scholarly journals Identification of white jewelry alloy based on silver and platinum for testing purposes

2021 ◽  
Vol 5 (12(113)) ◽  
pp. 47-59
Tatyana Artyukh ◽  
Inna Hryhorenko ◽  
Alla Ternova ◽  
Svitlana Yaheliuk ◽  
Oleksii Verenikin ◽  

The procedure for the identification of white jewelry alloys based on precious metals, in particular, silver, platinum and platinum group metals with different contents of alloying components, by testing on an assay stone and by the method of X-ray fluorescence analysis has been considered. The methodology for assessing the compliance of silver and platinum fineness in white jewelry alloys of different component composition with the requirements of regulatory documents and the procedure for their identification has been improved. It has been established that the silver fineness in precious alloys of the AgCu, AgZnCu system, determined using the potassium dichromate reagent on the test stone, depends on the manifestation of the contrast of the qualitative reaction from the standard sample (assay needle). It has been proven that for testing silver alloys containing palladium, the "Acid reagent for gold 750" is effective, which works to determine the qualitative and approximate content of silver in alloys. It was determined that the reagent "Ferrous-cyanide potassium" is very sensitive to changes in the alloy composition of silver alloys and makes it possible to establish the silver content with an accuracy of 5 %. The presence in silver alloys of such impurities as zinc, cadmium, nickel, gold, palladium and others increases the error in determining the fineness of silver and forms a different color and shade. It has been proven that testing of silver alloys on an assay stone with silver nitrate is effective only for the СрМ system. The presence of zinc in 925 sterling silver alloys visually increases the color intensity of the sediment, which indicates a higher overestimated fineness. It has been found that the identification of the content of precious alloys based on platinum for the presence of ligature components is carried out with a potassium iodide reagent at t=120 °C by the color and shade of the sediment. The procedure for using potassium iodide during testing of precious platinum-based alloys has been optimized

1995 ◽  
Vol 90 ◽  
pp. 137-153 ◽  
K. Demakopoulou ◽  
E. Mangou ◽  
R. E. Jones ◽  
E. Photos-Jones

Current technical interest in the nature of the black inlaid decoration on ancient metalware has stimulated an examination of some of the well-known bronze daggers, silver vessels, and other fragments, all with inlaid decoration and dating to the 16–14th centuries BC, from Mycenae, Prosymna, Dendra, Routsi, and Pylos. Results of non-destructive X-ray fluorescence analysis point to great versatility in working with copper (or bronze)–gold–silver alloys. The black inlaid decoration is usually copper/bronze–gold alloy with small quantities of silver. Four of the objects were also examined by X-ray radiography.

Science ◽  
2020 ◽  
Vol 369 (6505) ◽  
pp. eabc3183 ◽  
R. Morris Bullock ◽  
Jingguang G. Chen ◽  
Laura Gagliardi ◽  
Paul J. Chirik ◽  
Omar K. Farha ◽  

Numerous redox transformations that are essential to life are catalyzed by metalloenzymes that feature Earth-abundant metals. In contrast, platinum-group metals have been the cornerstone of many industrial catalytic reactions for decades, providing high activity, thermal stability, and tolerance to chemical poisons. We assert that nature’s blueprint provides the fundamental principles for vastly expanding the use of abundant metals in catalysis. We highlight the key physical properties of abundant metals that distinguish them from precious metals, and we look to nature to understand how the inherent attributes of abundant metals can be embraced to produce highly efficient catalysts for reactions crucial to the sustainable production and transformation of fuels and chemicals.

2000 ◽  
Vol 42 (5-6) ◽  
pp. 63-69 ◽  
H.G. Julsing ◽  
R.I. McCrindle

At Western Platinum Refinery in South Africa, zinc was used for the reduction of the platinum group metals (PGMs) in acidic effluent (palladium filtrate). Owing to the increasing cost of zinc and the risk of zinc pollution, sodium formate was investigated as an alternative reductant. It was found that pH 1.5 was the optimum starting pH for sodium formate reduction. The optimum concentration of sodium formate was found to be 18 g/dm3 at a temperature of approximately 100°C where the process time was 5 hours. The addition of sodium formate increased the pH of the final reaction mixture to approximately pH 4.5. Palladium was the most effectively reduced PGM, exhibiting an average precipitation efficiency of 98%. Difficulty was experienced with the precipitation of platinum (average precipitation efficiency of 47%). The precipitated PGMs were readily dissolved in hydrochloric acid (6 M) and sodium chlorate (2%). A reduction in costs resulted from the discontinuation of the use of zinc for reduction purposes. An additional advantage was that zinc was no longer introduced into the PGM refinery circuits. This effectively reduced the pollution potential of the acidic effluent.

2014 ◽  
Vol 798-799 ◽  
pp. 391-395
Sabrina Gonçalves Macedo Carvalho ◽  
R. Muccillo

Zirconia-8 mol% yttria porous solid electrolytes were obtained by mixing with different amounts (0 to 5 wt.%) of KI prior to sintering. Potassium iodide acts as sacrificial pore former, being removed from the ceramic pellet upon sintering at 1400 °C/2 h. The alkali halide content was evaluated by X-ray fluorescence analysis, the density of the pellets by the Archimedes method, and the pore content by observation in scanning probe (SPM) and scanning electron (SEM) microscopes of polished and etched surfaces. The oxide ion resistivity was determined by impedance spectroscopy analysis in the 5 Hz-13 MHz frequency range from 300 to 500 °C. Porous specimens with high skeletal density were obtained. The higher is the alkali halide content, the higher is the pore volume and the total electrical resistivity. A correlation is found between the pore content, evaluated by SEM and SPM, and the electrical behavior analysis from the impedance plots of the porous specimens.

П. Хоммель ◽  
П. Брай ◽  
В.А. Хвостиков ◽  
В.К. Карандашев ◽  
А.Ю. Лобода ◽  

Точное определение химического и изотопного состава серебряных изделий Бородинского клада позволило выявить сходство и различия в характеристиках серебряных сплавов, реконструировать технологические биографии изделий и определить, в какой степени они связаны друг с другом. При изготовлении копья 1, кинжала и втулки копья 3 к полученному методом купелирования серебру, состав которого связывается с чистым серебром копья 1, была добавлена мышьяковая медь, смешанная с оловом. Эти предметы клада имеют общую производственную биографию , связанную, вероятно, с металлургическими традициями степной зоны юга Восточной Европы. По типу и химическому составу копье 2 Бородинского клада можно связать с серебряными изделиями Турбинского могильника на Урале, при сопоставлении с которыми прослеживается единая технологическая схема: при их изготовлении к серебру добавлялась медь с повышенным содержанием мышьяка или никеля. The paper is dedicated to the studies of the Borodino hoard. Precise chemical and isotopic analysis of silver objects from the Borodino hoard enables a re evaluation of similarities and differences in the characteristics of the silver alloys, their technological biographies and the extent to which they are related to one another. Silver with traces of lead, gold and platinum group metals was identified as the primary component in the manufacture of large spearhead (1), the dagger and broken spearhead socket (3). To this, in the latter two cases, was added arsenical tin bronze, the former was produced from pure silver. These items share a common biography of production probably related to the metallurgical traditions of the south Eastern European steppe. Both the typology and chemical composition of the furcate spearhead (2) can be related to the silver products of the Turbino cemetery in the Urals, the analysis of which showed a single technological scheme: the addition of arsenic and/or nickel bearing copper was added in varying proportions to silver with very few natural impurities.

R. Alani ◽  
A. Ogunbanmwo ◽  
D. Nwude ◽  
M. Ogbaje

The main aim of this research was to assess the extent of the problems associated with inappropriate e-waste management and recycling practices. Electronic wastes (E-wastes) are generated from products that are designed for use with a maximum voltage of 1000 volts for alternating current and 1500 volts for direct current. These wastes contain hazardous materials such as lead, mercury, cadmium, brominated flame-retardants, valuable metals such as aluminium, nickel, copper, and certain precious metals such as gold, silver and platinum group metals (PGMs) which pose both human and environmental health threats. They have negative impacts on the health of workers and nearby residents; hence, residents of buildings located around and beside e-wastes dumpsites were randomly selected for this study. Well, run-off and borehole water samples as well as soil samples from different sites in Alaba international market, and Ikeja computer village in Lagos, Nigeria were analyzed for zinc, lead, iron, copper, nickel and chromium. Using additional information from questionnaires and interviews, impacts of e-waste dumps on the health of workers and residents near the study areas were investigated. The results were analysed using descriptive frequency count and tables which confirmed the presence of heavy metals in soils and water samples of the case study areas and hence appropriate recommendations were outlined to address the menace of e-waste disposal and as well as the need for improvement in e-waste management and recycling for economic opportunities and improved health standard within the Lagos Metropolis.

Molecules ◽  
2021 ◽  
Vol 26 (23) ◽  
pp. 7204
Olga Lanaridi ◽  
Sonja Platzer ◽  
Winfried Nischkauer ◽  
Andreas Limbeck ◽  
Michael Schnürch ◽  

Recovery of platinum group metals from spent materials is becoming increasingly relevant due to the high value of these metals and their progressive depletion. In recent years, there is an increased interest in developing alternative and more environmentally benign processes for the recovery of platinum group metals, in line with the increased focus on a sustainable future. To this end, ionic liquids are increasingly investigated as promising candidates that can replace state-of-the-art approaches. Specifically, phosphonium-based ionic liquids have been extensively investigated for the extraction and separation of platinum group metals. In this paper, we present the extraction capacity of several phosphonium-based ionic liquids for platinum group metals from model deep eutectic solvent-based acidic solutions. The most promising candidates, P66614Cl and P66614B2EHP, which exhibited the ability to extract Pt, Pd, and Rh quantitively from a mixed model solution, were additionally evaluated for their capacity to recover these metals from a spent car catalyst previously leached into a choline-based deep eutectic solvent. Specifically, P66614Cl afforded extraction of the three target precious metals from the leachate, while their partial separation from the interfering Al was also achieved since a significant amount (approx. 80%) remained in the leachate.

2007 ◽  
Vol 61 (1) ◽  
pp. 23-32
Marijana Acanski ◽  
Sladjana Savatovic ◽  
Mira Radic

Silver is, along with gold and the platinum-group metals, one of the so called precious metals. Because of its comparative scarcity, brilliant white color, malleability and resistance to atmospheric oxidation, silver has been used in the manufacture of coins and jewelry for a long time. Silver has the highest known electrical and thermal conductivity of all metals and is used in fabricating printed electrical circuits, and also as a coating for electronic conductors. It is also alloyed with other elements such as nickel or palladium for use in electrical contacts. The most useful silver salt is silver nitrate, a caustic chemical reagent, significant as an antiseptic and as a reagent in analytical chemistry. Pure silver nitrate is an intermediate in the industrial preparation of other silver salts, including the colloidal silver compounds used in medicine and the silver halides incorporated into photographic emulsions. Silver halides become increasingly insoluble in the series: AgCl, AgBr, AgI. All silver salts are sensitive to light and are used in photographic coatings on film and paper. The ZORKA-PHARMA company (Sabac, Serbia) specializes in the production of pharmaceutical remedies and lab chemicals. One of its products is chemical silver nitrate (argentum-nitricum) (l). Silver nitrate is generally produced by dissolving pure electrolytically refined silver in hot 48% nitric acid. Since the purity of silver nitrate, produced in 2002, was not in compliance with the p.a. level of purity, there was doubt that the electrolytically refined silver was pure. The aim of this research was the gravimetric and volumetric determination of the purity of electrolytically refined silver and silver nitrate, produced industrially and in a laboratory. The purity determination was carried out gravimetrically, by the sedimentation of silver(I) ions in the form of insoluble silver salts: AgCl, AgBr and Agi, and volumetrically, according to Mohr and Volhardt. The purity of electrolytically refined silver obtained volumetrically, according to Volhard, was 99.49%. The results suggest that the purity of electrolytically refined silver was higher than 99%. After all of these determinations, the purity of electrolytically refined silver was examined by atomic absorption spectrometry and the results confirmed that the purity of electrolytically refined silver was 99.99%. Electrolytically refined silver contained other metals: Mn, Cu, Fe, Zn, Pb, Cd, and the contents of these metals were: 1.15 ppm; 0.75 ppm; 0.65 ppm; 1.82 ppm; < 0.07 ppm and < 0.01 ppm, respectively.

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