铅试金富集-ICP-AES测定吸钯树脂中钯

通过铅试金富集树脂中的钯并用银作钯灰吹保护,得到银钯合粒。合粒用王水溶解,在10%的盐酸介质中,采用电感耦合等离子体原子发射光谱法(ICP-AES)测定其中的钯。实验确定了火试金熔剂的配比。结果表明,该法的富集效果好,银基体和合粒中的杂质对测定没有干扰,测定快速、准确,相对标准偏差RSD为1.51%,加标回收率在99.35%~100.90%之间。本方法可用于吸钯树脂中钯的测定。     

小试金法快速测定金泥中的金

金泥经配料、熔融。获得适当质量的贵金属的铅扣与易碎性的熔渣。铅扣经灰吹使金、银与铅扣分离,得到金、银合粒,合粒经硝酸分离后,用称量法测定金赶和银量。小试金法类同经典的火试金法,但采用铅粉代替商品PbO,并且用50mL白瓷坩埚在980％进行熔炼。对m（Au）为1％～50％的样品,测定结果与火试金重量法结果相符。此方法快速,简便,适用于氰化金泥金量（5％～30％）的分析。     

火试金富集—电感耦合等离子体质谱法测定铁精矿中金铂钯

采用铅试金法富集铁精矿中贵金属,用盐酸溶解贵金属合粒的银,再加入硝酸配成王水溶液溶解贵金属合粒,然后定容于容量瓶中,然后利用电感耦合等离子体质谱仪测定该溶液[1]。确定了在熔融温度为1150℃,熔融时间在20min,灰吹温度为1000℃,灰吹时间为1h。在王水溶解条件下,讨论加入酸量。确定了在100℃电热板上先加入5m L硝酸溶解10min再加入15m L盐酸溶解5min的方法,并对ICP-MS的干扰消除进行了讨论。测定的铁精矿的样品中的金、铂、钯的检出限分别为0.05,0.03,0.03 ng/g,相对标准偏差为1.1%~3.2%。     

火试金重量法测定载金炭中金的方法改进

载金炭样品采用火试金重量法分析,通常先经焙烧、面粉法配料、熔融获得适当质量的铅扣,铅扣经灰吹使金、银与铅分离,得到金、银合粒,合粒经硝酸分离后,称量金粒重量,从而计算出金、银含量。方法改进后,载金炭样品取样量减少,直接采用硝石法配料,省去了焙烧环节,与经典的火试金法以及其它化验室检测结果对比,结果可靠稳定。     

能用于多种镀液的添加剂

各种功能性和装饰性电镀层如:锌、铜、铬、镉、镍、钴、金、银、铂、钯、钌及其相互形成的合金以及锡和铅的合金镀层,已广泛地应用于各种工业。当前对电镀的要求,一是快速电镀;一是镀层的高质量。如:镀层厚度均匀,平滑,孔隙率低等。对于电子元件,尤其需要镀层细致,防止针晶结构跨过电路而造成短路。为达到     

干湿法测定硒碲混合物中金、银含量的研究

采用硫酸溶解、火试金法测定含硒碲混合物中金、银含量。硒碲混合物中硒、碲含量高，火试金法测定金银时有铅扣不易形成、合粒较脆等现象，因此采用硫酸除去硒碲混合物中铜、硒、碲，火试金法测定金银含量。讨论了硫酸用量、灰化时间、配料配比对金、银回收率的影响，使用该方法金加标回收率94.0%～97.1%、银加标回收率95.0%～97.7%。     

从铂钯精矿中回收贵金属工艺选择

概述了金、银、铂、钯回收提纯的有关化学反应原理,拟定了从铂钯精矿中回收金、银、铂、钯的工艺流程,采用硫酸化焙烧,酸浸除贱金属,富集贵金属,再氯化分别提取贵金属,获得了满意的生产指标,金属回收率分别为:Au 98.1%,Ag97.2%,Pt93.0%,Pd95.6%.     

脉冲电镀发展概况

总结脉冲电镀应用于镀铬、镀铜、镀镍及镍合金 ,镀金及金合金 ,镀银及银合金 ,镀钯及钯合金的现状 ,简述了脉冲换向电流电镀 ,脉冲电镀在复合镀层和制备非晶态合金等方面的研究。     

基于K金中金、银分离与提取新工艺的研究

研究K金中快速分离并提取金、银的方法,关键工艺是:在含金量37.5％ (9K)～75％ (18K)之间的首饰加工废料中加入其质量2.5 ～3倍的银,将合金与银充分熔融,重新淬粒,硝酸分离银后,提纯金、银.达到分离速度快、分离效果好、提纯贵金属纯度高的目的.工艺的理论依据是:当K金中含银量达到一定比例时,合金表面形成成膜...     

永冲电镀发展概况

总结脉冲电久竽镀铬、镀铜、镀镍及镍合金,镀金及金合金,镀银及银合金,镀钯及钯合金的现状,简述了脉冲换向电流电镀,脉冲电镀在复合镀层和制备非晶态合金等方面的研究。     

日本表面处理技术近期动向第一部分贵金属电镀

分别介绍了日本的镀金种类和用途,酸性金电镀和高速还原型化学镀金、化学镀硬质金的工艺配方,中性金电镀和置换型镀金的工艺特点,pH对酸性金合金电镀的影响以及影响化学镀硬质金镀层硬度的因素。对无氰光亮镀银和无氰冲击镀银、化学镀钯、酸性白金电镀和碱性白金电镀的工艺配方以及化学镀白金的工艺特点也进行了相应地介绍。     

On Homogeneous Gold/Palladium Catalytic Systems

Two substrates containing an aryl iodide and an allenoate ester were prepared and the gold‐induced cycloisomerisation to vinylgold(I) species and their proto‐deauration as well as the intramolecular palladium‐catalysed cross‐coupling reactions were investigated. Switching to catalytic amounts of gold and palladium and stoichiometric amounts of silver did indeed furnish the product of a cycloisomerisation/intramolecular cross‐coupling. Control experiments revealed that silver cannot substitute for gold or palladium in these reactions, but a different palladium catalyst in a different oxidation state also afforded the cycloisomerisation/intramolecular cross‐coupling products in only slightly reduced yields. By ICP analysis the palladium was shown to contain gold only at the sub‐ppm level. This shows how carefully results obtained with such systems have to be interpreted. Then a series of allylic and benzylic o‐alkynylbenzoates were investigated in gold‐ and palladium‐catalysed reactions. For esters of benzyl alcohol and cinnamyl alcohol no palladium co‐catalyst was needed for the conversion. All reagents were thoroughly checked for palladium traces by ICP analysis in order to thoroughly exclude a gold/palladium co‐catalysis. Optimisation of the gold complex, counter ion and solvent showed that gold(I) isonitrile pre‐catalysts and silver triflate as activator in dioxane are suitable to convert a number of substrates with aryl, alkyl and even cyclopropyl substituents. Crossover experiments proved an intermolecular allyl transfer.     

铜阳极泥脱铜渣中金、银、钯含量测定

建立了连续测定铜阳极泥脱铜渣中金、银、钯含量的分析方法,并与火试金法进行比较。首先,利用硝酸+乙二胺四乙酸（EDTA）+酒石酸消解铜阳极泥脱铜渣,得到含有银、钯和少量金的消解液,考察了硝酸、EDTA和酒石酸用量对消解效果的影响。结果表明,硝酸、EDTA和酒石酸用量分别为30mL、3mL、1.5g时,消解效果最好。然后,利用王水对残渣进行二次消解,得到含有金和少量银、钯的消解液,考察了王水用量对消解效果的影响。结果表明,王水用量为15mL时即可完成消解。最后采用火焰原子吸收光谱仪测定消解液中的金、银、钯含量。采用本方法测定铜阳极泥脱铜渣,Au、Ag、Pd各元素相对标准偏差均小于1%（n=10）,加标回收率在95.57%～98.70%之间,实验结果准确可靠、重现性好,与火试金法测定结果相一致。     

Binding of metal cations by natural substances

The binding of mercuric chloride and other metal salts to bark, activated sludge (Milorganite), chitosan, poly(p-aminostyrene), and other natural and synthetic materials was investigated by specific atomic absorption and x-ray fluorescence spectroscopy. The synthetic poly(aminostyrene) was included for comparison with the natural polyamine chitosan. Our results show that a wide range of natural materials are potentially useful for the removal of toxic and precious metals that may be present in industrial effluents, mine waters, or other water supply. Such metal salts include those of mercury, lead, zinc, cadmium, copper, nickel, cobalt, iron, manganese, silver, platinum, palladium, and gold.     

Novel and efficient electrochemical way for silver nanoparticles deposition onto solid conductors: a new concept of metal-silver cathodes

The deposit of very small silver particles onto a very large palette of solid electronic conductors was achieved by means of the cathodic reduction of alkyl iodides RIs in the presence of a suspension of silver–palladium alloy particles (diameter >250 μm). The potential applied to the conductor is so that RIs are not directly reduced at its surface. The observed cathodic reaction is then the discharge of silver grains reacted in surface and covered by a transient assigned to be [RAg⁺, I⁻]. The main heterogeneous products are homo-dimers R–R while the deposition of silver aggregates of very small size (nanometric scale) occurs onto the conductor. By this way, the efficient silverization of many surfaces is possible. Stable layers of Ag particles were made onto many solid surfaces like platinum, palladium, copper, nickel, iron, gold, graphite, and glassy carbon. Preliminary evidences for the use of those new silvered electrodes are presented.     

贵金属SiO2核壳纳米材料的研究进展

从单金属、双金属或多金属的SiO2核壳体系出发,论述了几种典型的贵金属金、银、铂、钯、铑等为核或壳与SiO2包覆的核壳纳米材料的制备方法,改进的性质和在催化、光学、生物等方面的应用,并对未来的发展方向进行了展望.     

电镀银/钯/硬金组合耐磨镀层工艺研究

为了提高镀硬金导电环的耐磨性,在黄铜基材上电镀铜/钯/硬金、镍/钯/硬金和银/钯/硬金三种组合镀层,通过工艺实验,组合镀层的外观、厚度、结合力、硬度、接触电阻及表面微观形貌等性能测试,以及装配后耐磨性能考核试验,发现银/钯/硬金组合镀层耐磨性最好。结果表明,该镀层耐磨可达100万次,能够满足产品抗磨性要求。     

Impedance of the oxygen-evolution reaction on noble metal electrodes

The impedances of the oxygen-electrode reaction on platinum, palladium, gold and silver electrodes in acidic and alkaline solutions were measured with an ac bridge in the range of frequency from 10 Hz to 20 kHz, under dc polarization. For these electrodes, plots of impedances on the complex plane give semi-circles whose diameter is proportional to the dc being passed through the cell. By analysing these plots and impedance/dc curves, it is shown that the oxygen-evolution reaction on these electrodes is controlled by a charge-transfer process, except for the case of platinum in perchloric acid solution. In the latter system, a chemical reaction on the electrode surface is rate-determining.     

Precipitate Flotation II. Separation of palladium from platinum,gold, silver,iron, cobalt and nickel

Palladium is completely removed from 5 × 10^?5 M-PdCl₂ solutions using the new technique of precipitate flotation of the second kind, in which no surfactant is used to float precipitates. Recoveries were best at pH 1–2 and were not markedly dependent on temperature. Increase in ionic strength had no deleterious effect, unlike conventional precipitate flotation. Palladium can be completely separated from a 400-fold excess of nickel, a 100-fold excess of platinum, iron and cobalt, a 10-fold excess of gold but not from silver in the presence of chloride ions. Equimolar amounts of palladium, nickel and platinum were completely separated from each other by successive flotations. Photographs taken of the bubbles during flotation showed that, at a flow-rate of 3.1 litre/hour, a mean surface area of 2.07 metre² passed through the cell per minute.     

Separation of Palladium and Silver from a Nitric Acid Solution by Liquid Surfactant Membranes

Abstract

The recovery of palladium from a nitric acid solution containing silver has been conducted by application of liquid surfactant membranes (LSMs) containing LIX 860, a β-hydroxyoxime, as a mobile carrier in a stirred tank. The extraction equilibria of palladium and silver using several different extractants were also studied. Palladium was selectively extracted from a silver-containing liquor with LIX 860 while it was also observed that both palladium and silver were extractable with a sulfur-containing extractant. The recovery of palladium with LIX 860 was selectively achieved by using perchloric acid solution as the LSM internal phase dosed with thiourea. In the LSM operation, the effects of several chemical parameters on the selective recovery of palladium were studied. The use of hydrochloric acid as an internal receiving phase prevented the transport of silver into the emulsion due to the formation of silver chloride in the external feed solution. Commercially available Span 80 was found suitable for the selective extraction of palladium as a surfactant in LSM operation. Under optimum conditions, palladium was successfully separated from silver and concentrated into a receiving phase in W/O emulsions.