Co-reporter:Wei Xiang, Shengke Liang, Zhiyong Zhou, Wei Qin, Weiyang Fei
Hydrometallurgy 2017 Volume 171(Volume 171) pp:
Publication Date(Web):1 August 2017
DOI:10.1016/j.hydromet.2017.04.007
•A counter-current extraction process was established to recover lithium from salt lake brine with a high Mg/Li ratio.•The overall lithium recovery was higher than 98%.•Mg/Li molar ratio changed from 94.8 in the salt lake brine to 0.03 in the stripping solution.Salt lakes in northwest China have rich lithium reserves. However, because of their high Mg/Li ratios, lithium recovery is very difficult. In this work, lithium was recovered from Qarhan salt lake using counter-current extraction. The Li+ ions were extracted using tributyl phosphate (TBP) in methyl isobutyl ketone (MIBK) as the extractant and FeCl3 as the coextractant. The process involved four sections: extraction, washing, stripping and regeneration. The optimal conditions for each section were first determined based on equilibrium data. Then the process was conducted in a 10-stage mixer–settler with LiCl/NaCl as the washing agent, HCl/NaCl as the stripping agent, and NaOH/NaCl as the regenerating agent. The operation was stable over 14 cycles. The overall recovery of lithium was higher than 98% and the Mg/Li molar ratio changed from 94.8 in salt lake brine to 0.03 in the stripping solution. The results show that solvent extraction is a highly effective method for lithium recovery from salt lake brines with high Mg/Li ratios.
Co-reporter:Houpeng Wang, Wei Qin, Yi-Gui Li, and Weiyang Fei
Industrial & Engineering Chemistry Research 2014 Volume 53(Issue 30) pp:12111-12121
Publication Date(Web):July 11, 2014
DOI:10.1021/ie501609w
Trin-octylphosphine oxide (TOPO) is a widely used extractant because of its high extractive ability. However, there is no systematic research on the thermodynamics of TOPO/n-dodecane in the separation of hydrochloric acid (HCl) from aqueous solution. In this study, the liquid–liquid equilibrium (LLE) system (water + n-dodecane + TOPO + HCl) was investigated. Both the equimolar series and slope methods were used to determine the composition of the complex formed in the equilibrated organic phase. The form of the water molecules in the equilibrated organic phase was first investigated by the thermodynamic method. The thermodynamic model was established with the Pitzer equation for aqueous phase and both Margules and organic Pitzer equations for the organic phase. Two chemical equilibrium constants and their corresponding interaction parameters were regressed from experimental LLE data. The correlated results were in good agreement with the experimental data. Furthermore, this model can also be used to predict the organic phase composition for this system. This confirmed that the thermodynamic model chosen was suitable for the extraction system.
Co-reporter:Zhiyong Zhou, Shengke Liang, Wei Qin, and Weiyang Fei
Industrial & Engineering Chemistry Research 2013 Volume 52(Issue 23) pp:7912-7917
Publication Date(Web):May 16, 2013
DOI:10.1021/ie303496w
The extraction equilibrium behavior of Li by tributyl phosphate (TBP), diisobutyl ketone, acetophenone, methyl isobutyl ketone, and 2-heptanone in kerosene were investigated. The partition coefficient of Li with TBP in kerosene decreased significantly when the volume concentration of TBP was greater than 60%. The values derived for the partition coefficients of four selected ketones in kerosene were smaller than that of TBP in kerosene. The stoichiometric coefficients between TBP and Li, the stoichiometric coefficients between the four selected ketones and Li, and the apparent equilibrium constant for the extraction reaction equation for TBP and the four ketones in kerosene were obtained. The tendency in extraction with the TBP and four selected ketones in kerosene can be predicted from these parameters. The polar solvents used as diluents for TBP can yield higher Li partition coefficients, strong dilution effects for TBP, and strong polarity and low density of the extracting solvents formed with both polar solvents and TBP.
Co-reporter:Zhiyong Zhou, Zhenyu Li, and Wei Qin
Industrial & Engineering Chemistry Research 2013 Volume 52(Issue 31) pp:10795-10801
Publication Date(Web):July 20, 2013
DOI:10.1021/ie4008002
Extraction equilibria for saturated aliphatic dicarboxylic acids, namely oxalic, malonic, succinic, and adipic acids, with trioctylamine (TOA) in 1-octanol were determined at various TOA concentrations. Using quantitative FT-IR spectra, we determined that the formation of 1:2 acid–amine complexes depends on the pKa2 value, and wavenumbers of specific peaks for the COO– of the acid–amine ion-pair complexes depend on the pKa1 value. An equilibrium model is presented that employs the mass action law and is used to determine model parameters and apparent extraction equilibrium constants (K11, K12, and K21). The extraction abilities for dicarboxylic acids depend on the pKa1 value. The typical overloading curves of TOA/1-octanol for dicarboxylic acids are given. The loadings of TOA calculated using the equilibrium model parameters and apparent extraction equilibrium constants agree with the experimental data. The apparent extraction equilibrium constants depend on the acidity of the dicarboxylic acid and the specific basicity of TOA. The quantitative correlation of log K11 (or log K12) is obtained using pKa1 (or pKa2) and pKa,B′.
Co-reporter:Zhiyong Zhou, Wei Qin, Shengke Liang, Yuanzhong Tan, and Weiyang Fei
Industrial & Engineering Chemistry Research 2012 Volume 51(Issue 39) pp:12926-12932
Publication Date(Web):September 11, 2012
DOI:10.1021/ie3015236
Lithium recovery from salt-lake brines was explored using the extraction equilibria of lithium with tributyl phosphate (TBP) in methyl isobutyl ketone (MIBK), with FeCl3 coextractant, for various volume concentrations of TBP, molar ratios of Fe to Li, and volume ratios of the organic to aqueous phases. Washing and stripping equilibria of magnesium and lithium ions with HCl, NH4Cl, and LiCl/HCl and NH4Cl/HCl combinations were investigated. The extraction of lithium ions from salt-lake brines was successful. NH4Cl was a suitable washing agent for magnesium ions but not for stripping lithium ions into the aqueous phase. HCl can wash magnesium ions and strip lithium ions but corrodes equipment. The LiCl/HCl and NH4Cl/HCl combinations reduced equipment corrosion and washed and stripped magnesium and lithium ions, respectively, at appropriate volume ratios. MIBK loss was reduced using high-salinity solutions and large volume ratios during extraction and adjusting the volume ratio and overall chloride-ion concentration during washing/stripping.
Co-reporter:Zhiyong Zhou, Wei Qin, Yang Liu, and Weiyang Fei
Journal of Chemical & Engineering Data 2012 Volume 57(Issue 1) pp:82-86
Publication Date(Web):October 28, 2011
DOI:10.1021/je200803h
To explore the feasibility of extracting lithium metal from brine sources, three salts, MgCl2, CaCl2, and NH4Cl, were selected as chloride sources, and the extraction equilibrium of lithium was studied with tributyl phosphate (TBP) in kerosene and FeCl3 as a coextracting agent at different values of Fe/Li. The extraction mechanism for lithium with TBP in kerosene and FeCl3 as a coextracting agent was investigated too. The results showed that the extraction of the lithium ion is a cation-exchange reaction, and the extraction of iron ion is the precondition of the extraction of lithium ion. All of the extractability of the iron ion increased with the chloride concentration with MgCl2, CaCl2, and NH4Cl as chloride sources, and the extraction capacity of lithium ion followed the sequence: MgCl2 > CaCl2 > NH4Cl, with recoveries from MgCl2 as chloride sources being much higher than that for CaCl2 and NH4Cl as chloride sources at all values of Fe/Li. There exists competitiveness between Li+ and NH4+, Ca2+, and Mg2+ when combined to TBP and FeCl3 and a salting-out effect of three salts. MgCl2 benefits from weaker competitiveness and a stronger salting-out effect than the other two. Choosing MgCl2 as chloride sources at Fe/Li = 1.9 obtains the highest partition coefficient with TBP/kerosene as an extractant and FeCl3 as a coextracting agent.
Co-reporter:Zhiyong Zhou
Journal of Chemical Technology and Biotechnology 2011 Volume 86( Issue 4) pp:492-496
Publication Date(Web):
DOI:10.1002/jctb.2486
Abstract
BACKGROUND: To explore the extraction properties of aromatic acids produced in the oxidation of coal, the extraction equilibrium of phthalic acid (as a typical product) was studied using three solvents, 1-octanol, 50% tributylphosphate (TBP)/kerosene, and 10% trialkylphosphine oxide (TRPO)/kerosene, and the feasibility of separating phthalic, [1,1′-biphenyl]-2,2′-dicarboxylic and trimellitic acids is discussed.
RESULTS: Phthalic acid extraction followed the sequence: 10% TRPO > 50% TBP > 1-octanol, with recoveries from the TRPO and TBP systems being much larger than that for 1-octanol. The stoichiometry of formation of the complexes of TBP and TRPO with phthalic acid was 1:1. The apparent extraction equilibrium constant for TRPO is much larger than that for TBP. The distribution coefficient of [1,1′-biphenyl]-2,2′-dicarboxylic acid is much larger than that of the other two acids using 1-octanol as the extractant and this acid could be removed by 1-octanol from a mixture of the three acids. The extraction equilibrium correlations obtained for the individual acid component systems can be used to predict that of the acid mixture.
CONCLUSION: The extent of phthalic acid extraction by the three solvents investigated is as follows: 10% TRPO > 50% TBP > 1-octanol. The stoichiometry of the complex formation of TBP or TRPO and phthalic acid is 1:1, and the apparent extraction equilibrium constant for TRPO is much larger than that for TBP. 1-octanol shows a good extractive selectivity for [1,1′-biphenyl]-2,2′-dicarboxylic acid as compared with phthalic and trimellitic acids. Copyright © 2011 Society of Chemical Industry
Co-reporter:Zhiyong Zhou, Wei Qin, and Weiyang Fei
Journal of Chemical & Engineering Data 2011 Volume 56(Issue 9) pp:3518-3522
Publication Date(Web):July 28, 2011
DOI:10.1021/je200246x
To explore the feasibility of extracting lithium metal from brine sources, three salt solutions, FeCl3, ZnCl2, and CrCl3, were selected as coextracting agents, and the extraction equilibrium of lithium was studied with tributyl phosphate (TBP) in kerosene, TBP in methyl isobutyl ketone (MIBK), and TBP in 2-octanol. The results showed that the extraction capacity followed the sequence: TBP/MIBK > TBP/kerosene > TBP/2-octanol, with recoveries from the TBP/MIBK and TBP/kerosene systems being much larger than that for TBP/2-octanol with FeCl3 solution as the coextracting agent. The third phase was found for the TBP/kerosene system with FeCl3 solution as the coextracting agent at a low volume concentration of TBP, which did not appear for other systems at all volume concentrations. Synergistic extraction exists between TBP and MIBK, and the weak hydrogen bond association exists between −OH in 2-octanol and −P═O in TBP. The coextracting capacity for FeCl3 was much larger than that for ZnCl2 and CrCl3, and that for TBP/2-octanol with CrCl3 was a little larger than that for others.
Co-reporter:Shaokai Huang;Youyuan Dai
Journal of Chemical Technology and Biotechnology 2008 Volume 83( Issue 5) pp:683-687
Publication Date(Web):
DOI:10.1002/jctb.1850
Abstract
BACKGROUND: Carboxylic acids are among the most important substances that can be manufactured from biomass. However, the recovery of carboxylic acids from fermentation broths presents a challenging separation problem. To avoid the production of waste salts and net consumption of chemicals in the calcium carboxylate salt process, the use of reversible chemical complexation with polymeric sorbents and extractants is attractive for carboxylic acid recovery. Pyruvic acid is widely used in the manufacture of medicines, pesticides and foodstuffs and can be produced by fermentation. Since the acidity of pyruvic acid (pKa = 2.49) is stronger than that of normal carboxylic acids, and as few reports on the recovery of pyruvic acid are available, the sorption of pyruvic acid from aqueous solution on two types of weakly basic polymeric sorbent, tertiary amine D301R and primary amine D392, was investigated over a wide pH range and at various salt (MgSO4) concentrations.
RESULTS: Overloading adsorption of pyruvic acid on both weakly basic polymeric sorbents occurred, with the overloading of D392 being greater than that of D301R. The adsorption of pyruvic acid on both sorbents was greatly affected by the solution pH and the salt concentration in the aqueous phase. An overloading model was able to predict the experimental uptake data very well.
CONCLUSION: Solution pH is one of the most important operating conditions, and both polymeric sorbents D392 and D301R can be used to recover pyruvic acid from dilute aqueous solution with high efficiency at a solution pH around 2. The uptake by D392 is greater than that by D301R owing to steric hindrance of the tertiary amine. Copyright © 2008 Society of Chemical Industry
Co-reporter:Xinchang Shan, Wei Qin, Zhiyong Zhou and Youyuan Dai
Journal of Chemical & Engineering Data 2008 Volume 53(Issue 2) pp:331-334
Publication Date(Web):January 31, 2008
DOI:10.1021/je7002034
The dissociation equilibrium constant (pKa) of an extractant is one of the main factors determining the reactive extraction behavior. A quantitative structure–property relationship (QSPR) was investigated for predicting the pKa of some pure extractants and the apparent basicity (pKa,B) of three typical mixture solvents, trioctylamine (TOA)/hexane, TOA/1-octanol, and TOA/methyl isobutyl ketone (MIBK). Novel QSPR models for the pKa of a pure extractant and the pKa,B of a mixture solvent were set up. The novel QSPR models include the concentration of extractant in the solvent and three kinds of molecular connectivity indices of extractant and diluent. The calculated values from the models of the pure extractant and mixture solvents show good consistency with experimental values.
Co-reporter:Xiaoyan YOU, Wei QIN, Youyuan DAI
Chinese Journal of Chemical Engineering (October 2009) Volume 17(Issue 5) pp:746-749
Publication Date(Web):1 October 2009
DOI:10.1016/S1004-9541(08)60271-2
Phase separation behavior of cocamidopropyl betaine/water/polyethylene glycol (PEG) system was studied. The effects of concentration and molecular weight of PEG on the phase separation behavior were investigated. Clouding occurred when the concentration of PEG was large enough in the betaine aqueous solution, and the concentration of PEG at cloud point decreased with the increase of PEG molecular weight for a constant betaine concentration. The bottom phase was the PEG-rich phase, and the upper phase was the betaine-rich phase. The volumetric ratio of PEG-rich phase to betaine-rich phase, at the same difference between the PEG concentration and the one at the cloud point, ΔCcp (0.1 g·ml−1), decreased as the PEG molecular weight increased and approached 1 for higher PEG molecular weight (about 20000), which was similar to the typical aqueous two-phase system. This volumetric ratio depended on the initial PEG concentration, but independent of PEG molecular weight. The concentration ratio of betaine to PEG in both phases depended on the ΔCcp, independent of PEG molecular weight.
Co-reporter:Zhiyong ZHOU, Wei QIN, Weiyang FEI, Yigui LI
Chinese Journal of Chemical Engineering (February 2012) Volume 20(Issue 1) pp:36-39
Publication Date(Web):1 February 2012
DOI:10.1016/S1004-9541(12)60360-7
To study the characteristic of liquid-liquid extraction equilibrium of lithium from brine sources, the complexes formed from tributyl phosphate (TBP) and methyl isobutyl ketone (MIBK) with lithium were investigated using FeCl3 as coextracting agent. Liquid-liquid extraction reaction mechanisms were proposed and the stoichiometry of tetrachloroferrate(III) complex with lithium was obtained by regressing the experimental data. It is found that the stoichiometry of tetrachloroferrate(III) to lithium in the complex is 1 : U1 with either TBP or MIBK as extractant in kerosene. The stoichiometry of the complex of TBP with Li was 1 : U1 and that of MIBK with Li was 2 : U1. The formed complexes of TBP and MIBK with lithium are determined to be LiFeCl4·TBP and LiFeCl42MIBK, respectively, according to the rule of neutralization.
Co-reporter:Zhiyong ZHOU, Wei QIN, Youyuan DAI
Chinese Journal of Chemical Engineering (December 2008) Volume 16(Issue 6) pp:867-870
Publication Date(Web):1 December 2008
DOI:10.1016/S1004-9541(09)60007-0
To explore the feasibility of extracting aromatic acid products from oxidizing coal, two aromatic acids, trimellitic and [1,1′-biphenyl]-2,2′-dicarboxylic acid, were selected as the solutes, and the extraction equilibrium of the acids were studied with 1-octanol, 50% tributyl phosphate (TBP) in kerosene, and 10% trialkylphosphine oxide (TRPO) in kerosene. The results showed that the degree of extraction of [1,1′-biphenyl]-2,2′-dicarboxylic acid was larger than that of trimellitic acid for all of the solvent, and the extraction capacity with TRPO is more effective than the one with TBP. The extraction behavior of aromatic polyacid is different from that of carboxylic acid, and the reactive extraction function of aromatic acids with TBP and TRPO is not as effective as that of carboxylic acid. 1-octanol could be used to remove [1,1′-biphenyl]-2,2′-dicarboxylic acid from the mixture of trimellitic acid and [1,1′-biphenyl]-2,2′-dicarboxylic acid. Because the weak hydrogen bond association exists between OH in 1-octanol and COOH in aromatic acid, the extractive selectivity of [1,1′-biphenyl]-2,2′-dicarboxylic to trimellitic acid depends on the stoichiometric ratio.
Co-reporter:Shuo WANG, Wei QIN, Youyuan DAI
Chinese Journal of Chemical Engineering (April 2012) Volume 20(Issue 2) pp:239-245
Publication Date(Web):1 April 2012
DOI:10.1016/S1004-9541(12)60384-X
A miniature process for separating the oil phase from dilute oil/water emulsion is developed. This process applies a confined space apparatus, which is a thin flow channel made of two parallel plastic plates. The space between the two plates is rather narrow to improve the collisions between oil droplets and the plate surface. Oil droplets have an affinity for the plate surface and thus are captured, and then coalesce onto the surface. The droplet size distribution of the residual emulsion resulted from the separation process is remarkably changed. The oil layer on the plate weakens the further separation of oil droplets from the emulsion. Three types of plate materials, polypropylene (PP), polytetrafluoroethylene (PTFE) and nylon 66, were used. It is found that PP is the best in terms of the oil separation efficiency and nylon 66 is the poorest. The interaction between droplets in the emulsion and plate surface is indicated by the spreading coefficient of oil droplet on the plate in aqueous environment, and the influences of formed oil layer and plate material on the separation efficiency are discussed.
