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670 results on '"BRUGGER, JOËL"'

12. Nutrient Supply to Planetary Biospheres from Anoxic Weathering of Mafic Oceanic Crust

Author

Syverson, Drew D., Reinhard, Christopher T., Isson, Terry T., Holstege, Cerys, Katchinoff, Joachim, Tutolo, Benjamin M., Etschmann, Barbara, Brugger, Joël, and Planavsky, Noah J.

Subjects
Astrophysics - Earth and Planetary Astrophysics
Abstract

Phosphorus is an essential element for life, and the phosphorous cycle is widely believed to be a key factor limiting the extent of Earth's biosphere and its impact on remotely detectable features of Earth's atmospheric chemistry. Continental weathering is conventionally considered to be the only source of bioavailable phosphorus to the marine biosphere, with submarine hydrothermal processes acting as a phosphorus sink. Here, we use a novel 29Si tracer technique to demonstrate that alteration of submarine basalt under anoxic conditions leads to significant soluble phosphorus release, with an estimated ratio between phosphorus release and CO2 consumption (P/CO2) of 3.99+/-1.03 umol/mmol. This ratio is comparable to that of modern rivers, suggesting that submarine weathering under anoxic conditions is potentially a significant source of bioavailable phosphorus to planetary oceans and that volatile-rich Earth-like planets lacking exposed continents could develop robust biospheres capable of sustaining remotely detectable atmospheric biosignatures., Comment: Manuscript under consideration in Geophysical Research Letters

Published
2020
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32. Coprecipitation of amorphous silica and gold nanoparticles contributes to gold hyperenrichment.

Author

McNab, Rory R., Brugger, Joël, Voisey, Christopher R., and Tomkins, Andrew G.

Subjects
*SILICA, *SILICA nanoparticles, *GOLD nanoparticles, *GOLD ores, *QUARTZ, *EARTHQUAKE aftershocks, *VEINS (Geology)
Abstract

Hyperenrichment of Au in orogenic ores occurs overwhelmingly within quartz veins, but the formation pathway of quartz veins in orogenic systems remains enigmatic. We conducted hydrothermal experiments simulating coprecipitation of Au and amorphous silica and subsequent recrystallization to test whether this is a viable mechanism to generate Au nuggets within quartz veins. Within minutes, coprecipitation of amorphous silica and Au nanoparticles occurred, representing an effective Au deposition mechanism. Within one week, amorphous silica had recrystallized to quartz, causing the coarsening of Au particles and their relocation to quartz grain boundaries and fractures. The experimental textures are similar to those observed in high-grade zones of orogenic gold deposits. In addition to trapping Au, amorphous silica may increase competency contrasts that facilitate short-term fracture reactivation during earthquake aftershock periods or swarms, allowing further Au input from fresh fluids. These findings demonstrate that amorphous silica precipitation may be an important transient stage in orogenic gold deposit formation, with significant implications for metal accumulation in quartz veins. [ABSTRACT FROM AUTHOR]

Published
2024
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41. Spent Lithium-Ion Battery Recycling Using Flotation Technology: Effect of Material Heterogeneity on Separation Performance.

Author

Verdugo, Luis, Zhang, Lian, Etschmann, Barbara, Brugger, Joël, Bruckard, Warren, Menacho, Jorge, Molina, Lorena, and Hoadley, Andrew

Subjects
FLOTATION, CIRCULAR economy, MATERIALS testing, ELECTRONIC waste, CATHODES
Abstract

In this study, two types of recycling scenarios are assessed for spent battery materials using froth flotation. The first is for a single cathode chemistry and would be considered as the most likely scenario for a large battery manufacturer, who takes back their own batteries for reprocessing. The second scenario is for mixed cathode chemistry, and this would be the most likely scenario for regional reprocessing. The mixed spent battery materials assessed in this work were sourced from such an industrial recycling operation in Australia. Good results were obtained for both recycling scenarios. The anode recovery and anode grade in the final concentrate for both materials evaluated were for the single spent battery material 80.1% and 90.3%, respectively, and for the mixed spent battery material, 77.4% and 82.0%, respectively. For the final tailings, the cathode grades for both materials tested were 93.9% and 87.1%, respectively, with the lower grade for the mixed spent battery attributed to the high content of impurities in the original material. These results highlight the importance of the preprocessing ahead of the flotation process. The results confirm froth flotation as a feasible technique that can be used to achieve the bulk of the separation. [ABSTRACT FROM AUTHOR]

Published
2024
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