Separation of zinc and nickel ions in a strong acid through liquid-liquid extraction

Many solid wastes contain both zinc and nickel at the same time. For recycling or recovery of metals, it is essential to separate materials. Among those materials, zinc and nickel are very difficult to be separated because there is not so much difference in the chemical and physical properties. This paper focuses on the separation of zinc and nickel ions in a diluted aqua regia solution. Liquid-liquid extraction by TBP, Cyanex 272 and Cyanex 301 was used and a distribution coefficient (D), a separation factor (S) and a relative purity (R) were induced to evaluate the degree of separation. All of the extractions were proportional to the concentration of the extractants, and zinc ions were extracted more easily than nickel ions. Among the extractants, Cyanex 301 showed the best characteristics regarding Zn/Ni separation. In particular, the extraction of zinc ions in the range of pH相似文献   

Processing of rayon waste effluent for the recovery of zinc and separation of calcium using thiophosphinic extractant

Zinc is used in various metallurgical, chemical and textile industries. In textile industries, waste effluent containing zinc is generated during the manufacture of rayon yarn. Due to the strict environmental regulations and the presence of toxic metallic and other constituents, the discharge of effluents in sewage is restricted. In view of above a process has been developed for the recovery of zinc from rayon waste effluent following solvent extraction technique using thiophosphinic extractants Cyanex 272 and 302. Before recycling of zinc sulphate solution in spinning bath, solution must be free from calcium, which is deleterious to the process as gypsum precipitates and forms scale. The extractant Cyanex 302 has been found selective for the recovery of 99.99% of zinc in the form of [R(2)Zn](org) from the effluent above equilibrium pH 3.4 maintaining the O/A ratio of 1/30 leaving all the calcium in the raffinate. The zinc from the loaded Cyanex 302 can be stripped with 10% sulphuric acid at even O/A ratio of 10. The stripped solution thus obtained could be recycled in the spinning bath of the rayon plant and raffinate could be disposed safely without affecting environment.     

Selective extraction of zinc(II) over iron(II) from spent hydrochloric acid pickling effluents by liquid-liquid extraction

The selective removal of zinc(II) over iron(II) by liquid–liquid extraction from spent hydrochloric acid pickling effluents produced by the zinc hot-dip galvanizing industry was studied at room temperature. Two distinct effluents were investigated: effluent 1 containing 70.2 g/L of Zn, 92.2 g/L of Fe and pH 0.6, and effluent 2 containing 33.9 g/L of Zn, 203.9 g/L of Fe and 2 M HCl. The following extractants were compared: TBP (tri-n-butyl phosphate), Cyanex 272 [bis(2,4,4-trimethylpentyl)phosphinic acid], Cyanex 301 [bis(2,4,4-trimethylpentyl) dithiophosphinic acid] and Cyanex 302 [bis(2,4,4-trimethylpentyl) monothiophosphinic acid]. The best separation results were obtained for extractants TBP and Cyanex 301. Around 92.5% of zinc and 11.2% of iron were extracted from effluent 1 in one single contact using 100% (v/v) of TBP. With Cyanex 301, around 80–95% of zinc and less than 10% of iron were extracted from effluent 2 at pH 0.3–1.0. For Cyanex 272, the highest extraction yield for zinc (70% of zinc with 20% of iron extraction) was found at pH 2.4. Cyanex 302 presented low metal extraction levels (below 10%) and slow phase disengagement characteristics. Reactions for the extraction of zinc with TBP and Cyanex 301 from hydrochloric acid solution were proposed.     

Leaching and separation of zinc from the black paste of spent MnO2-Zn dry cell batteries

Spent batteries represent a source of hazardous materials when discarded without appropriate treatment. Investigations on the recovery of zinc from the black paste of spent MnO(2)-Zn cell batteries were carried out. Leaching of zinc and manganese from the black paste of spent batteries using sulfuric or hydrochloric acid solutions was studied. It was found that leaching with sulfuric acid solution is more efficient than with HCl solution. Different parameters affecting the leaching of Zn(II) and Mn(II) with sulfuric acid were further studied. Extraction of Zn(II) and Mn(II) from the leaching sulfate medium by bis(2,4,4-trimethylpentyl) dithiophosphinic acid (CYANEX 301) diluted with kerosene was investigated. The factors affecting the extraction process, separately studied, include the effect of contact time, sulfuric acid concentration, CYANEX 301 concentration, phase ratio as well as temperature. The results indicated that, from sulfate medium, Zn(II) is more extracted than Mn(II). Selective stripping of Zn(II) was obtained using 5M HCl. Application of the method on the leaching sulfate solution of the spent MnO(2)-Zn dry cell black paste show the efficiency of the process, where the extraction and stripping of Zn(II) are 98% and 99%, respectively.     

A solvent extraction approach to recover acetic acid from mixed waste acids produced during semiconductor wafer process

Recovery of acetic acid (HAc) from the waste etching solution discharged from silicon wafer manufacturing process has been attempted by using solvent extraction process. For this purpose 2-ethylhexyl alcohol (EHA) was used as organic solvent. In the pre-treatment stage >99% silicon and hydrofluoric acid was removed from the solution by precipitation. The synthesized product, Na(2)SiF(6) having 98.2% purity was considered of commercial grade having good market value. The waste solution containing 279 g/L acetic acid, 513 g/L nitric acid, 0.9 g/L hydrofluoric acid and 0.030 g/L silicon was used for solvent extraction study. From the batch test results equilibrium conditions for HAc recovery were optimized and found to be 4 stages of extraction at an organic:aqueous (O:A) ratio of 3, 4 stages of scrubbing and 4 stages of stripping at an O:A ratio of 1. Deionized water (DW) was used as stripping agent to elute HAc from organic phase. In the whole batch process 96.3% acetic acid recovery was achieved. Continuous operations were successfully conducted for 100 h using a mixer-settler to examine the feasibility of the extraction system for its possible commercial application. Finally, a complete process flowsheet with material balance for the separation and recovery of HAc has been proposed.     

Automobile shredded residue valorisation by hydrometallurgical metal recovery

The aim of this work was developing a hydrometallurgical process to recover metals from automobile shredded residue (or car fluff). Automobile shredded residue (ASR) was characterised by particle size distribution, total metal content and metal speciation in order to guide the choice of target metals and the operating conditions of leaching. Characterisation results showed that Fe is the most abundant metal in the waste, while Zn was the second abundant metal in the fraction with diameter lower than 500 μm. Sequential extractions denoted that Zn was easily extractable by weak acid attack, while Fe and Al required a strong acid attack to be removed. In order to recover zinc from <500 μm fraction leaching tests were operated using acetic acid, sulphuric acid and sodium hydroxide at different concentrations. Sulphuric acid determined the highest zinc extraction yield, while acetic acid determined the highest zinc extractive selectivity. Sodium hydroxide promoted an intermediate situation between sulphuric and acetic acid. Zn recovery by electro winning using acetic leach liquor determined 95% of Zn electro deposition yield in 1h, while using sulphuric leach liquor 40% yield in 1h and 50% yield in 2h were obtained. Simulation results showed that the sulphuric leaching process was more attractive than acetic leaching process.     

Preconcentration and separation of copper, nickel and zinc in aqueous samples by flame atomic absorption spectrometry after column solid-phase extraction onto MWCNTs impregnated with D2EHPA-TOPO mixture

A solid phase extraction method has been developed for the determination of copper, nickel and zinc ions in natural water samples. This method is based on the adsorption of copper, nickel and zinc on multiwalled carbon nanotubes (MWCNTs) impregnated with di-(2-ethyl hexyl phosphoric acid) (D2EHPA) and tri-n-octyl phosphine oxide (TOPO). The influence of parameters such as pH of the aqueous solution, amount of adsorbent, flow rates of the sample and eluent, matrix effects and D2EHPA-TOPO concentration have been investigated. Desorption studies have been carried out with 2 mol L(-1) HNO(3). The copper, nickel and zinc concentrations were determined by flame atomic absorption spectrometry. The results indicated that the maximum adsorption of copper, nickel and zinc is at pH 5.0 with 500 mg of MWCNTs. The detection limits by three sigma were 50 μg L(-1) for copper, 40 μg L(-1) for nickel and 60 μg L(-1) zinc. The highest enrichment factors were found to be 25. The adsorption capacity of MWCNTs-D2EHPA-TOPO was found to be 4.90 mg g(-1) for copper, 4.78 mg g(-1) for nickel and 4.82 mg g(-1) for zinc. The developed method was applied for the determination of copper, nickel and zinc in electroplating wastewater and real water sample with satisfactory results (R.S.D.'s <10%).     

使用支撑液膜从Fe^3＋／Cu^2＋溶液中选择分离Fe^3＋的研究（I）液液萃取实验

支撑液膜在水溶液金属离子的分离中有着独特的优势。报道了从Fe^3 ／Cu^2 溶液中选择分离Fe^3 液／液萃取研究结果。水相为Fe^3 ／Cu^2 硫酸溶液,萃取相为正癸醇（n-de-canol）,载体为二（2－乙基己基）磷酸（D2EHPA）。实验研究了溶液相中硫酸浓度以及有机相中载体D2EHPA浓度金属离子萃取速率的影响。研究发现水溶液的酸浓度对Fe^3 的萃取影响较明显,而对Cu^2 的萃取影响很小。在两相界面处Fe^3 与D2EHPA的反应速度比Cu^2 快很多。Fe^3 、Cu^2 与D2EHPA的络合物在有机相中的扩散速度都较慢,但是Fe^3 与D2EHPA的络合物的界面反应速度比络合物的扩散速度快。有机相中载体浓度对金属离子萃取速率的影响也很明显。液液萃取研究结果显示,在使用支撑液膜进行铁离子选择分离时,可以通过改变溶液相酸的浓度,有机相中载体浓度,或者通过缩短分离时间来提高选择率。     

Selection of design parameters and optimization of operating parameters of soybean oil-based bulk liquid membrane for Cu(II) removal and recovery from aqueous solutions

The objectives of this work were to select suitable design parameters and optimize the operating parameters of a soybean oil-based bulk liquid membrane (BLM) for Cu(II) removal and recovery from aqueous solutions. The soybean oil-based BLM consists of an aqueous feed phase (Cu(II) source), an organic membrane phase (soybean oil (diluent), di-2-ethylhexylphosphoric acid (D2EHPA) (carrier) and tributylphosphate (phase modifier)) and an aqueous stripping phase (sulfuric acid solution (H(2)SO(4))). Effects of design parameters (stirring condition and stripping/membrane to feed/membrane interface area ratio) of soybean oil-based BLM on the Cu(II) removal and recovery from aqueous solutions were investigated and the suitable parameters were selected for further studies. Optimization of the operating parameters (D2EHPA concentration, H(2)SO(4) concentration, stirring speed, temperature and operating time) of soybean oil-based BLM for maximum percentage (%) recovery of Cu(II) was then conducted using Response Surface Methodology and the optimum parameters were determined. A regression model for % recovery was developed and its adequacy was evaluated. The experimental % recovery obtained under the optimum operating conditions was compared with the predicted one and they were found to agree satisfactorily with each other.     

用于电镀废水处理的PVDF中空纤维更新液膜性能的评价

采用实验室自制疏水微孔聚偏氟乙烯(PVDF)中空纤维膜组件,以2-乙基己基磷酸(D2EHPA)为载体、磺化煤油为溶剂配制成萃取剂、以硫酸为反萃剂,研究了中空纤维更新液膜萃取过程对镍离子的去除效果。考察了油水相比、不同操作模式、液相温度等系统运行条件及中空纤维和膜组件结构参数对镍离子去除率的影响。3h实验结果表明,油水相比为1∶50,废水与萃取剂混合液流经组件管程的操作模式下镍离子去除率达32.1%;增大纤维内径、减小纤维壁厚利于加速传质;优化的组件装填密度为26.9%,去除率达46.2%,增加组件长度也有助于镍离子的去除。     

硫酸铵低温焙烧中低品位氧化锌矿

以中低品位氧化锌矿为原料、硫酸铵为反应介质,通过低温焙烧得到热料,研究了焙烧温度对Zn提取率的影响。结果表明,培烧温度为450℃时锌的提取率最高,为91.8%。焙烧温度低反应不充分;焙烧温度过高H₂SO₄分解挥发,降低反应率。将熟料溶出过滤得到硫酸锌溶液,经净化除杂得到洁净的硫酸锌溶液。以硫酸锌溶液为原料、碳酸铵为沉淀剂,采用沉淀法制备出碱式碳酸锌前驱体,将其煅烧制备了微细氧化锌粉体。采用XRD、SEM及化学成分分析等手段对前驱体和氧化锌粉体进行了表征。结果表明,溶液中OH^-、HCO₃^-与Zn²⁺共同作用得到前驱体,前驱体受热脱水、分解得到ZnO粉体。碱式碳酸锌前驱体为Zn₄（CO₃）（OH）₆·H₂O,呈类球形颗粒团聚体,氧化锌粉体为六方铅锌矿结构,颗粒呈球形,分散性良好。     

Extraction and separation of nickel and cobalt by electrostatic pseudo liquid membrane

The extraction and separation of nickel and cobalt using electrostatic pseudo liquid membrane technology is the subject of this article. An electrostatic pseudo liquid membrane reactor was constructed and extraction tests were undertaken to determine the effects of various experimental variables on the extraction and separation of nickel and cobalt. At optimum conditions, devised as a result of this investigation, a nickel/cobalt ratio of 1000 in the raffinate from a synthetic feed solution containing 10?000 ppm nickel and 1000 ppm cobalt was achieved. Separation of nickel and cobalt from a pregnant leach solution was achieved in two stages.     

Synthesis of sol-gel silica chemically bonded with cyanex 272 for the removal of Cu(II), Ni(II), and Zn(II)

This article reported on the synthesis of SSCBB, a new solid-phase, sol-gel silica chemically bonded with [bis (2,4,4-trimethylpentyl) phosphinate], (BTMPP, anion of Cyanex 272) prepared with a sol-gel method, and its application as a reusable solid-phase sorbent for the selective removal of Cu(II), Ni(II), and Zn(II). The synthesized SSCBB was characterized by FTIR, EDX, SEM, BET, TGA, and DSC. To evaluate its extraction performance, various parameters such as equilibration time, pH of the aqueous phase, solid to liquid ratio, initial copper ion concentration and reusability of SSCBB were studied. Equilibrium time was found to be 60 min for all metals and almost 100% extraction occurred at a pH of 4.0, 6.0, and 8.8 for Zn(II), Cu(II), and Ni(II) extraction, respectively. The maximum extraction capacity was found to be 0.2 mmol of Cu(II) per gram of SSCBB. Moreover, it was also regenerated and reused for subsequent recovery in ten cycles. The uptake performance of regenerated SSCBB after ten regeneration cycles was found to be the same as the freshly prepared SSCBB. Finally, based on the results, a proposed flow sheet for the removal of Cu(II), Ni(II), and Zn(II) was provided.     

ZnS微球的水热/溶剂热法合成及其光催化性能研究

采用水热/溶剂热法, 以Zn(Ac)₂·2H₂O和 CH₄N₂S为反应物合成ZnS微球。对ZnS微球进行X射线衍射(XRD)、扫描电镜(SEM)及紫外可见漫反射光谱等表征。结果表明, 合成的ZnS微球为立方闪锌矿型晶体结构, 由ZnS纳米粒子自组装而成。在降解苯酚水溶液的光催化研究中, 以乙二醇-水为溶剂合成的ZnS光催化活性明显优于其他溶剂体系合成的ZnS, 循环使用3次仍保持较高的活性。ZnS微球光催化性能的提高可归结为以下三方面的协同作用: 较小的禁带宽度(3.39 eV)有利于吸收光子, 较完整的晶体结构使催化剂活性分子数增多和较大的比表面积(19.4 m²/g)有利于反应液与催化剂的充分接触。ZnS微球降解苯酚的中间产物为乙二酸、顺丁烯二酸和极少量的对苯二酚。     

Selective Supercritical Fluid Extraction of Uranium(VI) using N-Phenyl-(1,2-Methano-Fullerene C60)61-Formohydroxamic acid and Simultaneous On-line Determination by Inductively-Coupled Plasma-Mass Spectrometry (ICP-MS)

Uranium(VI) is extracted with N-phenyl-(1,2-methano-fullerene C₆₀)61-formohydroxamic acid, PMFFHA, in dichloromethane by supercritical carbon dioxide (SF-CO₂)-dichloromethane (modifier) medium. A 2.0 µL aqueous uranium is extracted accurately and also preconcentrated in an especially designed extraction vessel of 80 µL capacity. The extracted microdrop orange-red colored uranium(VI)-PMFFHA complex in dichloromethane was online measured by fiber optics spectrometry and ICP-MS. The distribution ratio (D_UO2²⁺) of U(VI) was determined. The slopes of log D_UO2²⁺ versus PMFFHA concentration plot, the extracted species both in SF-CO₂ extraction (SFE) and the solvent extraction (SE) were determined to be 2.0 as UO₂(PMFFHA)₂ complex. The uranium is determined as low as 0.10 ng mL^-1 in presence of several cations and anions. The effect of diluents, modifier concentration, temperature and pressure on the extraction and separation of uranium was studied. The uranium is determined in human blood serum, natural water, seawater, standard samples and also in monazite sand. The PMFFHA has been successfully used as carrier for the selective and efficient transport of uranium(VI). The feed comprised of a solution of uranium(VI) and aqueous solution of diverse cations and anions in pH 4.5, while 1M HNO₃ was used as a stripping agent in the receiving compartment of permeated cell. Maximum transportation was observed for 12 minutes with t_1/2 equal to 6.3 min. The uranium(VI) was determined in presence of uranium(IV).     

Energetic co-ordination compounds: synthesis, characterization and thermolysis studies on bis-(5-nitro-2H-tetrazolato-N2)tetraammine cobalt(III) perchlorate (BNCP) and its new transition metal (Ni/Cu/Zn) perchlorate analogues

Bis-(5-nitro-2H-tetrazolato-N²)tetraammine[cobalt(III)/nickel(III)] perchlorates (BNCP/BNNP) and mono-(5-nitro-H-tetrazolato-N)triammine [copper(II)/zinc(II)] perchlorates (MNCuP/MNZnP) have been synthesized during this work. The synthesis was carried out by addition of carbonato tetraammine metal [Co/Ni/Cu/Zn] nitrate [CTCN/CTNN/CTCuN/CTZnN] to the aqueous solution of sodium salt of 5-nitrotetrazole followed by reaction with perchloric acid. The precursors were synthesized by the reaction of aqueous solution of their respective nitrates with ammonium carbonate at 70 °C. The complexes and their precursors were characterized by determining metal and perchlorate content as well as infrared (IR), electron spectra for chemical analysis (ESCA) and X-ray diffraction (XRD) techniques. The TG profiles indicated that BNCP, BNNP and MNCuP are thermally stable up to the temperature of 260–278 °C unlike MNZnP (150 °C). Sudden exothermic decomposition was observed in case of bis-(5-nitro-2H-tetrazolato-N²)tetraammine cobalt(III) perchlorate, bis-(5-nitro-2H-tetrazolato-N²)tetraammine nickel(III) perchlorate and mono-(5-nitro-H-tetrazolato-N)triammine zinc(II) perchlorate resulting in the severe damage of the sample cup. Sensitivity data indicated that the Co/Ni/Cu complexes are more friction sensitive (3–4.8 kg) than mono-(5-nitro-H-tetrazolato-N)triammine zinc(II) perchlorate (14 kg). The impact sensitivity results of the complexes corresponded to h_50% of 30–36 cm.     

Processing of low grade tungsten ore concentrates by hydrometallurgical route with particular reference to India

Tungsten, because of its high strength and high melting point occupies a prime position amongst metals. With depletion of high grade resources considerable R and D work is still being carried out in tungsten producing countries around the world for the processing of low grade and secondary resources. The paper gives a brief review of the hydrometallurgical processes developed to recover tungsten from low grade concentrates. The R and D work carried out on purification and recovery of tungsten as tungstic oxide/ammonium paratungstate (APT) from a number of off-grade products such as table concentrate (WO₃=66%, SiO₂=2·2%, S=1·8%), middlings (18–20% WO₃, and 28–30% S) and jig concentrate (4·6% WO₃) are discussed in this paper. It has been found that more than 75% of silica and 90% of sulphur could be removed from the table concentrate by curing with hydrofluoric acid and subsequent roasting of the desilicated product at 650°C. In the case of middlings, it was possible to recover over 90% of tungsten as tungstic oxide by an oxidative roast followed by pressure leaching with soda. A detailed study on the low grade jig concentrate to recover tungsten as APT, showed that over 90% extraction was possible by adopting the pressure leaching-solvent extraction route. Effect of parameters such as soda concentration, time, temperature and pressure during leaching; as well as extraction and stripping behaviour of tungsten from leach solution at different pH and aqueous to organic ratio during solvent extraction with Alamine-336, were studied and a flow-sheet was developed for processing of jig concentrate analysing 4·6% WO₃.     

Removal of phenols from aqueous solutions by emulsion liquid membranes

The present study deals with the extraction of phenols from aqueous solutions by using the emulsion liquid membranes technique. Besides phenol, two derivatives of phenol, i.e., tyrosol (2-(4-hydroxyphenyl)ethanol) and p-coumaric acid (4-hydroxycinnamic acid), which are typical components of the effluents produced in olive oil plants, were selected as the target solutes. The effect of the composition of the organic phase on the removal of solutes was examined. The influence of pH of feed phase on the extraction of tyrosol and p-coumaric was tested for the membrane with Cyanex 923 as an extractant. The use of 2% Cyanex 923 allowed obtaining a very high extraction of phenols (97-99%) in 5-6 min of contact time for either single solute solutions or for their mixtures. The removal efficiency of phenol and p-coumaric acid attained equivalent values by using the system with 2% isodecanol, but the removal rate of tyrosol was found greatly reduced. The extraction of tyrosol and p-coumaric acid from their binary mixture was also analysed for different operating conditions like the volume ratio of feed phase to stripping phase (sodium hydroxide), the temperature and the initial concentration of solute in the feed phase.     

Acidic leaching and precipitation of zinc and manganese from spent battery powders using various reductants

The main objective of this study was to investigate the effects of reductive acidic leaching and further precipitation on the recovery of manganese and zinc from spent alkaline and zinc–carbon battery powders. Ascorbic acid (AA), citric acid (CA) and oxalic acid (OA) were tested as the reductants. Sodium hydroxide and potassium hydroxide were used as precipitating agents. OA with H₂SO₄ or HCl was not effective on the leaching of zinc due to the formation of zinc oxalate precipitates. However, the other reducing agents (CA and AA) tested under various experimental conditions were effective in the acidic leaching of both zinc and manganese. Leaching yields of both manganese and zinc were higher at leach temperature of 90 °C than those at 30 °C. Leach solutions were purified by the selective precipitation of manganese and zinc using KOH or NaOH. Complete precipitation was obtained for Mn at pH 9–10 and for Zn at pH 7–8. The use of ascorbic acid or citric acid as reductants in acidic leaching appears to be effective in the simultaneous leaching and further recovery of zinc and manganese from spent alkaline and zinc–carbon battery powders.     

Extractive removal of chromium (VI) from industrial waste solution

Extractive removal of Cr (VI) was carried out from chloride solutions using cyanex 923 mixed with kerosene. The efficiency of this extractant was studied under various experimental conditions, such as concentration of different mineral acids in the aqueous phase, concentration of cyanex 923 and Cr (VI) present in the initial aqueous feed, temperature and time of extraction, organic to aqueous (O/A) phase ratio. Percentage Cr (VI) extraction decreases with the increase in temperature at varying concentration of cyanex 923. The interference of the impurities usually associated with Cr (VI) such as Cr (III), Cu, Ni, Fe (II), Zn, Chloride and sulphate, etc., were examined under the optimized conditions and only Zn was found to interfere. Under the optimum experimental conditions 98.6-99.9% of Cr (VI) was extracted in 3-5 min at O/A of 2 with the initial feed concentration of 1g/L of Cr (VI). The extracted Cr (VI) was quantitatively stripped with 1M NaOH and the organic phase obtained after the stripping of Cr (VI) was washed with dilute HCl solution to neutralize any NaOH trapped/adhered to the solvent and then with distilled water. This regenerated solvent was reused in succeeding extraction of chromium (VI). Finally a few experiments were performed with the synthetic effluent from an electroplating industry.