by iodine in ferric sulfate media

Chalcopyrite leaching at moderate temperature exhibits slow kinetics due to surface passivation. The presence of iodine has been reported to significantly enhance copper dissolution from chalcopyrite in ferric sulfate media at ambient temperature. However, the key factors controlling the reaction rate and the mechanisms have not been well understood. This study quantified the effect of different parameters on the kinetics of copper extraction in the presence of iodine and elucidated the possible rate-limiting steps. A series of leaching tests was carried out in PTFE (polytetrafluoroethylene) bottles with high chemical resistance to investigate the effect of solution potential (673–769 mV vs SHE), total iodide concentration (50–200 mg/L), particle size (53–90 μm), and temperature (25–45 °C) on chalcopyrite concentrate leaching. PTFE bottles were used to prevent iodine loss via evaporation and iodine corrosion of the experimental apparatus. The experimental results show that redox potential was the principal factor determining the leaching performance via controlling the aqueous iodine speciation. In the potential range where triiodide or diiodine dominates, the copper extraction increased with increasing potential, increasing total iodide concentration, and increasing temperature. Particle size did not affect the kinetics, possibly resulting from the narrow size ranged used. A preliminary kinetic model shows that the reaction orders with respect to Fe(III)/Fe(II) concentration ratio and the total iodide concentration were 0.36 and 0.91, respectively. The activation energy (47 kJ/mol) was significantly lower than those reported for the conventional chalcopyrite leaching in ferric sulfate media, suggesting that the presence of iodine changed the reaction mechanism. Further investigation is required to uncover the exact role of different iodine species in the leaching process.

Kinetic models for the extraction of copper by Acorga M5640 after leaching of malachite ore in perchloric acid solutions and the stripping of copper from loaded organic phase

In the present work, the extraction kinetics of copper using the resulting actual leach solution obtained from the leaching of malachite ore in perchloric acid solutions and the stripping kinetics of copper from the loaded organic phase were examined. The organic phase was prepared by using Acorga M5640 and kerosene. In the extraction process, the effects of the initial pH of aqueous solution, initial concentration of copper, extractant concentration, temperature, and stirring speed on the extraction rate were investigated. In the stripping process, the effects of the concentration of perchloric acid, temperature, stirring speed, and extractant concentration on the stripping rate were examined. It was determined that the extraction rate increased with increasing the initial pH of aqueous solution, stirring speed, extractant concentration and temperature, and with decreasing the initial concentration of copper ions. In the stripping process, it was observed that the stripping rate increased with increasing the concentration of perchloric acid, temperature and stirring speed, and with decreasing the extractant concentration. It was determined that both the solvent extraction and stripping processes could be described by the first order pseudo homogenous reaction model. The activation energy for the extraction and stripping processes was calculated to be 50.04 kJ/mol and 32.42 kJ/mol, respectively.

Kinetics of copper extraction from copper smelting slag by pressure oxidative leaching with sulfuric acid

The accumulation of copper smelting slag not only pollutes the environment but also wastes resources, using oxygen pressure acid leaching process to treat copper slag has incomparable advantages over other processes, but there are few researches reported at home and abroad. In this paper, copper slag was treated by this process. Under the premise of fully studying the influence of various factors on copper dissolution, the selective leaching behavior and kinetics of copper oxy-pressure acid system in copper slag were expounded. The experimental results showed that the dissolution kinetics analysis of the experimental data based on the shrinking core model for various conditions indicated that the reaction rate of leaching was mainly controlled by the chemical reaction during its early stages, then switched to be controlled by mixed chemical-reaction and product-layer diffusion which could be ignored because of its short lifetime, and finally was controlled solely by diffusion through a surface product layer in the later stage. The activation energy was calculated to be 47.03 kJ·mol/L in the early surface chemical reaction controlling stage and 11.35 kJ·mol/L in the later diffusion controlling stage, respectively. The leaching rate of copper is mainly determined by the chemical reaction control stage, in which the reaction orders of sulfuric acid concentration, oxygen partial pressure and particle size are 0.83, 0.92 and −1, respectively.

A Kinetic Study of Copper(II) Extraction using LIX84-I Impregnated Polymeric Particles with Different Structures

Polymeric particles impregnated with LIX84-I having different structures, such as large interconnected -spherical pores (PDVB), small pores (XAD-4) and multi cores (PVA/NaAlg-GA crosslinked gel), were used for copper(II) extraction from an aqueous phase. The extraction kinetics of copper(II) from the aqueous solution into three different types of polymeric particles was influenced by the amount of LIX84-I impregnated in the polymeric particles and also their structures. The amount of copper(II) adsorbed into all types of the polymeric particles increased with time and reached a plateau after a longer contact time. The extraction mechanism of copper(II) into all types of polymeric particles impregnated with LIX84-I was found to obey Pseudo-second order kinetics. It is suggested that complex-formation and mass-transfer diffusion is the predominant rate-determining step in the copper(II) extraction process from aqueous solution into the polymeric particles.

Separation and recovery of copper from zinc leach liquor by solvent extraction using Acorga M5640

The present study deals with the separation of copper from zinc leach liquor obtained by acidic ferric sulphate leaching of an industrial sphalerite concentrate. The leach liquor was subjected to copper extraction using Acorga M5640 and its formulation was also tried to be modified with isotridecanol to enhance the overall process. The effect of pH and presence of isotridecanol on the separation of copper was examined. Also, the effect of this modifier on the equilibrium and kinetics of copper extraction was investigated. The co-extraction of iron was not found very significant and less than 10 mg/L was attained in the loaded 10% (v/v) Acorga M5640 at pH 1.35. The presence of alcohol did not boost the net copper transfer significantly, despite the rejection over iron was slightly favoured. The kinetics of copper extraction from zinc leach liquor using Acorga M5640 was very fast, even in the presence of 2.5% (v/v) isotridecanol.

Selective removal of Cu 2+ versus Ni 2+, Zn 2+ and Mn 2+ by using a new carrier in a supported liquid membrane

A study on transport, kinetic selectivity and stability in SLM operations using a new carrier, the molecule 2-hydroxy-5-dodecylbenzaldehyde (2H5DBA) in kerosene, is described. A simple transport model is derived to evaluate the mass transfer coefficient in the membrane. Finally a comparison with the di-(2-ethylhexyl) phosphoric acid (D2EHPA) carrier in kerosene is made. The SLM system was employed and tested in the removal of Cu 2+ from wastewater by using the operating conditions obtained from L–L extraction tests. Studies on the kinetics of copper extraction by using the 2H5DBA showed that complexation reaction is very fast. Transport tests were performed at different carrier concentrations (10%, 30%, 50% (v/v)) showing the improvement of SLM performance with increasing its concentration. Operating the SLM at optimum conditions (50% (v/v) 2H5DBA concentration in kerosene, feed pH 5, strip pH 2.2) final copper concentrations in the feed and strip phases were, respectively, 2.0 and 47.0 mg L −1, starting from 50 mg L −1 in the feed, meaning a significant up-hill transport. The fluxes (J) were calculated by fitting the experimental data of copper concentration in the feed by an exponential equation. They were used to calculate the transport (kinetic) selectivities of Cu 2+ SLM separation over Ni 2+, Zn 2+ and Mn 2+, given by the ratio J 0(Cu)/ J 0(M), where M = Ni, Zn and Mn. The values were 37.4, 48.2 and 42.1, respectively. Transport and stability tests at the optimal carrier concentration by using the 2H5DBA and the D2EHPA in kerosene were carried out to compare them in terms of flux, lifetime and mass transfer coefficients. Experimental data evidenced for 2H5DBA a lower copper flux (8.67 mmol h −1 m −2 versus 36.71 mmol h −1 m −2), a lower lifetime (20 h versus 57 h) and lower mass transfer coefficient in the membrane (3.00 × 10 −7 m s −1 versus 2.00 × 10 −6 m s −1) but the selectivity of the separation process can overcome the disadvantages.

Interfacial behavior of ACORGA CLX-50 and surface kinetics of copper extraction

Interfacial tension isotherms were determined and interpreted for ACORGA CLX-50. The hydration of extractant molecules in aqueous solution and at hydrocarbon/water interfaces was studied by molecular modelling. The usefulness of this technique to interpret the adsorption behavior was demonstrated. The interfacial kinetics was considered and relationships for various models of interfacial mechanism were derived and discussed. Despite its high hydrophobicity, ACORGA CLX 50 strongly adsorbs at the hydrocarbon/water interfaces and thus decreases effectively the interfacial tension. This high interfacial activity of ACORGA CLX 50 can be explained by the formation of hydrates. The interfacial tension isotherm can be well matched with the Szyszkowski equation. Molecular modelling suggests that ACORGA CLX 50 adsorbs at the hydrocarbon/water interface probably as a tetrahydrate containing two water molecules bonded to the same carbonyl oxygen atom (e.g., at position 3), one water molecule bonded to the oxygen atom of the second alkoxyl group (i.e., at position 5 when the hydration of carbonyl oxygen at position 3 is previously considered) and, finally, one water molecule bonded with the pyridine nitrogen atom. Positions 3 and 5 are equivalent. It is also shown that when the extraction of copper takes place in the kinetic regime, the reaction order with respect to ACORGA CLX 50 can change depending on the limiting step and the range of extractant concentration considered. Thus, a decrease of the extractant concentration from 10−5M to 3·10−3M causes a fall of the order with respect to ACORGA CLX 50 from 1 to 0 and 2 to 1 when the formation of the intermediate 1∶1 and final 2∶1 complexes are considered to be the limiting step, respectively.

STRUCTURE and PROPERTIES of ALKANAL OXIMES as COPPER EZTRACTANTS

ABSTRACT Composition, structure and interfacial activity of alkanal oximes and kinetics of copper extraction from chloride solutions are discussed. Semiempirical self-consistent field calculations are used to study the structure of alkanal oximes and their mono- and dihydrates. These calculations are in a qualitative agreement with the ratio of alkanal (Z)-and (E)-isomers, interfacial activity and kinetics data.

Extraction kinetics of copper, zinc, iron, and manganese from contaminated sediment using Disodium Ethylenediaminetetraacetate

One technique for cleansing heavy metal contaminated soils is to wash the excavated soil with an extraction solution of a chelating agent. The rate of extraction is an important parameter when considering the length of time needed for soil clean-up and the amount and concentration of wash solution required. The extraction kinetics of copper, zinc, iron and manganese from a contaminated sediment of the Clark Fork River in western Montana, U.S.A., with Disodiun Ethylenediaminetetraacetate (Na2EDTA) as the extraction agent, were investigated. The results showed the extraction process consisted of rapid extraction in the first minutes followed by much slower extraction for the remainder of the experiment. The rate of extraction, particularly in the rapid phase, demonstrated clear pH dependence: the lower the pH, the faster the extraction rate. In the EDTA concentration range of 0.01 M to 0.05 M, the effect of the EDTA concentration on the extraction rate was not important compared with that of the solution pH. Extraction kinetics for different size particles were similar, although in the first few minutes, EDTA extracted more metals from clay and silt than sand. The two reaction, diffusion, and two-constant kinetic models were compared to experimental results. The two reaction model did not fit any of the data well, and only iron extraction could be described with a simple diffusion model. In general the extraction rates can be well described by the two-constant model, C=A t B, up to 600 minutes and under different conditions such as solution pH, EDTA concentration, and different sediment particle size.

Equilibrium and kinetics of copper extraction from acidic sulfate solutions with isomeric 1-(2′-hydroxy-5′-alkyl-phenyl)-1-alkanone (E)-oximes

Equilibrium and kinetic data were determined for copper extraction by individual 1-(2′-hydroxy-5′-nonylphenyl)-1-ethanone (E)-oxime and 1-(2′-hydroxy-5′-methylphenyl)-1-decanone (E)-oxime having different locations of the nonyl group. Solubility in water, partition of oximes between water and toluene and the interfacial tension isotherms were also determined and used to interpret kinetic data and to discuss the mechanism of copper extraction. 1-(2-hydroxy-5′-nonylphenyl)-1-ethanone (E)-oxime extracts the same amount of copper and at the same pH range as 1-(2′-hydroxy-5′-methylphenyl)-1-decanone (E)-oxime. The extraction rate is much faster for copper extraction with 1-(2′-hydroxy-5′-nonylphenyl)-1-ethanone (E)-oxime. This can be qualitatively explained by its higher solubility in aqueous solutions or by its better adsorption and orientation at the interfaces as the bulk volume process or the interfacial process are considered.

Effect of anionic surfactant on copper extraction with E-2-hydroxy-5-nonyl-benzophenoneoxime.

The effect of the anionic surfactant sodium dioleylsulfosuccinate on the extraction rate of copper with E-2-hydroxy-5-nonylbenzophenoneoxime in n-heptane was studied.The extraction rate of copper was remarkably enhanced by the addition of the anionic surfactant under appropriate conditions and it was found that the electrostatic interaction between copper and the anionic surfactant and the binding between the extractant and surfactant in the interfacial zone played an important role in the extraction kinetics of copper with the extractant.An extraction mechanism of copper with E-2-hydroxy-5-nonylbenzophenoneoxime in the presence of the surfactant was proposed.

Catalytic effect of bisoleylphosphoric acid on copper extraction with N-8-quinolylsulfonamide.

The extraction kinetics of copper with N-8-quinolyl-p-hexylbenzenesulfonamide was studied in the presence of acidic and neutral organophosphorus compounds using a hollow-fiber membrane extractor. It was found that in the presence of bisoleylphosphoric acid the permeation rate of copper through the membrane is significantly accelerated, while in the presence of the other organophosphorus compounds, i.e., bis-2-ethylhexylphosphoric acid, 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester and trioleylphosphate, the permeation rate was not enhanced except at high concentration of the additive agents. From the kinetic data, the catalytic mechanism of the copper extraction was inferred.

Study of the Kinetics of Copper Extraction with (anti)-2-Hydroxy-5-nonylbenzophenone Oxime Using a Rotating Diffusion Cell

Abstract A rotating diffusion cell was used to study the chemical reaction in which copper is transferred from an aqueous sulfate phase to an organic phase containing a copper-complexing agent (purified anti-2-hydroxy-5-nonylbenzo-phenone oxime) dissolved in n-decane. A mathematical model was developed to describe the contributions of the kinetic and diffusive resistances to the overall resistance to mass transfer. Application of this model to the experimental data enabled an overall rate equation for the reversible copper extraction reaction to be written. The active oxime species in the extraction reaction was found to be the monomer with first-order kinetics. The extraction reaction rate was also found to be dependent on aqueous phase hydrogen ion concentration with negative first-order kinetics. The extraction rate constant was determined as 1.3 × 10−5 cm/s. Assumption that the reverse rate is dependent on hydrogen ion concentration with first-order kinetics enabled the reverse rate constant to be cal...

Kinetics of copper extraction using (anti)-2-hydroxy-5-nonylbenzophenone oxime

La reaction est du 1er ordre par rapport a Cu 2+ , du 1er ordre par rapport a l'isomere actif de l'oxime et de 1er ordre negatif par rapport a [H + ]. Constantes de vitesse

Extraction kinetics of copper with liquid surfactant membranes containing LIX65N and nonionic surfactant.

Using a newly synthesized surfactant, a kinetic study of copper extraction by liquid surfactant membranes containing anti-2-hydroxy-5-nonylbenzophenone oxime was carried out in a stirred tank, along with studies of the extraction equilibrium of copper with the extractant organic solution containing the surfactant and adsorption equilibrium of the surfactant between the organic and aqueous solutions at 303 K.The extraction rate by liquid surfactant membranes was analyzed by an interfacial reaction model between the carrier adjacent to the interface and the 1:1 copper chelate complex adsorbed at the interface. Furthermore, the change of extent of copper extracted with time was simulated by use of the constants of adsorption equilibrium and the interfacial reaction rate obtained from the analysis.

Extraction kinetics of copper with 2-ethylhexyl-phosphonic acid mono-2-ethylhexyl ester.

Extraction and stripping of copper with 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester dissolved in n-heptane were carried out at 303 K in both a stirred transfer cell and a membrane extractor using a hollow fiber, along with a study of the interfacial adsorption equilibria of extractant and copper complex between aqueous and organic solutions. These results obtained by use of both the stirred transfer cell and the membrane extractor were explained by a diffusion model with interfacial reaction.

Copper(II) extraction by alkyl- and alkenyl-substituted 8-quinolinols

The equilibrium and kinetics of copper extraction from water solutions of copper(II) perchlorate into chloroform by 8-quinolinol, 2-methyl-8-quinolinol, six 7-alkenyl-8-quinolinols (with C3 to C12 side chains) and by 7-(p-tert.butylbenzyl)-8-quinolinol were measured. The data were treated by previously derived models which take into account the complex nature of the extraction process. The equilibrium data were expressed as extraction constants Kex, the rate data as the rate parameter Θ and initial extraction rates J0, respectively. The influence of the position, size and structure of the substituents on these parameters is discussed. A strong effect of the position of the double bond C=C in the side chain was found.

KINETICS OF COPPER EXTRACTION WITH KELEX 100 USING A HOLLOW FIBER MEMBRANE EXTRACTOR

Abstract ABSTRACT The kinetics of copper extraction with Kelex 100 and stripping of copper chelate complex with sulfuric acid were examined in a tubular extractor consisting of a hollow fiber, along with the measurements of the distribution equilibria of Kelex 100 and cupric ion. The experimental results of the extraction and the stripping were analyzed by a diffusion model with interfacial reaction of which the rate determining step is the interfacial reaction between the adsorbed Kelex 100 (HR) and the adsorbed complex (CuR+).

Effect of hydrophobicity of extractant on extraction kinetics of copper with N-8-quinolylsulfonamide.

Using four kinds of alkylbenzene-substituted N-8-quinolylsulfonamides of different alkyl-chain length and their copper chelate complexes, kinetic studies concerning the extraction of copper with extractant and the stripping of copper with sulfuric acid were carried out in a membrane extractor using a hollow fiber. It was found that the interfacial reaction between the adsorbed copper complex (CuR+ad) and the adsorbed extractant (HRad) is a rate-controlling step among the interfacial reaction steps of the extraction and stripping processes, regardless of the alkyl-chain length of the extractants, and that the reaction rate constant of the ratecontrolling step is proportional to the equilibrium constant of this reaction for each of the four kinds of extractants. The validity of a diffusion model with the interfacial reaction was confirmed by agreement of the observed extents of copper extracted and stripped with those calculated over a wide range of experimental conditions.

Kinetics of copper extraction by benzoylacetone.

The aim of the present work is to elucidate the extraction mechanism of metals by chelating agents. We selected the benzoylacetone-copper system as a typical one, in which the reaction of the complex formation is very rapid due to the Jahn-Teller effect and the chelating agent has relatively large solubility in water. Therefore, the contribution of the aqueousphase reaction to metal extraction seems to be stronger in this system than in other systems involving slower complexation reaction with less watersoluble chelating agents. It will be shown that the interfacial reaction process plays an important role in metal extraction even in this case.