Low HF Concentration Research Articles

Sustainable fluoride removal with scrap aluminum: Co-producing cryolite and hydrogen

This study presents a novel continuous process for fluoride removal and re- source recovery as cryolite, using a scrap aluminum-packed column. Efficient aluminum dissolution in hydrofluoric acid (HF) generates hydrogen gas and provides cost-saving alkalinity. The process achieves high efficiency (Al/F molar ratio of 2/6) within short Empty Bed Contact Times (15 min) and at low HF concentrations (500 mg/L). Solution pH plays a crucial role, with Al/F ratios above 1 achievable at pH below 4. The exothermic reaction requires temperature control, with a strong correlation (R²=0.99) between HF concentration and heat generation. Hydrogen production matches theoretical predictions. Cryolite synthesis was confirmed at optimized pH (5–5.5) with a 1:1 bypass ratio, achieving 98 % fluoride removal. XRD and SEM- EDS analyses verified cryolite formation. This approach offers a promising solution for industrial fluoride management, resource recovery, and clean hydrogen production.

Mechanism and kinetics study of vanadium leaching from landfilled metallurgical residues by ultrasonic with ozonation enhancement in a low-acid medium

Landfilled metallurgical residues are valuable raw materials for the recovery of strategic vanadium resources. However, efficient separation of vanadium from these residues is challenging due to its strong oxidation resistance and coating within silicate inclusions. To address this issue, this study proposes an enhanced leaching process utilizing the synergistic effect of O3-catalyzed ultrasonic field in a low concentration sulfuric acid system. Results show that following a 10-minute O3 and ultrasonic treatment, the direct leaching rate of vanadium experienced a remarkable 46.7 % increase. Quenching experiments revealed a hierarchical order of active species within the reaction process:⋅OH >⋅O2−> H+, with⋅OH oxidation exhibiting the most pronounced capacity for disrupting the inclusion structure. Electron Paramagnetic Resonance analysis indicated that the highest⋅OH yield arose from the combined application of ultrasound and ozone. Kinetic investigations demonstrated that the vanadium leaching process is governed by interfacial chemical reactions. The activation energy of vanadium oxidation leaching under ultrasonic-O3 conditions was determined to be 40.41 kJ/mol, representing a 20.19 % reduction compared to ultrasonic conditions alone. Through the integration of analysis, characterization, and comparative evaluations, it was discerned that the synergistic impact of ultrasonic and ozone treatments significantly enhances the breakdown of silicate inclusions by low-concentration HF, particularly in the conversion of SiOSi bonds into SiOH bonds and SiF bonds. In summary, the refined leaching methodology incorporating ozone catalysis in conjunction with ultrasonic treatment provides a new idea for the separation and extraction of refractory residual vanadium.

Geochemistry and origin of the Late Carboniferous ultramafic, mafic, and felsic plutonic rocks (NW Iran)

The Late Carboniferous Gharabagh-Mamkan-Mingol plutonic complex (GMMP) consists of a variety of ultramafic, mafic, felsic intrusive rocks, including the 325–315 Ma Gharabagh gabbroic, granitic, and monzonitic rocks and Mamkan-Mingol 320–315 Ma massive appinites (hornblende-rich gabbros) and 300–295 Ma layered mafic-ultramafic (gabbro, appinitic gabbro, and appinite) rocks in the northwestern Sanandaj-Sirjan zone, Iran. The relationships between various rock types in the plutonic complex are unknown. To address these issues, we conducted a detailed petrologic and geochemical study of the complex, and its country rocks.The abundance of major and trace elements and isotopic ratios of 87/86Sr (0.70379–0.70428) and 143/144Nd (0.51228–0.51245) systems showed that the Gharabagh gabbros formed from a metasomatized amphibole-bearing spinel lherzolite from an ancient subduction-modified mantle source with OIB characteristics including high contents of light rare earth elements (LREEs), Ti, Nb, Ta, and Ba, as well as low concentrations of Sr, Hf, and Zr. The geochemical data show that monzonites had high concentrations of LREEs, Ba, U, K, Hand Zr, and the low contents of Th, Nb, Ta, Sr, P, and HREEs and Eu-positive anomalies and originated from the melting of the continental crustal base in the subducted mantle wedge. The granites are similar to monzonites, with their difference being in the high concentrations of Th and Eu-negative anomalies. Combining petrographic, petrological, geochemical, and isotopic data suggests that Gharabagh plutonic rocks were formed as a result of Paleo-Tethys slab break-off, and slab sinking, during trans-tensional collision between the Central Iranian microplate and Gondwanaland during the Late Carboniferous. As a result of this event, decompression melting began in the upwelling mantle, coeval with the formation of the pull-apart basin, during major strike-slip faulting, leading to a hydrous mafic melt with about 10–12% partial melting.The Mamkan-Mingol massive and layered masses have a tholeiitic affinity. The Mamkan-Mingol rocks are characterized by different trace element patterns, especially in the concentrations of REEs and high field strength elements (HFSEs) such as Nb, Ta, Hf, Zr, and P and large-ion lithophile elements (LILEs) such as Th, U, Sr, K, Rb, and Ba. The massive and layered rocks mostly show a variably developed negative anomaly in HFSEs, and widely varying ratios of (La/Yb)n (1.0–5.2). Massive appinites and layered gabbros of GMMP originated due to different partial melting in the upwelling zone of metasomatized OIB-like amphibole-bearing spinel lherzolite and a less hydrous- to dry upwelling mantle zone, respectively, in an environment associated with the initiation of rifting, where the remnants of the Paleo-Tethys subducted slab plunges deep into the mantle. Contrasting Nd isotopic ranges are present between the massive appinites (ɛNd = +0.39) and different types of mafic-ultramafic rocks in layered outcrops (ɛNd = +1.12 to +2.07) of the complex. Based on the geochemical and isotopic (ratios of Sr, Nd, and Pb) data, we suggest that variations in of contribution of slab-derived fluids or crustal components in the primary melt caused the generation of massive appinites and different types of layered gabbros.

Palynostratigraphy and Bayesian age stratigraphic model of new CA-ID-TIMS zircon ages from the Walloon Coal Measures, Surat Basin, Australia

The Surat Basin hosts significant coal and coal seam gas resources. New high-precision CA-TIMS U/Pb zircon ages from tuffs and Bayesian age stratigraphic models are combined with palynology from fine-grained sedimentary rocks and zircon trace elements to provide further chronostratigraphic and biostratigraphic constrains on the Walloon Coal Measures in the eastern margin of the Surat Basin and infer the palaeoenvironment and tectonic setting. The tuff ages range from 165.88 ± 0.11 Ma to 158.84 ± 0.05 Ma, with those from the stratigraphically lower Taroom Coal Measures ranging from 165.88 ± 0.11 to 163.05 ± 0.08 Ma and Juandah Coal Measures ranging from 159.91 ± 0.04 to 158.84 ± 0.05 Ma. This corroborates that the lower part of the Walloon Coal Measures is Callovian and the upper part is Oxfordian. The palynology results from mudstones show that all samples are dominated by microfossils of spore-pollen with conifers being the most abundant. Our samples fall within Price’s (1997) stratigraphic zonation of APJ4.2 and APJ4.3. Posterior ages for palynology samples were estimated through Bayesian age stratigraphic modelling using stratigraphic depths and U-Pb zircon ages. The palaeoenvironment in the eastern portion of the basin is inferred to be predominantly fluvial, with spores and pollen derived from fresh water or terrestrial plants. Higher concentrations of green algae in one sample suggest that at times the water was somewhat stagnant. The zircons were derived from predominantly intermediate magmas, as indicated by the generally low Ti, Ta, and Nb values. The tectonic environment that the zircons were derived from was most likely a continental subduction zone due to their high U/Yb, low Nb/Yb and relatively low Hf concentrations. These new data support previous conclusions of the Surat Basin palaeoenvironment, contribute to the ongoing discussion about the tectonic setting of the basin and add new regional age marker horizons.

Magmatic–hydrothermal stage recorded by mica zonation and Nb–Ta–W–Sn mineralization: New insight into the genesis of highly evolved Songshugang Nb–Ta deposit (Jiangxi, SE China)

The role of magmatic and hydrothermal processes in niobium-tantalum mineralization is still controversial and has been limited by a lack of mineralogical records in the evolving magmatic–hydrothermal system. Micas as essential rock-forming minerals and comprise the amount of elements (especially rare-metal elements), become one of the ideal indicator. The Songshugang rare-metal granite (RMG) located in the southern part of Jiangxi Province, China, is renowned as the largest tantalum reservoir in South China. The albite–topaz–K-feldspar granite is the major granite, with layers of pegmatite, topaz-K-feldspar granite, and greisen overlay on it. It is the typical highly evolved peraluminous with low phosphorous RMGs (PLP-type) according to geochemistry. The Songshugang pluton preserves analogical characters in topaz-albite-K feldspar granites and topaz-K feldspar granite, and partly reserves in greisen. Detailed petrographic, mineralogy, and chemical composition study of zoned mica and accessory Nb–Ta minerals suggest that zinnwaldite and Nb-Ta oxides have experienced magmatic fractionation with gradually decrease of K/Rb and Nb/Ta ratio in prismatic zinnwaldite and columbite-(Fe). The leap of Rb (Rb2O up to 4.08 wt%) and Ta (Ta# up to 0.29) at the rim of zinnwaldite and columbite is likely attributed to supersaturation. Afterwards the overgrowth of Rb-deficit zinnwaldite (0.56–0.72 wt% Rb2O) is coeval with the Ta-highest wodginite, taking place during the magmatic-hydrothermal transition associated with a fluid-melt interaction in hydrosaline melt. The ascent of fluxing elements contributes to the formation of hydrothermal zinnwaldite and cassiterite through greisenization. The systemic coupling mineralization of zinnwaldite and Nb–Ta oxides altogether record the both the melt-driven and fluid-driven processes in highly evolved Songshugang deposit that is critical for rare-metal mineralization. The Songshugang displays a great similarity to the typical PLP RMGs Cínovec cupola in geochemistry, which are metaluminous to peraluminous, containing low phosphorous, intermediate REE, Zr, Hf, and Th content. But Songshugang has experienced strong supersaturation; the latter is more akin to highly evolved melts alike Yichun or Beauvoir. The strong supersaturation and crystallization demonstrate its discrepant mineralization mechanism in Songshugang RMGs.

Ancient Metasomatism in the Lithospheric Mantle, Eastern North China Craton: Insights from In-Situ Major and Trace Elements in Garnet Xenocrysts, Mengyin District

Mantle metasomatism refers to the interaction between mantle melt, fluid, and mantle rock. It not only affects the physical and chemical properties of the lithospheric mantle but also plays an important role in the process of metal and gem mineralization. In order to explore the nature and evolution of metasomatism in the lithospheric mantle of the Mengyin area in the eastern part of the North China Craton, this paper combines the previous data of garnet inclusions in diamonds and analyzes the major and trace elements of garnet xenocrysts in the Shengli No. 1 kimberlite pipe from the EPMA and LA-ICP-MS experiments. The experiments show that the garnet xenocrysts of the Shengli No. 1 kimberlite pipe are mainly lherzolitic and harzburgitic garnets. The content of Zr and TiO2 in some garnets are low, which are the characteristics of depleted garnets. Conversely, another group of garnets display high Zr and TiO2 contents, indicative of high-temperature melt metasomatism. When comparing the Ti/Eu ratio of the depleted garnets to that of the primary mantle, a significantly lower value is observed. Additionally, the (Sm/Er)N value undergoes minimal changes, while the Zr/Hf value exceeds that of the primary mantle. These characteristics are indicators of carbonatite melt metasomatism. Garnets that are affected by high-temperature melt metasomatism exhibit low (Sm/Er)N content, a significant variation in the Ti/Eu ratio, and a Zr/Hf value greater than that of the primary mantle. These characteristics indicate the influence of kimberlite melt metasomatism. Garnets impacted by carbonatite melt metasomatism display a strong sinusoidal distribution pattern of rare earth elements (REE) and are often found as lherzolitic garnet xenocrysts and garnet inclusions in diamond. On the other hand, garnets influenced by kimberlite melt metasomatism exhibit a slight sinusoidal REE distribution pattern in harzburgitic garnets and a slight sinusoidal REE distribution or a flat pattern from medium rare earth elements (MREEs) to heavy rare earth elements (HREEs) in lherzolitic garnet xenocrysts. Based on these findings, it is evident that there are at least two types of metasomatism occurring in the lithospheric mantle of the Mengyin area in the eastern part of the North China Craton. The first type involves the metasomatism of early carbonatite melt to the mantle peridotite. Garnets formed under this condition exhibit high Sr and LREE contents, as well as low Zr, Hf, Ti, Y, and HREE contents, indicating depletion characteristics. The second type entails the metasomatism of late kimberlite melts affecting the mantle peridotite. Garnets formed under this process display high Zr, Hf, Ti, Y, and HREE contents.

Composition dependent charge retention in amorphous HfxAl1−xOy dielectric layers

Charge trapping properties in dielectric materials serve as a ground principle in data storage devices called NAND flash. High-density nonvolatile storage requires deep trapping centers and localized trapped charge distribution. Current NAND flash technology relies on Si3N4 during the development history, and further development requires a higher dielectric constant material with compatible deep trapping centers and localized trapped charge profiles. In this work, charge trapping properties of HfxAl1−xOy dielectric layers with various compositions are investigated by modeling retention characteristics with trap energy and μτ product, where the former represents the trapping center depth and the latter represents the trapped charge profiles. Comparing the conventional Si3N4, HfxAl1−xOy dielectric layer with a low Hf content may improve long-term charge retention in NAND flash, while a localized trapped charge profile needs improvement to be compatible with Si3N4.

Potential dust sources for loess deposits in Central Italy: A geochemical case study from the Loess-Paleosol-Sequence of Ponte Crispiero (Marche)

Identifying potential dust sources of Loess-Paleosol-Sequences (LPS) is important to understand past climatic and environmental conditions. For loess deposits of Central Italy different hypothesis on particle sources have been proposed, but none of them has been tested using a comprehensive geochemical approach yet.Here we present geochemical, mineralogical and grain-size data from selected deposits of a LPS situated at Ponte Crispiero (Marche, Central Italy) to obtain first insights on the provenance of particles deposited here.Loess deposits within the Ponte Crispiero succession are rather coarse (mostly coarse silt and fine sand) indicating a dominance of proximal dust sources. Applied geochemical indices suggest the alluvial plains of the Po River (Northern Italy) and its discharging area as major particle sources.According to these findings, the so-called “Great Po Plain” hypothesis, that claims the presence of a vast alluvial landscape related to the sea-level drop of the Adriatic Sea during the Pleniglacial (i.e. Marine Isotope Stage MIS 4–2), may be considered as a realistic scenario. Such a considerable alluvial plain would have the potential as major source for silt and sand particles not only for the Ponte Crispiero LPS, but also for the loess on the Adriatic side of Central Italy. The main geochemical characteristics of Ponte Crispiero loess are the low concentrations of Zr and Hf and the high contents of carbonate and transition elements compared to the Upper Continental Crust and other European loess sections. Overall, this study contributes towards a better understanding of the provenance and origin of Italian loess. However, for further testing the “Great Po Plain” hypothesis, more (geochemical) investigations need to be conducted, especially in the surrounding areas of the Po plain.

Petrology of the meta-mafic rocks from the Lolodorf area, Nyong complex (Southwest Cameroon): implication for the origin and emplacement conditions

This study presents the new petrology and geochemistry data for the comprehension of the origin and emplacement conditions of the Lolodorf mafic rocks whitin the Nyong Complex. The meta-mafic rocks consist of fine-grained garnet meta-mafic (FGM) and coarse-grained garnet meta-mafic (CGM) rocks presenting nearly similar mineral composition. They are made up of quartz, plagioclase, garnet orthopyroxene, clinopyroxene, amphibole, opaques, apatite and rutile. They also present recrystallization features such as quartz ribbons, corroded grain mineral, cuspate plagioclase boundary and necklace garnets in the matrix. These mineral assemblages suggest that the recrystallization took place under granulite facies condition. The meta-mafic rocks have basaltic and tholeiitic composition like the magmas (SiO2 FGM = 48.20–50.70 wt% and SiO2CGM = 46.68–50.27 wt% and MgFGM = 43.24–62.27 and MgCGM = 40.85–69.70) emplaced in the active continental margin context. The low La/Th ratio observed in the FGM and the high La/Th ratio in the CGM together with low Hf content imply that the FGM are reworked plutonic rocks that recorded both high grade partial melting and metamorphism whereas CGM recorded only metamorphism imprints. Thermobarometry results suggest that the partial melting and metamorphic peak occurred around the amphibolite-granulite facies transition. The fine-grained garnet meta-mafic rocks emplaced under pressure estimated at around 2.7–14.89 kbar with temperature interval between 672 and 952 °C while the coarse-grained garnet meta-mafics settled at around 1.5–16.09 kbar and 631–909 °C. The selected amphiboles display low water content (1.92–2.10 wt%) and plot between NNO and NNO + 2 buffers indicating that they crystallized under high oxidizing conditions. These results coupled with previous geochronological study suggest that the FGM may have occurred at the Mesoarchean and have been reworked during Eburnean whereas the CGM may have been formed at the Eburnean.

Source Characteristics of the Carboniferous Ortokarnash Manganese Deposit in the Western Kunlun Mountains

The specific source of ancient sedimentary manganese (Mn) deposits is commonly complex. Here we use systematic major and trace element data with strontium (Sr) and neodymium (Nd) isotopic analyses of the Ortokarnash Mn(II) carbonate ores and associated carbonate rocks from the Upper Carboniferous Kalaatehe Formation (ca. 320 Ma) in order to constrain the Mn source. This formation consists of three members: the first member is a volcanic breccia limestone, the second member is a sandy limestone, and the third member is a black marlstone with the Mn(II) carbonate interlayers. Petrographic observations in combination with low Al2O3 (<3.0 wt%) and Hf (<0.40 ppm) contents and the lack of correlations between the Al2O3 and 87Sr/86Sr ratios as well as εNd(t) values demonstrate a negligible influence of terrigenous detrital contamination on both Sr and Nd isotopic compositions of the Mn(II) carbonate ores. The Sr isotopes of Mn(II) carbonate ores are most likely affected by post-depositional alteration, while Nd isotopes remain unaltered. The initial 87Sr/86Sr ratios in the associated carbonate rocks are likely the result of a mixture of the chemical components (i.e., seawater) and the Al-rich components (e.g., volcanoclastic material), while the detrital effects on Nd isotopes are negligible. In addition, both Sr and Nd isotopes in these non-mineralized wall rocks remained unchanged during post-depositional processes. The relatively low Th/Sc ratios and positive εNd(t) values suggest that the aluminosilicate fraction in the calcarenite and sandy limestone was mainly derived from the weathering of a depleted mafic source, representing the riverine input into the seawater. Given that the Mn(II) carbonate ores are characterized by negative εNd(t) values, these suggest that seafloor-vented hydrothermal fluids derived from interaction with the underlying old continental crust mainly contribute to the source of the Mn(II) carbonates.

Provenance and tectonic setting of the Statherian Hangaoshan Group: Implications for evolution of the North China Craton during late Paleoproterozoic

The Hangaoshan Group, mainly composed of siliciclastic rocks, is one of the best-preserved sedimentary units exposed in the central North China Craton (NCC) from the Statherian Period. The Hangaoshan Group overlies the Paleoproterozoic Jiehekou Group and underlies Cambrian strata, with both contacts representing unconformities. Detrital zircon U-Pb dating and regional stratigraphic correlation constrain the depositional age of the Hangaoshan Group during ca. 1.8–1.69 Ga. High CIA (>62), low ICV (mostly 0.25–1.12) values and high SiO2/Al2O3 (2.5–22.2) ratios are suggestive of mature sources that experienced moderate to intensive chemical weathering. Low textural and compositional maturity indicate that the provenance of the Hangaoshan Group is mainly proximal deposition. Large proportion of quartz grains, light REEs enrichment relative to heavy REEs ((La/Yb)N = 4.37–33.7), negative Eu anomalies (δEu = 0.41–0.79), high Th/Co (0.44–20.5), high La/Sc (1.35–17.2) ratios, low La/Th (0.99–9.64) ratio and low Hf content (1.34–24.5) suggest that the provenances are mainly composed of felsic magmatic rocks with minor contributions from intermediate-basic meta-volcanic rocks, which is also supported by the A-CN-K, Al2O3-Fe2O3T*2-MgO*2 and Co-Nb-Y diagram. Detrital zircon ages from the Hangaoshan Group are mostly between 2.26 Ga and 1.84 Ga with a notable peak at 2.18 Ga and two subordinate peaks at 2.08 Ga and 1.98 Ga. Geochronological and isotopic similarity suggests that the Chijianling-Guandishan TTG and the Jiehekou Group in the Lvliang area are the dominant sources for the Hangaoshan Group, while the Yejishan Group, 2.2 Ga mafic meta-volcanic rocks, and Huijiazhuang and Xiyupi granite also contributed to lesser degrees. In terms of petrological characteristics, most gravels in the lower conglomerate of the 3rd Formation (Fm) are sandstone fragments of the 1st and 2nd Fm, suggesting that the 3rd Fm is mainly derived from the older diagenetic rocks of the Hangaoshan Group, with a lesser amount of basement rocks. Generally, the Hangaoshan Group was likely deposited in a rift basin. In combination with previous studies on other late Paleoproterozoic volcanic-sedimentary sequences, we consider that the Xiong’er rift in southern NCC extended into the midcontinent at the Lvliang area during ca.1.78 Ga and then the continental crust was uplifted in the Lvliang area during the Mesoproterozoic–Neoproterozoic.

Electrochemical synthesis of monoclinic BiPO4 nanorod film for efficient PEC degradation

BiPO4 film with an active monoclinic phase (space group: P21/n) has been newly reported via a simple electrochemical anodization method. The prepared film is found to be composed of BiPO4 nanorods with a diameter ranging from 80 to 160 nm. The crystallinity and particle size are demonstrated to be influenced by the electrolyte HF concentration. The data illustrates that low HF concentration results in poor crystallinity and large particle size, while high HF concentration leads to the formation of impurity phase of BiO0.51F1.98 and small particle size. The BiPO4 film prepared in 5 M HF exhibits the best activity due to its good crystallinity and small particle size.

Mixing of cognate magmas as a process for producing high-silica granites: Insights from Guanmenshan Complex in Liaodong Peninsula, China

Ascertaining how high-silica granites form is important for understanding why Earth has a high-silica continental crust and how the composition of the continental crust has evolved through time. This study presents a systematic dataset for the petrology, mineralogy, geochronology, and geochemistry of the granite porphyries and related microgranular enclaves and diabases from the Early Cretaceous Guanmenshan Complex (126–123 Ma) in Liaodong Peninsula, North China Craton, to reveal the complex, multi-stage, magmatic evolution in a shallow silicic magma system prior to and during emplacement of high-silica granites. Zircons from the granite porphyries and microgranular enclaves can be classified into two groups: those with dark-CL cores surrounded by light-CL rims, and those comprising entirely light-CL domains, without dark-CL cores. Our results indicate that dark-CL zircon domains with high Th (46–579 ppm), U (120–1274 ppm), and Hf (6709–12,493 ppm) contents and low Ti contents (1.52–7.85 ppm) and Ti-in-zircon temperatures (TTiZ = 622–751 °C) formed from highly evolved magmas, whereas light-CL zircon domains with low Th (14–157 ppm), U (24–236 ppm), and Hf (4749–10,474 ppm) contents and high Ti contents (7.59–29.36 ppm) and Ti-in-zircon temperatures (TTiZ = 748–885 °C) formed from low evolved magmas. These characteristics, combined with the similar UPb ages and Hf isotopic compositions of the dark-CL zircon cores and light-CL zircon domains and insignificant intra- or inter-grain (87Sr/86Sr)i variations of plagioclase from the granite porphyries and microgranular enclaves, reflect mixing between two cognate magma batches with contrasting evolved signatures. This study presents a model in which the highly evolved magmas were derived from initial interstitial melts that were extracted from a crystal mush leaving behind residual cumulates, whereas the less evolved magmas were the products of re-melting of the cognate cumulates. The diabases likely represent the mafic recharge magma that contributed necessary heat but limited mass to remobilize the cumulate mush, inducing the internal self-mixing and formation of the hybrid high-silica magmas. Feeder-dyke related emplacement of the hybrid magma generated more mafic rocks that became incorporated and dispersed into the high-silica granite porphyries as cognate microgranular enclaves. Our results lend new insights into the important role of cognate magma mixing induced by mafic recharge in generation of high-silica granites.

Processing, Preaging, and Aging of NiTi-20 at.% Hf High-Temperature Shape Memory Alloy from Laboratory to Industrial Scale

High-temperature shape memory alloys (HTSMAs) are a growing area of research in active materials that exhibit recoverable transformation strain and shape memory responses. They show promise for applications such as actuators in the aerospace, automotive, and energy exploration industries. NiTiHf is a cost-effective HTSMA solution with increased transformation temperatures above 115 °C. In this study, processing and aging treatments were performed on an industrially produced, hot-extruded Ni50.3Ti29.7Hf20 (at%) HTSMA. Portions of the extruded material were hot-rolled, pre-aged for 12 h at 300 °C, aged for 3 h at temperatures ranging 450–750 °C, or a combination. The goal of the aging treatments is to establish coherency between the interface of the matrix and H-phase nano-precipitates in the HTSMAs. After processing, the samples were characterized by differential scanning calorimetry, Vickers hardness testing, scanning electron microscopy, and synchrotron radiation x-ray diffraction. Previous studies have shown that pre-aging is effective for controlled nucleation of H-phase precipitates in low Hf content NiTiHf high-temperature shape memory alloys, this study shows that pre-aging of high Hf containing NiTiHf high-temperature shape memory alloys plays a small contributing role on thermal or mechanical properties, but is essentially ineffective and unnecessary at the pre-aging conditions examined here. Additionally, it is shown that hot-rolling can be used to control the orientation of H-phase in NiTiHf HTSMAs.

Provenance, nature, and U–Pb zircon geochronology of Ngaye rocks (Adamawa‐Yadé Shield, Central Cameroon): New insights into the evolution of Archean crust within the Pan‐African belt

Petrographical, geochemical, and geochronological data obtained from Ngaye high‐grade metasedimentary rocks have contributed to determine the provenance, nature, and evolutionary history of the Adamawa‐Yadé Domain from the Archean to Pan‐African events. The rocks are migmatites formed after TTG and granitic crusts were reworked by partial melting at T = 683–994°C. Geochemical features, for example, low Rb/Sr ratio (0.03–0.53), high Cr/V, and Cr/Th ratios (9.91–100.75; 28.41–686.15), respectively, indicate that these samples were derived predominantly from a mafic crust source. The primordial mantle‐normalized spidergrams are characterized by negative Nb‐Ta anomalies, suggesting melting of crustal rocks. REE fractionation shown (La/Yb)N = 8.48–197.89) indicate melting of crustal source rocks (meta‐TTGs). Low Hf and Zr contents (0.95–5.65 ppm and 23–262.85 ppm, respectively), low Sr/Y ratios (9.17–200.65), and a positive correlation between Th/Sc and Zr/Sc, point to crustal reworking. U–Pb ages on detrital zircon in tonalitic and granodioritic gneisses indicate contribution of Mesoarchean and Paleoproterozoic sources and suggest a maximum deposition age during the Early Paleoproterozoic for their magmatic protoliths. Magmatic zircon grains of granodiorite, with a round shape, Th/U ratio values ranging from 0.02 to 1.23, and an oscillatory zonation yield post emplacement metamorphic ages at 2,077 Ma. The lower intercept ages obtained in this study, match the tectonic reworking of the crust during the Pan‐African event associated with partial melting due probably to regional‐scale shear zone activities and magmatic accretion of juvenile magmas.

Tailoring Mesoporous Silicon Surface to Form a Versatile Template for Nanoparticle Deposition

Porous silicon (PS) can be used as a loading template in sensing or as a matrix to develop nanoparticle arrays. We present a comprehensive study of PS morphology and optical properties before and after the pore opening process, including the determination of thickness, pore size, and pore density of PS layers, its surface wettability, and reflectivity. The PS samples were fabricated by electrochemical anodization of monocrystalline silicon wafer in 5–20 wt.% hydrofluoric acid (HF) solution at a current density in the range of 20–200 mA/cm2. Anodization was followed by the pore opening process, i.e., the removal of a parasitic superficial layer with a “bottleneck” structure by reactive ion etching (RIE). The results illustrate that “bottleneck”-free PS allows to achieve a high pore density using a low HF concentration and a reduced current density. We established that this structure demonstrates higher hydrophobicity in comparison to the samples before RIE. The applicability of the developed “bottleneck”-free PS was tested via filling the pores with silver nanoparticles, indicating its potential use as a template for the fabrication of nanoparticle arrays.

Carboniferous sedimentary provenance and tectonic setting in the Darbut region of Western Junggar (NW China): evidence from mineralogy, geochemistry and detrital zircon U–Pb dating

The Carboniferous tectonic evolution of Western Junggar is crucial to understanding the subduction–accretion process of the Central Asian Orogenic Belt, but the nature of this setting is still controversial. In this work, composite mineralogical, geochemical and detrital zircon U–Pb geochronological investigations have been conducted on Carboniferous clastic rocks in the Darbut region. The chemical compositions and sedimentary features show low sediment maturity and limited recycling, suggesting short-distance transportation and rapid accumulation. The samples contain igneous rock debris, mainly andesite and small amounts of basalt and granite, and a heavy mineral assemblage of Zr + Ap + Aug + Hbl + iron-bearing minerals (Hem-Lm, Ilm, Mag and Py). The samples feature moderate ratios of Zr/Sc (average 15.47) and Th/Sc (average 0.61), and low ratios of La/Sc, Co/Th and La/Th, as well as low Hf content, suggesting intermediate to felsic arc-related igneous provenances. Detrital zircon grains from the clastic rocks show prominent age peaks in the Devonian and Carboniferous with positive ε Hf ( t ) values, indicating a consistent provenance associated with the Tiechanggou–Halaalate island arc. Combining the petrology, geochemistry and geochronology of the sedimentary and magmatic rocks, we conclude that the Darbut Carboniferous volcanic–sedimentary strata were deposited in a back-arc basin during c. 327–311 Ma. Supplementary material : Tables S1-S6 and Figures S1-S6 are available at https://doi.org/10.6084/m9.figshare.c.5357293

Measurement of the melting temperature of ZrB2 as determined by laser heating and spectrometric analysis

AbstractThe melting temperatures of two different ZrB2 ceramics were studied using laser induced melting. ZrB2 having a low Hf content, produced by reaction hot pressing, had a melting temperature of 3546 K and a commercial grade ZrB2 had a melting temperature of 3553 K. Uncertainty of the temperature measurements was 1% of the absolute temperature, or ~35 K for both materials based upon 2‐sigma and a 95% confidence interval. While these values were consistent with the previously reported ZrB2 melting temperature of 3518 K, this study was able to measure Tm with less uncertainty than previous studies (±45 K). Furthermore, this study assessed the effect of Hf content on melting temperature, finding that melting temperature did not change significantly for hafnium contents of 1.75 to 0.01 at%. This study also measured a normal spectral emissivity of 0.34 for ZrB2 at 3000 K. The emissivity decreased to 0.28 at the melting temperature, then, stabilized at 0.30 in a liquid phase.

Differentiating Zr/HfIV Aqueous Polyoxocation Chemistry with Peroxide Ligation.

This work complements our recent discovery of new phases derived from zirconium perchlorate by addition of hydrogen peroxide. Here, we investigate analogous reactions with hafnium perchlorate, which is found to have modifications of the Clearfield-Vaughan tetramer (CVT). For hafnium perchlorate derivatives, we find distorted versions of CVT by X-ray diffraction and study the reaction solutions by SAXS, Raman spectroscopy, and ESI-MS. Furthermore, we investigate mixed Hf-Zr solution and solid phases and find the latter resemble the zirconium family at low Hf concentrations and the hafnium family at higher hafnium contents.

Banded iron formation from Antarctica: The 2.5 Ga old Mt. Ruker BIF and the antiquity of lanthanide tetrad effect and super-chondritic Y/Ho ratio in seawater

Here we report the first detailed geochemical data for Banded Iron-Formation (BIF) from Antarctica. Micro drill cores were taken from adjacent magnetite/haematite and metachert bands from the 2.5 Ga old Mt. Ruker BIF, Prince Charles Mountains, East Antarctica. Low concentrations of Al, Zr, Hf, and Sc reveal the purity of the samples. The chemical composition matches closely that of other early Precambrian BIF, except for an enrichment of Ni, and high Ba/Sr ratios in the metachert. Shale-normalized Rare Earths and Yttrium (REYSN) patterns show all the features of modern seawater such as depletion of light vs heavy REYSN, positive anomalies of LaSN, GdSN, and YSN (i.e. super-chondritic Y/Ho ratios) and the W-type lanthanide tetrad effect (LTE), but positive EuSN and no CeSN anomalies (and no positive Eu anomalies in chondrite-normalized REY patterns). This distribution is fully compatible with that of other pure Early Precambrian BIFs, suggesting high-temperature hydrothermal input of REY into seawater and a redox level of the atmosphere-hydrosphere system too reducing for Ce oxidation. The uniform, super-chondritic Y/Ho ratios in adjacent iron-oxide and metachert BIF bands most strongly suggest that the conspicuous banding does not result from post-depositional separation of an initially homogenous Fe-silicate precipitate, but argues for a primary origin of the banding. The super-chondritic Y/Ho ratios fit well within the range reported for other BIF worldwide, corroborating that positive Y anomalies, although possibly of smaller size than today, have always been a characteristic feature of seawater. The Mt. Ruker BIF further complements the set of Early Precambrian marine chemical sediments in which the W-type LTE has been observed, and demonstrates the antiquity of the LTE in seawater. These subtle features reveal that the distribution of the redox-insensitive REY in seawater did not change significantly over the almost 4 billion years geological record of seawater. The super-chondritic Y/Ho ratios and W-type LTE in this and other oxide-facies BIF are in marked contrast to the REY distribution in Modern and Cenozoic oxidic hydrogenetic ferromanganese crusts, pointing towards fundamentally different removal mechanisms of REY from Modern vs Early Precambrian seawater.