SOLVENT EXTRACTION OF LEAD BY TRILAURYLAMMONIUM CHLORIDE DISSOLVED IN TOLUENE FROM DIFFERENT CHLORIDE MEDIA

The extraction of Pb(II) from chloride solutions by trilaurylammonium chloride (TLAHC1) dissolved in toluene has been studied by metal distribution measurements. The work has been performed at three different aqueous chloride concentrations (1.0, 2.0 and 3.0 mol.dm^?3NaCl). The treatment of the experimental data at each chloride concentration agrees with the stoichiometry of the extracted metal species in the organic phase while the values of their equilibrium constants are different for the various chloride concentrations. The extraction process is explained by the following extraction reactions

The corresponding logarithmic values of K₂and K₅at the different chloride concentrations, I, are: K₂K₅, I; 4.62, 8,51, 1.0; 4.54, 8.38, 2.0; 4.48, 8.32, 3.0. The values obtained have been correlated by using the Specific Interaction Theory (S.I.T.) and the interaction coefficient for the Pb²⁺,Cl^?ions as well as the thermodynamic constants, Kn⁰, have been determined.     

KINETICS OF PHENOL EXTRACTION FROM AQUEOUS PHASE BY SULFURIC ACID SALTS OF TRIOCTYLAMINE

The kinetics of the extraction of phenol from the aqueous phase by sulfuric acid salts of trioctylamine (TOA salts) in kerosene and the stripping of phenol from the organic phase by sodium hydroxide solution were studied using a constant interfacial area cell. Measurements of the extraction and stripping rates were made by measuring the time-dependent phenol concentrations in the aqueous phase. It is found that the extraction rate of phenol is strongly dependent on the initial concentration of phenol in the aqueous phase and on the initial concentration of TOA salts in the organic solvent. However, the effect of the total sulfate concentration and the acidic concentration on the extraction rate are not significant. The stripping rate is only a function of the initial concentration of phenol in the TOA salt-organic phase. By analyzing the experimental data, it was recognized that the extraction of phenol occurs at the interface, rather than in the bulk of the solution. The diffusion resistance, rather than the resistance of chemical reaction, is the rate-controlling step for the phenol extraction. Based on the experimental data, simple expressions of the extraction rate and stripping rate of phenol were obtained.     

KINETICS OF SUPERCRITICAL FLUID EXTRACTION OF ETHANOL FROM AQUEOUS SOLUTION

A 1.3 dm³ high-pressure vessel was used to extract ethanol from aqueous solution of 10 wt% using supercritical carbon dioxide as a solvent. Experiments were carried out in a semibatch mode. A mathematical model based on the two-film theory was derived for estimating the over all mass transfer coefficient. The effects of operating variables, including pressure, CO₂ superficial velocity, and agitation rate, on the mass transfer coefficient were investigated. In general, the mass transfer coefficient increased with increasing pressure, CO₂ superficial velocity, and agitation rate. The concentration of ethanol recovered in the collector after 180 minutes reached 50 wt%, starting with a feed of 10 wt% ethanol.     

EXTRACTION OF COPPER FROM ACID CHLORIDE SOLUTIONS BY N-ALKYL-AND N,N-DIALKYL-3-PYRIDINECARBOXAMIDES

ABSTRACT

Model individual N-alkyl-3-pyridinecarboxamidee and N,N-di-alkyl-3-pyridinecarboxamides were synthesized and used for copper(II) extraction from chloride solutions. The stoichiometry of its reaction with copper(II) in chloride media was determined. N-alkyl-3-pyridinecarboxamides are stronger extractanta than N,N-dialkyl-3-pyridinecarboxamides but N-alkyl-3-pyridinecarboxamides and their complexes are slightly dissolved in the hydrocarbon diluents.     

酸性氯化物水溶液电积铜的反应机理研究

采用多种电化学研究方法探讨了酸性氯化物水溶液中Cu（Ⅰ）和Cu（Ⅱ）离子在铜电极上阴极还原的电极反应机理和电极过程动力规律。研究表明，酸性氯化物水溶液中Cu（Ⅰ）和Cu（Ⅱ）离子在铜电极上阴极还原的电极过程都表现为扩散传质步骤控制的可逆电极过程动力学规律。Cu（Ⅰ）离子主要以CuCl^2-3络离子形式存在时的电极反应机理为：CuCl^2-3＝CuCl^-2 Cl- CuCl^-2 e→Cu 2Cl^-Cu(Ⅱ)离子主要以C uCl^2-4络离子形式存在时的电极反应机理为：CuCl^2-4 Cu 2Cl^-=2 CuCl62-3 2 CuCl^2-3=2CuCl^-2 2C k^- 2CuCl^-2 2e→2Cu 4Cl^-。     

EXTRACTION KINETICS OF ZINC BY TRILAURYLAMM0NIUM CHLORIDE AT DIFFERENT CHLORIDE CONCENTRATIONS

The rate of the extraction of zinc by trilaurylammonium chloride (TLAHC1) dissolved in toluene was investigated at different aqueous chloride concentrations, using lithium chloride as bulk electrolyte, ranging from 0.5 mol.dm -3 to 2.0 mol dm -3. The experiments were performed using a modified Lewis cell at 25?°C. The rate of metal extraction was found to increase by increasing the aqueous chloride concentration. The data treatment indicated that ZnCl₂ and ZnCl₄ ^2- are both kinetically active species. The addition reaction with ZnCl₂ is favoured at low chloride concentration while the anion exchange of ZnCl₄ ^2- prevails at high chloride concentration. The addition reaction was explained in terms or interfacial reaction steps. The anion exchange reaction, due to its fast nature, seems to be controlled by diffusion.     

SOLVENT EXTRACTION OF COPPER(II) FROM CHLORIDE SOLUTIONS BY SOME PYRIDINE CARBOXYLATE ESTERS

n-octyl-3-pyridine carboxylate (NOPC), an analogue of the commercial reagent DS5443, was synthesized, and the stoichiometry of its reaction with copper(II) in chloride media was determined. At low metal loadings, copper(II) was extracted by the solvation reaction:

The factors affecting the separation of iron and copper from solutions containing copper(II),iron(II), and zinc(II)chlorides were determined in countercurrent extraction tests using DS5443.     

SOLVENT EXTRACTION OF ZINC FROM CHLORIDE MEDIA WITH SECONDARY LONG-CHAIN ALKYLAMINE

In the solvent extraction of zinc from chloride media with a secondary long-chain alkylamine, Amberlite LA-2, aggregations of ammonium chloride salt of alkylamine and zinc-complex with alkylamine and distribution equilibrium of zinc were investigated at 30 "C using n-hexane as a diluent. The ammonium chloride salt of alkylamine exists as monomeric, dimeric, trimeric and tetrameric species (BHCl, (BHCl)₂, (BHCl)₃ and (BHCl)₄, respectively). The zinc-complex exists as monomeric and dimeric species ((BH)₂ZnCl₄ and ((BH)₂ZnCl₄)₂, respectively). Zinc is extracted according to the extraction reaction in the lower loading region of zinc to alkylamine and according to the extraction reaction in the higher loading region.     

EXTRACTION OF COPPER(II) FROM ACID CHLORIDE SOLUTIONS BY N-DODECYL- AND N.N-DIHEXYLPYRIDINECARBOXAMIDES

ABSTRACT

N-dodecyl- and N,N-dihexylpyridinecarboxamides with amide group at 2, 3 or 4 position were synthesized. Model individual amides were used to recover copper(II) from chloride solutions at constant water activity and constant total concentration of dissolved species in aqueous solution. It was found, that pyridine-2-carboxamide forms with copper complexes (CuCl₂)_x (Ext)₂. Remaining amides form with copper complexes CuCl₂(Ext)₂. Monoalkylamides are not suitable for extraction because they and their complexes are slightly soluble in the hydrocarbon diluents. N,N-dialkylpyridinecarboxamides and their copper complexes are sufficiently soluble in the hydrocarbon phase to carry out extraction. However, they are strong extractants and extract efficiently copper already from dilute chloride solutions ([Cl] = 0.1 M). They extract also significant amounts of copper from concentrated (3-4M) nitrate solutions.     

CORROSION INHIBITION OF CARBON STEEL IN LOW CHLORIDE MEDIA BY AN AQUEOUS EXTRACT OF HIBISCUS ROSA-SINENSIS LINN

The inhibition efficiency (IE) of an aqueous extract of white flower, namely, Hibiscus rosa-sinensis Linn., in controlling corrosion of carbon steel immersed in an aqueous solution containing 60 ppm of Cl^-has been evaluated by the mass loss method. The flower extract (FE) shows good IE. In the presence of Zn²⁺, excellent IE is shown by the flower extract. A synergistic effect exists between the flower extract and Zn²⁺. The mechanistic aspects of corrosion inhibition have been investigated by polarization study and AC impedance spectra. Polarization study reveals that the formulation consisting of flower extract and Zn²⁺ functions as a mixed inhibitor. AC impedance spectra reveal that a protective film is formed on the metal surface. The active principle in the flower extract is quercetin-3-O-glucoside. This has been confirmed by UV-visible absorption spectra. The protective film formed on the metal surface has been analyzed by FT-IR and AFM spectra. It is found that the protective film consists of Fe²⁺-quercetin-3-O-glucoside complex and Zn(OH)₂.     

PHOTO-DEGRADATION OF HYDROPHOBIC DERIVATIVES OF PYRIDINECARBOXYLIC ACID AS COPPER EXTRACTANTS FROM CHLORIDE MEDIA

ABSTRACT

The photo-stability of 2-ethylhexyl pyridine-3-carboxylate and N,N′-di(2-ethylhexyl)pyridine-3,5-dicarboxamide as the model extractants of copper from chloride media were studied and compared with the photo-stability of di(2-ethylhexyl) pyridine-3,5-dicarboxylate, N,N,N′,N′-tetrahexylpyridine-3,5-dicarboxamide and the hydroxyoxime copper extractants. Also the resistance against the UV light the copper(II) complexes of tested extractants were done. The obtained results of photo-degradation indicate that the UV light degraded amide derivatives and esters of pyridine-3,5-dicarboxylic acid and pyridine-3-carboxylic acid. A comparison of the photo-stability of oximes and derivatives of pyridine-3,5-dicarboxylic acid and pyridine-3-carboxylic acid indicates that all tested derivatives of pyridinecarboxylic acid are more stable than hydroxyoxime copper extractants. The copper complexes of derivatives of pyridinecarboxylic acid are less stable than the copper complexes of hydroxyoxime.     

液膜法从海水中提取溴的动力学研究

本文报导了利用液膜技术从海水中提取溴的动力学的部分研究工作，在不同组分的液膜、不同组分的内相条件下，分别测定了对溴分离，浓缩的反应速率常数，并给出了该反应的简化传质速率方程。     

COPPER EXTRACTION FROM CHLORIDE SOLUTIONS WITH MIXTURES OF SOLVATING AND CHELATING REAGENTS

ABSTRACT

Equimolar mixtures of N,N,N',N'-tetrahexylpyridine-3,5-dicarboxamide (L) with 2-hydroxy-5-t-octylbenzophenone oxime or l-phenyldecane-l,3-dione (HB), were used to extract copper from chloride solutions of various concentration of chloride ions. Chloride ions were then scrubbed out with water or ammoniacal solutions and copper was transferred from the solvate CUCl₂L₂ to chelate CuB₂- Both studied systems permit effective extraction of copper and removal of chloride ions from the organic phase. Some protonation of solvating reagent L occurs, however, when copper is stripped from the chelate with hydroxyoxime. This negative effect can be suppressed when 1-phenyl decane-1,3-dione is used as a chelating agent. The scrubbing of chloride ions must be then carried out with ammoniacal solutions to avoid simultaneous stripping of copper.     

NONDISPERSIVE LIQUID-LIQUID EXTRACTION OF COPPER AND ZINC FROM AN AQUEOUS SOLUTION BY DEHPA AND LIX 984 IN A HOLLOW FIBER MEMBRANE MODULE

ABSTRACT

A liquid-liquid extraction procedure was used to study the amounts of Zn²⁺ and Cu²⁺ that could be simultaneously extracted from aqueous solution with di(2-ethylhexyl) phosphoric acid (DEHPA) and LIX 984 diluted with n-heptane at equilibrium. LIX 984 is a 1:1 volume blend of LIX 860 (5-dodoecylsalicylaldoxime) and LIX 84 (2-hydroxy-5-nonylacetophenone oxime). At equilibrium, a 0.3 mol/L DEHPA-20% (v/v) LIX 984 solution extracted 99% of both the zinc and copper from a solution that had 100 ppm of each metal.

A polysulfone hollow-fiber membrane module with 1 mm ID and 5,000-molecular weight cutoff was used to study the amounts of Zn²⁺ and Cu²⁺ that could be simultaneously extracted with a mixture of DEHPA and LIX 984. The aqueous and organic streams were operated at 100% recycle. With a 0.6 mol/L DEHPA-10% (v/v) LIX 984 solution, a 90.5 ± 1.7% (s.d.) extraction of zinc and a 93.70 ± 0.79% (s.d.) extraction of copper was obtained after 180 min.     

EXTRACTION OF GOLD fill) FROM HYDROCHLORIC ACID SOLUTIONS BY TRI-ISOBUTYL PHOSPHINE SULFIDE IN TOLUENE.

The extractant th-isobutyl phosphine sulfide (TIBPS ), Cyanex 471, in toluene has been investigated for the extraction of Au (III) from aqueous HCI solutions. Analysis of the equilibrium data shows that the extraction proceeds via a solvating type mechanism by the formation of the species AuCI3.FI and AuCl₃.2R, for which formation constants are log 677 β= 34.84 and log β= 42.04 respectively (R =TIBPS).     

THE EXTRACTION OF RHODIUM FROM AQUEOUS HITRIC ACID BY ORGANOPHOSPHINE SULPHIDES

The organophosphine sulphides, tri-phenyl phosphine sulphide (TPPS), tri-n-butyl phosphine sulphide (TBPS) and N,N',N"-tri-n-hexyl phosphorothioic-triamide (THPS) have been investigated for their potential use as extractants for the recovery of fission product rhodium from aqueous nitric acid solutions. The ease with which the extractions proceed can be rationalised in terms of the polarisability of the P=S bond, and in the case of THPS, the extraction is shown to proceed via a solvating type mechanism. Equilibration times for the extraction are of the order of 3-6 hours.     

氯化铁预浸铜金精矿选择性提铜

本工作试验了用氯化铁浸出法预提取回收铜全精矿中的铜，使之适于氰化提取其中的金研究了各种主要浸出参数并加以优化试验证明该浸出法可有效而选择性地提取精矿中的铜，在优化的条件下铜的提取几近完全、而不包裹金的黄铁矿未受触动     

THE EXTRACTION OF RHODIUM FROM AQUEOUS NITRIC ACID BY DINONYLNAPHTHALENE SULPHONIC ACID

The extraction of rhodium from aqueous nitric acid using dinonylnapthalene sulphonic acid has been investigated. The extraction occurs readily from 0.1M to 1.0m nitric acid and, since the rhodium is extracted as [Rh(H₂O)₆] ³⁺into the inverted micelles of the organic solution,equilibration times are less than 5 minutes. Extraction is enhanced by the addition of nitrite ion to form [Rh(H₂O)₅NO₂] ²⁺as the extracted species.