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Due to their high density, the ilmenite-bearing cumulates (IBC) (with or without KREEP) formed during the late-stage lunar magma ocean solidification are thought to sink into the underlying lunar mantle and trigger lunar mantle overturn. Geophysical evidence implied that IBC may descend deep inside the Moon and remain as a partially molten layer at the core-mantle boundary (CMB). However, partial melting may have occurred on the mixed mantle cumulates during the sinking of IBC/KREEP and the silicate melt may be positively buoyant, thus preventing the IBC/KREEP layer from sinking to the CMB. Here, we perform thermodynamic simulation on the stability of lunar mantle cumulates at different depths mixed with different amounts of IBC/KREEP from an updated LMO model. The modeling results suggest that the sinking of IBC/KREEP will cause at least 5 wt% partial melting in the shallow (~ 120 km) and a much larger degree of partial melting in the deep lunar mantle (~ 420 km). Due to the density contrast with the surrounding mantle, IBC/KREEP-bearing melts could potentially decouple under certain conditions. The modified lunar mantle by sinking of IBC/KREEP can better explain the formation of different kinds of lunar basaltic magma than the primary lunar mantle formed through differentiation of lunar magma ocean. Sinking of IBC/KREEP back into the lunar mantle may introduce plagioclase, clinopyroxene, garnet, and incompatible radioactive elements into the deep lunar mantle, which will further affect the thermal and chemical evolution of the lunar interior. [ABSTRACT FROM AUTHOR]

The paper reports comprehensive petrological, geochemical and mineralogical studies of osumilite-bearing andesite-dacitic lavas of Kordieritoviy Volcano (Keli Highland, Greater Caucasus) erupted at the end of the Pleistocene (about 200 ka). The petrographic and microprobe analysis showed that the rocks contain three paragenetic mineral associations: (1) "xenogenic" (metamorphic) association consisting of garnet (XPrp = 0.42, XAlm = 0.51–0.53, XGrs = 0.04–0.05) + hercynite + sapphire + bronzite + pargasite + ilmenite; (2) early magmatic association represented by hypersthene + hercynite + garnet (XPrp = 0.21–0.31, XAlm = 0.52–0.71, XGrs = 0.04–0.13) + ferro-kaersutite + ilmenite; (3) late magmatic association including hypersthene-ferrohypersthene + labradorite + garnet (XPrp = 0.04–0.14, XAlm = 0.65–0.81, XGrs = 0.06–0.18) + osumilite-(Mg) + phlogopite + tridymite + ilmenite + apatite. The osumilite-(Mg) (phenocrysts, xenomorphic aggregates in the rock matrix, and crystals in miarolic cavities), the average formula for dacites of Kordieritoviy Volcano can be written as (K0.73Na0.06Ca0.02 )1.00(Mg1.06 Mn0.04)2.00(Al2.75 Ti0.01)3.00(Si10.34Al1.66)12O30, formed mainly at late magmatic stages – in intermediate chambers immediately prior to the rise of the melt to the surface or after its eruption. Accordingly, this mineral in the studied lavas has a purely magmatic origin. Thermobarometric calculations and petrological modeling showed that the deep magma chamber of Kordieritoviy Volcano was located at a depth of 45–53 km near the Moho discontinuity. The temperature of the melt at the early magmatic stage was no less than 1100°C at 17–23 kbar. Crystallization of osumilite-(Mg) in intermediate magmatic chambers (at depths of 30–40 km) and during the lava ejection occurred at 1030–870°C and pressure progressively decreasing from 14–9 to 1 kbar. A petrogenetic model has been proposed to explain the genesis of exotic osumilite-bearing lavas of Kordieritoviy Volcano. It includes several stages: (1) formation of an enriched upper-mantle source (lithospheric mantle metasomatized by permanent interaction at the Moho discontinuity with the overlying lower crust composed of metamorphosed terrigenous-volcanogenic complexes); (2) generation of "dry" basaltic magmas in the source; (3) crystallization differentiation in the source (fractionation of olivine and chromium spinels) with the formation of a "dry" overheated andesitic melt; (4) limited-scale assimilation of the lower crustal material made up of leucocratic granulites by highly differentiated andesitic melts rising to the surface, with simultaneous fractionation of garnet, orthopyroxene and ilmenite from the melt. [ABSTRACT FROM AUTHOR]

Due to the similar physical and chemical properties of ilmenite and olivine, separating them is challenging. The flotation process, with the use of collectors, is an effective method. In this study, a ternary collector consisting of aluminum ion (III), benzohydroxamic acid (BHA), and sodium oleate (NaOL) was prepared for the flotation separation of ilmenite and olivine. Through micro-flotation experiments, molecular dynamics simulation (MD), density functional theory (DFT), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and time-of-flight secondary ion mass spectrometry (TOF-SIMS) analysis, the synergistic effect between the components of the ternary collector and the adsorption configuration on the surface of ilmenite was investigated. The results revealed that at pH = 8, Al (III), BHA, and NaOL could coordinate and adsorb effectively on the surface of ilmenite, enhancing its floatability for separation from olivine. The adsorption configuration differed from previous reports, showing a co-adsorption of multiple forms on the surface of ilmenite. [ABSTRACT FROM AUTHOR]

Akimotoite, ilmenite-type MgSiO3 high-pressure polymorph can be stable in the lower-mantle transition zone along average mantle and subducting slab geotherms. Significant amounts of Al2O3 can be incorporated into the structure, having the pyrope (Mg3Al2Si3O12) composition. Previous studies have investigated the effect of Al2O3 on its crystal structure at nearly endmember compositions. In this study, we synthesized high-quality ilmenite-type Mg3Al2Si3O12 phase at 27 GPa and 1073 K by means of a Kawai-type multi-anvil press and refined the crystal structure at ambient conditions using a synchrotron X-ray diffraction data via the Rietveld method to examine the effect of Al2O3. The unit-cell lattice parameters were determined to be a = 4.7553(7) Å, c = 13.310(2) Å, and V = 260.66(6) Å3, with Z = 6 (hexagonal, R 3 ¯ ). The volume of the present phase was placed on the akimotoite-corundum endmember join. However, the refined structure showed a strong nonlinear behavior of the a- and c-axes, which can be explained by Al incorporation into the MgO6 and SiO6 octahedral sites, which are distinctly different each other. Ilmenite-type Mg3Al2Si3O12 phase may be found in shocked meteorites and can be a good indicator for shock conditions at relatively low temperatures of 1027–1127 K. [ABSTRACT FROM AUTHOR]

Ilmenite (Fe2+TiO3) and geikielite (MgTiO3) are important terrestrial minerals relevant to the geology of the Earth, the Moon, Mars, and meteorite samples. Raman spectroscopy is a powerful technique that allows for mineral cation determination for the ilmenite-geikielite solid solution. We report on a suite of nine samples within the ilmenite-geikielite solid solution and provide context for their quantitative interpretation. We compare a univariate Raman peak position model for predicting ilmenite composition with a multivariate machine learning model. The univariate model is currently recommended, though the multivariate model may become superior if the data set size is increased. This study lays the groundwork for quantifying Fe (ilmenite) and Mg (geikielite) within oxide minerals using a cheap, portable, and efficient technology like Raman spectroscopy. [ABSTRACT FROM AUTHOR]

Perchlorate and chlorate are present in various extraterrestrial celestial bodies throughout the solar system, such as Mars, the moon, and asteroids. To date, the origin mechanisms of perchlorate and chlorate on the Martian surface have been well-established; however, relatively little attention has been cast to airless bodies. Here, we experimentally investigated the potential oxidation mechanisms of chloride to chlorate and perchlorate, such as ultraviolet irradiation under H2O- and O2-free conditions and mechanical pulverization processes. Individual minerals, olivine, pyroxene, ilmenite, magnetite, TiO2 and anhydrous ferric sulfate, and lunar regolith simulants (low Ti, CLRS-1; high-Ti, CLRS-2) and their metallic iron (Fe0) bearing counterparts were examined. We found that pulverization of dry matrix material-halite mixtures, even in the presence of O2, does not necessarily lead to perchlorate and chlorate formation without involving water. Under photocatalytic and H2O- and O2-free conditions, olivine and pyroxene can produce oxychlorine (ClOx−) species, although the yields were orders of magnitude lower than those under Martian-relevant conditions. Nanophase-Fe0 particles in the lunar regolith and the common photocatalyst TiO2 can facilitate the ClOx− formation, but their yields were lower than those with olivine. The oxides ilmenite and magnetite did not efficiently contribute to ClOx− production. Our results highlight the critical role of H2O in the oxidation chloride to chlorate and perchlorate, and provide essential insights into the environmental influence on the formation of oxychlorine species on different celestial bodies. [ABSTRACT FROM AUTHOR]

Per- and polyfluoroalkyl substances (PFAS) are fluorinated and refractory pollutants that are ubiquitous in industrial wastewater. Photocatalytic destruction of such pollutants with catalysts such as TiO2 and ZnO is an attractive avenue for removal of PFAS, but refined forms of such photocatalysts are expensive. This study, for the first time, utilized milled unrefined raw mineral ilmenite, coupled to UV-C irradiation to achieve mineralization of the two model PFAS compounds perfluorooctanoic acid (PFOA) and perfluoro octane sulfonic acid (PFOS). Results obtained using a bench-scale photocatalytic reactor system demonstrated rapid removal kinetics of PFAS compounds (>90% removal in less than 10 h) in environmentally-relevant concentrations (200–1000 ppb). Raw ilmenite was reused over three consecutive degradation cycles of PFAS, retaining >80% removal efficiency. Analysis of degradation products indicated defluorination and the presence of shorter-chain PFAS intermediates in the initial samples. End samples indicated the disappearance of short-chain PFAS intermediates and further accumulation of fluoride ions, suggesting that original PFAS compounds underwent mineralization due to an oxygen-radical-based photocatalytic destruction mechanism induced by TiO2 present in ilmenite and UV irradiation. The outcome of this study implies that raw ilmenite coupled to UV-C is suitable for cost-effective reactor operation and efficient photocatalytic destruction of PFAS compounds. [ABSTRACT FROM AUTHOR]

This article takes a low grade ilmenite in the western Sichuan region as the research object. In response to the low grade, complex mineral composition, close symbiotic relationship between valuable minerals, and fine embedded particle size of the ilmenite, a magnetic flotation mixed separation process was used to beneficiate ilmenite. Through the experimental study, the beneficiation process and regime of agent are optimized, which provides theoretical basis and technical support for the development and utilization of low grade ilmenite. The experimental results show that magnetic flotation combined process performed excellent effect on the ilmenite ores with TiO2 grade of 7. 45%, and titanium concentrate with TiCO2 grade of 42. 6% and recovery of 77. 51% can be obtained by using a highly selective carboxylic acid collector TOH. [ABSTRACT FROM AUTHOR]

Hydrogen reduction for low-grade iron is consistent with carbon neutrality, which can promote product and heat recycling, fostering environmentally friendly. This study focuses on comparing fluidized bed and fixed bed reduction to determine the optimal hydrogen reduction process, and investigates the improvement of the reduction process by pre-oxidation treatment for ilmenite. The results show that the fluidized bed increases the reduction degree by 7.4% compared with the fixed bed at 60 min, 950 °C. It enhances the crystal transformation of FeTiO 3 →FeTi 2 O 5 →Fe, and decreases particle size of reduced iron to remain a suitable fluidized state. Pre-oxidation treatment during fluidized bed reduction can promote the reduction process, resulting in an 8% increase in reduction degree at 800 °C for 40 min. The kinetic analysis reveals that the fluidized bed reduction is mixed controlled by interfacial chemical reaction and diffusion, whereas the fixed bed is solely governed by interfacial chemical reaction. Fluidized bed reduction effectively reduces the total activation energy by 36.0 kJ/mol in comparison with fixed bed. Pre-oxidized ilmenite reduces the two controlling processes by 19.2 kJ/mol and 5.3 kJ/mol, respectively, in contrast to raw ilmenite. This work provides an effective reduction method for complex low-grade iron ore and realizes high-efficiency iron reduction with zero carbon emission. [Display omitted] • Fluidized bed reduction can provide the crystal phase changing. • Reduced products in fluidized bed have pits, cracks and pores to promote mass and temperature transfer. • There are various kinetic controlling steps for fluidized and fixed bed reduction. • Pre-oxidation treatment can accelerate reduction process and decrease activation energy. [ABSTRACT FROM AUTHOR]

A high-density water-based drilling fluid (WBDF) is crucial for maintaining wellbore stability, controlling formation pressures, and optimizing drilling performance in challenging subsurface conditions. In the present research, the effect of micronized calcium carbonate (calcite), extracted from the Aruma formation outcrop, is evaluated as one of the additives that could be added to the ilmenite-weighted WBDF to enhance and optimize its properties. Various concentrations of Calcite microparticles were introduced into identical fluid formulations to assess their impact. The concentrations ranged from 0, 10, 20, to 30 lb/bbl, providing a comprehensive examination of the effects of calcite microparticles across a spectrum of concentrations within the fluid. The results highlighted that adding Barite microparticles to the WBDF revealed a notable enhancement in rheological properties. Specifically, the yield point demonstrated an increase of 37%, 37%, and 11% for concentrations of 10, 20, and 30 lb/bbl of calcite, respectively. Equally significant, high-pressure-high-temperature (HPHT) filtration analysis indicated a considerable enhancement for the fluids containing calcite microparticles. A reduction of 14.5%, 24.6%, and 13% were observed in HPHT filtrate for concentrations of 10 lb/bbl, 20 lb/bbl, and 30 lb/bbl respectively. Simultaneously, there is a reduction in filter cake thickness by 20%, 40%, and 20%, respectively. No ilmenite settling was observed in the sample containing 20 lb/bbl of calcite, unlike the other concentrations. These diverse results strongly suggest that the optimal concentration for calcite microparticles is 20 lb/bbl. The combined utilization of the optimal concentration of calcite microparticles alongside the established additives proves to be an effective strategy for optimizing the ilmenite-weighted WBDF performance in terms of both thermal stability and rheological behavior. [ABSTRACT FROM AUTHOR]

This paper presents the influence of adding rinsed ilmenite mud waste (R-MUD) on the microstructure of Portland cement composites, compared to similar composites containing fly ash (FA). The aim of the study is the assessment of the pozzolanic activity of ilmenite mud waste by its impact on the microstructure of the cement matrix in comparison to the undoubted pozzolanic activity of fly ash. The presented test results include pore size distribution, phase composition, pozzolanic activity using thermal analysis, R3 bound water test, and microstructural analysis using scanning electron microscopy (SEM). Tests were performed on mortars cured for up to 360 days. The results presented in this paper have shown that R-MUD has a pozzolanic activity level similar to FA or better, which influences pore size distribution in the composite and its microstructure. During the curing process, the microstructure of composites containing R-MUD became more compact and sealed than those with FA, which might also increase their durability. The results of the R3 tests have proven the pozzolanic activity of R-MUD but its level was lower than FA. R-MUD might be a useful substitute for fly ash, especially given the lack of good-quality fly ash on the market. [ABSTRACT FROM AUTHOR]

The text is a collection of poetic verses by Forrest Gander, titled "From Mojave Ghost." The verses explore themes of self-reflection, grief, language, and the power of art. Gander, a writer and translator, draws on his personal experiences and observations to create evocative and introspective poetry. The collection delves into the complexities of human emotions and the search for meaning in life. [Extracted from the article]

This paper addresses the study of a pillow lava interbedded with Late Albian-Early Cenomanian sediments that crops out in Armintza (Bizkaia, Northern Spain). The lava flow is an alkaline basalt with abundant macrocrysts of clinopyroxene, kaersutite, Ca-rich plagioclase (50-86% An) and ilmenite, which display a variety of textures and complex zoning patterns indicative of open-system magmatic behaviour. Macrocryst cores are likely to be inherited antecrysts that underwent complex processes under deep pre-eruptive conditions (≈ 700-800 MPa). Microcrysts and macrocryst rims formed during magmatic ascent and emplacement at shallower levels (≈ 35 MPa). Hypothetical melts in equilibrium with clinopyroxenes and amphiboles have trace element compositions like metasomatic vein melts containing amphibole, and their patterns overlap with those of the Armintza pillow lava. This suggests a metasomatised lithospheric mantle with amphibole-rich veins as a potential source for the alkaline basaltic melt. It is even conceivable that the Armintza pillow lava and other alkaline volcanic manifestations of the Basque-Cantabrian Basin were part of the same magma plumbing system through which a series of time-limited eruptions of different batches of magma ascended from the lithospheric mantle to the upper crust during the Albian to the Santonian. [ABSTRACT FROM AUTHOR]

Aggregates of ilmenite with varying amounts of rutile, ferropseudobrookite, and pseudorutile in suevites from the Ries impact structure have been analyzed by light microscopy, analytical scanning electron microscopy, electron microprobe analysis, and Raman spectroscopy to constrain their formation conditions. The tens to hundreds of micrometer aggregates comprise isometric ilmenite grains up to 15 μm in diameter that form a foam structure (i.e., smoothly curved grain boundaries and 120° angles at triple junctions). Grains with foam structure show no internal misorientations, indicating a post-impact formation. In contrast, ilmenite grains with internal misorientation occurring in the core of the aggregates are interpreted as shocked remnant ilmenite originating from the target gneisses. They can contain twin lamellae that share a common {11 2 0} plane with the host, and the c-axis is oriented at an angle of 109° to that of the host. Similarly, the new grains with foam structure display up to three orientation domains, sharing one common {11 2 0} plane for each pair of domains and c-axes at angles of 109° and 99°, respectively. This systematic orientation relationship likely reflects a cubic supersymmetry resulting from the transformation of the initial ilmenite upon shock (>16 GPa) to a transient perovskite-type high-pressure phase (liuite), subsequent retrograde transformation to the polymorph wangdaodeite, and then back-transformation to ilmenite. Whereas, the new grains with foam structure formed from complete transformation, the twin domains in the shocked ilmenite are interpreted to represent only partial transformation. Ferropseudobrookite occurs mostly near the rim of the aggregates. An intergrowth of ferropseudobrookite, ilmenite, and rutile, as well as magnetite or rarely armalcolite occurs at contact with the (devitrified) matrix. The presence of ferropseudobrookite indicates high temperature (>1140 °C) and reducing conditions. The surrounding matrix provided Mg2+ to form the ferropseudobrookite-armalcolite solid solution. Rutile can occur within the aggregates and/or along the ilmenite boundaries; it is interpreted to have formed together with iron during the decomposition of ilmenite at lower temperatures (850–1050 °C). We suggest magnetite in the rims formed by electrochemical gradients driven by the presence of a reducing agent, where Fe2+ within ilmenite diffused toward the rim. Subsequent cooling under oxidizing conditions led to the formation of magnetite from the iron-enriched rim as well as pseudorutile around ilmenite grains. Our study demonstrates that the specific crystallographic relationships of ilmenite grains with foam structure indicate a back-transformation from high (shock) pressures >16 GPa; moreover, the presence of associated Fe-Ti-oxides helps indicate local temperature and oxygen fugacity conditions. [ABSTRACT FROM AUTHOR]

A green technique that emerged as a promise in the degradation of numerous organic contaminants is photocatalysis. The aim of this study concerns photocatalytic degradation of organic using titanium dioxide nano particles (TiO2 NPs) which syntheses from ilmenite by different leaching methods using different ingredients such as HCl, HNO3 and Aqua Regia. The affecting factors such as rate of addition, reaction time, ilmenite grain size, acid to ilmenite ratio and reaction temperature were conducted. Comprehensive physicochemical characterization of Ilmenite and TiO2 NPs were conducted using different analytical techniques such as XRD, XRF, SEM, TEM and FTIR. Photocatalytic degradation of organics is confirmed by studies of affecting factors on the effectiveness of TiO2 NPs such as dose, agitation forces, light intensity, initial concentration, pH, time, and temperature. The removal percentages of TSS, COD, BOD and TN of organics were explored. From the results the maximum removal percentage of TSS were 97.3 and 96.9% before and after secondary treatment conducted using ferric chloride (FC). The maximum removal percentage of TKN, BOD, and COD before secondary treatment were conducted using mixture of TiO2 NPs, FC, and chitosan, which reached 44.2, 44 and 46.3%, respectively. The maximum removal percentage of TKN, BOD, and COD after secondary treatment were conducted using mixture of TiO2 NPs, FC, and chitosan, which reached 94.9, 99.7 and 99.6%, respectively. Overall, the results derived from this investigation suggest that the TiO2 NPs/UV holds significant advanced treatment of sewage water, making it a viable choice for water reuse applications. [ABSTRACT FROM AUTHOR]

Various pyrometallurgical processes to produce TiO2 slag have been reviewed, focusing on the solid-state reduction aspects of ilmenite. Most of the upgradation processes from ilmenite to titania slag involve direct smelting of ilmenite and, therefore, are generally considered energy-intensive and not environmentally friendly. On the other hand, the pre-reduction of ilmenite, followed by the smelting processes, is advantageous because of its low energy consumption, furnace stability, and negligible slag foaming. In this paper, the impact of different reducing agents on the ilmenite reduction kinetics has been reviewed. The gas-based reduction techniques, primarily with hydrogen or hydrogen-enriched syngas as reductants, show better reaction kinetics and are more environment-friendly than the carbon-based reduction of ilmenite. Hence, the titania slag production from ilmenite can be made efficient and sustainable by incorporating the pre-reduction concept and gas-based reduction for the pre-reduction step. Numerous ways of improving ilmenite pre-reduction have been investigated intensively, featuring pre-oxidation, additives, mechanical activation, and microwave-assisted reduction. Since ilmenite is a good microwave absorber and the microwave-assisted reduction process provides faster kinetics, the method is also very promising for large-scale applications. [ABSTRACT FROM AUTHOR]

The Duluth Complex is a large mafic intrusive system located in northeastern Minnesota emplaced as part of the 1.1-Ga Midcontinent Rift. Several Fe–Ti oxide-bearing ultramafic intrusions are hosted along the Western Margin of the Duluth Complex, and are discordant bodies present in a variety of geometries, hosted in multiple rock types, and dominated by peridotite, pyroxenite, and semi-massive to massive Fe–Ti oxide rock types. Their origin has been debated, and here we present geochemical evidence and modeling that supports a purely magmatic origin for the Titac and Longnose Fe–Ti oxide-bearing ultramafic intrusions. Ilmenite and titanomagnetite textures indicate a protracted cooling process, and δ34S values of sulfides reveal little assimilation of the footwall Virginia Formation, a fine-grained pelitic unit that contains sulfide-rich bands. We model the crystallization of a hypothetical parental magma composition to the host intrusion of Longnose using Rhyolite-MELTS and demonstrate that the accumulation of Fe–Ti oxides in the discordant intrusions cannot be explained by density-driven segregation of crystallized Fe–Ti oxides. Instead, we show that the development of silicate liquid immiscibility, occurring by the unmixing of the silicate melt into conjugate Si- and Fe-rich melts, can result in the effective segregation and transportation of the Fe-rich melt. The Fe-rich melt is ~2 orders of magnitude less viscous than the Si-rich melt, allowing the Fe-rich melt to be more effectively segregated and transported in the mush regime (crystallinities >50%). This suggests that viscosity, in addition to density, plays a significant role in forming the discordant Fe–Ti oxide-bearing ultramafic intrusions. We propose a genetic model that could also be responsible for the Fe–Ti oxide-rich layers or bands that are hosted within the igneous stratigraphy of mafic intrusions of the Duluth Complex. [ABSTRACT FROM AUTHOR]

Basaltic volcanism on the Moon produced low- and high-Ti mare basalt suites that are also distinct with respect to their iron, titanium, and magnesium isotopic compositions. Here, the equilibrium fractionation of Fe and Ti isotopes between ilmenite and melt was experimentally investigated in order to evaluate the role of ilmenite in generating the isotopic compositional variability among the lunar mare basalts. Ilmenite crystallization experiments were conducted using two bulk compositions: an ilmenite-saturated basaltic andesite and an ilmenite-saturated Apollo 14 black glass, and the Fe and Ti isotopic compositions of the experimental ilmenites and glass (quenched melt) were analyzed using solution MC-ICPMS after hand-picking. Additionally, Nuclear Resonant Inelastic X-ray Scattering (NRIXS) measurements on synthetic ilmenite were conducted and compared to previous NRIXS measurements on synthetic lunar glasses in order to derive temperature-dependent equilibrium ilmenite-melt Fe isotopic fractionations. Experimentally determined ilmenite-melt fractionations were then incorporated into a lunar magma ocean crystallization model that tracks the major element and isotopic compositional evolution of lunar magma ocean cumulates and residual liquid. There is good agreement between the Fe equilibrium isotopic fractionation measured by NRIXS and the laboratory equilibration experiments, and we find that the isotopic fractionation is sensitive to ilmenite compositional differences (0 vs. 10% Fe3+). Further, the light Ti isotopic composition of ilmenite relative to the melt (Δ 49 Ti = ilmenite-melt − 0.09 ± 0.03 ‰ at 1100 ∘C) is consistent with the higher coordination of Ti in ilmenite relative to melts and results of previous studies. The modeled Ti isotopic compositions for lunar magma ocean cumulates display Ti isotopic variability sufficient to explain the low- and high-Ti mare basalt sources. However, the difference in Fe isotopic composition between the low- and high-Ti mare basalts cannot be attributed solely to ilmenite fractionation. Instead, Fe isotopic fractionation by additional products of lunar magma ocean crystallization, such as clinopyroxene, is required to generate the inferred Fe and Mg isotopic variability in the lunar mantle. Alternatively, the Fe and Mg isotopic compositions of the lunar mare basalts may indicate Fe-Mg interdiffusion has occurred in the Ti-rich component of the mare basalt source regions via reaction between ilmenite cumulates and the olivine- and pyroxene-rich lunar mantle. [ABSTRACT FROM AUTHOR]

Plasma technology has emerged as a very helpful tool in a variety of sectors, notably metallurgy. Innovators and scientists are focused on the problem of finding a more ecologically friendly way of extracting titanium and iron metal from natural ilmenite concentrate for industrial applications. A direct current (DC) plasma torch operating at atmospheric pressure is used in this study to describe a decarbonization process for reducing an ilmenite concentrate. The plasma gases employed in this torch are CO2 and CH4. The molar ratio of the gases may be crucial for achieving a satisfactory reduction of the ilmenite concentrate. As a result, two molar ratios for CO2/CH4 have been chosen: 1:1 and 2:1. During torch operation, a thin layer of graphite is formed on the cathode to establish a protective barrier, prolonging the cathode's life. The material was analyzed using X-ray diffraction (XRD) and scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS). The output gases were analyzed using mass spectrometry (MS). In addition, a thermodynamic analysis was performed to predict the development of thermodynamically stable phases. An economic assessment (including capital expenditures (CAPEX) and operating expenditures (OPEX)) and a carbon balance were developed with the feasibility of the piloting in mind. [ABSTRACT FROM AUTHOR]

Black sand is beach deposits that come from the headwaters of the Nile, which are rich in heavy minerals. The major economic mineral is ilmenite. It represents around 60 – 70 % of economic minerals quantity. To increase the adding value of the national resources, a series of experiments to study the smelting process for producing high Titania slag and cast iron. The effect of many factors such as time (20, 25 & 30 min), carbon content (15 %, 20 % & 30 %) and using a flux (1 %, 2 % & 3 %) were studied. The results revealed that time of the experiment has the most significant affecting on the iron yield among other factors. The maximum obtained iron yield was about 80.5 % and the assay of titanium dioxide in Titania slag was about 77.6 % for 30% carbon at 30 minutes. [ABSTRACT FROM AUTHOR]

The development of new tanning agents in the leather sector is urgently needed to cope with the increasing environmental pressure on the use of current tanning materials and processes. The best alternative tanning agent to replace chromium which is not environmentally friendly is titanium-based sulfate salts (IV). These compounds are most recommended to be developed and used in new, cleaner tanning processes for the leather industry. The main source of Ti(SO4)2 comes from the mineral ilmenite (FeTiO3) extracted using H2SO4. The extraction process will produce a mixture of Ti(SO4)2 and Fe(SO4) in the H2SO4-FeSO4-Ti(SO4)2-H2O system at high acidity of H2SO4. The purpose of this study is to separate each of these compounds based on their solubility in methyl alcohol. This study discusses the comparison of feed and residue with FTIR, residual characteristics with XRD and XRF. While the results of quantitative analysis of each final product of Ti(SO4)2 and Fe(SO4) compounds using XRF. Qualitative results using FTIR show that Ti(SO4)2 images are different from FeSO4. The %recovery result in the optimal state of H2SO4 extraction obtained Ti(SO4)2 was 20.6%, while FeSO4 was only 9.2% from the feed of 30 g ilmenite. [ABSTRACT FROM AUTHOR]

Shergottites have provided abundant information on the volcanic and impact history of Mars. Northwest Africa (NWA) 14672 contributes to both of these aspects. It is a vesicular ophitic depleted olivine–phyric shergottite, with average plagioclase An61Ab39Or0.2. It is highly ferroan, with pigeonite compositions En49‐25Fs41‐61Wo10‐14 like those of basaltic shergottites, for example, NWA 12335. Olivine (Fo53‐15) has discrete ferroan overgrowths, more ferroan when in contact with plagioclase than when enclosed by pyroxene. The pyroxene (a continuum of augite, subcalcic augite, and pigeonite) is patchy, with ragged "cores" enveloped or invaded by ferroan pyroxene. Magma mixing may be responsible for capture of olivine and formation of pyroxene mantles. The plagioclase is maskelynite‐like in appearance, but the original laths were (congruently) melted and the melt partly crystallized as fine dendrites. Most of the 14% vesicles occur within plagioclase. Olivine, pyroxene, and ilmenite occur in part as fine aggregates crystallized after congruent melting with limited subsequent liquid mixing. There are two fine‐grained melt components, barred plagioclase with interstitial Fe‐bearing phases, and glass with olivine dendrites, derived by melting of mainly plagioclase and mainly pyroxene, respectively. Rare silica particles contain coesite and/or quartz, and silica glass. The rock has experienced >50% melting, compatible with peak pressure >~65 GPa. It is the most highly shocked shergottite so far, at shock stage S6/7. It may belong to the group of depleted shergottites ejected at ~1 Myr from Tooting Crater. [ABSTRACT FROM AUTHOR]

Iron‐titanium oxides such as ilmenite (FeTiO3), titanite (CaTiSiO5) and perovskite (CaTiO3) are the common Ti‐rich mineral phases crystallised during magmatic and metamorphic processes on Earth. Depending on magma types or conditions of phase equilibria, formation of these Ti‐rich minerals can result in Ti isotopic fractionation in the range of ‐1.52‰ to +2.90‰ on δ49TiOL‐Ti (i.e., the per mil difference of 49Ti/47Ti ratio relative to the OL‐Ti reference material), making the Ti isotope ratios of these minerals potential tracers for conditions of magmatism and metamorphism. Due to their resistance to aqueous alteration, these Ti‐rich accessory minerals are also commonly present as pristine, detrital phases in sedimentary rocks, which offer an opportunity to study the evolution of magmatism and metamorphism throughout the Earth's geological history. Here we have developed a novel technique for in situ Ti isotopic measurement in ilmenite, titanite and perovskite using femtosecond laser ablation multi‐collector inductively coupled plasma‐mass spectrometry (fs‐LA‐MC‐ICP‐MS) under wet plasma conditions. Samples were ablated with different laser spot sizes (15–50 μm) and different laser energy densities (0.6–4.2 J cm‐2) to obtain adequate Ti signal intensity at a fixed laser repetition rate of 2 Hz. When 49Ti signal intensity of samples ranged from 0.3 to 3.7 V, no significant signal‐dependent Ti isotopic fractionation was observed under wet plasma conditions. Repeated measurements on twelve Ti‐rich minerals using different analytical protocols provided comparable δ49TiOL‐Ti values within uncertainties, confirming the accuracy of the proposed fs‐LA‐MC‐ICP‐MS method. With one exception (i.e., RUS1), all analysed minerals are homogeneous in their Ti isotopic compositions between individual chips with an intermediate precision of ±0.13‰ to ±0.17‰ (2s) on δ49TiOL‐Ti. Collectively, these minerals record a significant δ49TiOL‐Ti variation ranging from ‐0.46‰ to +2.12‰. These warrant the suitability of these materials as Ti isotopic reference materials for in situ Ti isotopic measurement. [ABSTRACT FROM AUTHOR]

The large Mo isotopic fractionations between diferent geological reservoirs make this isotopic system a potentially useful tool for constraining the origins of magmatism. However, the efect of magmatic diferentiation on Mo isotopes is still controversial. In this study, we obtained Mo isotope data for the Panzhihua gabbroic intrusion (i.e., including mineral separates of clinopyroxene, plagioclase, magnetite, and ilmenite). The whole-rock samples and mineral separates exhibit large Mo isotopic fractionations with δ98/95Mo values as follows: magnetite (–0.73‰ to –0.32‰) < clinopyroxene (–0.32‰ to –0.10‰) < ilmenite (0.06‰ to 0.36‰) < plagioclase (0.33‰ to 0.83‰). Iron-Ti oxides have Mo contents that are one order of magnitude higher than those of clinopyroxene and plagioclase. Mass balance calculations based on Mo isotopes and contents are consistent with an accumulated origin for the Panzhihua intrusion. Rayleigh fractionation modeling shows that the removal of magnetite and ilmenite results in significant Mo isotopic fractionation in the residual magma. Due to the low Mo contents of clinopyroxene and plagioclase, Mo isotopes are not significantly fractionated by the removal of these minerals. Therefore, our study highlights that fractionation of Fe-Ti oxides can cause considerable Mo isotopic fractionation; consequently, caution is needed when using Mo isotopes to infer magma origins. [ABSTRACT FROM AUTHOR]

Anatase‐TiO2 and α‐Fe2O3 were successfully separated from Indonesia ilmenite minerals using a modification of the hydrometallurgy process. Sodium salt was used as an initiated roasting before hydrochloric leaching. The study investigated parameters that affect separation such as mass ratios of sodium salt to ilmenite and leaching temperature. The results revealed that Ti composition in residue‐TiO2 increased to 76 % while Fe‐composition in filtrate‐Fe2O3 was 87 %. The XRD diffractogram analysis confirmed that main phase formed in residue of separation was anatase‐TiO2 whereas in hydrolysed of filtrate from separation was hematite. Both residue‐TiO2 and filtrate Fe2O3 had high thermal stability. The photocatalytic activity of anatase‐TiO2 and α‐Fe2O3 showed about 97 % and 85 % of Eriochrome Black‐T dye solution was degraded, respectively, when conducted to 4 hours of UV light irradiation. Photocatalytic kinetics study of anatase‐TiO2 and α‐Fe2O3 in degradation process followed pseudo‐first order with reaction rate at 0.0144 and 0.0070 min−1, respectively. [ABSTRACT FROM AUTHOR]

Herein, we reduce raw and pre-oxidized ilmenite concentrates by H 2 , CO, and a gas mixture (H 2 /CO = 1) at different temperatures. The results show that the reduction rate of both concentrates increases with increasing H 2 concentration. Furthermore, the reducing ability of the three types of reducing gases increases in the order of CO < H 2 < gas mixture. Moreover, we elucidate the coupling effect of H 2 –CO on the reduction process and propose a comprehensive utilization index for hydrogen-rich reduction gas. The results indicate that H 2 –CO coupling plays a positive role in both the concentrate reduction processes, improving the reduction rate and gas utilization efficiency. The maximum reducing gas comprehensive utilization indices for the hydrogen-rich reduction of the raw and pre-oxidized ilmenite concentrates are observed at 1000 and 950 °C, respectively. Additionally, changing the reducing atmosphere and pre-oxidation treatment significantly affects the distribution of metallic iron in the product particles. • The comprehensive utilization index of reducing gases in reduction was proposed. • The H 2 –CO coupling plays a positive role in both concentrates reduction processes. • The order of reducing ability of gases for both concentrates is CO < H 2 < mixtures. • The micromorphology of the reducing product is affected by the reducing atmosphere. [ABSTRACT FROM AUTHOR]

In this work, amorphization of ilmenite mineral was obtained by solid NaOH alkaline fusion at 550 oC. The material was tested as an adsorbent towards crystal violet (CV) removal from an aqueous matrix. Several techniques, such as X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), energy dispersive spectroscopy (EDS), and N 2 adsorption/desorption isotherms (BET) were used to characterize the material, and revealed an amorphous structure with superior surface area (88.84 m² g-1) compared to raw sample (5.90 m² g-1). These intrinsic characteristics resulted in a satisfactory adsorption capacity, reaching 133 mg g-1 at a temperature of 328 K. Kinetic studies on the adsorption process indicated that the equilibrium condition was reached within 50 min, being well represented by the Avrami model. The thermodynamic study revealed that the CV adsorption onto ilmenite is spontaneous, endothermic, and favorable. The amorphized material maintains the same adsorptive performance after three reuse cycles. Therefore, the amorphization route proposed in this work was satisfactory for producing a porous adsorbent from the ilmenite mineral, with potential use for wastewater treatment. [Display omitted] • Amorphization of ilmenite mineral by NaOH alkaline fusion route. • Amorphous structure and high surface area were obtained. • Amorphized ilmenite presented satisfactory adsorption capacity towards organic pollutants. • The amorphized material maintains the same adsorptive performance after three reuse cycles. [ABSTRACT FROM AUTHOR]

Targeted synthesis of oxynitride composites is implemented by means of organizing coupled processes. Interaction of ferrosilicon with nitrogen during combustion is considered as the main (inducing) process. The phase composition of the products of the coupled processes is determined by the chemical and phase compositions of the components added to ferrosilicon before performing self-propagating high-temperature synthesis. The influence of the basic products of the synthesis on the burning rate, fraction of nitrogen, phase composition, and morphology of synthesis products is considered. Chemical stages of ferrosilicon interaction with additives of natural minerals (zircon, ilmenite, and shungite) and aluminum in a nitrogen medium are demonstrated. The phase composition is determined by chemical transformations in a combustion wave. It is found that addition of aluminum leads to reduction or elimination of the Si2N2O phase in synthesis products with an increase in the aluminum fraction and obtaining composites based on the Si3N4 (SiAlON) solid solution. The microstructure of combustion products is presented by aggregates (5–10 m) composed of small faceted crystals, shapeless structures, and crystal flakes. Oxynitride composites with an open porosity value of 51.0–68.8% are obtained. [ABSTRACT FROM AUTHOR]

Orthoamphibole, clinoamphibole and magnetite are common minerals in altered rocks associated spatially with Palaeoproterozoic volcanogenic massive sulfide (VMS) deposits in Colorado, USA and metamorphosed to the amphibolite facies. These altered rocks are dominated by the assemblage orthoamphibole (anthophyllite/gedrite)–cordierite–magnetite±gahnite±sulfides. Magnetite also occurs in granitoids, banded iron formations, quartz garnetite, and in metallic mineralisation consisting of semi-massive pyrite, pyrrhotite, chalcopyrite, and sphalerite with subordinate galena, gahnite and magnetite; amphibole also occurs in amphibolite. The precursor to the anthophyllite/gedrite–cordierite assemblages was probably the assemblage quartz–chlorite formed from hydrothermal ore-bearing fluids (~250° to 400°C) associated with the formation of metallic minerals in the massive sulfide deposits. Element–element variation diagrams for amphibole, magnetite and ilmenite based on LA-ICP-MS data and Principal Component Analysis (PCA) for orthoamphiboles and magnetite show a broad range of compositions which are primarily dependent upon the nature of the host rock associated spatially with the deposits. Although discrimination plots of Al/(Zn+Ca) vs Cu/(Si+Ca) and Sn/Ga vs Al/Co for magnetite do not indicate a VMS origin, the concentration of Al+Mn together with Ti+V and Sn vs Ti support a hydrothermal rather than a magmatic origin for magnetite. Principal Component Analyses also show that magnetite and orthoamphibole in metamorphosed altered rocks and sulfide zones have distinctive eigenvalues that allow them to be used as prospective pathfinders for VMS deposits in Colorado. This, in conjunction with the contents of Zn and Al in magnetite, Zn and Pb in amphibole, ilmenite and magnetite, the Cu content of orthoamphibole and ilmenite, and possibly the Ga and Sn concentrations of magnetite constitute effective exploration vectors. [ABSTRACT FROM AUTHOR]

Accurate computational modeling allows the use of software as a first approach to some petrological problems that typically require experimentation, but most programs have not yet been fully tested for accuracy with lunar or Martian melt compositions. The programs pMELTS, MAGPOX, and Perple_X stand out for phase equilibrium modeling, as their calibrations include experiments of lunar compositions or have precise thermodynamic constraints for similar compositions. A set of lunar mare basalts, picritic glasses, and basaltic Martian compositions with known experimentally determined multiple saturation point (MSP) conditions were used here for phase equilibrium modeling. The accuracy of each program was tested through the determination of MSPs on the liquidus of the selected compositions. This point in pressure–temperature space can be considered as a direct proxy of the stable phases and the equilibrium conditions during partial melting of mantle sources. We identify a trend in experimental data between MSP temperature and MgO, CaO, and SiO2 concentrations, and similar trends are found in model results. However, only Perple_X is able to closely match the experimental data, despite the fact it does not accurately model ilmenite saturation for high‐Ti lunar basalts. We find that pMELTS miscalculates olivine saturation for MgO‐rich compositions and MAGPOX systematically underestimates MSP pressure and temperatures and can only be used when olivine is the liquidus phase. For modeling lunar or Martian basalt compositions, Perple_X can be used for optimal results, although no software is yet capable of bypassing the need to constrain MSP conditions through experimentation. [ABSTRACT FROM AUTHOR]

To quantify fluorine (F) evolution during lunar magma ocean (LMO) crystallization, high-pressure, high-temperature experiments have been conducted to determine mineral-melt partitioning of F for lunar minerals (plagioclase, orthopyroxene and ilmenite). Results constrain the F abundance in the magma ocean to 21–41 ppm at the time crust-forming plagioclase started crystallizing. Forward modeling shows that 352–703 ppm F would remain in the final 1 % of magma toward the end of magma ocean solidification. This range overlaps that inferred for the urKREEP reservoir (660 ppm). Taking into account model uncertainties, from the perspective of F abundances the urKREEP reservoir can be formed at 98.9–99.5% LMO solidification, with negligible loss of F from the Moon since the onset of crust formation. Backward modeling from initial crust-forming plagioclase, an initial LMO would contain 4.2–8.5 ppm F, which is consistent with estimates of the lunar primitive mantle F content derived from melt inclusions in Apollo samples. This finding is consistent with previous suggestions that the bulk silicate Moon is depleted in F relative to the bulk silicate Earth (which contains ∼25 ppm F). A BSE-like initial LMO would yield a magma containing 122 ppm F at the onset of crust formation, significantly higher than our calculated 21–41 ppm F. Fluorine depletion could have occurred by degassing during the early LMO stages (between the onset of LMO crystallization and first crust formation), and/or prior to the LMO stage (e.g., depletion during the giant impact or vapor drainage in the protolunar disk), but seems to have ended by the time the crust started forming. [ABSTRACT FROM AUTHOR]

Titanium (Ti) is a crucial metal with wide-ranging applications in various industries. Ilmenite minerals are the main source of Ti metal. As a valuable petrogenetic indicator and geochronometer, ilmenite mineral occurs commonly in igneous and metamorphic rocks and different types of deposits (e.g., Fe–Ti oxide, diamonds, and placer deposits). Ilmenite U–Pb geochronology started by isotope dilution-thermal ionization mass spectrometry thirty years ago and by in situ methods recently due to low U and Pb concentrations. A constrained calibration method has been established using rutile TB-1 due to the lack of reference material (RM). However, rutile (e.g., RMJG) cannot be a primary standard in all our analyses. Thus, a new primary standard and accurate calibration method for further applications is urgently needed. By laser ablation sector field inductively coupled plasma mass spectrometry (LA-SF-ICP-MS), optimizing ablation settings and adding N2 (∼3.0 mL min−1) have been employed to minimize the matrix effects between zircon 91500 and ilmenite. Thus, zircon 91500 can be utilized as a RM to measure the Pb/U ratio in ilmenite. Zircon 91500 has a similar U–Pb fractionation and average normalized Pb/U ratio with ilmenite BC269, instead of rutile RMJG, probably owing to the different ablation settings used by us compared to the two previous studies. More accurate ages with much smaller age offsets of ≤1.6% were obtained for the five ilmenite samples calibrated by zircon 91500 compared to those calibrated by Ti- and Fe-bearing minerals, including rutile RMJG, garnet PL-57, and wolframite YGX. These results demonstrate that the direct calibration method used here with 91500 as an external standard is effective for in situ U–Pb dating of ilmenite samples under a wide range of ablation settings, i.e., spot sizes varying from 44 to 120 μm, repetition rate from 5 to 10 Hz, and laser fluences from 3 to 4 J cm−2. HG79, XL32333, and BC269 have high U and Pb contents and can be utilized as potential RMs for ilmenite minerals. This approach offers new insights into understanding the diagenetic and ore-forming processes related to ilmenite minerals. [ABSTRACT FROM AUTHOR]

Shock lithification of regolith breccias is a ubiquitous process on the surfaces of airless planetary bodies and may induce thermal effects, including melting on regolith breccia minerals. However, potential thermal effects on lithic and mineral clasts in regolith breccias have seldom been quantitatively constrained. Here, we report two types of micro-textures of armalcolite [(Mg,Fe2+)Ti2O5] in an Mg-suite lithic clast from lunar regolith breccia meteorite Northwest Africa 8182. One type of armalcolite contains oriented fine-grained ilmenite grains; the other occurs as an aggregate of ilmenite, rutile, spinel, and loveringite. We propose that the two types of micro-textures formed through subsolidus breakdown of armalcolite by different processes. The formation of ilmenite inclusions in armalcolite is related to slow cooling after the solidification of its source rock, whereas the ilmenite-rutile-spinel-loveringite aggregates probably formed during the shock lithification event of NWA 8182. The results indicate that the temperature at the margin of lithic clasts could be raised up to at least 600 °C during strong shock lithification of lunar regolith and has profound thermal effects on the mineralogical and isotopic behaviors of lithic and mineral fragments in lunar regolith breccias. [ABSTRACT FROM AUTHOR]

AbstractThe hydrometallurgical procedure is suggested in this work to upgrade the ilmenite mineral which is separated from black sand at Rosetta, Egypt, to obtain high TiO2. The ilmenite concentrate is subjected to a digestion process using sulfuric acid solution in the presence of date molasses. Date molasses is chosen as new, cheap, eco-friendly and effective reductant. The relevant factors for titanium and iron dissolution from ilmenite concentrate include: the acid concentration, sample/acid ratio, reaction time, temperature in addition reductant percentage. These factors are studied and optimized. The optimum conditions are realized at 10 M H2SO4 acid with a solid/liquid ratio of 1/10 at 120 °C for 2 h in the presence of a definite amount of date molasses. Under these conditions, titanium and iron leaching efficiencies are attained at 98.4% and 92.8%, respectively. The resultant leach liquor is then subjected to a hydrolysis step for titanium separation as Ti(OH)2, dried at 110 °C and ignited at 850 °C to obtain high-grade titanium oxide (93.5%) TiO2. [ABSTRACT FROM AUTHOR]

Rosetta ilmenite concentrate has been applied for uranium adsorption from its aqueous solution using batch sorption techniques. The optimised adsorption conditions included, solution pH 5, adsorbent dose (0.025 g/25 ml), uranium initial concentration 200 mg/L, 1 h contact time, and at room temperature (25°C), corresponding to uranium adsorption efficiency of about 74% and uranium uptake 148 mg/g. From kinetic parameters, it was found that uranium adsorption followed pseudo second order kinetics. Besides, the equilibrium data fitted the Langmuir isotherm model well. The various thermodynamic parameter rs were calculated (∆Ho = −14.3 kJ mol−1, ∆So = 0.075 kJ mol−1K−1, ∆Go = −36.65 kJ mol−1), these values an exothermic, randomness, and spontaneous adsorption process, respectively. Uranium is successfully desorbed from loaded ilmenite using 0.5 M H2SO4 for 15 min. contact time. [ABSTRACT FROM AUTHOR]

The cellulose impregnated phosphorus oxychloride (COP) was newly prepared. Its efficiency was assessed for the first time by removing Cr6+, Pb2+, V5+, and Cd2+ ions from a diluted sulphuric solution of titanium liquor to gain the purified titanium dioxide. For the complete characterisation of the synthetic COP adsorbent, we used different instrumental performances namely; FTIR, SEM, EDX, and 1H NMR. The factors of adsorption and removal of Cr6+, Pb2+, V5+, and Cd2+ ions from a diluted sulphuric leach liquor solution of titanium liquor have been optimized. The removal of Cr6+, Pb2+, V5+, and Cd2+ ions was achieved using a new COP at 0.25 M/L acid concentration using 100 mg COP adsorbent for 60 minutes. The maximum Cr6+, Pb2+, V5+, and Cd2+adsorption capacity and the removal efficiency were 132.5, 141.7, 121.5, 113.7 mg/g and 88.3, 94.5, 81.0, 75.8%, respectively. Finally, titanium sulphate leaching liquor produced from ilmenite concentrate was treated with optimum adsorption parameters for Cr6+, Pb2+, V5+, and Cd2+ ions removal to gain the purified titanium dioxide. [ABSTRACT FROM AUTHOR]

With both ferrocene and air as the redox catalysts, for the first time, the low-cost natural ilmenite (FeTiO3) was successfully used for photocatalytic bond formations. Under the assistance of a traceless H-bond, and HCHO as the methylene reagent, a variety of imidazo[1,5-a]quinoxalinones were semi-heterogeneously photosynthesized in high yields with good functional group compatibility. [ABSTRACT FROM AUTHOR]

The unit-cell parameters and volumes of geikielite (MgTiO3) and ilmenite (FeTiO3) were investigated at high temperatures up to 700 K and ambient pressure, using in-situ angle-dispersive synchrotron X-ray diffraction. No phase transition was detected over the experimental temperature range. Using (Berman in J Petrol 29:445–522, 1988. 10.1093/petrology/29.2.445) equations to fit the temperature-volume data, the volumetric thermal expansion coefficients at ambient conditions (αV0) of MgTiO3 and FeTiO3 were obtained as follows: 2.55 (6) × 10–5 K−1 and 2.82 (10) × 10–5 K−1, respectively. We infer that the larger effective ionic radius of Fe2+(VI) (0.78 Å) than that of Mg2+(VI) (0.72 Å) renders FeTiO3 has a larger volumetric thermal expansivity than MgTiO3. Simultaneously, the refined axial thermal expansion coefficients under ambient conditions are αa0 = 0.74 (3) × 10–5 K−1 and αc0 = 1.08 (5) × 10–5 K−1 for the a-axis and c-axis of MgTiO3, respectively, and αa0 = 0.95 (5) × 10–5 K−1 and αc0 = 0.92 (12) × 10–5 K−1 for the a-axis and c-axis of FeTiO3, respectively. The axial thermal expansivity of MgTiO3 is anisotropic, but that of FeTiO3 is nearly isotropic. We infer that the main reason for the different axial thermal expansivity between MgTiO3 and FeTiO3 is that the thermal expansion mode of the Mg-O bond in MgTiO3 is different from that of the Fe–O bonds in FeTiO3. [ABSTRACT FROM AUTHOR]

In the south of the Russian Far East, a new promising type of source of strategic and critically important metals (titanium, gold, platinum, niobium, hafnium, copper, antimony, etc.) has been discovered: these are complex ores and placers that are spatially and genetically related to the Late Mesozoic (Cenomanian?) synorogenic intrusions of ultramafic–mafic rocks of the Sikhote-Alin orogenic belt. One example is the Ariadnensky massif of ultramafic, mafic and granitoid rocks with gold-titanium mineralization in its mafic part, gold-antimony mineralization at the exocontact, and gold-copper mineralization in the circum-intrusive zone. The main mineralogical and geochemical features of these ore formations have been determined. The typomorphic properties of native gold from ultramafic rocks have been revealed. It is shown that mantle and crustal processes were involved in the formation of different types of ore. The materials we obtained provide new opportunities for the reassessment of potential of strategic metal resources in Primorye. [ABSTRACT FROM AUTHOR]

In this work, a complete beneficiation technical route combining physical and chemical methods, namely a roasting-flotation-leaching scheme, is proposed to produce a qualified grade Ti-concentrate from altered Vanadium titanomagnetite (VTM) ore. Based on the character of the ore sample, it is recommended to recover the Ti-bearing minerals, ilmenite and anatase, as composite mineral. Pretreatment experiments indicate that the oxidation roasting (800 °C) and acid washing methods increase the flotation indexes significantly. Flotation condition tests show that the optimal conditions are a grinding fineness of −0.045 mm 83%, sulfuric acid dosage of 2000 g/t, water glass dosage of 1500 g/t, oxalic acid dosage of 200 g/t, and EM328 dosage of 1500 g/t. An open flotation circuit test obtains a flotation concentrate with a TiO2 grade and recovery of 38.30% and 25.99%, respectively. A leaching exploration test shows that the TiO2 grade of the flotation concentrate can be improved to 53.90%. XRD analyses reveal that the ilmenite in the VTM ore is converted into anatase and rutile during the roasting process at 600–800 °C, but pseudobrookite begins to form at 900 °C. Compared to the flotation concentrate, it is confirmed that the content of Ti-bearing minerals is increased significantly in the leaching residue. [ABSTRACT FROM AUTHOR]

Pristine depositions of beach sediments containing heavy minerals (HM) along the shorelines of Mangalore, south–west coast of India is reported in the study. Primordial radionuclide concentrations in the beach sediments collected were determined by high purity germanium (HPGe) gamma spectrometry method. The mineral identification and counting were performed using polarizing microscope. Geometric mean values (GM) [Geometric Standard Deviation (GSD)] of concentrations of 40K, 232Th and 226Ra are obtained to be 139 (2), 482 (5) and 110 (4) Bq kg−1 respectively and total heavy mineral weight percentage (TM%) of Monazite, Zircon, Ilmenite and Lithic fragments are obtained to be 0.17 (3.5), 0.51 (2.9), 5.3 (3.2) and 2.3 (2.5)% respectively. Seasonal variation studies and statistical analysis of the data are also performed to examine correlations between the origins of the radionuclides and elevated percentage of HM in these sediment depositions. [ABSTRACT FROM AUTHOR]

Red mud produced from the Bayer process was used for the high temperature metallurgical processing of ilmenite. The major components of the red mud were Fe2O3, Al2O3, Na2O, and TiO2, which play important roles in the flux material. The process temperature of ilmenite slag was lowered from 1794 K (1521°C) to 1687 K (1414°C), as a preliminary study by a high-temperature microscope. Thermochemical calculations using FactSageTM 7.0 confirmed the effect of red mud on the lowered melting temperature of ilmenite slag. The discrepancy between the observed results of the microscope and the calculated phase diagram was due to the slag viscosity, which was significantly affected by Al2O3 in red mud. The reduction of ilmenite at lower temperatures by the addition of red mud was investigated at 1723 K (1450°C). Ilmenite, pseudobrookite, and associated clay minerals were the major phases in the reduced ilmenites which was confirmed by X-ray diffraction (×RD) analysis. Microscopic images obtained by scanning electron microscopy (SEM) showed variations in the pseudobrookite phases according to the amount of fluxed red mud. The benefits of red mud utilization are discussed with regard to the lower energy consumption and recovery of resources. [ABSTRACT FROM AUTHOR]

In this study, the oxidation powder sample of ilmenite concentrate with 15% magnetite concentrate was prepared, and the subsequent isothermal reduction was investigated at temperatures in the range of 950–1050 °C with CO, H 2 , and their mixtures. The hydrogen-rich atmosphere, magnetite effect, apparent activation energy, and micromorphology of the reduced samples were investigated. The results indicated that the mass loss of the raw sample in the reduction process exhibited a similar tendency to that of the preoxidized ilmenite concentrate, although the addition of the magnetite concentrate increased the total mass loss. The influence of Fe 2 O 3 , which is produced by the oxidation of magnetite, on the mass-change ratio in the reduction process is separated and drawn novelty. The interaction between the magnetite and ilmenite concentrates in the oxidation process did not exhibit an apparent hindering effect following the hydrogen-rich reduction of the raw sample powder. The reducing atmosphere had a slight influence on the average apparent activation energy. The average apparent activation energies of the reduction of the raw sample were 55.34, 53.54, 52.78, 59.14, and 53.85 kJ/mol when the reducing atmosphere was CO, H 2 /CO = 0.4, H 2 /CO = 1, H 2 /CO = 2.5, and H 2, respectively. Furthermore, the change in micromorphology of the reduced sample with the hydrogen-rich content in the reduction atmosphere is also discussed. • Effect of Fe 2 O 3 oxidized by magnetite on the mass-change in the reduction is drawn. • Magnetite had little effect on the stage-division mechanism of reduction process. • Magnetite does not hinder the hydrogen-rich reduction of oxidized ilmenite powder. • Fluctuation of apparent activation energy decreased with H 2 contents increasing. • Morphology of the metallic iron in the reduced sample was affected by H 2 content. [ABSTRACT FROM AUTHOR]

Diogenites are thought to have originated from asteroid 4 Vesta asteroid, and it has been previously shown that they mostly consist of orthopyroxene, chromite, and olivine minerals. In this study, the Aioun El Atrouss (AAT‐1) diogenite was analyzed by vibrational spectroscopic (FT‐IR and micro‐Raman), EDXRF, and XRD techniques. AAT‐001 is mainly composed of pyroxene and with lesser olivine. XRD investigation confirmed magnetite, kamacite, ilmenite, and albite. A troilite‐orthopyroxene intergrowth was revealed by XRF. The olivine composition was estimated to be approximately Fo66 by Raman olivine characteristic doublets. Pyroxenes in AAT‐01 were found to be En80Fs20. Finally, approximate peak shock pressure of more than 86 GPa for AAT‐1 was suggested based on previous hypervelocity impact experiments on olivine. [ABSTRACT FROM AUTHOR]

The article deals with the kinetics process of alkaline leaching of ilmenite from the Irshan deposit; the prospects of obtaining potassium titanate in comparison with sodium titanate are presented. Using the methods of X-ray diffraction and electron microscopy, it has been studied that potassium and sodium titanates, obtained by the method of alkaline melting from ilmenite concentrate, correspond to the structures described in the reference literature. The degree of extraction depends on the time of interaction of ilmenite with sodium and potassium hydroxides, and the optimal kinetic conditions are determined. We have established that during alkaline leaching of titanium(IV) with potassium hydroxide, in the temperature range of 453 K - 533 K, the maximum degree of extraction is 86 % - 89 %. It is shown that the dependence "degree of transformation - time of isothermal interaction" is best described by the "compressed sphere" model. From the temperature dependences of the potassium titanate leaching process, the activation energy has been calculated, which is 22 kJ mol-1, which may indicate a kinetic regime with a low activation energy, where the limiting stage is the chemical interaction between the melt components. [ABSTRACT FROM AUTHOR]

In order to address the challenge of recovering fine ilmenite from tailings in Panxi region, experimental research was conducted for ilmenite ore tailings using SLon-100 cyclic pulsating high-gradient magnetic separator (PHGMS)and SL-400 centrifuge separator. The results showed that for tailings with TiO2 grade at 4.77%, the PHGMS pre-concentration process with one roughing, one scavenging, one cleaning and one screening was able to gain a primary concentrate with TiO2 grade at 18.36% for -0.037 mm fractionl. This -0.037 mm fraction of the primary concentrate was further processed using SL centrifuge separator with one roughing, one scavenging, one cleaning process, and after one more SL centrifuge separation for the mixture of cleaning tailings and scavenging concentrate, and the process was able to yield a titanium concentrate with an operation yield at 42.39%, TiO2 grade at 30.77%, and TiO2 operational recovery at 71.04%, These results create favorable conditions for subsequent flotation of the concentrate and production of qualified titanium concentrate products. The study demonstrates the feasibility of using SL centrifuge for the separation of fine-grained ilmenite in the Panxi region and provides a new technological approach to enhance the utilization level of ilmenite resources in the Panxi region. [ABSTRACT FROM AUTHOR]