Platinum-group elements

Zientek, Michael L.; Loferski, Patricia J.; Parks, Heather L.; Schulte, Ruth F.; Seal, Robert R.

doi:10.3133/pp1802n

Cited by 37 publications

(27 citation statements)

References 45 publications

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“…Over the last half century, the world production of platinum group elements has increased more than tenfold (Zientek, Loferski, Parks, Schulte, & Seal, 2017). They have excellent properties i.a.…”

Section: Platinum Group Elements Exposures Have Multiplied In Recent mentioning

confidence: 99%

“…Major uses concern catalysts to decrease automobile exhaust emissions. Jewelry and investment metals are other examples of uses (Zientek et. al., 2017).…”

Section: Platinum Group Elements Exposures Have Multiplied In Recent mentioning

confidence: 99%

“…The consequences for environment and health of such increases are difficult to assess. A typical statement by assessors reads: "Broader human health effects of PGEs appear to be limited because of the low concentrations of PGEs in the environment" (Zientek et. al., 2017); those authors do not even address ecological thresholds for the elements under their heading "Ecological Health Concerns".…”

Section: Little Information Exists On Toxcicity and Ecotoxicitymentioning

confidence: 99%

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Hypothetical Thresholds for Effects of Platinum Group Elements

Bengtsson¹

2019

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The platinum-group elements are rhodium, ruthenium, palladium, osmium, iridium, and platinum. Together with rhenium and gold they form the highly siderophilic (“iron-loving”) elements. These are poorly known with respect to toxicity and ecotoxicity. The mobilization by man of the eight metals is about 100 times to 1 million times the natural mobilization. Mean soil concentrations in Europe may now be more than doubled for gold, rhenium and rhodium. The objective of the current work was to enable a preliminary assessment of the consequences of such high environmental levels. Thresholds for ecological effects found in the literature were divided by the element’s mean soil concentration and plotted against group and period in the periodic system. Thresholds for health effects were correspondingly divided by the mean dietary intake of the element over large population groups. For health effects, an upper limit of intake is commonly used. This was shown to be about 4 times the mean normal intake for most period 4 elements. For other periods, occupational exposure thresholds entail upper limits of intake in µg/day of: Ru 18, Rh 8, Pd 17, Re 60, Os 15, Ir 4, Pt 20 and Au 160. For ecological effects, the no effect thresholds for period 4 were 1-5 times the soil concentrations. Very scarce data suggest higher relative thresholds for periods 5 and 6. The current high contaminations of European soil by Rh and possibly Pd may be of concern. Since the estimates of risks are uncertain, further research is warranted.

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Section: Platinum Group Elements Exposures Have Multiplied In Recent mentioning

confidence: 99%

“…Major uses concern catalysts to decrease automobile exhaust emissions. Jewelry and investment metals are other examples of uses (Zientek et. al., 2017).…”

Section: Platinum Group Elements Exposures Have Multiplied In Recent mentioning

confidence: 99%

Section: Little Information Exists On Toxcicity and Ecotoxicitymentioning

confidence: 99%

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Hypothetical Thresholds for Effects of Platinum Group Elements

Bengtsson¹

2019

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“…However, Grandell et al predicted a reinforcement of Pt mining which is undesirable due to its high environmental impact [43]. Zientec et al declared that the availability and accessibility of PGMs could be disrupted by economic, environmental, political and social events [45]. Previous disruptions have been observed for Pd in 1999 and 2000 due to the blockade of exports from Russia, or for the disruption in Pt supply in 1986, 2011 and 2012 due to miner strikes in South Africa [46].…”

Section: Supply Disruption Is It Going To Occur?mentioning

confidence: 99%

Evaluating critical metals contained in spintronic memory with a particular focus on Pt substitution for improved sustainability

Palomino

Marty

Auffret

et al. 2021

Sustainable Materials and Technologies

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Thanks to their unique combination of properties: non-volatility, speed, density and write endurance, spintronic memory called spin transfer-torque Magnetic Random Access Memory (STT-MRAM) is expected to play a major role in the future development of the Internet of Things (IoT) and more generally in information and communication technologies. This type of spintronic device is usually made of materials, some of which can be classified as critical. Recent studies have evaluated critical materials contained in magnetic random access memory [1,2]. However, in those cases the type of memory analyzed belongs to the first generation of MRAMs developed in the early 2000s. Nowadays, the memory devices are magnetized perpendicularly to the plane of the layers and contain a synthetic antiferromagnet (SAF) that provides a high coercivity to the STT-MRAM reference layer with reduced stray field. This SAF is typically made of cobalt (Co) and platinum (Pt) multilayers antiferromagnetically coupled across a thin ruthenium (Ru) layer. Due to the high-embodied energy of platinum group metals (PGMs), a common concern when evaluating these materials is the environmental risk associated with their production. An evaluation of the environmental and economic risks of using such multilayers is first reported here, followed by a discussion of its supply risk. Substitution of Co/Pt multilayers by Co/Ni multilayers can lead to a reduction by 3-4 orders of magnitude in terms of energy requirements or global warming potential (GWP) associated with the use of these multilayers. An alternative concept based on perpendicular shape anisotropy (PSA) can also yield a reduction by 1-2 orders of magnitude in these quantities. However, for the case of STT-MRAM, tiny quantities of PGM layers are used in comparison with the mass of the silicon wafer on which these type of devices are grown. Therefore, the environmental and economic impact of the silicon wafer fabrication is found to be much higher than that of the PGM materials incorporated in the STT-MRAM stacks. Nonetheless, the high supply risk associated with PGMs remains a reason for awareness. One explored possibility is a SAF structure based on Co/Ni multilayers which can have similar performance. A second more challenging alternative is also proposed based on the aforementioned PSA concept. Finally, we address the case of several other metals identified by the European Commission as critical and used in MRAM such as W or Ta, both recently included in the EU's Conflict Minerals Regulation released in January 2021 [3].

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“…The BIC is the largest layered mafic intrusion in the world (ca. 66,000 km 2 ) and also hosts the largest reserves of platinum-group elements (PGE; Maier et al 2013;Zientek et al 2014;Zeh et al 2015;Zientek et al 2017). The BIC intruded into the Rooiberg Group, Transvaal Supergroup, and Archean basement, and it is composed of three main suites: (1) the Rustenburg Layered Suite (RLS), a sequence of mafic to ultramafic layered rocks;…”

Section: Introductionmentioning

confidence: 99%

Strontium isotope stratigraphy through the Flatreef PGE-Ni-Cu mineralization at Turfspruit, northern limb of the Bushveld Igneous Complex: evidence of correlation with the Merensky Unit of the eastern and western limbs

et al. 2020

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The origin of PGE-Ni-Cu mineralization in the Platreef, northern limb of the Bushveld Igneous Complex (BIC), and the possible correlation with the Merensky Reef in the eastern and western limbs has been long debated. The Platreef and Merensky Reef share the same stratigraphic position in the uppermost part of the Upper Critical Zone (UCZ), near the transition to the overlaying Main Zone (MZ). However, discrepancies in interpretations have been difficult to resolve due to the effects of intense magma-country rock interaction throughout most of the northern limb succession. To address this problem, we generated a detailed stratigraphic profile of the initial strontium isotopic ratio [Sr i = ( 87 Sr/ 86 Sr) i ] in plagioclase across a Flatreef interval lacking macroscopic evidence of country rock assimilation. The in situ Sr isotopic ratios in plagioclase were determined using LA-MC-ICP-MS analysis on 37 samples from a drill core (UMT094) at the Turfspruit project. Strontium isotope stratigraphy is useful because of a well-documented shift in Sr i near the base of the Merensky Unit in the eastern and western limbs. The results show the existence of a significant shift (from Sr i = 0.7060 to Sr i = 0.7090) that matches the isotopic shift documented through the Merensky Unit in the eastern and western limbs. Thus, this new Sr isotope data indicates that the main mineralized interval of the Flatreef can be stratigraphically correlated to the Merensky Reef in the remainder of the BIC. In addition, we interpret these results as compelling evidence to suggest that the main mineralization processes in the Flatreef were likely similar to those operating in the eastern and western limbs and that interaction with local country rocks was not a necessary condition. Electronic supplementary material The online version of this article (10.1007/s00126-020-01006-3) contains supplementary material, which is available to authorized users.

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Platinum-group elements

Cited by 37 publications

References 45 publications

Hypothetical Thresholds for Effects of Platinum Group Elements

Hypothetical Thresholds for Effects of Platinum Group Elements

Evaluating critical metals contained in spintronic memory with a particular focus on Pt substitution for improved sustainability

Strontium isotope stratigraphy through the Flatreef PGE-Ni-Cu mineralization at Turfspruit, northern limb of the Bushveld Igneous Complex: evidence of correlation with the Merensky Unit of the eastern and western limbs

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