Platinum group metal particles aggregation in nuclear glass melts under the effect of temperature

Hanotin, Caroline; Puig, J.R.; Neyret, Muriel; Marchal, Philippe

doi:10.1016/j.jnucmat.2016.04.033

Cited by 12 publications

(50 citation statements)

References 22 publications

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“…Notably, experiments show that in some cases, at low rates of shear, even a comparatively small volume fraction ( ~ 0.02) of particles can increase the system viscosity by the same amount. This effect has been observed for suspensions where the inclusion phase contains PGEs, such as RuO 2 crystals, implying that these PGE-bearing particle types have an effect distinct from that of other crystal types 15 – 17 . It has been proposed that these PGE-bearing particles suspended in silicate melts increase the system viscosity anomalously due to their tendency to aggregate by interparticle forces 15 – 17 .…”

Section: Introductionmentioning

confidence: 84%

“…This effect has been observed for suspensions where the inclusion phase contains PGEs, such as RuO 2 crystals, implying that these PGE-bearing particle types have an effect distinct from that of other crystal types 15 – 17 . It has been proposed that these PGE-bearing particles suspended in silicate melts increase the system viscosity anomalously due to their tendency to aggregate by interparticle forces 15 – 17 . Yet the detailed mechanisms controlling this effect, and predictive models for this behaviour, remain unclear.…”

Section: Introductionmentioning

confidence: 84%

“…In addition to the anomalously high apparent viscosity observed for these suspensions at low shear rates, a shear-thinning rheological response is observed, which connects a high viscosity plateau at low shear rates with a low plateau viscosity at high shear rates 15 – 17 . The critical shear rate for shear-thinning remains poorly predictable for these systems, a likely consequence of the lack of a full understanding of the mechanisms at play during flow.…”

Section: Introductionmentioning

confidence: 85%

“…Thus, in both natural and industrial systems, a common feature of PGE-bearing silicate melts is the formation of a suspended fraction of PGE-bearing crystals. In all cases, it is important to understand the rheological impact of these phases, especially given existing evidence that even a low volume fraction of such particles can induce a large and anomalous viscosity change relative to the silicate melt phase alone 15 – 17 .…”

Section: Rheology Of Silicate Melts Containing Pge-bearing Particles:...mentioning

confidence: 99%

“…To understand better the rheological behaviour of silicate melts with PGE-bearing particles, we collated existing experimental data from published sources 15 – 17 . Here, we present a brief description of the extracted data as well as the rheological behaviour of such systems, then demonstrate that PGE-bearing particles can increase the viscosity of silicate melts much more than can silicate crystals.…”

Section: Introductionmentioning

confidence: 99%

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Interparticle and Brownian forces controlling particle aggregation and rheology of silicate melts containing platinum-group element particles

Pereira

Vasseur

Wadsworth

et al. 2022

Sci Rep

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We study the rheology of silicate melts containing platinum-group element (PGE) particles. They exhibit a shear-thinning behaviour, an intense aggregation tendency, and an anomalously high apparent viscosity in the low shear rate limit, even at very low particle volume fraction. Using a compilation of published experimental data, we analyse these effects in three steps. Firstly, we observe that the viscosities of these suspensions are much higher than those of natural silicate crystal-bearing melts for low shear rate regimes. Secondly, we demonstrate that the viscosities at low shear rate limit cannot be estimated by classical rheological models but rather may be understood as the result of particle aggregation, trapping dead fluid, and thereby increasing the effective particle volume fraction. Finally, we scale the critical shear rates for shear-thinning using a Peclet number analysis—invoking a competition between random thermal particle motion and hydrodynamic shearing motion—and, using an empirical extension, we additionally account for the particle–particle interaction energetics. We propose a framework in which the rheology of this family of particle-bearing melts can be predicted, and demonstrate that at low Peclet numbers, PGE-bearing particle aggregation is driven by interparticle forces and Brownian motion.

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Section: Introductionmentioning

confidence: 84%

Section: Introductionmentioning

confidence: 84%

Section: Introductionmentioning

confidence: 85%

Section: Rheology Of Silicate Melts Containing Pge-bearing Particles:...mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Interparticle and Brownian forces controlling particle aggregation and rheology of silicate melts containing platinum-group element particles

Pereira

Vasseur

Wadsworth

et al. 2022

Sci Rep

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Thixotropic behavior of a glass melt of nuclear interest containing platinum group metal particles

et al. 2022

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Contrary to some other elements such as Iron, Nickel and Chromium, the Platinum Group Metals particles (PGM) are not incorporated chemically in molten glasses. These particles are generally found in nuclear borosilicate glasses resulting from the melting, at 1200°C, of a glass precursor and fission products issued from spent fuel reprocessing. During the melting step, the presence of theses metals as suspended particles of a few microns has an impact on the rheological properties of the material, leading to a Non-Newtonian behavior. Their impact on the process is the object of characterization and modeling of many studies that have established that the melt presents a shear-thinning and thixotropic behavior. At high shear rate, the glass behaves as a suspension of individual particles, whose rheological behavior is controlled by the viscosity of the vitreous matrix. On the other hand, at low shear rate, below a stress threshold, and above a certain volume fraction in PGM particles, the formation of aggregates composed of needle-like Ru/RuO2 chains and Pd-Rh-Te spherical particles, strongly influences the viscosity of the glass. In this work, a deeper analysis of the thixotropic behavior of a simulated nuclear glass melt containing 3.0 wt% (1.02 vol%) of PGM particles will be presented. Steady and transient state measurements were performed over a wide shear rate range using an imposed-stress rheometer at temperatures ranging from 1100 to 1250 °C. Using Houska model, this work shows that it is possible to predict the transient behavior of the sample from their steady-state rheological behavior.

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Novel approach to additively manufacture high-strength Al alloys by laser powder bed fusion through addition of hybrid grain refiners

Gan

Zhou

et al. 2021

Additive Manufacturing

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Platinum group metal particles aggregation in nuclear glass melts under the effect of temperature

Cited by 12 publications

References 22 publications

Interparticle and Brownian forces controlling particle aggregation and rheology of silicate melts containing platinum-group element particles

Interparticle and Brownian forces controlling particle aggregation and rheology of silicate melts containing platinum-group element particles

Thixotropic behavior of a glass melt of nuclear interest containing platinum group metal particles

Novel approach to additively manufacture high-strength Al alloys by laser powder bed fusion through addition of hybrid grain refiners

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