KINETICS OF URANIUM EXTRACTION BY MACROPOROUS BIFUNCTIONAL PHOSPHINIC ACID RESIN

ABSTRACT

The rate of extraction of uranium by macroporous bifunctional phosphinic acid (MPBPA) resin from nitric acid medium has been studied under particle diffusion controlled conditions. The internal diffusion coefficient was found to increase with increase in temperature and decrease with increase in particle size. The activation energies and entropies suggest that the extraction of uranium essentially follows ion exchange mechanism at low concentration of nitric acid while it is through linkage of >P=0 group of the resin at high concentrations.     

EXTRACTION OF ACTINIDES BY BIFUNCTIONAL PHOSPHINIC ACID RESIN

ABSTRACT

The extraction of U(VI), Am( III), Pu( IV), Np( IV) and ThIV) by bifunctional phosphinic acid resin of various cross linkages is reported as function of nitric acid concentration. From the comparison of the distribution coefficient values it is suggested that the recovery of these actinide elements from waste solutions as we II as their mutual separations is possible by using phosphinic acid resin.     

离子交换树脂回收L-苯丙氨酸

为降低Ａｓｐａｒｔａｍｅ生产成本,建立了１套水解二肽母液,并用离子交换树脂分离Ｌ苯丙氨酸的回收工艺。该工艺可使Ｌ苯丙氨酸回收率达７２％以上,且其质量完全达到生产Ａｓｐａｒｔａｍｅ的要求     

SOLVENT EXTRACTION OF URANIUM( VI) AND THORIUM( IV) FROM NITRATE MEDIA BY CARBOXYLIC ACID AMIDES

ABSTRACT

A series of nineteen N-alkyl carboxylic acid amides (R.CO.NHR') has been prepared, in which the alkyl groups R and R' have been varied in order to introduce different degrees of steric complexity into the compounds. A smaller number of N,N-dialkyl amides (R.CO.NR₂) and non-substituted amides (R.CO.NH₂) has also been prepared for comparison purposes. These amides were characterized by measurement of their boiling points, melting points, refractive indices and densities.|The solvent extraction of uranium(VI) and thorium(IV) from sodium nitrate media by solutions of the amides in toluene was studied. Increasing steric bulk of the alkyl groups R and R' was found to cause a marked decrease in the extraction of thorium, with a much smaller effect on the extraction of uranium, thus considerably enhancing the separation between these metals. Vapour pressure osmometry studies indicate that the N,N-alkyl amides are self-associated in toluene solution, with aggregation numbers up to about 2.5 for 0.6 M solutions at 35°C. In contrast, the N,N-dialkylamides behave as monomers under these conditions. The distribution ratios for the extraction of uranium and thorium show second- and third-order dependences, respectively, on the extractant concentration for both the N-alkyl and N,N-dialkyl amides.     

膜法回收钛白废液中硫酸的实验研究

本文研究了自制的均相渗析阴膜对对钛白废液中废酸的回收效果,实验考察了膜的交换容量,苯环卤含量,废液中的组分的相对浓度等因素对渗析过程的影响,结果表明,用自制的阴膜回收膜废液中的Ｈ２ＳＯ４是可行的,能实现Ｈ２ＳＯ４与其他成分如ＦｅＳＯ４,Ｔｉ（ＳＯ４）２的良好分离,其分离系数分别不低于２６．０和５１．０。     

萃取-蒸馏法处理与回收糠醛废水中醋酸的研究

本文研究了溶剂萃取法去除糠醛废水中醋酸的工艺过程。通过实验得出，用含磷溶剂和烷烃化合物组成的混合溶剂处理糠醛废水中，醋酸的回收率较高。含醋酸的溶剂可以通过蒸馏回收醋酸，回收的溶剂可以循环使用，经处理过的废水可以利用，从而达到不排放或少排放的闭路循环。     

大孔树脂在高纯过氧化氢生产中的应用

研究了抗氧化性较好的大孔吸附树脂和大孔阴阳离子交换树脂生产高纯过氧化氢的方法。通过实验选择了D990 4作为脱除有机物的树脂 ,在 8BV/h的流速下 ,总有机碳 (TOC)净化度为 88.7%。通过电感耦合等离子直读光谱仪 (ICP)分析离子含量的变化 ,考察了大孔阴阳离子交换树脂的净化效果。在 8BV/h的流速下 ,ICP检出物总净化率达 98.5 % ,总P去除率大于 99.9% ,可满足电子工业的需要。     

LIQUID - LIQUID EXTRACTION OF GALLIUM(m) FROM ACIDIC NITRATE MEDIA WITH BIS(2-ETHYLHEXYL) PHOSPHINIC ACID IN TOLUENE

ABSTRACT

The distribution equilibria of gallium(III) between bis(2-ethylhexyl) phosphinic acid dissolved in toluene and acidic aqueous nitrate media has been investigated as a function of the concentration of extractant in organic phase and concentration of hydrogen ion and gallium(III) ion in aqueous phase. The extraction characteristics of bis(2-ethythexyl) phosphinic acid are compared with that of bis(2-ethylhexyl) phosphoric acid to get further information. The stoichometry of the extracted species is determined on the basis of slope analysis and IR spectra. Gallium is extracted by a cation exchange mechanism as GaRs₃ by bis(2-ethylhexyl) phosphinic acid and as GaRs₃-HR by bis(2-ethylhexyl) phosphoric acid. Temperature dependence of the extraction equilibrium is examined by temperature variation method. Both extraction processes are endothermic in nature and increase in temperature is favorable.     

EXTRACTION CHEMISTRY OF COBALT AND NICKEL BY DI(1-METHYLHEPTYL)PHOSPHINIC ACID

The fundamental characteristics and mechanism of extraction of cobalt (II) and nickel(II) by di-(1-methylheptyl) phosphinic acid (DMHPA) were studied. The extraction ability of cobalt(II), nickel (II) and various metals by DMHPA decreases in the order Fe(III) > Zn ? Pb(II) > Mn(II) > Cu(II) > Co(II) > Mg > Ca > Ni(II). The difference of the pH_½ values for nickel and cobalt reaches 2.06 pH units, which is apparently greater than those from extraction by di(2-ethylhexyl)phosphoric acid (DEHPA)and 2-ethyl-hexyl ester 2-ethylhexylphosphonic acid(DHEHPA).The slope analysis and IR spectroscopy reveal that the stoichiometrics of cobalt and nickel extracted species are Co(HA₂)₂ and Ni(HA₂)₂(H₂O)₂ respectively. As demonstrated by the study of the electronic spectroscopy the structure of the extracted complexes were shown as tetrahedral and octahedral configuration respectively. Furthermore, the coordination field parameters of the complexes were calculated.     

DILUENT EFFECT ON THE EXTRACTION OF URANIUM(VI) FROM HYDROCHLORIC ACID SOLUTIONS BY TRIOCTYLMETHYLAMMONIUM CHLORIDE

ABSTRACT

The extraction of uranium(VI) from hydrochloric acid solutions by trioctylmethylammonium chloride (TOMAC) has been examined using various diluents such as benzene, chlorobenzene, o-dichlorobenzene, toluene, m-xylene, nitrobenzene, carbon tetrachloride, chloroform and 1,2-dichloroethane. It was found that by assuming a regular solution, the distribution coefficient and the enthalpy change associated with the metal extraction can be expressed in terms of the solubility parameter of TOMAC, diluent and the complex formed in the organic phase and their molar volumes. Additionally an empirical relation holds between distribution coefficient and the viscosity of diluent. Further results for the extraction of divalent manganese, cobalt, copper, zinc and cadmium from hydrochloric acid solutions by TOMAC are investigated in comparison with those of uranium(VI).     

ENRICHMENT AND PURIFICATION OF BITESPIRAMYCIN USING MACROPOROUS RESIN

Bitespiramycin was purified by selective adsorption. The adsorption and desorption properties of bitespiramycin on six different macroporous resins (HZ806, HZ816, HZ820, HZ830, XAD16, and SP207) were compared systematically. According to the adsorption capacity and selectivity towards 4″-O-isovalerylspiramycin, HZ820 was chosen as the most suitable resin for bitespiramycin purification. The equilibrium data on HZ820 in a batch system were well described by Langmuir and Freundlich models. The film and pore diffusion model was successfully measured in batch adsorption kinetics. Dynamic adsorption and desorption experiments were also performed using a packed column of HZ820 to optimize the separation process of 4″-O-isovalerylspiramycin from aqueous solution. After being treated with HZ820, the 4″-O-isovalerylspiramycin content increased from 80.4% to 91.7%, and the 4″-O-isovalerylspiramycin III content increased from 41.7% to 64.4%.     

SORPTION OF URANIUM FROM NITRIC ACID SOLUTION USING TBP-IMPREGNATED ACTIVATED CARBONS

ABSTRACT

The concept of extracuon chromatography has been used to study the sorption of uranium from nitric acid solutions using tri-n-butyl phosphate ( TBP) impregnated activated carbons. Batch equilibrium data and kinetic and breakthrough column behaviour of uranium are reported. Wood based activated carbon has shown better capacity and breakthrough characteristics than shell based activated carbon. Sorption rate on impregnated carbons was relatively slow indicating that diffusion is the rate controlling step within the pore structure of the activated carbon. Uranium distribution on impregnated activated carbons is compared with equivalent bulk liquid extraction and a mechansim of uranium sorption is discussed.     

活性炭与离子交换树脂提取L－苯丙氨酸

根据活性炭对Ｌ－苯丙氨酸的选择吸附特性，通过活性炭吸附及氨水、乙醇溶液解析从酶转化液中成功地分离提取了Ｌ－苯丙氨酸、Ｌ－天冬氨酸，并利用７１７＃树脂脱色和去杂离子，浓缩结晶得到符合标准的Ｌ－苯丙氨酸晶体。整个工艺路线对Ｌ－苯丙氨酸的洗脱收率接近１００％，原料总收率大于７０％。     

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.     

硫酸法钛白粉生产工艺中的偏钛酸回收新技术研究

本文采用无机分离膜技术对硫酸法钛白粉生产产生的废酸、废水中的偏钛酸回收进行了实验研究，结果表明，采用粒子烧结生产的α－Ａｌ２Ｏ３陶瓷膜处理废酸、废水具有性能稳定、再生容易、操作成本低等突出优点，既解决了环保问题，又提高了钛白粉的收率，具有明显的社会、经济效益。     

硝酸氧化淀粉水解液制备草酸过程中NOx的回收利用

用淀粉水解液吸收硝酸氧化碳水化合物生产草酸过程中的ＮＯｘ，吸收率≥９９．２％。吸收过ＮＯｘ后的淀粉水解液进一步用硝酸氧化制备草酸时，可节约硝酸６７％，草酸收率也由原来的５６％提高到８０％以上。氧化条件温和，几乎无二次污染。     

大孔树脂吸附处理PTA精制废水的研究

采用大孔吸附树脂对PTA废水进行处理,对吸附树脂进行了初步筛选,研究吸附操作的工艺条件对吸附效率的影响。结果表明,HPD-950型大孔树脂对PTA精制废水具有较强的处理能力。试验同时通过静态试验考察得出了较佳的操作条件:树脂加入量为8 g/L、振荡时间为2.5 h、吸附温度为25℃、振荡强度为200 r/min和pH为4。通过动态试验考察了工业化所关注的停留时间,运行时间和再生时间对树脂吸附效果的影响,得出了最佳的操作条件为:停留时间为30 min、运行时间为50 h、再生时间为30 min。     

COBALT-NICKEL SEPARATION BY SOLVENT EXTRACTION WITH BIS(2,4,4 TRIMETHYLPENTYL)PHOSPHINIC ACID

Abstract

The use of an organophosphinic acid to separate cobalt from nickel by solvent extraction is described. Comparative data indicate that the phosphinic acid is superior to analagous phosphoric and phosphonic acids in terms of cobalt-nickel selectivity and the ability to reject calcium. Important reagent properties, such as low aqueous solubility and hydrolytic stability, are discussed. The results of continuous, counter-current, mini-plant tests demonstrate the recovery of high purity cobalt from concentrated nickel sulphate solutions.     

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.     

均三甲苯液相催化氧化制备间二甲基苯甲酸

研究了均三甲苯液相催化氧化制备间二甲基苯甲酸 ,氧化剂为富氧 ,考察了催化剂浓度、通气量、反应温度等工艺条件对反应的影响。结果表明适宜的反应条件为氧浓度 5 6 .6 %、通气量 1.3L/min、催化剂浓度为每mol均三甲苯中含Co2 3 .3× 10 -4 mol,反应温度为 130～ 140℃