Upper-rim-modified thioether thiacalix[4]arene used for liquid-liquid extraction of Au(Ⅲ)and Pd(Ⅱ)in hydrochloric acid medium

Gold(Au)and palladium(Pd)play an increasing role in the production and human life;Therefore,it is of great significance to study their recovery.A 5,11,17,23-tetra-ethylthio-25,26,27,28-tetra-hydroxyl thiacalix[4]arene(TCAET)was synthesized specifically for the capture of Au(Ⅲ)and Pd(Ⅱ)from HCl medium by liquid-liquid extraction.In a 0.1 mol·L^(-1)HCl medium,the transfer of Au(Ⅲ)and Pd(Ⅱ)from the aqueous phase to the organic phase was highly efficient,with a transfer ratio of 100%for Au(Ⅲ)and 98%for Pd(Ⅱ).Furthermore,the extraction equilibrium time for Au(Ⅲ)was just 5 min.Job's method data demonstrated that TCAET formed complexes with Au(Ⅲ)and Pd(Ⅱ)in a ratio of 2:3 and 1:1,respectively,during the extraction process.TCAET showed high selectivity toward Pd(Ⅱ)and Au(Ⅲ)over other competing metal ions.Moreover,both Au(Ⅲ)and Pd(Ⅱ)could be successfully stripped from the loaded organic phases with a 1.0 mol·L^(-1)thiourea in 0.5 mol·L^(-1)HCl and 0.5 mol·L^(-1)thiourea in 0.5 mol·L^(-1)HCl,respectively.Results obtained from five consecutive extraction-stripping cycles showed good reusability of TCAET toward Au(Ⅲ)and Pd(Ⅱ)recovery.The conclusion can provide a certain reference for thiacalixarene in the recovery of precious metal species.

Selective extraction and conversion of lignin in actual biomass to monophenols: A review

Our over dependency on the fossil resource for industrial chemicals and fuels faces great challenges. Recently, the production of monophenols from lignin in lignocellulosic biomass is regarded as a promising process for sustainable biofuels. This article discusses the conversion of lignin in actual biomass directly to monophenols. The two step way including extraction of lignin from biomass and further degradation of the lignin oligomers to monophenols is especially discussed. The obtained monophenols can also be converted to chemicals with low-oxygen content via hydrodeoxygenation process. For extraction of lignin, co-solvent system is the most adopted for hydrolysis or solvolysis of lignin assisted by acid or alkaline catalysts. The structure of the obtained oligomers derived from lignin is discussed in detail. For lignin depolymerization, hydrogenolysis is an efficient method with the use of gaseous hydrogen or alcohols as hydrogen source. At the meantime, depolymerization mechanism and the route for repolymerization of the reaction intermediates are presented here. In hydrodeoxygenation process, metal catalysts, especially noble metal catalysts are required. The precise effects of the reaction solvents and catalysts on extraction and degradation of lignin need to be further investigated, and this will benefit to design more efficient strategies for lignin utilization. ? 2016 Science Press

Application and challenge of rare earth automotive catalysts in CHINA Ⅵ

China is setting to roll out more strict emissions rule of CHINA Ⅵ Emission Standard which poses huge challenge to automotive catalytic technology.Rare earth elements are the key compositions of the catalysts coating.To develop multiple-component rare earth materials is an important way to improve the performance of the catalyst.The study concluded that quaternary or quinary rare earth materials for CHINA Ⅵ Emission Standard,can improve substantially the oxygen storage capacity and high thermal stability of the catalyst,after the modification by Pr/NdAT elements.It improved the utilization efficiency of precious metal.

Transport of yttrium metal ions through fibers supported liquid membrane solvent extraction

A novel idea of transport of yttrium(Ⅲ) metal ions through fibers supported liquid membrane in two stage processes namely source to membrane and membrane to receiving phase has been proposed.The fibers supported liquid membrane was impregnated with different concentrations carrier.The experimental variables explored were concentration of yttrium(Ⅲ) ions,pH of source phase,PC-88A concentration in membrane phase,acid concentration in receiving phase and stirring speed.The pre-concentration of yttrium(Ⅲ) ions ...

Magnetic Iron Oxide Nanoparticles Modified with Moringa Seed Proteins for Recovery of Precious Metal Ions

Precious metals are highly demanded economic value metals that require to be recovered from industrial wastes and electronic used products (e-waste). They are such as gold (Au) as well as Platinum Group Metals (PGMs) for instance palladium (Pd) and platinum (Pt). The study was conducted to test the magnetic iron oxide nanoparticles modified with Moringa oleifera seed proteins as adsorbent for recovery of Au(III), Pd(II) and Pt(IV) from aqueous solutions. Different functional groups responsible for adsorption, morphology, thermal stability, and surface charges of the nanoparticles were characterized with FTIR, SEM, TGA and Zeta potential respectively. Batch adsorption method was used, and precious metal ions percentage recovery was measured using ICP-OES. The effects of pH, initial adsorbate concentration, adsorption agitation time and adsorbent dosage were studied at room temperature of 25°C. Au(III) yielded a maximal recovery of 99.8%, followed by Pt(IV) with 87.7%, then Pd(II) with 72.7% at a pH 2.5, 10 mg/L initial adsorbate concentration, 120 minutes agitation time and 0.065 g adsorbent dosage. These results suggested that modified iron oxide nanoparticles were effective in selective recovery of the precious metal ions.

Recovery of rare and precious metals from urban mines —— A review

Urban mining is essential for continued natural resource extraction. The recovery of rare and precious metals （RPMs） from urban mines has attracted increasing attention from both academic and industrial sectors, because of the broad application and high price of RPMs, and their low content in natural ores. This study summarizes the distribution characteristics of various RPMs in urban mines, and the advantages and shortcomings of various technologies for RPM recovery from urban mines, including both conventional （pyrometallurgical, hydrometallurgical, and biometallurgical processing）, and emerging （electrochemical, supereritieal fluid, mechanochemical, and ionic liquids processing） technologies. Mechanical/physical technologies are commonly employed to separate RPMs from nonmetallic components in a pre-treatment process. A pyrometallurgical process is often used tbr RPM recovery, although the expensive equipment required has limited its use in small and medium-sized enterprises. Hydrometallurgical processing is effective and easy to operate, with high selectivity of target metals and high recovery efficiency of RPMs, compared to pyrometallurgy. Biometallurgy, though, has shown the most promise for leaching RPMs from urban mines, because of its low cost and environmental friendliness. Newly developed technologies electrochemical, supercritical fluid, ionic liquid, and mechanochemical have offered new choices and achieved some success in laboratory experiments, especially as efficient and environmentally friendly methods of recycling RPMs. With continuing advances in science and technology, more technologies will no doubt be developed in this field, and be able to contribute to the sustainability of RPM mining.

Phase transfer-based high-efficiency recycling of precious metal electrocatalysts

Recycling precious metals with high-efficiency is undoubtedly beneficial to optimize resource utilization for environmental remediation and sustainable development.Herein,we report an efficient route to recycle the palladium(Pd)and platinum(Pt)electrocatalysts using a phase transfer method.This strategy involves acidic dissolution of deactivated precious metal(Pd/Pt)electrocatalysts from their loading substrates,mixing with an ethanolic solution of dodecylamine(DDA),subsequent extraction of metal ions into a non-polar organic phase,and final reduction by sodium borohydride to reproduce high-performance electrocatalysts towards typical electrochemical reactions,e.g.,oxygen reduction reaction(ORR)and ethanol oxidation reaction(EOR).In specific,the transfer efficiencies are up to 98%and the final recovery rate is over 85%for Pd and Pt electrocatalysts in each cycle.This approach symbolizes a facile and efficient way to recover precious metals,which might be applied to recycling a wide range of metals in various realms after appropriate modifications.

Oxygen Storage Capacity of Pt-, Pd-, Rh/CeO_2-Based Oxide Catalyst

CZO （CeO2-ZrO2） and CZYO （CeO2-ZrO2-Y2O3） series of mixed oxides were prepared by coprecipitaion, and a part of these oxides were loaded with precious metals （PM）. XRD, BET, and oxygen storage capacity （OSC） investigations were performed on samples aged at 750, 900, and 1050 ℃. It was observed that BET surface area and OSC showed a marked decrease in CeO2 aged at high temperature, and the erystallite size showed an obvious increase. The CZO samples consist of cubic- and tetragonal crvstal phases, and their crystallite size increase rapidly when aged at high temperature. The CZYO samples consist of single crystal phase when the content of Y exceeds 0.15 mol, and their erystallite size increases slowly during high-temperature aging. It is concluded that additive Y can stabilize the performance of CZYO oxides. In the aged CZO and CZYO mixed-oxide systems, addition of a small amount of precious metals （Pt, Pd, Rh） increased the rate of reduction and led to an obvious improvement in OSC. OSC of CZO and CZYO with precious metals are related to their composition and the type of precious metal.

Influence of Ce_(0.35)Zr_(0.55)Y_(0.10) Solid Solution on Performance of Pt-Rh Three-Way Catalysts

Ce0.35Zr0.55Y0. 10 solid solution was prepared by co-precipitation technique and characterized by specific surface area measurements （BET） and X-ray diffraction （XRD）. Ce0.35Zr0.55Y0.10 was used to prepare low Pt-Rh threeway catalyst （TWC）, and its influence on the performance of TWC was investigated. The results revealed that Ce0.35 Zr0.55Y0.10 had a cubic structure similar to Ce0.50Zr0.50O2 and its specific surface area can maintain higher than Ce0.50 Zr0.50O2 after 1000 ℃ calcination for 5 h. Being hydrothermal aged at 1000 ℃ for 5 h, the catalyst containing Ce0.35 Zr0.55Y0.10 still exhibited higher conversion of C3H8, CO and NO and lower light-off temperature in comparison with Ce0.50Zr0.50O2 TWC.

Extraction and separation of Nd(Ⅲ), Sm(Ⅲ), Dy(Ⅲ), Fe(Ⅲ), Ni(Ⅱ), and Cs(Ⅰ) from concentrated chloride solutions with N,N,N',N'-tetra(2-ethylhexyl) diglycolamide as new extractant

The feasibility of using N,N,N＇,N＇-tetra（2-ethylhexyl）diglycolamide （TEHDGA） in 75 vol.% n-dodecane-25 vol.% n-octanol as agents for the extraction and separation ofNd（III）, Sm（III）, Dy（llI）, Fe（III）, Ni（II）, and Cs（I） from concentrated chlo- ride solution was investigated. Different extraction behaviors were obtained towards rare earth elements （REE） studied and Fe（IIl）, Ni（II） and Cs（I）. Efficient separation of Nd（III）, Sm（III） and Dy（III） from Fe（III）, Ni（II）, and Cs（I） was achieved by TEHDGA, depending on the HCI, HNO3 or H2SO4 concentration. A systematic investigation was carried out on the detailed extraction prop- erties of Nd（III）, Sm（III）, and Dy（III） with TEHDGA from chloride media. The IR spectra of the extracted species were investi- gated.

Recovery of rare earths from acid leach solutions of spent nickel-metal hydride batteries using solvent extraction

The extraction of rare earths from acid leach solutions of spent nickel-metal hydride batteries using a primary amine ex- tractant of N 1923 was studied. The effects of feed pH, temperature, agitation rate and time on the extraction of rare earths, as well as stripping agent composition and concentration, phase ratio on the stripping were investigated. In addition, the extraction isotherm was determined. The pilot plant test results showed that the extraction of rare earths reached 99.98% after a five-stage counter current extraction. The mixed rare earths oxalates with the 99.77% purity of rare earth elements and impurity content less than 0.05% were obtained by the addition of oxalic acids in loaded strip liquors. The extractant exhibited good selectivity of rare earths over base metals of iron, nickel, copper and manganese.

Enhancing extraction ability by rational design of phosphoryl functionalized ionic liquids and mechanistic investigation on neodymium(III) extraction

Four ionic liquids （ILs）： 3-（diethoxyphosphoryl）propyl triphenylphosphinium hexafluorophosphate [Ph3PC3P（OEt）2][PF6] （IL-1）, 3-（ethoxyphenylphosphoryl）propyl triphenylphosphinium hexafluorophosphate [Ph3PC3PPh（OEt）][PF6] （IL-2）, 3-（diphenylphosphoryl）propyl triphenylphosphinium hexafluorophosphate [Ph3PC3P（Ph）2][PF6] （IL-3）, and 3-（diethoxyphosphoryl）propyl triphenylphosphinium bis（trifluoromethanesulfonyl）imide [Ph3PC3P（OEt）2][NTf2] （IL-4） were synthesized and characterized by IR and 31p, 1H, 13C NMR spectroscopy. The liquid-liquid extraction of neodymium（Ⅲ） by these phosphorus functionalized ionic liquids （PFILs） diluted with common room temperature ionic liquid 1-hexyl-3-methylimidazolium bis（trifluoromethylsulfonyl）imide [C6mim][NTf2] was studied. The extraction percentage of Nd（Ⅲ） was measured as a fimction of various parameters, such as the ini- tial pH of aqueous phase, equilibrium time, temperature, and concentration of PFIL extractant. The influence of the nature of diluents and salting-out reagents on extraction was also investigated. The results indicated that the extraction process was exothermical and the extraction percentage of Nd（Ⅲ） by IL-1 was the highest among the PFILs investigated. A possible metal complexation mechanism was proposed for the present PFIL/IL extraction system. And the loaded Nd（Ⅲ） ions by PFIL could be stripped completely from the ionic liquid phase by 1 mol/L nitric acid.

从赤泥酸浸液中分离提取稀土试验研究

研究了用P507从赤泥酸浸液中分离提取稀土。首先用35%N235+15%TBP+50%磺化煤油萃取赤泥酸浸液中的铁,再用氧化镁浆液沉淀萃取铁后萃余液中的钛、钪、铝、稀土,稀土沉淀物经盐酸溶解后用P507萃取,最终得到高浓度氯化稀土产品。结果表明:以35%P507+65%磺化煤油为有机相萃取稀土,在常温、萃取时间1 min、萃取相比V_(a)/V_(o)=50/1条件下进行2级萃取,稀土萃取率可达94.34%;再用6 mol/L盐酸,在反萃取相比V_(o)/V_(a)=14/1、反萃取时间5 min条件下进行2级反萃取,稀土反萃取率达97.16%。该法可实现赤泥中稀土的有效分离提取。

蒸硒渣中稀贵金属提取工艺

针对粗硒真空蒸馏产出的蒸硒渣,开发了碱性氧化焙烧/硫酸化焙烧-湿法联合梯级处理工艺,对比研究了不同处理方法对蒸硒渣中稀贵金属浸出率的影响。结果表明:采用碱性氧化焙烧-湿法联合工艺处理蒸硒渣时,Au、Ag、Pt、Pd的浸出率分别为53.18%、18.32%、96.64%、98.14%,Se浸出率>99%,Te、Cu的浸出率分别为74.66%、83.55%;采用硫酸化焙烧-湿法联合工艺处理蒸硒渣时,Au、Ag、Pt、Pd的浸出率分别为99.33%、99.95%、96.49%、95.26%,Se浸出率为99.97%,Te、Cu的浸出率分别为98.52%、99.98%。碱性氧化焙烧-湿法联合梯级处理工艺对设备腐蚀较严重,操作难度较大;硫酸化焙烧-湿法联合梯级处理工艺对Au、Ag及Te、Cu的回收效果优于碱性氧化焙烧处理工艺,且操作简便,可直接嫁接于现有的生产线,应用前景广阔。

Cyanex272作载体的乳状液膜提取稀土的研究

以新型萃取剂Cyanex2 72作乳状液膜的载体 ,从南方离子型稀土矿浸矿液中提取稀土。采用单因子循环法考察了膜溶剂、载体浓度、表面活性剂种类及浓度、油内比、内相酸度、料液浓度、水乳比、时间、温度等因素对提取率的影响 ,得到优化的膜配方及工艺条件。结果表明 :对初步除杂的实际浸矿液 ,经一次间歇式富集 ,其稀土提取率大于 99% ,富集液中稀土浓度大于 90g L ,提取效果好。

酸雨和有机配体(EDTA)对已污染红壤中稀土元素释放的研究

选用不同污染程度的红壤,采用化学成分模拟自然雨水,加入有机配体(EDTA),并调节pH值(5.6、4.0、3.0),作为萃取剂,研究了酸雨和有机配体(EDTA)对已污染红壤中稀土元素释放的影响。结果表明,相同pH值下,萃取率随着EDTA的浓度升高而升高;EDTA浓度一定时,随着萃取溶液的pH值降低,萃取率降低。在相同条件下,萃取率大小的顺序为Nd>Pr>Ce>La,与EDTA及4种稀土元素的条件络合常数大小顺序相同。

镓的萃取分离研究进展

稀散金属镓由于不规则晶体结构和较大的原子内部结合力,使其具有熔沸点相差大的独特特性,现如今被广泛应用于各高新技术领域.目前应用最为广泛的分离镓方法是溶剂萃取法,对稀散金属镓的萃取分离体系及近几年在萃取体系上的研究进展进行了综述.

溶液中镓的提取与分离研究进展

从钢铁、有色金属、煤化工及磷化工等行业中的含镓物料中回收镓,需面临从含有多种金属离子的溶液中分离镓的问题。综述了含镓溶液中提取和分离镓的研究现状,分析和讨论了溶剂萃取、液膜萃取、萃淋树脂萃取等工艺的关键影响因素,并展望了研究趋势。溶剂萃取、液膜萃取及萃淋树脂萃取工艺皆能有效提取和分离溶液中的镓,其中协同萃取、液膜萃取及萃淋树脂萃取的选择性和萃取效率高,而且流程短、环境友好,应用前景好,是今后研究的发展方向。

复杂稀有金属伴生矿富集渣提取稀土和铌的工艺研究

研究了从复杂稀有金属伴生矿富集渣中提取稀土和铌的工艺。结果表明,采用硫酸酸化-分段浸出工艺可实现富集渣中稀土和铌的高效浸出。在酸矿质量比1.8、酸化温度350℃、酸化时间120min、一段浸出液固比1∶1、浸出温度80℃、浸出时间90min、二段浸出液固比8∶1、浸出温度25℃、浸出时间90min的条件下,浸出渣中REO含量为0.96%,Nb2O5含量为0.75%,稀土浸出率为85.03%,铌浸出率为80.88%。其中铌一段浸出率为80.26%,稀土二段浸出率为83.85%,可通过分别处理一段浸出液和二段浸出液实现铌和稀土的回收。

干法氟化制备高纯金属镝的工艺研究

介绍了一种制备无水高纯氟化镝的新方法 ,在氟化炉内的镍制料盘中直接完成了Dy2 O3和无水氟化氢气体的氟化反应 ,然后将钙热还原DyF3制得的粗镝进行熔盐萃取提纯处理。用此工艺可使工业规模化生产的镝金属中的氧、氟含量均小于 0 .0 2 % ,使金属镝的纯度达99 9%以上。