织金磷矿酸浸液萃取分离稀土试验研究

研究了用溶剂萃取法从织金磷矿酸浸液中分离稀土,考察了各因素对稀土萃取率和反萃取率的影响,确定了适宜的萃取条件。结果表明:用P204作萃取剂,控制相比为3∶1、P204浓度为1.5 mol/L、初始水相P2O5质量浓度为101.20g/L、在室温下萃取15min,稀土萃取率为89.62%;在相比1∶8、6mol/L盐酸为反萃取剂、室温下反萃取10min条件下,稀土反萃取率为87.86%。     

P204-N235体系协同萃取稀土钇和钆的实验研究

普遍的稀土分离采用一种萃取剂萃取,其萃取率较低,为提高稀土萃取率使其资源最大化利用,本文采用P204-N235混合共同萃取体系来萃取氯化钇和氯化钆的混合稀土料液,通过研究P204-N235相比、P204-N235体积比、震荡时间、P204-N235协同萃取氯化钇与氯化钆水相初始料液PH值及稀土离子浓度,实验结果表明P204-N235协同萃取稀土当P204-N235相比为3∶1、P204与N235萃取剂体积比为1∶1、震荡时间为10 min、P204-N235协同萃取氯化钇与氯化钆水相初始料液PH值=3、稀土离子浓度为0.1 mol/L时可强化稀土的萃取效果。     

P_(204)萃取含铜酸性废水中铁的研究

本文采用P204萃取剂对湿法炼铜酸性废水中的铁进行了萃取反萃研究。研究了混合时间、P204体积浓度和相比对萃取铁的影响,同时检测了萃取过程中水相硫酸浓度的变化。针对本试验研究的原料液,采用50%P204在相比(O/A)为9/1时进行萃取,Fe3+的萃取率达到85.96%。采用6N盐酸溶液对负载Fe3+的50%P204有机相进行反萃,当反萃相比(O/A)达到1∶9时,Fe3+的反萃率达到77.44%。     

高浓度稀土浸出液的协同分步萃取试验研究

P204和P507常用作萃取剂用于稀土浸出液的萃取,采用单一萃取剂萃取难以有效分离、富集稀土,本文利用P507萃取高浓度稀土溶液时对轻稀土萃取能力较弱而P204萃取能力强的特点,创新性提出采用P507与TBP协同萃取中重稀土,然后采用P204与TBP协同萃取轻稀土的工艺,并进行了萃取、反萃取试验,得出以下结论。在试验原料条件下,采用二级萃取工艺,当相比A/O=10/1、pH值4.0、常温、P507体积分数35%、TBP体积分数5%时,P507+TBP对中、重稀土的萃取率较佳,均能达到90%以上;采用二级萃取工艺,在P204体积分数35%、TBP体积分数5%、相比A/O=15/1、常温、萃取时间5 min的条件下,P204+TBP对轻稀土的萃取率达到97%。P507与P204的负载有机相在适当的酸性条件下,P507负载有机相经二级逆流反萃、P204负载有机相经三级逆流反萃后均可得到高浓度的稀土富集液,浓度值达到直接进入萃取分离线的要求。该研究在低能耗、低试刘消耗条件下实现了稀土提取利用及初步分离,所生产的氯化稀土溶液可以直接进入稀土分离厂进行分离提纯,为高浓度稀土回收分离提供了参考。     

P204-P350萃取体系萃取稀土铈的研究

用P204和P350组成的二元协同萃取体系萃取氯化铈稀土料液,研究萃取体系的震荡时间、相比及稀土离子浓度对萃取率的影响,结果表明,当P204与P350体系的振荡时间9 min、相比1:1、稀土离子浓度为0.1 mol/L时,协同萃取体系具有最佳萃取效果,此时萃取率为71％;红外表征中萃取相出现的特征峰,可定性说明萃取反...     

改性PVDF中空纤维液膜富集Er~(3+)的研究

为改善聚偏氟乙烯(PVDF)液膜稳定性并获得较高Er~(3+)萃取率,采用0.5%LiCl共混改性膜自制膜萃取器,研究了LiCl改性PVDF中空纤维膜对稀土离子Er~(3+)的富集。结果表明,Er~(3+)的萃取率随着载体HEHEHP浓度、反萃剂盐酸浓度和两相流速的增加先增大后减小,随着料液相初始H~+浓度增加而降低。研究获得Er~(3+)的最佳萃取工艺为:料液相初始H~+浓度为0.065 mol/L,反萃剂盐酸浓度为3.0 mol/L,载体HEHEHP浓度为0.25 mol/L,两相流速为10 mL/min。在此条件下,进一步考查了不同LiCl含量改性中空纤维膜富集Er~(3+)的效率。     

硫酸体系中反萃取Ni(Ⅱ)的动力学研究

采用恒界面池法研究了用P507-硫酸体系反萃取Ni(Ⅱ)的动力学，考察了搅拌速度、界面积、温度、硫酸浓度、负载镍有机相(NiA₂)浓度对Ni(Ⅱ)初始反萃取速率的影响。结果表明：Ni(Ⅱ)初始反萃取速率随温度升高而升高，反萃取反应表观活化能为23.3 kJ/mol,反萃取过程受扩散和化学反应混合控制，且反应发生在相界面处，硫酸反萃取Ni(Ⅱ)的动力学速率方程为：r₀=K[NiA₂]^1.01[H⁺]^1.83。     

富集稀土磷酸溶液中稀土的萃取研究

研究了P204从富集稀土磷酸溶液中稀土元素钇、镧、钕的萃取行为,并考察了初始水相中P_2O_5浓度、萃取相比、萃取剂浓度、萃取时间对稀土萃取效果的影响。结果表明,低磷酸浓度、较大相比、较高萃取剂浓度和较长萃取时间有利于萃取稀土,并得到了萃取优化条件:初始水相中P_2O_5浓度10%、萃取相比V_0/V_1=3/1、萃取时间15min、P204浓度30%,在室温下萃取钇、镧、钕3种稀土,单级萃取率均可达到90%以上。     

非平衡体系络合交换分离钆铒的研究

以P204为萃取剂及二乙基三胺五乙酸（DTPA）为水相络合剂,研究了用非平衡溶剂萃取法从氯化稀土溶液中分离钇 铒的水相pH值,适合时间,DTPA浓度等因素对分离钇铒的影响,结果表明,在水相加入DTPA,钇的萃取速度较快,铒的萃取速率较慢,控制两相混合时间,用非平衡溶剂萃取法可有效分离钇铒。     

薄层油膜层流萃取分离相邻稀土铕和钆

相邻稀土元素铕（Eu）和钆（Gd）的物理化学性质相似,分离尤其困难。常规平衡萃取方法Eu、Gd的分离效率低。采用薄层油膜层流萃取法,不仅可以加快界面更新速度,还可以控制水相层流运动。以双功能离子液体[A336][P204]为萃取剂,发现萃取剂浓度升高和油膜层厚度减小,均有利于萃取,但不利于分离。而水相流速增加,不利于萃取,但有利于分离。基于薄层油膜层流萃取法,依靠Eu、Gd传质速度的差异,可以实现动力学调控相邻稀土的分离。     

D2EHPA-HCl-HAc体系萃取Pm(Ⅲ)的机理与平衡常数

在pH>1条件下,采用EDTA容量滴定法测定D2EHPA-HCl-HAc体系萃取Pm(Ⅲ)过程两相中的Pm浓度,分别考察溶液酸度和萃取剂浓度对Pm的分配比的影响,通过红外光谱测试探究D2EHPA-HCl-HAc体系萃取Pm的机理,并确定萃取平衡常数。结果表明,萃取过程的实质是Pm离子与基团P-OH发生置换,遵循阳离子交换机制,以及与基团P=O发生的络合配位作用,其萃取平衡常数KPm为3.02。     

复杂镍浸出液萃取净化的研究

以D2EHPA为萃取剂,从钼镍矿的复杂镍浸出液中萃取分离锌、铜。考察了萃取平衡时间、D2EHPA体积浓度、相比(O/A)、料液pH对萃取分离锌、铜效果的影响,确定了D2EHPA萃取锌、铜的最佳条件。室温下萃取除杂的最佳工艺条件为:萃取平衡时间3 min,D2EHPA的体积浓度20%,相比1∶1,料液pH=2.0,一级萃取率锌为89.5%,铜为11.0%。负载有机相经1 mol/L的H2SO4反萃,锌、铜和镍均可完全反萃。经三级逆流萃取可将料液中锌降低到0.01 g/L,萃取率达98.9%。     

Solvent extraction of cadmium from sulfate solution with di-(2-ethylhexyl) phosphoric acid diluted in kerosene

In the present paper, solvent extraction process has been used for extraction of cadmium from sulfate solution using di-(2-ethylhexyl) phosphoric acid (D2EHPA) with 1% isodecanol in kerosene diluent expected from industrial effluents or leaching of ores/secondary materials. Different process parameters such as pH, contact time, extractant concentration, O/A ratio etc. were investigated. Results demonstrated that quantitative extraction of cadmium was feasible from 4.45 mM cadmium feed solution in single stage at equilibrium pH 4.5, time 2 min and O/A ratio 1:1 with 0.15 mM D2EHPA. The extraction mechanism of cadmium from sulfate solution by D2EHPA in kerosene could be represented at equilibrium by Cd²⁺ + 3/2 (H₂A₂)_org ⇔ CdA₂(HA)_org + 2H⁺. The loading capacity of 0.15 mM D2EHPA in sulfate solution was determined to be ∼ 8.9 mM cadmium. The loaded cadmium was effectively stripped using 180 g/L sulfuric acid. The metal or salt could be produced by electrolysis or crystallization from the stripped solution.     

Synergistic extraction of iron(III) at higher concentrations in D2EHPA-TBP mixed solvent systems

The extraction of iron(III) from chloride solutions at macrolevel concentration by different solvents such as tri-n-butyl phosphate (TBP), di(2-ethylhexyl) phosphoric acid (D2EHPA), and their mixture in various proportions has been investigated at different acid concentrations. The synergistic extraction of iron(III) with a mixture of TBP and D2EHPA was studied and the results were compared with that of the extraction by individual solvent alone. An increase in the concentration of the synergist, TBP, in the D2EHPA-TBP solvent system resulted in an increase in the synergistic co-efficient value. The experimental data are treated graphically to explain the formation of organic phase extracted species, and the equilibrium extraction constants for the species are determined. It is found that a maximum of two molecules of TBP are adducted to the extracted species of the corresponding nonsynergistic system. Stripping of iron(III) with hydrochloric acid from loaded D2EHPA was found to increase with an increase in acid concentration. In the case of D2EHPA-TBP mixtures, stripping efficiency was increased with an increase in acid concentration up to a certain level and then it was decreased. The experimental results indicate that an iron exchange reaction between loaded D2EHPA and TBP proceeds during stripping at a higher concentration of hydrochloric acid (from mixed loaded solvent system). A plausible mechanism for iron(III) extraction and stripping has been discussed.     

P507D从稀硫酸溶液中萃取铟的研究

介绍了一种可替代Ｐ２０４用于萃取的Ｐ５０７改良萃取剂。研究了萃取剂的萃取性能，考察了有机相中萃取剂浓度、有机相与水相的体积比相互接触的时间，以及水溶液酸度对铟的萃取和Ｉｎ、Ｆｅ分离的影响。在最佳操作条件下，经过两有逆流萃取，９８％以上的铟得到提取。并进一步考察了以剂经多次循环运行后的抗老化性能。     

Study on a novel flat renewal supported liquid membrane with D2EHPA and hydrogen nitrate for neodymium extraction

The Nd(III) extraction in flat renewal supported liquid membrane(FRSLM),with polyvinylidene fluoride membrane and renewal solution including HNO3 solution as the stripping solution and di(2-ethylhexyl) phosphoric acid(D2EHPA) dissolved in kerosene as the membrane solution,was investigated.The effects of pH in the feed phase,volume ratio of membrane solution to stripping solution,concentra-tion of HNO3 solution and concentration of carrier in the renewal phase on extraction of Nd(III) were also studied,respectively.As a result,the optimum extraction conditions of Nd(III) were obtained when concentration of HNO3 solution was 4.00 mol/L,concentration of D2EHPA was 0.100 mol/L,and volume ratio of membrane solution to stripping solution was 1.00 in the renewal phase,and pH was 4.60 in the feed phase.When initial concentration of Nd(III) was 2.00×10-4 mol/L,the extraction percentage of Nd(III) was up to 92.9% in 75 min.     

The Recovery of a Mixed Rare-Earth Oxide and the Preparation of Cerium,Europium and Neodymium Oxides from a South African Phosphoric Acid Sludge by Solvent Extraction

Abstract

A novel process based largely on solvent-extraction methods has been developed for the recovery of rare-earth oxides from waste calcium sulphate sludges obtained during the manufacture of phosphoric acid from a South African apatite ore. A mixed rare-earth oxide (90-98% purity) was first recovered from calcium nitrate leach liquors by extraction with TBP or DBBP, after which it was dissolved in nitric acid to enable pure cerium dioxide (99.98%) to be prepared by selective extraction of cerium(IV) nitrate into TBP. The heavy (yttrium), middle, and light rare-earth fractions were then separated by sequential extraction into D2EHPA at controlled pH values. Pure europium oxide (99.98%) was isolated from the middle fraction by reductive precipitation of europim(II) sulphate, followed by conversion to soluble europium(II) chloride and removal of trivalent rare-earth impurities by extraction with D2EHPA or Versatic 10 acid. Finally, magnet-grade neodymium oxide (95-96%) was obtained from the light rare-earth fraction by extraction of the contained lanthanum, cerium and praseodymium into Aliquat 336 nitrate.     

Extraction of chromium (III) from spent tanning baths

Extraction of chromium(III) from a model spent tanning bath of the leather industry has been investigated using ammoniated and non-ammoniated di(2-ethylhexyl)phosphoric acid (D2EHPA) and bis(2,4,4-trimethylpentyl)phosphinic acid (Cyanex® 272). Chromium extraction of 95% by 15% (v/v) D2EHPA, 10% (v/v) isodecanol in kerosene and 86.1% by 15% (v/v) Cyanex® 272, 10% (v/v) p-nonylphenol in kerosene was obtained at equilibrium pH values of 4.0 and 5.0, respectively. The separation of small amounts of iron (III) and aluminium (III) present in the solution along with the Cr(III), was also examined and it was found that Cyanex® 272 was a better reagent than D2EHPA. The slow kinetics of extraction and stripping observed in the case of AI(III) was advantageous for its separation from Fe(III) at low pH values. Difficulties faced in the stripping of loaded metals were also studied because only about 80% chromium recovery by 8 M HCl was obtained from both solvents. The incomplete stripping of the metal may be a result of the formation of a stable species in the organic phase and needs further investigation. The Cr(III) can be recovered as chloride from the strip liquor and recycled for retanning purposes.     

Application of the Phase Transfer Catalysis in Rare Earth Solvent Extraction

ＡｐｐｌｉｃａｔｉｏｎｏｆｔｈｅＰｈａｓｅＴｒａｎｓｆｅｒＣａｔａｌｙｓｉｓｉｎＲａｒｅＥａｒｔｈＳｏｌｖｅｎｔＥｘｔｒａｃｔｉｏｎＹａｎＣｈｕｎｈｕａ（严纯华）；ＺｈａｎｇＹａｗｅｎ（张亚文）；ＬｉａｏＣｈｕｎｓｈｅｎｇ（廖春生）；ＪｉａＪｉａｎｇ...     

Extraction of Zinc‐Cobalt from Sulphate Solution of Cobalt Cake by D2EHPA in the Processing of Indian Ocean Nodules

During the processing of Indian ocean nodules, cobalt cake containing zinc in equal proportion is produced. In order to get pure cobalt and zinc from the sulphate leach solution of cake, a solvent extraction process has been considered using an organic extractant, di‐(2‐ethylhexyl) phosphoric acid (D2EHPA). Separation of cobalt and zinc has been carried out by mixing aqueous and organic phases in a rectangular vessel and separating the phases after equilibration in a glass funnel. The analysis of the metal from the aqueous phase was made by atomic absorption spectrometer to compute the metal transfer. The extraction and separation studies carried out under the different operating conditions indicated favourable zinc extraction at the lower pH (~ 2) with partially saponified D2EHPA. The small amount of cobalt co‐extracted with zinc was scrubbed with dilute sulphuric acid. With completely saponified D2EHPA, a high degree of cobalt extraction (99.8%) was achieved at aqueous feed pH of 5.0. The flow sheet developed could be used for the selective extraction and separation of zinc and cobalt from the leach liquor of cobalt cake.