巯基棉纤维在贵金属分析中的应用 Ⅰ.冶金物料中金、钯和铂的富集及分离

巯基棉纤维(简称S.C.F.)富集和分离由于简单、易行和便于普及,已在环境样品分析中多有应用,用于贵金属实样分析则仅见于矿石中金和冶金物料中金和钯的分离及测定。本文研究了盐酸介质中七种贵金属元素和铜、镍、铁、钴等在S.C.F.上的吸附行为,拟订了从相应冶金物料中富集和分离金、钯及铂的方法。即先在3 N盐酸中用S.C.F.吸附金和钯,然后向流出液中入少量氯化亚锡,再用S.C.F.吸附铂。被吸附的铂可用2 N氢氧化钠溶液定量洗脱,而金和钯则需将S.C.F.同硝酸、高氯酸和硫酸一起冒烟破坏,然后分别转化成盐酸溶液,用分光光度法测定。方法     

Ag—AgI指示电极电位滴定法测定钯

研究了铂、钯、金、铂镀金、石墨及Ag—AgI指示电极,提出了一个用Ag～AgI指示电极(vs.SCE),碘化钾电位滴定钯的方法。该方法可应用于钯合金、氯化钯、钯催化剂中钯的测定。对于含钯60％和O.5％的物料,变异系数分别为0.5％和4％。     

钯钌合金中钌的测定

研究了钯钌合金中钌的测定方法。在强酸性溶液中（CHCl=5．0mol／L）和在有乙醇作稳定剂时,钌（Ⅲ）可与硫脲形成稳定的蓝绿色配合物;在最大吸收波长（λmax=620nm）处测定,50μg／50ml～250μg／50ml的钌（Ⅲ）符合比尔定律。大量的钯不干扰钌的测定。对钌含量为0．5％的钯钌合金8次测定,相对标准偏差为51％,加料回收率为95％～104％。该方法可用于含钌0．5％～2．5％的钯钌合金中钌的准确测定。     

跟起落 走势趋弱——4、5月份钯市场评述及后市预测

1．4、5月份的钯价跟随铂价起落，走势趋弱 钯价在3月4日冲上590美元／盎司后快速回落，3月下旬跟随铂价反弹，但力度趋弱。3月份到5月份的起伏中，钯价的跌幅居冠首，达到32．71％，金价的跌幅最小，为18．12％；铂价和银价分别为21．18％和24．81％。     

用金作保护剂铅试金富集汽车尾气净化催化剂中铂钯铑的研究

建立了用金作保护剂,铅试金一步富集汽车尾气净化催化剂中铂钯铑的方法。研究了金保护剂的条件,对比了不同方法的富集效果。结果表明:加入20～40 mg金作保护剂,试金配料硅酸度为1.0,进炉温度900℃1,130℃恒温10 min,熔炼时间50～60 min,灰吹温度910℃,可完全富集500μg铂钯铑。方法富集效果好,操作简便,适用于汽车尾气净化催化剂、熔炼渣以及日常样品中0.x～xxxx g/t铂钯铑的分析。     

二波长,三波长分光光度法同时测定铂铑

研究了铂、铑与氯化亚锡和2-巯基苯并噻唑显色反应的二波长、三波长分光光度联合测定法.测定铂λ_1=483nm,λ_2=390nm,佬λ_1=460nm,λ_2=448.5nm,λ_3=437nm.铂、铑含量的线性范围和各自存在的允许量分别为0～6μg/ml和1∶5.方法已成功地应用于某些贵金属冶金物料中铂、铑的测定.     

DDO法连续测定Pd、Pt方法之改进

W.D.Jacobs等曾推荐双十二烷基二硫代乙二酰二胺(简称DDO)作钯的显色剂,但没有把试剂用于铂的测定。林玉南等研究了该试剂连续测定钯与铂的方法,并用于试金合粒中钯与铂的测定。但其不足在于试剂同钯、铂显色的盐酸浓度过大(6～8N),同时钯的反应速度较慢。     

《贵金属》2002～2003年目录

篇　　　　　　　名年 ,卷 (期 ) :页码贵金属冶金学双 (正 -辛基亚磺酸 )乙烷 -乙酸丁酯萃取体系分离富集钯、铂 2 0 0 2 ,2 3 ( 1 ) :1环状亚砜衍生物的合成及萃金机理的研究 2 0 0 2 ,2 3 ( 1 ) :1 1江西铜业公司贵金属及铼、钼生产评述 2 0 0 2 ,2 3 ( 1 ) :5 7改性活性炭吸附铂和钯的研究 2 0 0 2 ,2 3 ( 2 ) :1 1DTMSO的萃钯机理研究 2 0 0 2 ,2 3 ( 2 ) :1 6从碱性氰化液萃金有机相中反萃金的研究进展 2 0 0 2 ,2 3 ( 2 ) :47用硫氰酸钾从季铵盐载金有机相中反萃金的研究 2 0 0 2 ,2 3 ( 3 ) :8类二丁基卡必醇新金萃取剂的合成与性…     

贵金属合金中铑的测定

用硝酸六氨三价钴重量法测定铂—铑、铂—铑—金、铂—钯—铑合金中的铑(5～35毫克)。文中介绍了沉淀体积、放置时间、沉淀酸度及试剂用量等系统条件试验及所选定的测定条件。90毫克铂、20毫克钴、10毫克钌、钯、锇、镍、铜、铅,0.3毫克铁不干扰测定。铱对测定严重干扰。按合金组成比合成试验,相对误差为≤±1％并提出对这些合金分析的测定手续。     

直接灰吹﹣ICP-AES测定粗铅中的金、银、铂和钯

含有铅、铋、锑、金、银、铂和钯等元素的粗铅采用火试金重量法测定时,不能同时得到铂和钯的含量数据.采用铅箔包裹样品置于灰皿中,于860℃直接灰吹得到贵金属的合粒(含少量铋、铅),合粒可用硝酸溶银,补加过量盐酸溶解金、铂和钯,试液用电感耦合等离子体原子发射光谱仪(ICP-AES)测定其中金、铂、钯和主要杂质元素(铋和铅)的...     

Comparison of geometries and electronic structures of polyacetylene,polyborole, polycyclopentadiene,polypyrrole, polyfuran,polysilole, polyphosphole,polythiophene, polyselenophene and polytellurophene

Geometries of monomers through hexamers of cylopentadiene, pyrrole, furan, silole, phosphole, thiophene, selenophene and tellurophene, and monomers through nonamers of borole were optimized employing density functional theory with a slightly modified B3P86 hybrid functional. Bandgaps and bandwidths were obtained by extrapolating the appropriate energy levels of trimers through hexamers (hexamers through nonamers for borole) to infinity. Bandgaps increase with increasing π-donor strengths of the heteroatom. In general, second period heteroatoms lead to larger bandgaps than their higher period analogs. Polyborole is predicted to have a very small or no energy gap between the occupied and the unoccupied π-levels. Due to its electron deficient nature polyborole differs significantly from the other polymers. It has a quinoid structure and a large electron affinity. The bandgaps of heterocycles with weak donors (CH₂, SiH₂ and PH) are close to that of polyacetylene. For polyphosphole this is due to the pyramidal geometry at the phosphorous which prevents interaction of the phosphorus lone pair with the π-system. The bandgap of polypyrrole is the largest of all polymers studied. This can be attributed to the large π-donor strength of nitrogen. Polythiophene has the third largest bandgap. The valence bandwidths differ considerably for the various polymers since the avoided crossing between the flat HOMO — 1 band and the wide HOMO band occurs at different positions. The widths of the wide HOMO bands are similar for all systems studied. All of the polymers studied have strongly delecalized π-systems.     

Microstructure,Mechanical Properties,and Corrosion Behavior of MoNbFeCrV,MoNbFeCrTi, and MoNbFeVTi High-Entropy Alloys

The development of high-entropy alloys(HEAs) has stimulated an ever-increasing interest from both academia and industries.In this work, three novel MoNbFeCrV, MoNbFeCrTi, and MoNbFeVTi HEAs containing low thermal neutron absorption cross section elements were prepared by vacuum arc melting. The microstructure, mechanical properties, and corrosion behaviors were investigated. A dominant body-centered cubic(BCC) phase was present in all these three HEAs. In addition,an ordered Laves phase was found to be another major phase in both MoNbFeCrV and MoNbFeCrTi alloys, whereas an ordered BCC(B2) phase was observed in the MoNbFeVTi alloy. The phase formation in these three alloys was discussed. It is found that the formation of the secondary phase in these alloys is mainly ascribed to the large atomic size difference and electronegativity difference. All the three HEAs show high hardness, high yield strength but limited plasticity. Moreover, the MoNbFeCrV, MoNbFeCrTi and MoNbFeVTi alloys exhibit excellent corrosion resistance in both deaerated 1 mol/L NaCl and 0.5 mol/L H _2 SO _4 solutions at room temperature. However, further composition adjustment and/or thermomechanical processing is required to enhance the mechanical properties of the three alloys.     

The production,recovery, properties,and applications of americium and curium

Nuclear reactors produce mixtures of Am-241 and Am-242, and beta decay of plutonium produces radioactively pure Am-241. Curium is a product of intense neutron exposure of Pu-239. Separation and purification processes for americium and curium include ion exchange, precipitation, and both liquid-liquid and molten-salt extraction. This article reviews the principal production, recovery, and waste treatment processes and briefly discusses the chemical properties and uses of americium and curium.     

Electrical resistivities and phase transformations of lanthanum,cerium, praseodymium,and neodymium

The electrical resistivities of high purity lanthanum, cerium, praseodymium, and neodymium were investigated as a function of temperature over the range from room temperature to near the melting points of the metals. Transformation temperatures were observed in these metals which were confirmed by supplementary X-ray diffraction studies.     

XRD analysis and microstructure of milled and sintered V, W, C, and Co powders

In the current study, results of the milled and sintered V, W, C, Co powders are presented. Analytical techniques such as SEM equipped with EDS and XRD were used to study microstructure and phase evolution, respectively. In addition to B1 (VW)C solid solution, a rhombohedral V₂O₃ and new τ-type (Cr₂₃C₆) carbide were formed after sintering. The possible formation mechanisms behind detected phases are discussed. It is evident that complete MA process depends strongly on the starting compositions of pure elements, their lattice coherency according to Hume-Rothery rules on crystal structure and atomic size, and enough milling time that provides adequate kinetics.     

敏感创新品牌——星球石墨设备的发展之路

民营企业要发展,靠的是什么？南通星球石墨设备有限公司在前十年里,年产值均未能超千万元,但进入新世纪之后,企业效益却突飞猛进,2005年、2006年销售额过亿元。回顾这几年来的道路,对市场的敏感、对产品的创新和对品牌的构建是星球公司发展过程中不可缺,步的因素。