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A simple method for the direct transformation of Sr-exchanged titanosilicate with the sitinakite structure (IONSIV) into ceramic material through cold pressing and subsequent sintering at 1100 °C for 4 h is presented. The temperature transformation of Sr-exchanged sitinakite showed the stages of recrystallization of the material with the formation of Sr-Ti phases matsubaraite (Sr4Ti5[Si2O7]2O8), jeppeite (SrTi6O13), tausonite (SrTiO3), and rutile. Leaching experiments showed the efficiency of fixation of Sr cations in a ceramic matrix; extraction into water does not exceed 0.01% and desorption in 1 M HNO3 solution is only 0.19% within three days. The leaching rates of immobilized Sr demonstrate the structural integrity of the formed phases in the ceramic (2.8 × 10−5–1.0 × 10−5 g/(m2·day). The decrease in the crystallinity of the initial Na-sitinakite, which is achieved by reducing the synthesis temperature from 250 to 210 °C, does not affect the sorption capacity and the fixation of cations in the ceramic matrix. The obtained results confirm the prospect of using inexpensive precursors, titanium ore enrichment waste, for the synthesis of sorption materials. [ABSTRACT FROM AUTHOR]

Titanosilicates comprise a broad class of materials with promising technological applications. The typical obstacle that restricts their industrial applicability is the high manufacturing cost due to the use of specific organotitanium precursors. We herein report a new approach to the synthesis of titanosilicates using an inexpensive inorganic precursor, ammonium titanyl sulfate (ATS or STA), (NH4)2TiO(SO4)2∙H2O. The latter is an intermediate in the processing of titanium-bearing concentrates produced from apatite-nepheline ores. In this paper, the new synthetic approach is exemplified by the microwave-assisted synthesis of IONSIVE-911, one of the most effective Cs-ion scavengers. The method can be modified to synthesize various titanosilicate compounds. [ABSTRACT FROM AUTHOR]

Copyright of Geology & Exploration is the property of Geology & Exploration Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Ukraine has the largest reserves of titanium in Europe. Over the past decades, in the country has also established and estimated significant amounts of promising resources of titanium ores. Now the resource potential is several times the reserves of industrial ores. The mineral base of titanium ores is represented by magmatic in bedrocks, residual and alluvial deposits. New objects with estimated resources are located within the western part of the Ukrainian Shield. These are the of titanium ores with apatite in mafic rocks and their crust of weathering. In the northeast of the Ukrainian Shield there are titanium deposits with zirconium. In the central part also found magmatic, residual and alluvial deposits. And, finally, prospective resources of complex vanadium-containing titanomagnetite ores of the central part of the Pokrovo-Kyriiv structure in the junction zone of Donbas and the Azov megablock were evaluated. In order to provide potential investors with information on the existence of investment objects with certain resources and geological and economic evaluation, the State Service of geology and subsoil of Ukraine launched an investment atlas of the subsoil user. In order to supplement the investment atlas with objective data on the resource potential of solid minerals of the country, it is necessary to create an information base of promising and forecasted resources of metallic and non-metallic minerals and, first of all, those related to strategic mineral raw materials. In connection with the rapidly growing demand for titanium-zirconium products in the world, there was a need to involve in the development of new objects of titanium ores with favorable economic indicators. The accumulated material on the state of the resource potential of titanium and titanium-zirconium ores provides an opportunity to supplement new content of investment information for subsurface user. [ABSTRACT FROM AUTHOR]

Due to the low content of associated valuable elements such as phosphorus and titanium in an iron ore dressing tailings, it will result high beneficiation cost, and affect the economy of recovery of phosphorus and titanium by directly grinded and beneficiated of the iron ore dressing tailings. Moreover, it has a great interference on flotation recovery of very low grade phosphorus minerals from the iron ore dressing tailings and improvement of the grade of phosphorus concentrate due to higher content of calcium-bearing, easily-floating and easily-slimed gangue minerals. According to the characteristics of the ore property, the mineral processing tests were conducted by adopting the technological process of pulp flotation of raw ore--discarding tailings after phosphorus rough concentrate reground and rebeneficiated, namely, firstly flotation recovery of phosphorus with high-efficiency combination phosphorus minerals activator(sodium carbonate+BK116A) and selective collector BK410B under condition of non-grinding was adopted, and then discarding tailings after the phosphorus rough concentrate reground and rebeneficiated, and it realized the effective recovery of very low grade phosphorus minerals from the ore. The results of closed-circuit test were obtained the phosphorus concentrate with grading 30. 10% P2O5 and a recovery rate of 87. 61%. [ABSTRACT FROM AUTHOR]

The HIsarna process is one of the emerging technologies for reducing the carbon footprint of the ironmaking process, which is currently in the pilot plant stage. A kinetic HIsarna process simulation model based on the effective equilibrium reaction zone concept has been developed using the FactSage macro programming facility to advance understanding of the whole process. In the model, the HIsarna process is conceptually divided into various equilibrium zones involving combustion, coal pyrolysis and gasification, gas/slag/carbon reactions, and slag/metal reaction. The model has been validated through the pilot plant data, and the results are in good agreement with the quantity and composition of hot metal, slag, and gas. The HIsarna off-gas stream with high CO2 content can potentially allow capture and storage directly for carbon mitigation. The utilization of titanium magnetite ore in the HIsarna process has also been investigated via the developed model. The injection of titanium magnetite ore which has high FeO content decreases coal consumption. Still, it increases the slag volume as higher gangue content when keeping the same productivity as the pilot plant trial. The HIsarna process shows promising potential in using low-quality high titania iron ore as feed materials, but the slag system needs to be further optimized. From the heat distribution, the off-gas sensible heat accounts for a large part of the input heat due to its high temperature but can be recovered with good efficiency. The present model is an efficient tool for understanding the HIsarna process and providing theoretical guidance for future pilot research. [ABSTRACT FROM AUTHOR]

Technological mineralogy of titanium ores is the basis for assessing their complexity. It enables, from a unified standpoint, to trace the entire course of changes in mineral matter through operating procedures, including beneficiation, processing, and obtaining target industrial products. The study targets are Pizhemskoye ilmenite-leucoxene sandstones, which are distinguished by a complex polymineral composition. Along with the main ore components, there are other metals with different speciation (isomorphic admixture, independent mineral phases). The optimal set of mineralogical analysis methods for the predictive assessment of their further use is substantiated exemplified by titanium ores of the Pizhemskoye deposit, which are complex, noted for a variable content of iron oxides and contain rare earth metals. Examinations by X-ray phase analysis and scanning electron microscopy confirm that the main titanium phases of sandstones are pseudorutile and a polymineral aggregate, “leucoxene”. Considering the granulometric peculiarities of the magnetic and non-magnetic fractions of the gravity concentrate, the prospects of technologies for processing titanium raw materials are discussed. Along with the problems of obtaining high-quality raw materials, the transformations of mineral phases as a result of extreme impacts and their physicochemical properties as a consequence of isomorphic substitution of a part of Ti atoms with natural modifier agents (Fe and V) in the synthesis of titanium oxide nanostructures for industrial applications are considered (photocatalytic nanoreactor).

BACKGROUND: Despite the large reserves of titanium ores, their treatment by basic approaches to obtain titanium products is not always economically feasible due to various factors. One of these problems is the high content of silicon in the ores. RESULTS: The paper considers the desiliconization of a leucoxene concentrate with an aqueous solution of ammonium bifluoride. It was found that at 80 °C the main impurities, such as silicon and iron, pass into solution in the form of corresponding ammonium–fluorine complex compounds. CONCLUSIONS: The degree of desiliconization was up to 99%. Aluminium reacts with ammonium bifluoride, but is almost not leached into solution due to its low solubility. Titanium does not react due to its relatively higher reaction Gibbs energy among other metals in reaction with ammonium bifluoride. The content of titanium oxide in the calcined leaching residue was 85.52 wt%. The resulting residue corresponds to the raw material used in industry for the production of titanium dioxide pigment or titanium metal by the chlorine method. Iron and silicon can be precipitated from the leaching solution. Furthermore, the resulting filtrate can be evaporated in order to regenerate and reuse ammonium bifluoride. © 2022 The Authors. Journal of Chemical Technology and Biotechnology published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry (SCI). [ABSTRACT FROM AUTHOR]

Copyright of Inzynieria Mineralna is the property of Polskie Towarzystwo Przerobki Kopalin and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Anuario do Instituto de Geociencias is the property of Universidade Federal do Rio de Janeiro, Instituto de Geociencias and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Antibiotics such as ciprofloxacin (CIP) remain in aquatic environments, causing environmental and public health disturbances. Furthermore, in traditional wastewater treatment plants (WWTP), those compounds are not removed efficiently; owing to the effluent complexity and the ions present in it. The CIP degradation was assessed in real (RWW) and simulated (SWW) effluents of a WWTP, using the activated persulfate mechanism with the magnetic fraction (MF) of a low-grade titanium ore and simulated sunlight (SSL). All tests were performed in a 1000 mL raceway reactor under SSL. CIP and persulfate concentrations were measured using a high-performance liquid chromatography and UV spectroscopy, respectively. A 100% removal of CIP was achieved for RWW and SWW in 15 and 60 min, respectively without residual persulfate. These results may indicate that the contents of nitrate, chloride and total solids present in these samples of wastewater, did not have a significant negative effect on the CIP degradation efficiency. The final pH average value (~ 8.5) of real and simulated wastewater tests may indicate the presence of both hydroxyl and sulfate radicals without pH modification needed. However, only the sulfate radical was identified in the tests. An increase in toxicity was observed in the CIP degradation test with SWW (11%) and RWW (0.8%), which might be associated with the presence of CIP transformation products. The biodegradability also increased after the treatment. Both data showed that the MF-PS-SSL system produced an effluent that can be discharged or eventually treated using biological processes for indirect potable water reuse. These results highlight the use of the magnetic fraction as a strong alternative Fe2+ source instead of costly commercial compounds, for wastewater treatment, which allows the valorization of a raw material generally rejected in conventional TiO2 production. [ABSTRACT FROM AUTHOR]

For the first time, the fungicide thiabendazole (TBZ) and its transformation products (TPs) were monitored under outdoor conditions, using natural sunlight (NSL) as a photon source, and the Magnetic Fraction of a low-grade titanium ore (MFTO) as an iron catalyst, in a raceway pond reactor. The TBZ degradation (TBZD) was performed by two systems: solar photo-Fenton-like (MFTO-H2O2-NSL) and solar photo Fe/NaOCl (MFTO-NaOCl-NSL), both treatments were carried out using distilled water spiked with 1 mg/L TBZ under natural sunlight. The TPs were determined by a highly sensitive method based on liquid chromatography (LC) coupled to hybrid quadrupole time-of-flight mass spectrometry (QTOF-MS). The TBZD results of four TPs were detected throughout the MFTO-NaOCl-NSL operation, and only two of them remained after t = 75 min. While, twelve TPs were formed during the TBZD in the MFTO-H2O2-NSL system, and all reached stable concentrations after t = 180 min. That might be related with a faster degradation when NaOCl was used as an oxidant instead of H2O2. Thus, 80% of TBZD was achieved at t = 40 and 240 min by the MFTO-NaOCl-NSL and MFTO-H2O2-NSL systems, respectively. Consequently, the pseudo-first-order kinetic constant of MFTO-NaOCl-NSL (0.059 min−1) was almost tenfold higher than the value obtained by MFTO-H2O2-NSL (0.006 min−1). The results obtained emphasize that the use of NaOCl as an alternative oxidant to H2O2, not only improves the reaction kinetics but also reduces the number of TPs at the end of the degradation process. [ABSTRACT FROM AUTHOR]

Ti-isotope fractionation on the most Ti-rich minerals on Earth has not been reported. Therefore, we present a chemical preparation and separation technique for Ti-rich minerals for mineralogic, petrologic, and economic geologic studies. A two-stage ion-exchange column procedure modified from the previous literature is used in the current study to separate Ti from Fe-rich samples, while α-TiO2 does not require chemical separation. Purified solutions in conjunction with solution standards were measured on two different instruments with dry plasma and medium-resolution mode providing mass-dependent results with the lowest errors. 49/47TiOL-Ti for the solution and solids analyzed here demonstrate a range of >5 ‰ far greater than the whole procedural 1 error of 0.10 ‰ for a synthetic compound and 0.07 ‰ for the mineral magnetite; thus, the procedure produces results is resolvable within the current range of measured Ti-isotope fractionation in these minerals. [ABSTRACT FROM AUTHOR]

Recent developments of acid leaching of titanium concentrates and ores have produced renewed industrial and commercial interest. However, the leaching kinetics and mechanism of these concentrates and ores had received little attention. This work, therefore, addresses the leaching kinetics and mechanism of Ti from a rutile concentrate in sulfuric acid solution. The leaching reaction was controlled by diverse parameters like temperature, particle size, acid concentration, liquid/solid (L/S) ratio, and stirring speed. The leaching kinetics was investigated using the Shrinking Core Model in order to determine the optimum criteria which control the reaction. The kinetics analysis showed that the rate of dissolution of Ti increased by increasing reaction temperature, L/S ratio, and stirring speed, while it decreased upon increasing particle size. The kinetics analysis revealed that the dissolution reaction is controlled by the chemical reaction at the rutile particle surface. Applying the Arrhenius relation, the apparent energy of activation Ea for the leaching reaction was calculated to be 23.4kJ/mol. A semi-empirical overall rate equation was introduced to describe the combined effects of the process variables upon the rate of the dissolution reaction: 1 - (1 - x)1/3 = k0 C0.803[H2SO4] (dp)-0.518 (L/S)0.793 (w)0.668 e(9B(C++/DE)t. [ABSTRACT FROM AUTHOR]

Copyright of Comunicaçõe Geológicas is the property of Laboratorio Nacional de Energia e Geologia, I.P. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Titanium ores are plentiful in the earth crust, and the corresponding metal content ranks as the fourth among structural metals; the application of titanium metal is restricted for its high cost in spite of its excellent mechanical properties, corrosion, and oxidation resistance. Titanium metal was first produced with Hunter process yet this has been practically replaced by Kroll process which contains carbochlorination of rutile and ilmenite to obtain TiCl4, followed by metallothermic reduction with magnesium. The complex procedure, huge investment, and considerable energy consumption have markedly prevented the development of titanium. Electrolysis has been proposed by Fray et al. in the early twenty-first century, developed and derived by many other researchers, involving both anodic and cathodic process, use TiCl4 and titania as raw materials. However, the efficiency and continuity issues remain inevitable, while self-propagating high-temperature synthesis (SHS) seems a good alternative for its rapid, continuous, and controllable characteristics. The extractive metallurgy of titanium and its alloy plays an important role in the effective utilization of titanium. At present, there is a lack of the latest review on the extractive metallurgy technology of titanium and its alloys. In this paper, the development status of extractive metallurgy of titanium and its alloys are reviewed, and finally, the direction of extractive metallurgy of titanium and its alloys is prospected. [ABSTRACT FROM AUTHOR]

Perovskite nanomaterials have become a new research hotspot due to the many novel physical properties of quantum effects and have good application prospects in the field of optoelectronics. Among them, the realization of controllable fabrication of perovskite nanomaterials is the basis of performance studies and applications and is also a difficult point. Reducing production costs to improve manufacturing methods, further improve product controllability, promote advantages, or improve disadvantages will be very important for further application of perovskite nanomaterials. Therefore, this paper studies the construction of titanium ore nanomaterials by designing a novel preparation process and, at the same time, analyzes the related optoelectronic properties of the obtained materials. In this paper, a triangular PbI2 nanosheet having a uniform and controllable shape and size was successfully fabricated by physical vapor deposition through the introduction of a limited space, and related characterization was performed to show uniform controllability and high crystallinity. Using PbI2 nanosheets as the substrate, MAPbI3 nanosheets were further prepared and related characterizations proved that the obtained nanosheets had high crystallinity and excellent optical properties. The experiment proves that the peak position of the fluorescence spectrum obtained by Gaussian fitting is 800 nm and the half-peak width is about 45 nm. At the same time, MAPbI3 exhibits strong light absorption characteristics when the wavelength is less than 800 nm. This shows that this enclosed space deposition method can improve the uniformity and controllability of PbI2 and MAPbI3 nanosheet fabrication, which provides the basis for further research on MAPbI3 nanomaterials and references to the controllable growth of other nanomaterials. [ABSTRACT FROM AUTHOR]

In this work, the activated persulfate oxidation of ciprofloxacin (CIP) using a low-grade titanium ore under sunlight or simulated sunlight were conducted to analyze the CIP degradation efficiency and to identify the transformation products (TPs) generated during oxidation under both types of irradiation sources by using liquid chromatography-quadrupole time-of-flight mass spectrometry (LC-QTOF-MS). All advance oxidation process experiments were performed in a 2700-mL raceway reactor at a pH value of ~ 6.5 and an initial CIP concentration of 1 mg/L, during 90 min of reaction time. The control experiments carried out under simulated sunlight achieved a 97.7 ± 0.6% degradation efficiency, using 385 W/m2 of irradiation with an average temperature increase of 11.7 ± 0.6 °C. While, the experiments under sunlight reached a 91.2 ± 1.3% degradation efficiency, under an average irradiation value of 19.2 ± 0.3 W/m2 in October–November 2019 at hours between 11:00 am and 3:00 pm with an average temperature increase of 1.4 ± 0.8 °C. Mass spectrometry results indicated that 14 of the 108 possible TPs reported in the literature were detected. The calculated exact mass, measured accurate mass, and its characteristic diagnostic fragment ions were listed, and two new TPs were tentative identified. The TP generation analysis showed that some specific compounds were detected in different time intervals with kinetic variations depending on the irradiation used. Consequently, two CIP degradation pathways were proposed, since the type of irradiation determines the CIP degradation mechanism. [ABSTRACT FROM AUTHOR]

We report the first observation of low power drive level sensitivity, hyperparametric amplification, and single-mode hyperparametric oscillations in a dielectric rutile whispering-gallery mode resonator at 4.2 K. The latter gives rise to a comb of sidebands at 19.756 GHz. Whereas, most frequency combs in the literature have been observed in optical systems using an ensemble of equally spaced modes in microresonators or fibers, the present work represents generation of a frequency comb using only a single-mode. The experimental observations are explained by an additional 1/2 degree-of-freedom originating from an intrinsic material nonlinearity at optical frequencies, which affects the microwave properties due to the extremely low loss of rutile. Using a model based on lumped circuits, we demonstrate that the resonance between the photonic and material 1/2 degree-of-freedom, is responsible for the hyperparametric energy transfer in the system. [ABSTRACT FROM AUTHOR]

A low-cost and simplistic approach for the synthesis of nanosized SO42-/TiO2 photocatalyst was successfully performed using Binh Dinh ilmenite ore and H2SO4 as titanium and sulfur sources, respectively. The experimental results indicate that the obtained material exists in the form of particles with a size of about 22 nm and has a specific surface area of about 49 m2 g-1. Compared with the TiO2 sample, the SO42-/TiO2 sample shows much higher photocatalytic degradation of rhodamine B (RhB) under the sunlight irradiation. In more details, the nanosized SO42-/TiO2 sample obtained is capable of completely decomposing RhB after 9 hours of irradiation by a 60 W LED lamp with a corresponding intensity of 9,500 Lux. However, when the SO42-/TiO2 is irradiated by the sunlight with the intensity of 65,000 Lux, it only takes 2 hours to completely decompose rhodamine B (RhB), facilitating the use of SO42-/TiO2 as a potential photocatalyst for the RhB photodegradation. [ABSTRACT FROM AUTHOR]

TiC was examined as a starting material for Ti metal production by sulfidation and electrochemical reduction in molten salt. The sulfur evaporation temperature, sulfidation temperature, and time were optimized in a dual-zone furnace for the efficient and sustainable formation of TiS2 as well as carbon removal from TiC by S2 gas sulfidation. A mixture of TiS2 and Ti2.45S4 powders was synthesized from TiC at 1200 °C, and a perfect carbon removal was achieved to a very clean level as low as 0.025 mass pct C. The sulfides derived from TiC were then electrochemically reduced in molten CaCl2-0.5 mol pct CaS salt. The spherical shape Ti powder consisting of high-purity Ti sheets was obtained from TiS2 without the carbon contamination. This method might be applied for sustainable recycling of waste carbides and for production of low-cost Ti powders via TiC or TiOxCyNz from the titanium ore. [ABSTRACT FROM AUTHOR]

The use of the magnetic fraction (MF) of a low-grade titanium ore (TO) and two oxidants (H2O2 and NaClO), testing each one separately, were compared in photo-Fenton like systems to degrade thiabendazole (TBZ) as a model micropollutant. As far as the author's knowledge goes, this work presents for the first time the assessment of NaClO as an alternative to H2O2 in heterogeneous systems, where the Fenton-type photocatalyst is a natural mineral; TO has a Mexican origin and its magnetic fraction is mainly composed of Ilmenite (47.8% w/w FeTiO3). The experiments were carried out at bench scale in a solar simulator, using a batch raceway pond reactor. Oxidant and MF concentrations were optimized by a composite experimental design, which allowed to achieve 97% TBZ degradation at 15 and 30 min for NaClO and H2O2 systems, respectively, when the initial concentration of TBZ was 37 µM. Pointing out that both pseudo-first order rate constants ( k ′ ), k NaClO ′ = 0.226 min−1 and k H 2 O 2 ′ = 0.065 min−1, are in the order of homogeneous photo-Fenton applied to degrade TBZ; however, the time to achieve the same level of TBZ degradation is halved when NaClO is used instead of H2O2, thus the capacity of treatment plants can be increased. Furthermore, better results of mineralization (54%), DQO (76%), DBO5 (44%) and acute toxicity (74%) removal were observed when NaClO was used as an oxidant compared to H2O2, whose values were 42, 67, 38 and 58% for the parameters aforementioned. These positive results demonstrate the feasibility of the use of NaClO as an alternative oxidant to H2O2 in the heterogeneous photo Fenton like process. [ABSTRACT FROM AUTHOR]

A new approach is proposed to improve the strength of the vanadium titanium magnetite (VTM) sinter by adding preformed calcium ferrite (CF) to partially substitute the CaO. The effects of the sintering temperature, oxygen partial pressure (pO2), heating time, and substitution ratio of preformed CF on the mineralogy of the VTM sinter are examined through tablet sintering. The results indicate that sintering temperature significantly affects the matrix structure and pore morphology by influencing solid–liquid assimilation and bubble coalescence. With an increase in pO2, the generation of calcium ferrites and hematite is favored, and the matrix transforms into a melting corrosion structure. Heating time mainly affects the pore shape. The addition of preformed CF to VTM sintering can not only inhibit the generation of perovskite and promote the formation of calcium ferrites but also increase the quantity of melts and promote solid–liquid assimilation. [ABSTRACT FROM AUTHOR]

[Display omitted] • A new synthesis scheme for high-temperature CO 2 capture materials was proposed. • Applicable KNaTiO 3 -based CO 2 sorbent was synthesized from cheap rutile sand. • Structurally improved KNaTiO 3 pellets reached high CO 2 removal rate within 4 min. • Optimized sorbent exhibited high CO 2 uptake and excellent stability for 100 cycles. For the practical applications of CO 2 sorbents, more studies on pellet rather than powder-type sorbents is a more mainstream research trend. In addition, high sorption kinetics, excellent cycling stability, and cheap raw precursors are far more important than its initial CO 2 uptake value to a certain extent. Recently, alkali titanates have attracted growing attention as emerging and attractive high-temperature CO 2 sorbent materials. Among the existing Na-doped alkali titanates, potassium sodium titanate (KNaTiO 3) is one of the most promising high-temperature CO 2 sorbent due to its high CO 2 sorption rate and excellent cyclic stability. In order to promote its practical application in industry, a low-priced titanium ore was selected for the synthesis of KNaTiO 3 , and the optimized resulting sorbent maintained a rapid and reversible sorption capacity of 15.5 wt% after 100 cycles. Spherical pellets were fabricated by extrusion-spheronization method with cellulose and alumisol additives. The optimal pellets exhibited a relative compression strength of 4.15 MPa and an attrition rate of 1.2 wt% as well as maintaining a sorption capacity of 14.3 wt% after 50 cycles. It also showed superior CO 2 capture kinetics, reaching a high CO 2 removal rate of 92.5% within only 4 min (under 20% CO 2). The role and mechanism of cellulose as pore-former were explored by SEM analysis and diffusion model fitting. In all, the optimized resulting sorbent pellets not only retained rapid CO 2 sorption kinetics, high CO 2 removal rate, excellent cyclic performance, but also ensure robust mechanical properties. These properties, as well as the low cost aspect, makes this newly developed KNaTiO 3 -based pellets to be highly promising for high temperature CO 2 capture such as for biomass fired power plants or hydrogen production. [ABSTRACT FROM AUTHOR]

The excellent properties of titanium pellet Z in the blast furnace hearth protection were determined by studying the composition, metallurgical properties and a over four years period of application practice of titanium-containing pellets(C&Z) and ores (J, G&D) in a domestic blast furnace. The reduction and softening-melting properties of titanium pellet Z were better than those of titanium lump ore G, D and J, and titanium pellet C. Under the condition of a titanium load of 7–8 kg TiO2/tHM, the fuel rate, pressure drop and slag ratio of the blast furnace using titanium pellet Z were better than that for the titanium-bearing resources. Using pellet Z had an obvious effect on the decrease of the hearth temperature and sustained stability. It was concluded that pellet Z was an excellent titanium-bearing burden for both laboratory research and industrial trial. [ABSTRACT FROM AUTHOR]

In this study, the magnetic fraction (MF) of a low-grade titanium ore (TO) was successfully used as an alternative Fe2+ source in five reuse cycles, in combination with persulfate (PS) and simulated sunlight (SSL) for the degradation of ciprofloxacin (CIP). The best response of the CIP initial concentration, irradiation time, and doses of MF and PS to degrade completely this pollutant were determined based on an experimental design. However, the individual application of MF, PS, or SSL fails to achieve this goal at the optimal experimental condition. Furthermore, the MF-PS-SSL system showed a higher production of sulfate radicals and a concentration of dissolved Fe2+ ions compared with data obtained for the MF-PS system. The best performance attained by the former system is due to the synergy produced between the photo-generated electrons, and the reaction of PS with the Fe2+ ions leached gradually from the MF, which increased sulfate radical production. After five reuse cycles of the MF, the oxidation system showed a CIP degradation of 100% in 100 min, no residual content of PS, a CIP mineralization of 6%, a marginal increase in the biodegradability (BOD5/COD ratio), a MF loss of 7.5%, and a twofold increase in toxicity; however, this parameter was lower than the effective concentration at 50% inhibition (EC50). The substitution of MF with an iron salt decreased the degradation efficiency of the antibiotic by 14%, probably owing to the immediate excess of Fe2+ in the solution, which can be oxidized to Fe3+ ions, and as a consequence of this, the production rate of the sulfate radical was also reduced. [ABSTRACT FROM AUTHOR]

Titanium is widely recognized to show an excellent resistance in highly corrosive environments, and the resource of titanium ore is abundant. However, the applications are limited because of the high cost for titanium production. In addition to the chlorination and reduction process, the fabrication process to sheet or foil is expensive. A cost‐effective production process for titanium sheet is therefore investigated. A procedure to mechanically peel off electrodeposited titanium sheet from electrodes is established. Glassy carbon and molybdenum electrodes are found to be suitable for this purpose. [ABSTRACT FROM AUTHOR]

The carbothermic smelting reduction process of ilmenite ore at high temperature was investigated by thermodynamic calculations in conjunction with smelting experiments. Based on thermodynamic calculations, conducting the smelting process at a higher temperature was recommended to achieve a larger amount of FeO reduction, i.e., higher Ti-enrichment, as less precipitate and thus large amounts of a liquid slag were predicted. However, even though the reduction of FeO in ilmenite ore at the initial stage seemed to be faster as the temperature increased, no significant difference in the TiO2 or FeO concentration was observed after the reaction was complete, regardless of the temperature. This was caused by the precipitation of pseudobrookite due to the local depletion of FeO during reaction at higher temperatures, by which further reduction reaction was prohibited. The apparent rate constant increased with increasing temperature and the activation energy of the reduction process was estimated to be 144 kJ/mol, from which it was concluded that the reduction reaction of FeO in ilmenite slag by carbonaceous reductant was generally controlled through the mass transfer in the slag phase. Additionally, the formation of TiC also occurred in the iron bath. At 1923 K (1650 °C), approx. 20 pct more TiC was generated as compared to TiC formation at 1823 K (1550 °C), which also prevented further reduction of Fe at higher temperatures. [ABSTRACT FROM AUTHOR]

We present a model combining ab initio concepts and molecular dynamics simulations for a more realistic treatment of complex adsorption processes. The energy, distance, and orientation of water molecules adsorbed on stoichiometric and reduced rutile TiO2(110) surfaces at 140 K are studied via constant temperature molecular dynamics simulations. From ab initio calculations relaxed atomic geometries for the surface and the most probable adsorption sites were derived. The study comprises (i) large two-dimensional surface supercells, providing a realistically low concentration of surface oxygen defects, and (ii) a water coverage sufficiently large to model the onset of the growth of a bulk phase of water on the surface. By our combined approach the influence of both, the metal oxide surface, below, and the bulk water phase, above, on the water molecules forming the interface between the TiO2 surface and the water bulk layer is taken into account. The good agreement of calculated adsorption energies with experimental temperature programmed desorption spectra demonstrates the validity of our model. © 2004 American Institute of Physics. [ABSTRACT FROM AUTHOR]

SnO[sub 2] and its Mn alloy thin films have been grown on Al[sub 2]O[sub 3](0001) substrates by reactive radio-frequency magnetron sputtering performed in the presence of O[sub 2] gas. The prepared films showed preferred orientation in the [100] direction of the rutile structure of SnO[sub 2]. The O[sub 2]/Ar gas-flow ratio maintained during the sputtering was found to significantly affect the crystalline quality and stoichiometry of the films. The optical constants of the SnO[sub 2] and Sn[sub 1-x]Mn[sub x]O[sub 2] (x<=0.27) films were measured by spectroscopic ellipsometry in the 2–5 eV photon energy region. The band-gap energy of SnO[sub 2] is determined to be 3.86 eV and that of Sn[sub 1-x]Mn[sub x]O[sub 2] increases for x<=0.11 and then decreases for the higher x, exhibiting a negative bowing. The initial increase of the band-gap energy is attributable to the hybridization between localized Mn d states located near the band gap and O p-like valence bands. The decrease of the band-gap energy is interpreted as due to the SnO[sub 2]–MnO[sub 2] alloying effects. © 2003 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Electrochemical extraction of titanium using a consumable anode of TiCxOy solid solution has been considered as a low-cost and environmentally friendly method. This method is normally referred to as the USTB process when using TiO2 as the starting material, or as the Chinuka process when using titanium ores as raw materials. However, scaling-up of this process is limited by anode preparation and slow electrochemical dissolution. Here, an arc furnace was used to prepare a Ti2CO solid solution that was cast to form a consumable anode for the electrochemical preparation of metallic titanium in a NaCl-KCl molten salt without low-valance titanium ions. The dissolution potential of the as-prepared Ti2CO solid solution is more negative than that of conventional powder sintering. A constant-current electrolysis was carried out in a NaCl-KCl molten salt at 1023 K. The results indicate that titanium ions were stably dissolved from Ti2CO anode into melts, and then metallic titanium was deposited on the cathode. It was confirmed that the cast Ti2CO solution was a promising consumable anode for the USTB process for stable and effective preparation of metallic titanium. [ABSTRACT FROM AUTHOR]

Carbothermic selective reduction of titanium concentrate ore for the preparation of titanium oxycarbide was presented and SiO2 was found to be partly reduced during the process. The equilibrium relationship between Si dissolved in metallic Fe and SiO2 existed in corresponding slag was analyzed thermodynamically, and then revealed by a series of designed equilibration experiments. The results are in accordance with the calculated values obtained from thermodynamic analysis and have well explained the phenomenon that part of SiO2 is reduced during selective reduction processing of titanium concentrate ore. [ABSTRACT FROM AUTHOR]

Graphical abstract Addition of Ag and borate into the aqueous suspension of rutile can promote phenol oxidation by a factor of 4.6. Highlights • Rutile activity increases and decreases on addition of Ag and borate, respectively. • Rutile activity was further increased by a synergism of Ag and borate. • Ag and borate act as catalysts for O 2 reduction and phenol oxidation, respectively. • Photocurrent of phenol oxidation is stable during five recycles. Abstract Rutile TiO 2 (RT) is usually used as photocatalyst for water oxidation, but seldom for organic oxidation, probably due to the slow reduction of O 2. Herein we report a mutual effect of Ag nanoparticles and borate anions greatly increasing the photocatalytic activity of RT for phenol oxidation in neutral aqueous solution. RT was home-made, followed by calcination at 200―800 °C. With a given RT, the rates of phenol oxidation on the addition of Ag and borate were increased and decreased, respectively. In the presence of both Ag and borate, interestingly, the rate of phenol oxidation was larger than that in the presence of Ag. A (photo)electrochemical measurement revealed that Ag and borate, in contact with the irradiated RT, could catalyze O 2 reduction and phenol oxidation, respectively. Since the electron and hole transfer processes would promote each other, the positive effect of Ag is further enhanced in the presence of borate. This work demonstrates that RT could be developed as a promising photocatalyst for organic oxidation through a surface co-catalyst. [ABSTRACT FROM AUTHOR]

Graphical abstract The bridged mechanism of barite/ilmenite mixture via drilling mud. Highlights • Barite/ilmenite mixture (BIM) has the potential to be used as alternative weighting material to barite in drilling mud. • The rheological properties of barite/ilmenite mixture are similar to that of barite and therefore could be used in place of barite. • BIM gives the same or better yield point and gel strength than of barite. • In terms of rheological properties, BIM was found to give comparable results as barite. Abstract It is common knowledge in the technology of drilling fluids, monitoring of the drilling mud weight is critical in developing a mud system that yields good well stability. Alternative weighting materials should be in demand to offer superior properties such as barite, available in sufficient reserves to meet field requirements and be competitively priced. A weighting material that can be sourced locally to substitute barite would be a good innovation in the drilling industry. The present work was performed for enhancement the weighting of the drilling fluids by using mixture of barite and ilmenite. Micro-sized ilmenite ore (FeTiO 3) particles were obtained by a direct solid phase milling process to replace a certain percentage of barite as weighting material of the drilling mud. X-ray diffraction (XRD) analysis was carried out to underline the phase identification of the crystalline ilmenite, used drilling mud weighting agent as barite and Na-bentonite particles. The lamellar shape and the arrangement in overlapping plates of ilmenite particles, Platy-like shaped Na-bentonite grains against sub-angular and square-shaped barite particles were confirmed by scanning electron microscope (SEM) technique. Three mud samples with different densities were prepared which be made up of fresh water, sodium bentonite and weighting material. The weighting materials were added up to the mud separately to form the required mud density ranges between 8.65 and 18 lb/gal. The first sample was water-based mud with barite; second sample was water-based mud with local ilmenite ore and third sample was water-based with barite and ilmenite in which were added in parts as 50:50 by ratios. These samples were investigated at different temperatures (normal, 120, 160, 180 °F) and the employed mud density range to determine solid content, density, rheological properties and filtration losses. The study showed that the rheological properties of barite/ilmenite mixture were found to give comparable results as barite and has the potential to be used as alternative weighting material especially in a heavier drilling mud. Two significant advantages could be observed through using the mixture; it produces lower solids content and fluid loss which in turns reduces the formation damage, respectively. [ABSTRACT FROM AUTHOR]

For many years, rutile-like crystals have given rise to pronounced enthusiasm amongst mineralogists. In this context, rutile-type ZnF 2 has found numerous applications across a variety of disciplines, ranging from material sciences to optoelectronics. Surprisingly, very limited literature is concerned with the molecular adsorption on ZnF 2 surfaces and related energetics. Additionally, surface probing with small particles is a well-entrenched technique to analyze the interfacial properties. In this regard, small organic species are valuable picks. In the present work, we have employed electronic structure calculations to simulate the adsorption of methane, chloroform, pyrrole, benzene, naphthalene, anthracene, tetracene and pentacene at the (110) plane of rutile ZnF 2 . Dispersion-corrected DFT method was chosen to predict the binding energies and structures of molecule-adsorbed surfaces. Interestingly, a linear proportionality relationship was found between the binding energies of aromatic adsorbates and their respective molecular lengths. By applying this relationship, we were able to predict the adsorption energy of pentacene on ZnF 2 to within 2% of our DFT-based result. [ABSTRACT FROM AUTHOR]

Using high-resolution scanning tunneling microscopy (STM), we have studied the oxidation of rutile TiO 2 (1 1 0)–(1  ×  1) surfaces with H ad species at room temperature. We followed the evolution of various stable species as function of the O 2 exposure, and the nature of the ultimately dominating species in the Ti troughs is described. When O 2 saturation was accomplished using a glass-capillary array doser, we found that on-top O (O ot ) adatoms are the predominant surface species. In contrast, when O 2 was supplied via backfilling of the chamber the predominant surface species are tentatively assigned to terminal OH groups. We argue that unintended reactions with the chamber walls have a strong influence on the formed surface species, explaining scattered results in the literature. On the basis of our STM data we propose an alternative, easy way of preparing oxidized TiO 2 (1 1 0) surfaces with O ot adatoms ( o -TiO 2 ). It is certain that o -TiO 2 (1 1 0) surfaces prepared according to this recipe do not have any residual surface O vacancies. This contradicts the situation when oxidizing reduced TiO 2 (1 1 0) surfaces with O vacancies, where some O vacancies persist. [ABSTRACT FROM AUTHOR]

Extraction of titanium from its ores by carbon-thermal reduction followed with hydrometallurgical treatment is a traditional process that is costly due to the huge consumption of acid for the complete dissolving of oxide slag. In this work, a new proposal was put forward to separate the slag by flotation process. The feasibility of selective separation of titanium oxycarbide (Ti2CO) by flotation process from the MOx(M = Ca, Mg, Si, Al) was investigated by using the simulated slag with single and mixed components. The flotation products were analysed by X-ray diffraction, chemical analysis, scanning electron microscopy and Fourier transform infrared spectrum. It was found that in the case of single Ti2CO or its mixing sample with MOx, the Ti2CO will float up effectively at the pH range of 1–5 to separate from the slag with oleic acid as the main floating reagent, and the results are beneficial to the design of a new process for titanium extraction from the complex ore at much lower cost. [ABSTRACT FROM AUTHOR]

Comparison of the results obtained in integrated processing of a titanium-containing ore based on three minerals (ilmenite, sphene, and rutile) demonstrated the high efficiency of the high-temperature carbochlorination (at 800°C for 60 min). The degree of titanium extraction was 99%, and that of iron, 98%, whereas hydrometallurgical methods enable not more than a 47% extraction. [ABSTRACT FROM AUTHOR]

The effects of aliovalent dopants on the kinetics of spinodal decomposition in a rutile-type TiO 2 -VO 2 system were studied by means of x-ray diffraction and transmission electron microscopy. In this study, as-prepared polycrystalline samples were annealed at 673 k inside the spinodal. For undoped samples, phase decomposition occurred along the [001] direction, and a lamellar structure formed on the nanometer length scale. The phase decomposition kinetics in this system were sensitive to the type of aliovalent dopant; the decomposition rate in a sample doped with Al 2 O 3 was more than one order of magnitude higher than a sample doped with Nb 2 O 5 . These observations could be explained on the basis of the premise that cation interstitial mobility is greater than cation vacancy mobility. The obtained results are consistent with those for a TiO 2 -SnO 2 system, indicating that phase separation in both rutile-type oxide systems can be interpreted through a common framework. [ABSTRACT FROM AUTHOR]

This paper presents further experimental testing of the Gas Switching Combustion (GSC) concept where ilmenite is used as oxygen carrier and CO as fuel for integration into an IGCC plant. In contrast to conventional chemical looping combustion (CLC), GSC keeps the oxygen carrier in a single fluidized bed reactor where it is alternately exposed to fuel and air. This reactor configuration greatly simplifies scale-up under the pressurized conditions required for competitive efficiency in gas-fuelled chemical looping applications. Autothermal operation of the lab-scale GSC reactor was achieved for ilmenite and a synthetic Ni-based oxygen carrier. Even though the synthetic oxygen carrier clearly outperformed the ilmenite ore in terms of reactivity and oxygen transport capacity, ilmenite performance was found to be good enough for efficient application in GSC-IGCC power plants. The experiments also suggest that ilmenite kinetics is not negatively affected by increases in pressure as has been reported for other synthetic oxygen carriers, thereby further increasing the attractiveness of ilmenite as an oxygen carrier for the high-pressure GSC-IGCC application. [ABSTRACT FROM AUTHOR]

Rutile TiO 2 is seldom studied as anode material for Na-ion battery for its much poorer Na storage performance than anatase phase. Herein, strategies of carbon coating and nitrogen doping are proposed and achieved together by a facile ball milling method followed by a high temperature sintering process to improve its electrochemical properties. The feature of this work lies in the dual N doping, not only to the carbon layers but also to the TiO 2 lattice, resulting in sufficient oxygen vaccancies and defects in TiO 2 /C. Although the pristine TiO 2 prepared by the similar method shows only 10 mAh g −1 capacity, the Na storage performance of N-doped TiO 2 /C is significantly enhanced. It demonstrates a high reversible discharge capacity of 211.2 mAh g −1 at 16.8 mA g −1 (0.1C). Moreover, a capacity retention of 92.3% is achieved after 500 cycles at 168 mA g −1 (1C), verifying ultrahigh reversible capacity and excellent cycling performance for rutile TiO 2 . The excellent Na storage performance of N-doped TiO 2 /C should be ascribed to the improved electronic and ionic conductivity resulting from dual N-doping strategy and shortened Na ion diffusion length due to the particle downsizing. [ABSTRACT FROM AUTHOR]

Urban gardening has recently experienced rapid development; however, the risk of the transfer of toxic elements from neighboring industry needs to be evaluated. We performed a multi-elemental analysis with several common edible crops (cucumber, pepper, cabbage, and lettuce) and poplar grown directly on a titanium ore landfill as a maximized scenario of exposure. Despite elevated concentrations of soil Ca, Fe, Mn, and Ti resulting from the industrial process, we did not register higher accumulation of these elements in the edible parts of crops or in poplar leaves grown on red gypsum compared with the control soil. Only S concentrations were higher in plants grown on the red gypsum, especially for cabbage. The principal component analysis among elements for plants grown on red gypsum indicated that S and Mn were accumulated by different plant species than Cd, Cu, and Zn. The poplar clone had a significantly higher transfer of S and Cr than the control and is a suitable tree species for monitoring element transfer to vegetation in this industrial context. By comparing our data with tolerable daily intake (TDI) recommendations, we demonstrated the low risk of cultivating edible crops directly on an industrial substrate in a maximized scenario of exposure, except for Cr, for which the toxicity depends on the bioavailable form. However, we did not consider the cumulative effects of the various elements because there are no current guidelines, and further research is needed to address this question. [ABSTRACT FROM AUTHOR]

Recently, titanium metal production by molten salt electrolysis using CaCl as molten salt and TiO or rutile (94 to 96 pct TiO) as feedstock has been drawing attention. However, when a low-grade Ti ore (mainly FeTiO) is used as feedstock, removal of iron (Fe) from the ore is indispensable. In this study, the influence of reaction temperature, reaction time, particle size of the ore, and source country for the ore on the removal of iron by selective chlorination using CaCl was assessed. Experimental results showed that the mass percent of iron in the ore decreased from 49.7 to 1.79 pct under certain conditions by selective removal of iron as FeCl. As a result, high-grade CaTiO was produced when the ore particles smaller than 74 µm reacted with CaCl at 1240 K (967 °C) for 8 to 10 hours. Therefore, this study demonstrates that the removal of iron from the ore is feasible through the selective chlorination process using CaCl by optimizing the variables. [ABSTRACT FROM AUTHOR]

Ni 3 TeO 6 semiconductor was synthesized by the sol-gel route. The crystalline phase was verified by XRD measurements together with Rietveld refinements. The surface morphologies were studied by TEM, SEM, EDX and XPS measurements. Ni 3 TeO 6 semiconductor shows a high optical absorption for UV and visible light with a band gap of 2.48 eV characterized by the charge-transfer transitions of O 2− →Ni-3d in UV and visible wavelength light. The photochemistry characteristic was investigated by the photocatalytic degradation of methylene blue (MB) dye solutions driven by visible-light. The nanoparticles were efficient in photo-degrading organic dye solutions. The photocatalysis activity and the mechanism were discussed on its structural properties. [ABSTRACT FROM AUTHOR]