scholarly journals The Sampling and Assay of the Precious Metals: comprising Gold, Silver, Platinum, and the Platinum Group Metals in Ores, Bullion, and Products

Nature ◽  
1914 ◽  
Vol 93 (2320) ◽  
pp. 157-158
Author(s):  
T. K. R.
Keyword(s):  
Precious Metals ◽  
Platinum Group Metals ◽  
Gold Silver ◽  
Platinum Group

scholarly journals Evaluation of the Environmental Impacts of Electronic-Waste Management in Lagos Using Alaba International Market and Ikeja Computer Village as Case Studies

2020 ◽  
Vol 4 (2) ◽  
pp. 283-297
Author(s):  
R. Alani ◽  
A. Ogunbanmwo ◽  
D. Nwude ◽  
M. Ogbaje
Keyword(s):  
Waste Management ◽  
Water Samples ◽  
Flame Retardants ◽  
Electronic Waste ◽  
Precious Metals ◽  
International Market ◽  
Platinum Group Metals ◽  
Additional Information ◽  
Waste Dumps ◽  
Gold Silver

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.

scholarly journals A Combined Deep Eutectic Solvent–Ionic Liquid Process for the Extraction and Separation of Platinum Group Metals (Pt, Pd, Rh)

Molecules ◽  
2021 ◽  
Vol 26 (23) ◽  
pp. 7204
Author(s):  
Olga Lanaridi ◽  
Sonja Platzer ◽  
Winfried Nischkauer ◽  
Andreas Limbeck ◽  
Michael Schnürch ◽  
...  
Keyword(s):  
Ionic Liquids ◽  
Mixed Model ◽  
Deep Eutectic Solvent ◽  
Precious Metals ◽  
Platinum Group Metals ◽  
Environmentally Benign ◽  
Extraction Capacity ◽  
Acidic Solutions ◽  
Extraction And Separation ◽  
Platinum Group

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.

Biorecovery of Platinum Group Metals from Secondary Sources

2007 ◽  
Vol 20-21 ◽  
pp. 651-654 ◽  
Author(s):  
Angela J. Murray ◽  
I.P. Mikheenko ◽  
Elzbieta Goralska ◽  
N.A. Rowson ◽  
Lynne E. Macaskie
Keyword(s):  
Catalytic Activity ◽  
Precious Metals ◽  
Bacterial Biomass ◽  
Platinum Group Metals ◽  
X Ray ◽  
Secondary Sources ◽  
Price Increases ◽  
Valuable Product ◽  
Platinum Group

Since 1998 demand for the platinum group metals (PGM) has exceeded supply resulting in large price increases. Undersupply, combined with rising costs prompts environmentally friendly recycling technologies. Leachates containing PGM were produced from secondary waste sources using microwave leaching technology with the aim of recovering precious metals using bacterial biomass. Previous studies showed that metallised biomass exhibits catalytic activity; hence metal is not only recovered but can be converted into a valuable product. Cells of Escherichia coli MC4100 that had been pre-metallised with Pt were more effective at reducing PGM from the leachates. The solid recovered from the leachate onto the bacteria was characterised using X-ray Powder Diffraction (XRD) and Energy Dispersive X-ray Microanalysis (EDX). Metallised biomass was tested for catalytic activity (reduction of Cr(VI) to Cr(III)) to compare the ‘quality’ of polymetallic bacterial-based catalysts versus counterparts made from single and mixed metal model solutions.

Spectrographic Analysis of Fire Assay Beads for the Platinum Group Metals and Gold

1974 ◽  
Vol 28 (1) ◽  
pp. 23-25 ◽  
Author(s):  
P. G. Sim
Keyword(s):  
Precious Metals ◽  
Platinum Group Metals ◽  
Rapid Screening ◽  
Spectrographic Analysis ◽  
Fire Assay ◽  
Platinum Group

By arcing a 10-mg fire assay bead at 7 A on a Cu cathode, bead ejection is avoided without buffering. Sensitivities for the precious metals are in the range 0.01 to 0.5 µg and precisions between 8 and 18%. The technique is suitable for rapid screening of fire assay beads for the precious metals.

scholarly journals Precious metals recovery from aqueous solutions using a new adsorbent material

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Oana Grad ◽  
Mihaela Ciopec ◽  
Adina Negrea ◽  
Narcis Duțeanu ◽  
Gabriela Vlase ◽  
...  
Keyword(s):  
Experimental Data ◽  
Aqueous Solutions ◽  
Precious Metals ◽  
Platinum Group Metals ◽  
Isotherm Models ◽  
Order Kinetic ◽  
Metallic Ions ◽  
Good Efficiency ◽  
Gas Treatment ◽  
Platinum Group

AbstractPlatinum group metals (PGMs) palladium, platinum, and ruthenium represent the key materials for automotive exhaust gas treatment. Since there are no adequate alternatives, the importance of these metals for the automotive industry is steadily rising. The high value of PGMs in spent catalysts justifies their recycling. Therefore, it is really important to recovery platinum group metals from aqueous solutions. Of the many PGMs recovery procedures, adsorption is a process with a good efficiency, but an important role is played by the adsorbent material used into the process. In order to improve the adsorption properties of materials were developed new methods for chemical modification of the solid supports, through functionalization with different extractants. In present paper a new adsorbent material (Chitosan-DB18C6) was used for PGMs recovery. The new adsorbent material was produced by impregnating Chitosan with dibenzo-18-crown-6-ether using Solvent Impregnated Resin (SIR) method. The crown ethers were chosen as extractant due to their known ability to bind metallic ions, whether they are symmetrically or unsymmetrically substituted. In order to determine the PGMs recovery efficiency for new prepared adsorbent material the equilibrium and kinetic studies were performed. Also, to study the PGMs adsorption mechanism the experimental data were modelled using pseudo-first-order and pseudo-second order kinetic models. Experimental data were fitted with three equilibrium isotherm models: Langmuir, Freundlich and Sips. The results proved that new adsorbent material (Chitosan-DB18C6) is an efficient adsorbent for PGMs recovery from aqueous solutions.

scholarly journals Recovery of Platinum Group Metals from Spent Automotive Catalysts Using Lithium Salts and Hydrochloric Acid

Materials ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 6843
Author(s):  
Shunsuke Kuzuhara ◽  
Mina Ota ◽  
Ryo Kasuya
Keyword(s):  
Precious Metals ◽  
Lithium Ion ◽  
Platinum Group Metals ◽  
Leaching Rate ◽  
Electrolytic Solution ◽  
Matrix Component ◽  
Aqua Regia ◽  
Automotive Catalysts ◽  
Chlorine Gas ◽  
Platinum Group

The recovery of platinum group metals (PGMs) from waste materials involves dissolving the waste in an aqueous solution. However, since PGMs are precious metals, their dissolution requires strong oxidizing agents such as chlorine gas and aqua regia. In this study, we aimed to recover PGMs via the calcination of spent automotive catalysts (autocatalysts) with Li salts based on the concept of “spent autocatalyst + waste lithium-ion batteries” and leaching with only HCl. The results suggest that, when Li2CO3 was used, the Pt content was fully leached, while 94.9% and 97.5% of Rh and Pd, respectively, were leached using HCl addition. Even when LiF, which is a decomposition product of the electrolytic solution (LiPF6), was used as the Li salt model, the PGM leaching rate did not significantly change. In addition, we studied the immobilization of fluorine on cordierite (2MgO·2Al2O3·5SiO2), which is a matrix component of autocatalysts. Through the calcination of LiF in the presence of cordierite, we found that cordierite thermally decomposed, and fluorine was immobilized as MgF2.

Survey of Methods of Refining Catalysts for the Extraction of Platinum Group Metals

2019 ◽  
Vol 946 ◽  
pp. 528-532
Author(s):  
E.A. Devyatykh ◽  
T.O. Devyatykh ◽  
A.N. Boyarsky
Keyword(s):  
Catalytic Activity ◽  
Chemical Reactions ◽  
Precious Metals ◽  
Platinum Group Metals ◽  
Significant Part ◽  
High Catalytic Activity ◽  
Important Condition ◽  
Special Position ◽  
Global Demand ◽  
Platinum Group

Currently, about 80% of all industrial chemical reactions are carried out with the help of catalysts or depend on catalytic processes. In this case, catalysts containing platinum group metals (hereinafter - PGM) occupy a special position, due to their high catalytic activity and selectivity. A significant part of the net global demand for PGM is for the production of catalysts, accounting for approximately 45% for platinum, 30% for palladium, 92% for rhodium, 35% for ruthenium, 15% for iridium. The most important condition for the economical use of catalysts containing precious metals is their efficient recycling, which will be discussed below.

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