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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]

Chemical looping combustion is a highly efficient CO2 separation technology without direct contact between combustion air and fuel. A metal oxide is used as an oxygen carrier in dual fluidized beds to generate clean CO2. The use of biomass is the focus of current research because of the possibility of negative CO2 emissions and the utilization of biogenic carbon. The most commonly proposed OC are natural ores and residues, but complete combustion has not yet been achieved. In this work, the direct utilization of CLC exhaust gas for methane synthesis as an alternative route was investigated, where the gas components CO, CH4 and H2 are not disadvantageous but benefit the reactions in a methanation step. The whole process chain, the coupling of an 80 kWth pilot plant with gas cleaning and a 10 kW fluidized bed methanation unit were for this purpose established. As OC, ilmenite enhanced with limestone was used, combusting bark pellets in autothermal operation at over 1000 °C reaching high combustion efficiencies of up to 91.7%. The fuel reactor exhaust gas was mixed with hydrogen in the methanation reactor at 360 °C and converted with a methane yield of up to 97.3%. The study showed especially high carbon utilization efficiencies of 97% compared to competitor technologies. Based on the experimental results, a scale-up concept study showed the high potential of the combination of the technologies concerning the total efficiency and the adaptability to grid injection. [ABSTRACT FROM AUTHOR]

Based on the difficulty of extracting titanium from ilmenite, this study modified ilmenite by alkali roasting to improve the leaching rate of titanium. The leaching behaviour and kinetics of titanium in pretreated slag and the mechanism of limiting titanium leaching were studied. The results indicate that alkaline roasting pre-treatment of the ilmenite ore can transform acid-resistant FeTiO3 into more reactive Na2TiO3 and NaFeO2, which are more amenable to leaching. Simultaneously, under the following pre-treatment conditions—a sodium hydroxide to ilmenite ore mass ratio of 1.5:1, roasting temperature of 1123.15 K and roasting time of 1 h—the optimal leaching conditions are found to be a leaching temperature of 363.15 K, sulphuric acid mass fraction of 60% and liquid–solid mass ratio of 6:1. Under these conditions, the titanium extraction was most efficient, achieving a titanium leaching rate of 97.36%. The leaching reaction of titanium in the pre-treated slag follows the shrinking core model of the internal diffusion-controlled step. The apparent activation energy for the leaching reaction is determined to be 77.45 kJ/mol. Analysis through XRD, XPS and SEM–EDS reveals the formation of silica gel during leaching, which also has an adsorption effect, preventing complete titanium leaching. [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]

Avoiding the formation of anosovite phase during the ilmenite reduction process is crucial for the preparation of boiling chloride stove. In this study, the dominant regions of different reduction products of ilmenite in CO-CO2 system and the phase transformation behavior of pure ilmenite in the reduction process were studied by XRD and SEM-EDS analysis. It was confirmed that the reduction of ilmenite (FeTiO3) at < 1150°C went through two stages: the formation of metal iron (Fe) with rutile (TiO2) and metal iron (Fe) with anosovite (Ti3O5). At > 1150°C, the reduction of ilmenite went through two stages: the formation of metal iron (Fe) with pseudobrookite (FeTi2O5) and metal iron (Fe) with anosovite (Ti3O5). As a typical ilmenite resource, Panzhihua ilmenite is used to study the reduction behavior of actual ore in CO-CO2 system. The reaction of forming metal iron (Fe) with pseudobrookite (FeTi2O5) could occur at 1000°C, and magnesium was dissolved in the product during the formation of anosovite. The presence of magnesium reduces the dominant area of metal iron (Fe) with rutile (TiO2), which is not conducive to the reduction of iron. [ABSTRACT FROM AUTHOR]

The results of research on the processing of ilmenite concentrate from the Obukhovskoye deposit are presented in this article. As the concentrate has a high chromium content, the study involved converting the iron into metal and the titanium into slag through the addition of soda. Positive results were obtained during the smelting of the ilmenite concentrate, and a one-stage smelting mode was established. This mode involved an increase in the temperature up to 1700 °C, with a heating step of 10 °C/min and using an argon supply. The holding time at this temperature was 30 min, followed by cooling to 700 °C in argon. The optimal parameters for sintering the non-magnetic fraction with soda and leaching the sinter with water and hydrochloric acid solution were also determined. [ABSTRACT FROM AUTHOR]

Oxidation roasting was proposed to treat the problem of the weak magnetic properties of ilmenite. The effects of roasting temperature, roasting time and cooling method on the results of ilmenite magnetic separation were studied. At the same time, the mechanism of the oxidation roasting process was analyzed by XRD, VSM, SEM-EDS. Determine ilmenite suitable oxidation roasting conditions for roasting temperature 750 °C, roasting time of 20 min, and cooling method of air cooling; at this time, the yield of 96.79% can be achieved in the magnetic field intensity of 238.74 kA/m. The XRD results showed that phase changes in the roasting process occur in the order of ilmenite to hematite and rutile to pseudobrookite. The results of VSM showed that the maximum specific magnetization coefficient of ilmenite increased from 3.25x10-5 m³/kg to 5.58x10-5 m³/kg after roasting, and the magnetic property was enhanced. The results of SEM-EDS showed that the phase transition of ilmenite during the roasting process occurs in a spatial order from the edge of the particles to the interior. [ABSTRACT FROM AUTHOR]

The article presents information on the geological structure and ore content of the Trostyanytsky ilmenite deposit located in the northern part of the Volodarsk-Volynskyi massif of the Korostensky pluton bedrock. The deposit is localized in the weathering crust of the basement crystalline rocks and continental deluvial-alluvial and alluvial sediments of the Middle Jurassic-Lower Cretaceous, which were formed by erosion and redeposition of eluvium. Weathering crust together with deluvial-alluvial and alluvial sediments formed the productive deposits of the Trostyanytsky deposit. On the basis of the created target database containing conditional coordinates of wells, their description and testing results, mapping constructions (isohypses of the roof, sole, isopachites of the thickness of the weathering crust of crystalline rocks of the basement, alluvial sands and redeposited kaolins of the Middle Jurassic-Lower Cretaceous) were carried out; lateral distribution of the average ilmenite content in the weathering crust, in the Middle Jurassic-Lower Cretaceous fluvial deposits and productive sediments, distribution ilmenite content in the vertical section of wells). These mapping constructions were created based on the results of preliminary (1999) and detailed (2008) geological exploration. The direction and strength of correlations between the topography of the sole and the surface, topography of the sole and the thickness of ilmenite-bearing formations, sole relief and ilmenite content, sediment thickness and ilmenite content in the weathering crust, alluvial deposits of the Middle Jurassic-Lower Cretaceous and in productive deposits. The obtained results made it possible to clarify the structural and material parameters of the ore-bearing rocks, the lateral and vertical distribution of ore bearing in different genetic and different age’s formations. [ABSTRACT FROM AUTHOR]

The article provides generalized data on the geological structure, the results of laboratory analyzes of the heavy fraction of the main placer-forming minerals of the Vovchansk zircon-rutile-ilmenite deposit, which was being developed by Demurinsky Mining and Processing Plant LLC in 2002. The geological structure of the Vovchansk deposit includes a complex of Precambrian rocks of the crystalline basement, the Paleozoic-Cenozoic weathered crust, the Paleozoic-Cenozoic sediments, and Quaternary deposits. The industrial concentration of heavy minerals is confined to the middle and upper parts of the Middle Sarmatian subsuite of the Neogene, composed of fine-grained, essentially quartz sands, with a total thickness of 0.4 to 63 m. The content of heavy minerals in the ore-bearing horizon of the deposit ranges from 93.8 to 485 kg/m³ (ilmenite from 37.6 to 242.6 kg/m³, rutile from 15.9 to 64.6 kg/m³, zircon from 2.9 to 9.4 kg/m³, sillimanite and disthene from 20.4 to 117.5 kg/m³). The content of major and minor elements-impurities in individual minerals of the ore-bearing horizon (178 grains) was determined: ilmenite (18 samples), rutile (40 samples), zircon (35 samples), sillimanite (30 samples), staurolite (25 samples), tourmaline (12 samples), ganite (8 samples), monazite (10 samples). The conducted research clarified the typomorphic features of minerals from the sands of the Vovchansk deposit, established their absolute age and probable original sources. [ABSTRACT FROM AUTHOR]

The Ghansura Rhyolite Dome (GRD) is an integral part of the Bathani volcano-sedimentary sequence (BVSs), which in turn is a vital component of the Chotanagpur Granite Gneiss Complex (CGGC), eastern India. The rhyolite dome represents a shallow-level felsic magma chamber that underwent intrusion by basaltic magma during its evolution. The rocks present in the felsic dome such as basalts, rhyolites, and intermediate hybrid rocks preserve evidence of magma mixing and mingling. The objective of this contribution is to take into account, for the first time, that magma mixing processes can play an important role in the generation of calcite in magmatic rocks. The present study focuses on the mingled rocks exposed within the rhyolite dome. Previous reports have documented the existence of two distinct zones (mafic and felsic) interfacing each other in the mingled rocks of the rhyolite dome. The mafic zones dominantly consist of mineral phases such as actinolite, hornblende, biotite, plagioclase, ilmenite, calcite, and titanite. The felsic zones comprise quartz, K-feldspar, plagioclase, and biotite. When mafic magma intruded into the felsic magma chamber, interaction between the mafic and felsic magmas caused diffusion of H, Al, and K ions from the felsic to the mafic endmember. Such diffusive activities resulted in the breakdown of augite, already crystallized in the mafic magma, to form newer minerals like actinolite, hornblende, biotite, calcite, and ilmenite. The presence of ilmenite in the mingled rocks indicates the prevalence of reducing conditions during magma interaction and evolution. Breakdown of hornblende to biotite in such a reduced environmental condition led to the formation of calcite in the mingled rocks. From the results presented in this work, we are proposing that magma mixing can be a viable mechanism to form calcite in igneous rocks by magmatic processes.

Abstract 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.

Minerals containing TiO2 are common in Indonesia, such as ilmenite in iron sand deposits scattered along the country's coasts. Ilmenite is an important source of titanium. One method for making TiO2 from ilmenite is by solubilizing both the Fe and Ti elements in HCl and then immediately hydrolyze the Ti. The leaching of low-grade ilmenite (ground to 0.177-0.149 mm) is studied kinetically by HCl in a stirred reactor. The research was conducted using the caustic fusion method followed by HCl leaching. The leaching reaction kinetics at the optimum conditions are analyzed using response surface methodology (RSM) with a second-order polynomial equation model and SSE with the shrinking core model (SCM). The results showed that HCl concentration and leaching time were directly proportional to the leached titanium concentration. In contrast, the leaching temperature was inversely proportional. The optimum operating conditions were obtained at a temperature of 30 °C, 9 M HCl, and 120 min of leaching time. The shrinking core model is a better representation of the kinetics than RSM with a second-order polynomial equation model. Based on SCM, the rate of the leaching reaction of titanium from low-grade ilmenite is controlled by diffusion through the ash layer.

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]

Given the increasing relevance of lunar activities, the location selection for in situ resource utilisation (ISRU) facilities is necessary for identifying the most suitable configuration duringmission planning. To gather information about the dominant location dependencies, a scenario is established wherein an ISRU product is exported to an orbital depot and its mass costs are used for classification. In the selected scenario, oxygen is produced in an ilmenite reduction plant and subsequently exported to the lunar gateway via an oxygen--hydrogen fuelled launcher operated in a round-trip to refuel oxygen at the lunar surface and hydrogen at the lunar gateway. This showed that the transport cost variations could be avoided entirely or have a recessive influence on the mission's total costs over an extended period of time, such as 20 years. The identification of the top-10 most optimal locations for various resolutions was altered only slightly upon consideration of flight costs as compared to considering only the ISRU factors; this indicates the insignificance of flight cost dependencies for the analysed case. [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]

This paper discusses the natural radioactivity levels in ilmenite ore and its final product. Two economically viable ores of titanium are ilmenite (FeO.TiO2) and rutile (TiO2). High-purity germanium (HPGe) detector was used to analyse samples of raw ore, its purified fraction and the final product (synthetic rutile). Radioactivity levels due to 238U and 232Th and its daughter products were estimated. The concentration of 238U and 232Th in raw ore, purified ore and synthetic rutile was found to be 204 ± 4 and 1208 ± 5, 89.0 ± 4 and 597.0 ± 4, 119 ± 2.5 and 398.0 ± 3 Bq/kg, respectively. The dose rates due to gamma photons estimated in raw ore and synthetic rutile were 572 nSv/h and 277 nSv/h, respectively. The activity index estimated was 5.3 for raw ore and 2.3 for final product (synthetic rutile). The final product contained only 25% of the radioactivity compared to the ore showing significant reduction in radioactivity due to the processing of the ore. [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]

In the current study, an effort has been made to prepare aluminum alloy (hypereutectic Al-Si17Cu4Mg)-based composites reinforced with ilmenite (FeTiO3; sea beach mineral). For the study, fine-sized (32-50 µm) and dual-sized (F:C:: 4:1, where F (32-50 µm) and C (75-106 µm)) ilmenite particles (15 wt.%) have been selected as reinforcement. In the metallic matrix, homogeneous distribution of ilmenite particles was observed through optical microscopy. Here, primary and secondary silicon refinement has also been observed up to ~ 60% as a result of incorporation of ilmenite particles. When compared to hypereutectic Al-Si17Cu4Mg alloy, the prepared composite samples exhibited ~ 10% higher wear resistance. Further, the presence of lubricating additives (graphite and tin) in the composite samples decreased the overall ~ 9% wear loss. The wear behavior of composite sample was compared to that of grey cast iron to evaluate the industrial utility of prepared sample. Based on these results, a detailed wear loss mechanism has also been proposed under 68.67 N as applied load for 3000 m sliding distance in which the dominance of delamination wear was observed over adhesive wear in SEM microstructures. [ABSTRACT FROM AUTHOR]

The research object is the ilmenite concentrate from the Irshansky deposit. This study describes an elemental composition of the mineral raw material and confirms its structure using the X-ray diffraction and scanning electron microscopy. Experimental studies have shown that the ilmenite concentrate from the Irshansky deposit has a significant titanium content in terms of titanium dioxide (79 %). Mineral raw materials with such a chemical composition are unique, so there is a need to find alternative methods for its processing. The research demonstrates that the maximum degree of extraction in the process of alkaline leaching of the ilmenite concentrate is achieved under the condition that the average diameter of particles of the mineral raw material should be ≤71 μm. As a result of temperature studies, it has been found that a temperature of 453 K would suffice to obtain potassium titanate at atmospheric pressure. Further temperature increase does not provide for a significant increase in the degree of titanium extraction, and also contributes to the formation of polytitanates of various compositions. The study of the influence of the molar ratio of the starting reagents on the degree of extraction of titanium(IV) from the ilmenite concentrate has showed that the optimal molar ratio between the components corresponds to the stoichiometric one and is 1:2. Increasing the amount of potassium hydroxide in the reaction mixture is impractical as it reduces the yield of potassium titanate, and the final product will have high alkalinity due to excess alkali. The optimal time for alkaline leaching is three hours of continuous heating in a glycerin bath. A further increase in the duration of heating does not lead to an increase in the degree of extraction, which is associated with the diffusion of alkali from the surface of the nucleus into the volume of ilmenite particles due to the formed products of interaction and annihilation of the initial nuclei [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]

Synthesis of N-doped MgTiO3 with an ilmenite structure was examined as a new ilmenite-type oxynitride material. N-doped MgTiO3 with Scsubstitution was successfully obtained by flux-assisted nitridation using a LiCl-KCl eutectic under pure NH3 or 5% NH3. The oxynitrides gave visible light absorption which MgTiO3 did not show, and were active for sacrificial O2 evolution using AgNO3 under visible light irradiation. [ABSTRACT FROM AUTHOR]

For the purpose of characterizing the chemical composition indices of ilmenites from the fluvial system in southwestern Cameroon, electron probe microanalysis of mineral chemistry was carried out on ilmenite grains selected from the collected sediment samples. Previously, various particle size parameters (mean size, standard deviation, kurtosis, and skewness) were applied to the sand fraction to describe textural characteristics and heavy minerals. The study reveals sands with a coarse to medium size trend, with a predominance of coarse, poorly to moderately sorted. These traits point to a high-energy setting. The 0.125–0.063 mm grain size fractions of the sands were used for the recovery of heavy minerals. The occurrence of unstable heavy minerals, such as hornblende, zoisite, garnet, and augite, in these sands denote immature sediments. According to a quantitative evaluation, the main accompanying opaque heavy minerals that may contain ilmenite are zircon and zoisite. The major and minor element compositions of ilmenite, TiO2 (43.75–56.98%; average 48.41%) and FeO (34.31–48.86% (average 43.89%), with MnO (3.06%), V2O5 (2.15%), and Nb2O5 (0.29%) including, indicate composite igneous rock. The Ti/(Ti + Fe) ratio values (0.42 to 0.52) of the samples are characteristic of ferri-ilmenites and hydrated ilmenites which have favorable to the sulfate process for the manufacture of ferrotitanium pigment. [ABSTRACT FROM AUTHOR]

The community in Central Bangka Regency carried out an increase in illegal mining in 2021, which could potentially threaten the loss of strategic natural resources. Rocking table miners in Central Bangka Regency produce zircon sand, tin sand, monazite, ilmenite, and tailings, which are potential natural resources containing rare earth metal elements. This research aims to analyze the radioactive content of the minerals zircon sand, tin sand, monazite, ilmenite, and tailings as a threat to human health. The research showed that monazite samples from all villages still had a lot of rare earth metals in them, like yttrium (Y), lanthanum (La), cerium (Ce), samarium (Sm), neodymium (Nd), and gadolinium (Gd). The test results showed that monazite had the highest average concentrations of Rare Earth Elements (REEs), with values of 10.27±3% for La, 12.15±3% for Ce, 24.40±3% for Sm, 7.37±3% for Nd, and 0.69±3% for Gd. For tin samples, the average (Ce) was 2.79±3%, zircon samples had an average (Ce) of 4.33±3%, and (Nd) 1.04±3%. In the ilmenite samples, the average value (Y) was 6.64 ± 3%. Monazite has the most rare earth metal elements, but it has a very low selling price. Monazite plays a crucial role in safeguarding and preventing the loss of strategic natural resources and health threats. It provides policy advice to related institutions through various roles and functions, including investigation, early prevention, and forecasting of these threats.

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]

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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]