磷酸三丁酯和二异丙醚溶剂萃取 体系净化湿法磷酸的研究

以磷酸三丁酯（TBP）与二异丙醚为溶剂,采用溶剂萃取法净化湿法磷酸。研究了萃取剂中TBP体积分数、相比、萃取时间、搅拌转速、反萃取剂加入量对湿法磷酸净化效果的影响,确定了TBP与二异丙醚混合溶剂体系净化湿法磷酸的工艺条件。适宜工艺条件：萃取剂组成为TBP与二异丙醚体积比为1∶1,有机相与水相的体积比为 4∶1,萃取时间为25 min,搅拌转速为300 r/min,反萃取剂加入量为萃取相体积的20%。在此条件下,TBP与二异丙醚萃取体系对金属阳离子和氟离子有较好的分离能力。     

Separation of phenylacetic acid, 6-aminopenicillanic acid and penicillin G with electrodialysis under constant current

The separation behavior of phenylacetic acid (PAA), 6-aminopenicillanic acid (6-APA) and penicillin-G (Pen-G) with electrodialysis under constant current was studied. The effects of ionic concentrations and current density on their separation behavior were investigated. The sorption of PAA, 6-APA and Pen-G and in the anion exchange membrane, and the variations of the applied voltage and current efficiencies with time during electrodialysis were also examined. It was found that the molecular size and the affinity toward the anion exchange membrane played a key role for the electrodialysis of PAA, 6-APA and Pen-G. Phenylacetic acid had the lowest affinity toward the membrane but the fastest transport rate. Penicillin-G had the highest affinity toward the membrane but the slowest transport rate. With the increase of Pen-G concentration, the concentration polarization of Pen-G in the vicinity of anion exchange membrane became very serious, which severely retarded the transport of PAA and 6-APA. Although the increase of current density accelerated the transport of PAA, 6-APA and Pen-G, more serious concentration polarization of Pen-G occurred and the separation ratio of PAA to 6-APA decreased.     

Efficacy of tri-n-octylamine,tri-n-butyl phosphate and di-(2-ethylhexyl) phosphoric acid for reactive separation of protocatechuic acid

ABSTRACT

Owing to its chemical and pharmacological significances, the efficacy of reactive separation of protocatechuic acid (0.001–0.01 kmol m^?3) from aqueous stream by means of tri-n-octylamine (TOA), di-2-ethylhexyl phosphoric acid (D2EHPA) as well as tri-n-butyl phosphate (TBP) in octanol has been investigated, in terms of extraction efficiency, loading ratio, equilibrium complexation constants, and distribution coefficients. Extraction ability was obtained in the order TOA (91.2%) > TBP (88.64%) > D2EHPA (86.43%). In all cases, 1:1 protocatechuic acid:extractant complex is obtained. Further, diffusion coefficients, number of stages for extraction systems, and relative basicity model were used for relating the efficacy.     

Opposite selectivities of tri-n-butyl phosphate and Cyanex 923 in solvent extraction of lithium and magnesium

The synergic solvent extraction system of tri-n-butyl phosphate (TBP) and FeCl₃ (or ionic liquids, ILs) has been extensively studied for selective extraction of Li from Mg-containing brines. However, Cyanex 923 (C923), which extracts many metals stronger than TBP, has not yet been examined for Li/Mg separation. Here, we report on the unexpected observation that the C923/FeCl₃ system has opposite Li/Mg selectivity compared to the TBP/FeCl₃ system. Detailed investigations show that the opposite selectivity of the C923/FeCl₃ (or IL) system is due to three factors: (1) the strong extraction of Fe by C923 leads to a low concentration of [FeCl₄]⁻ in the system, which is essential for Li extraction; (2) C923 in combination with an IL extracts Mg strongly by an ion-pair mechanism; (3) most importantly, C923 extracts Mg by solvation, resulting in an insufficient concentration of C923 for Li extraction. The unexpected poor Li/Mg selectivity of C923 highlights the irreplaceable role of TBP in the selective recovery of Li.     

废旧磷酸铁锂正极粉磷酸浸出过程的优化及宏观动力学

随着新能源汽车产业快速发展,磷酸铁锂动力电池退役量爆发式增长,回收需求迫切,但面临回收利用经济性较差的难题。正极材料价值较高,本文提出采用磷酸浸出废旧正极材料以制备电池用磷酸铁,但铝等杂质的分离是关键。本文以含铝的磷酸铁锂正极粉为原料,开展了磷酸浸出过程优化及宏观动力学研究,重点研究了酸料比、浸出温度、液固比、搅拌速度等参数对磷酸铁锂及铝浸出效果的影响规律,并考察了磷酸铁锂在磷酸溶液中浸出的宏观动力学。研究结果表明,在酸料比1.1mL/g、温度20℃、液固比（5∶1)mL/g、搅拌速度400r/min、浸出时间120min条件下,磷酸铁锂浸出率大于93%,铝浸出率小于20%;磷酸铁锂正极粉磷酸浸出过程符合无固态产物层的收缩核模型,表观活化能为24.62kJ/mol,浸出过程受扩散控制。     

脲硫酸分解磷矿宏观动力学研究

以保康矿为基础,对脲硫酸分解磷矿的宏观反应动力学进行了研究,该反应过程中阻化作用对反应速率影响很大,阻化系数β随反应温度升高、矿粉粒度减小而增大,随酸解剂摩尔比而变化。在磷矿粒度为0.110—0.174mm,反应温度为339—359 K和酸解剂摩尔比为n(尿素)∶n(硫酸)=2.0—3.6∶1的条件下,实验得到包含阻化系数的脲硫酸分解磷矿过程的宏观动力学方程,方差分析表明模型可靠,为工艺条件的优化和反应器的设计提供了理论依据。     

硫酸分解磷矿第一阶段反应动力学研究

对硫酸分解磷矿粉的第一阶段反应进行了动力学研究,通过对实验数据的分析,证明此阶段反应为一级反应。反应速率常数与温度的关系符合阿累尼乌斯方程,活化能Ea为8．65kJ／mol。     

高镁磷尾矿在磷酸中的溶解动力学

对高镁磷尾矿在磷酸中的溶解动力学进行了研究,考查了磷酸中P2O5质量分数及反应温度对酸解过程的影响.选用考虑了自阻化因素的德罗兹多夫方程1/tln100/100-α-βα%/t=k来描述该过程的酸解动力学.研究结果表明:反应速率常数随温度的升高和磷酸中P2O5质量分数的增加而增加.该反应属于扩散控制,反应活化能约为29.2kJ/mol.     

高镁磷尾矿在硫酸中的溶解动力学

对高镁磷尾矿在硫酸中的溶解动力学进行了研究.考查了硫酸质量分数及反应温度对酸解过程的影响;选用考虑了自阻化因素的德罗兹多夫方程1/tln100/100-α-βα%/t=k描述酸解过程的动力学.研究结果表明:反应速率常数随温度的升高而增加,随硫酸质量分数的增加而减小.该反应属于扩散控制,反应活化能约为4～7kJ/mol.     

A kinetics study of the leaching of a calcareous phosphate rock by lactic acid

This study has been made of the leaching process to reduce carbonate content in calcareous phosphate rock using lactic acid. The samples mineralogical constituents were apatite, calcite, quartz and dolomite. In this study, the effect of important variables such as reaction time, acid concentration, liquid/solid ratio, particle size and temperature in laboratory scale was optimized. It was found that the leaching rate of carbonate material increased with increasing the acid concentration, temperature, reaction time and decreasing solid/liquid ratio and particle size. The experimental data were tested through graphic and statistical methods and a shrinking core kinetics model was presented to describe the dissolution and to analyze the data. The activation energy for leaching was found to be 43.58 kJ/mol and, consequently, the rate of the reaction based on a chemical reaction-controlled process could be expressed as 1 − (1 − α)^1/3 = 6.05 × 10⁶ e^−43.58/RTt.     

复盐结晶法生产磷酸二氢钾结晶动力学研究

研究了用三聚氰胺结晶法由湿法磷酸生产磷酸二氢钾的结晶动力学过程。考察了搅拌、振动、杂质对结晶过程的影响及不同降温速率对结晶习性的影响,拟合并给出结晶动力学方程,采用差热分析和热重分析仪测试了结晶产品的脱水特性。     

磷矿在磷酸中的浸出行为

为改进湿法磷酸生产工艺,提高副产石膏的品质,缓解湿法磷酸中固体副产物磷石膏带来的环保压力,进行了磷-硫两步法酸解磷矿制磷酸的研究。着重对贵阳某磷矿在磷酸中的浸出行为进行研究。结果表明,磷矿粒度小于75 μm、搅拌速度为500 r/min、反应温度为70 ℃、五氧化二磷质量分数为40%、反应时间为60 min时,磷矿分解率达到98.5%。德罗兹多夫动力学经验模型能够较好地描述40%五氧化二磷中磷矿反应速率的变化规律,且阻缓系数较大,表观活化能为6.048 kJ/mol,表明40%五氧化二磷中磷酸分解磷矿的反应速率受扩散控制。酸解渣SEM和EDS分析表明反应产物磷酸二氢钙结晶析出是影响扩散的主要因素。     

Equilibria and kinetics for reactive extraction of lactic acid using Alamine 336 in decanol

Lactic acid is an important commercial product and extracting this from aqueous solution is a growing requirement in fermentation‐based industries. The design of an amine extraction process requires (i) equilibrium and (ii) kinetic data for the acid–amine (solvent) system used. The equilibrium complexation constants for ratios of (1:1) and (2:1) have been estimated. The kinetics of extraction of lactic acid by Alamine 336 in decanol has also been determined. The reaction between lactic acid and Alamine 336 in decanol in a stirred cell falls in Regime 3, ie extraction accompanied by a fast chemical reaction occurring in the diffusion film. The reaction has been found to be zero order in Alamine 336 and first order in lactic acid with a rate constant of 0.21 s^?1. These data will be useful in the design of extraction processes. © 2002 Society of Chemical Industry     

Reactive extraction of 6-aminopenicillanic acid with aliquat-336: Equilibrium and kinetics

The reactive extraction of 6-aminopenicillanic acid (6-APA) from aqueous buffer solution has been studied using a liquid anion exchanger, tricaprylylmethyl ammonium chloride (Aliquat-336) in n-butyl acetate as the solvent. The extraction equilibrium constant and partition coefficient increase with increase in pH up to a limiting value of pH, beyond which extraction decreases due to coextraction of OH^? and buffer anions and hydrolytic decomposition of 6-APA. The experimental data could be predicted from an equilibrium model which takes into account the ideal behaviour of the two liquid phases. The coextraction of the buffer anion under low pH conditions was found to be negligible. The extraction rate measured in a stirred cell of constant interfacial area appears to be dependent on the interfacial mass transfer of the reactive species as well as on the interfacial reaction through its dependence on the concentration of 6-APA in the aqueous and organic phases, respectively.     

Transformation kinetics and potential availability of specifically-sorbed phosphate in soils

The improvement of P management in agriculture and environment requires a good understanding of residual effect of applied P in soils. The specific adsorption of P on variable charge minerals has been considered as the major mechanism that leads to a very low utilization of P fertilizer by crops within a growing season in Chinese red soils. Soil incubation and isotope tracing analysis were carried out to examine the transformation kinetics and potential availability of added specifically sorbed ³²P in two pH contrasting light textured soils. The ³²P recovered by 0.5 M NaHCO₃ extraction and microbial biomass-P measurement from the added specifically sorbed ³²P in the soils was well described by a first-order reaction and a Langmuir-type kinetic model, with correlation coefficients (R) being, on average, 0.938 and 0.959, respectively. The half-life (t_1/2, from the first-order model) of the four tested mineral-P complexes ranged from 29 to 47 d in the acid sandy soil and 33 to 105 d in the neutral silty soil. Goethite-P was the most stable among the four tested mineral-P complexes. The potential availability of the mineral complex P (q _m , in percent of total ³²P added) obtained from the Langmuir equation ranged from 43.7 to 90.9% for the four mineral-P complexes, and decreased in the order: Al oxide-P (90.9%) > montmorillonite-P (86.2%) > kaolinite-P (77.5%) > goethite-P (60.2%) in the acid sandy soil, whereas the order was Al oxide-P (89.3%) > kaolinite-P (86.2%) > montmorillonite-P (82.6%) > goethite-P (43.7%) in the neutral silty soil. Based on the release rate and potential availability, kaolinite-P and Al oxide-P could be important sources for residual effect of applied P in variable-charge soils. The goethite-P has the lowest release rate and potential availability among the mineral-P complexes, implying that iron oxides may be the most important variable-charge mineral responsible for P fixation in the Chinese red soils.     

Separation of hydroxybenzoic acid isomers using the molecular imprinting technique

Molecular imprinting polymers (MIPs) for salicylic acid (SA), 3‐hydroxybenzoic acid (3HBA), and 4‐hydroxybenzoic acid (4HBA) were synthesized using styrene and 4‐vinylpyridine (4‐VPy) as functional monomer and divinylbenzene (DVB) as crosslinker. The adsorption characteristics of hydroxybenzoic acid (HBA) isomers on each MIP were investigated. The materials used for the polymerization of each 3HBA and 4HBA‐MIPs were adsorbed relatively well. This verifies that the MIPs that can adsorb template selectively were synthesized. However, SA‐MIP had no molecular imprinting effect. SA has intramolecular hydrogen bond and it is difficult to adsorb on recognition site of SA‐MIP, because its structure differs from that of recognition site of SA‐MIP. It indicates that SA‐MIP had no recognition effect. 1,2,3,4‐Tetrahydro‐1‐naphthol (THN)‐MIP was synthesized, which is similar to SA with intramolecular hydrogen bond. SA was separated selectively using THN‐MIP. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Reactive separation of p-nitro phenol (PNP) from aqueous solution using tri-n-butyl phosphate: equilibrium and COSMO-RS studies

ABSTRACT

The present study is aimed to optimized diluent type, tri-n-butyl phosphate (TBP) composition and temperature for the reactive extraction of p-nitro phenol (PNP) in two different PNP concentration ranges [(0.00036–0.00646) kmol·m^?3 and (0.00646–0.01437) kmol·m^?3] as found in industrial effluents. 1-Octanol is investigated as the best diluent with TBP based on COSMO-RS theory. Equilibrium study based on mass action law is performed to find the insights of extraction mechanisms, equilibrium constant (K = 295.12 k·mol^?1) and stoichiometry (m:n = 1:1) as also confirmed by FTIR. Thermodynamic parameters, enthalpy (ΔH°), and entropy (ΔS°) are determined 27.51 K J mol^?1 and ?50.21 J mol^?1 K^?1, respectively.     

鹤峰磷矿在硫、磷混酸中的溶解动力学

对鹤峰磷矿在硫、磷混酸中的溶解动力学进行了研究,考查了硫酸质量分散及反应温度对酸解过程的影响;选用考虑了自阻化因素的德罗兹多夫方程In100/(100-Kp)-βKKp%=kt描述酸解过程的动力学.研究结果表明:鹤峰磷矿在硫、磷混酸中的反应速率常数随温度升高而增加,随硫酸质量分效的增加而减小.该反应属于扩散控制,平均反应活化能约为32.7kJ/mol.     

磷尾矿煅烧及酸浸过程动力学研究

以湿法磷酸生产的经浮选后的废弃磷尾矿为原料,从其中分离回收钙镁,制备新型土壤调节剂糖醇钙镁,对磷尾矿进行了煅烧活化和酸浸动力学的实验研究。基于热重分析及钙镁酸解浸出率分析的研究结果表明,磷尾矿中白云石热分解过程为吸热反应,白云石热分解遵循二维相界面反应模型;钙、镁浸出反应表观活化能分别为13.157、23.023 kJ/mol;煅烧活化后的尾矿酸浸出速率受内扩散控制,获得白云石热分解及钙、镁浸出反应的动力学方程。     

Extraction of citric acid from aqueous solutions with Alamine 336: equilibrium and kinetics

Citric acid is one of the organic acids for which the world market is growing every year. This article describes equilibria and kinetic studies for the extraction of citric acid by Alamine 336 with methyl‐iso‐butylketone (MIBK) as diluent. The theory of extraction accompanied by a chemical reaction has been used to obtain the intrinsic kinetics of extraction of citric acid by Alamine 336 in MIBK. The reaction has been found to be first order in both Alamine 336 and citric acid with a rate constant of 0.013 m³ kmol^?1 s^?1. Copyright © 2004 Society of Chemical Industry