Amounts Of Rutile Research Articles

Новые данные o титановой минерализации в фенитизированных докембрийских карбонатных породах быстринской серии Среднего Тимана

Fenitized Precambrian carbonate rocks (Middle Timan) are parent rocks for bauxite — phosphate weathering crusts. Therefore, the mineral composition of fenites, characterized by rich and varied mineralization, is of great interest. Titanium minerals especially attract attention, since their high concentrations are noted in bauxite-phosphate weathering crusts. For example, in the bauxites of the Verkhne-Shchugorsk area, the amount of rutile may reach 6000—7000 g/t. Titanium mineralization is represented by titanite, rutile, anatase, and cassite.

Investigations into the structure of PEO-layers for understanding of layer formation

Plasma electrolytic oxidation (PEO) is a type of high-voltage anodic oxidation process capable of producing a thick oxide layer with a wide variety of structural and chemical properties influenced by the electrolytic system. This process enables the combined adjustment of various characteristics, i.e. the morphology and chemical composition. The procedure facilitates the possibility of generating an individual structure as well as forming a crystalline surface in a single step. A highly porous surface with a high crystalline content consisting of titanium dioxide phases is ensured through the process of plasma electrolytic oxidizing pure titanium. In the present study plasma electrolytic oxidized TiO2-layers were investigated regarding their crystallinity through the layer thickness. The layers were prepared with a high applied voltage of 280 V to obtain a PEO-layer with highly crystalline anatase and rutile amounts. Raman spectroscopy and electron backscatter diffraction (EBSD) were selected to clarify the structure of the oxide layer with regard to its crystallinity and phase composition. The composition of the TiO2-phases is more or less irregularly distributed as a result of the higher energy input on the uppermost side of the layer. Scanning transmission electron microscopy (STEM) provided a deeper understanding of the structure and the effects of plasma discharges on the layer. It was observed that the plasma discharges have a strong influence on crystallite formation on top of the oxide layer and also at the boundary layer to the titanium substrate. Therefore, small crystallites of TiO2 could be detected in these regions. In addition, it was shown that amorphous TiO2 phases are formed around the characteristic pore structures, which allows the conclusion to be drawn that a rapid cooling from the gas phase had to take place in these areas.

Study of the free surface energy of epoxy composites using an automated measurement system

Results of development of the automated measurement system (AMS) for determining contact wetting angles and calculations of components of free surface energy (FSE) of solid surfaces by the Van Oss-Chaudhury-Good method were presented. It was shown that AMS allows for calculations based on experimental measurement of geometrical parameters of a lying drop on the surface and energy characteristics of test fluids. It was found that the measured contact wetting angles and calculated values of FSE components of surfaces of epoxy polymer composites, steel and glass are adequate and reliable. Based on the conducted measurements and calculations, relationship between FSE, the structure and properties of epoxy polymer composites, filled with rutile, was established. In the course of research that was conducted using AMS, it was found that at an increase of the content of rutile, total FSE (γ s ), dispersive (γ d ) and acidic-basic (γ ab ) components of composites increase. Dependences γ s and γ d on the filler’s content are extreme in character, and γ ab increases and does not change at a subsequent increase in the amount of rutile. The influence of rutile is represented most vividly by dependences of the acidic (γ a ) and basic (γ b ) components, into which the polar (acidic-basic) FSE component γ ab is disintegrated. It was found that structural transformations are associated with the acidic-basic mechanism of intermolecular and inter-phase interactions in epoxy compositions

Efficient photoelectrodes from anatase TiO2 nanotube arrays decorated with particles/rods/3D microflower rutile crystals for photoelectrochemical water splitting

Efficient photoanodes are designed of vertically aligned anatase TiO2 nanotube arrays (anatase TNTAs) decorated with different shaped rutile TiO2 structures (particles, 1D nanorods, 3D microflowers) to improve the photoelectrochemical water oxidation performance of pristine TNTAs. Anatase TNTAs were prepared by anodic oxidation of Ti substrate in NH4F electrolyte, and the rutile percent and shape are controlled by tuning the TiCl4 treatment time (20–120 min). The effects of treatment time on the morphology, crystal structure, band gap, photocurrent, and photoconversion efficiency are characterized by FESEM, HRTEM, XRD, UV–Vis diffuse reflectance spectroscopy, and photoelectrochemical measurements. XRD data confirmed that TiCl4 treatment induced the formation of the rutile phase of TiO2 over anatase TNTAs and the rutile amount in the TNTAs was increased upon increasing the treatment time. Additionally, the band gap of TNTAs was gradually decreased by increasing the rutile percent. The optimum treatment time is 80 min, which produces TiO2 photoanode array that possess the following characteristics: rutile/anatase mixed phase, nanorode/nanotube mixed morphology, 3.09 eV band gap, two times increase in photocurrent, and almost more than twofold enhancement in the photoconversion efficiency relative to pure TNTA.

Study on Comprehensive Recycling of an Ilmenite Ore Beneficiation Test

Ilmenite phase is complex in Shaanxi.There are mainly magnetite, limonite and ilmenite, and associated with extremely small amount of rutile. According to the occurrence iron and titanium in the ilmenite ore。Paper discussed comprehensive recycling of the ilmenite using wet low-intensity magnetic separation by stage grinding process . The results show that it obtains better mineral processing indexes。The productivity of ilmenite concentrate was 28.83%, the grade of iron in concentrate was 62.05%, the content of titanium was 13.11%, iron recovery was 61.73%, titanium recovery was 43.40%.

Alpha-Decay Damage in Murataite-Based Ceramics

AbstractSamples of murataite ceramics with the composition (wt.%) 3.8 Al2O3, 10.5 CaO, 54.0 TiO2, 10.6 MnO, 6.0 Fe2O3, 4.6 ZrO2, 8.1 ThO2, 2.4 Cm2O3 (1.8 244Cm) and a specific activity of 5.5×1010 Bq/g were prepared by cold pressing and sintering at 1250 °C for 24 hrs or by melting and recrystallisation in a resistive furnace at 1325 °C and 1350 °C for 1 hr. In the sintered ceramics murataite polytypes with five-fold (5C) or three-fold (3C) repeats of the fluorite unit cell and crichtonite were found to be the major phases. Perovskite, pseudobrookite, and pyrochlore were observed as minor phases. The 5C polytype was rendered X-ray amorphous at a cumulative dose of 2.73×1018 μ–decays/g (0.21 dpa) whilst the 3C polytype, which contained only traces of Cm, remains crystalline at this dose. In the melted ceramics the 5C and 8C murataite polytypes were found to be the major phases (80–90 % of the bulk) and minor amounts of rutile, crichtonite and perovskite were also observed. Complete amorphization of the murataite polytypes in the ceramics melted at 1325 and 1350 °C was achieved at doses of 2.46×1018 μ-decays/g (0.19 dpa) and 2.53×1018 μ-decays/g (0.20 dpa), respectively.

Partitioning of species-forming and impurity cations among growth pyramids of pinacoid and prism faces in crystals of beryl, cordierite, and beryllian indialite

The face effect was observed in all individual compounds with beryl structure having grown at a rate of 1–8 unit cells a second, with spontaneous crystallization in the system beryl (or cordierite)–Mg,Ca/Cl,F–impurity, where impurities are Ti, V, Cr and/or Fe oxides. By “face effect” is meant a difference in chemical compositions and symmetry of growth pyramids of crystallographically nonequivalent crystal faces. In the studied compounds of beryl structural type the simple crystal forms, prism and pinacoid, are characterized by hexagonal (pseudohexagonal in cordierite) and rhombic symmetry of face patterns. Degrees and characters of distinction of growth pyramids of prism and pinacoid faces of beryls, beryllian indialites, cordierites and their varieties vary in a wide range depending on the accumulation of species-forming and impurity elements. Most likely, this effect appears when crystallographically nonequivalent faces entrap chemically different “building units” (clusters spontaneously formed in a feeding medium and composed of fragments of beryl-type structure). It is supposed that the final isomorphous substitution of an impurity for the species-forming element occurs immediately on the face and/or attached unit. The character, direction, and degree of isomorphism depend on the initial composition of the medium, type of the main compound to be formed, and the presence of synchronous impurity phases. The same ratio of Si and Al concentrations in building units of the prism-pinacoid couple of cordierite with and without Ti and V suggests the persistent action of the patterns of these faces on the medium in the range of sampled concentrations of impurities and rates of growth. The contrasting face effect with respect to Si and Al in an indialite-cordierite individual is due to a drastic dissymmetry of the latter. The Ti- or V-related effects of cordierite faces are negligible. The study of beryllian indialite and its varieties showed that in some cases changes in Si-Al-Mg composition of units feeding faces with different crystallographic patterns are quite the same, with the considerable evolution of the total composition of the crystal-forming medium. As to the face effects of beryllian indialites (chiefly, with respect to Ti, V, Cr, and Fe impurities), they are owing to a considerable difference in degree of isomorphism with the participation of these elements in the building units that feed pinacoid and prism faces. Beryls demonstrate drastically contrasting face effects with respect to Ti (up to 0.20 f.u.) and in the presence of impurities, to Al (up to 0.21 f.u.); distinct effects were related to Cr (0.06 f.u.), in all varieties to Mg (up to 0.10 f.u.), and quite rarely, to Fe (0.01 f.u.), which is seen from comparison of the schemes of isomorphism implemented in prism and pinacoid. The effects under consideration and their evolution in the process of development of individuals are also clearly recognized from crystallochemical formulas of the building units feeding faces with different crystallographical patterns. By the example of beryl, it has been shown that the face effect inversion with respect to a component during the crystal growth indicates the inversion of the degree of isomorphous substitution of this element in the process of evolution of the individual (because of a drastic change in phase formation in the system) rather than the absence of relationship between face pattern and effect. Thus, in the system beryl–Mg,Ca/F,Cl–TiO 2 the inversion of Mg-related effect (resulting from inversion of degrees of substitution Al 3+ → Mg 2+) is linked to a drastic increase in rutile amount (TiO 2) crystallized together with beryl at a certain stage of solution cooling.

Influence of Doping on the Antibacterial Effect of TiO<sub>2</sub> Nanoparticles

TiO2 nanoparticles doped with V, Mn or Zn, respectively, were synthesized from pure TiO2 and dopants calcinating at definite temperature. The physical properties of prepared TiO2 nanoparticles were characterized by TEM, XRD and UV-vis spectrum. The TEM images showed that the diameters of the particles were 20~50 nm. There was no peak of doping elements in the XRD spectrum of nano-sized TiO2 doped, but the peak of a little amount of rutile was observed, which demonstrated that V, Mn and Zn might locate in the TiO2 octahedral lattice, or might be highly dispersed within crystalline of TiO2. In the meanwhile, doping of the TiO2 decreased the temperature for TiO2 transforming from anatase into rutile, and promoted the transforming. It was found that a little amount of V5+ may take the place of Ti4+ in the lattice of TiO2. The red-shift was clearly observed in the UV-vis spectrum of TiO2 nanopowders doped with V. As a result, the band gap was changed and the TiO2 nanopowders doped with V enable to absorb visible light. The red-shift could be assigned to the charge transfer transition between the 3d orbital of V5+ and the TiO2 conduction or valance band. The red-shift was not observed in the UV-vis spectrum of TiO2 nanopowders doped with Mn and with Zn, the shape of which was similar to that of pure TiO2. The results of the minimum inhibition concentration (MIC) for Escherichia coli and Staphylococcus aureus showed that vanadium ions doping intensely improved the antibacterial efficiency of nanocrystallites. This was attributed to the change of surface properties of metal ions doped semiconductor, such as O vacancies, Ti interstitial ions and vanadium ions which took the place of titanium.

The interfacial study of sol–gel-derived fluoridated hydroxyapatite coatings

Fluoridated hydroxyapatite (FHA) coatings have been investigated as an alternative for pure hydroxyapatite (HA) coatings because FHA are less soluble and are equally bioactive. In this study, Ca(NO 3) 2, P 2O 5, and HPF 6 have been used to prepare FHA coatings on Ti–6Al–4V substrates by sol–gel dip-coating method. The interface between the coating and the substrate is characterized by high-resolution transmission electron microscopy (HRTEM), secondary ion mass spectroscopy (SIMS), and X-ray photoelectron spectroscopy (XPS). A TiO 2 (rutile)-rich layer is found at the interface. The fluorine content fluctuates basically in sync with the oxygen content near the interface, which is ascribed to the formation of Ti(O 2− x F 2 x ). It is also found that the amount of rutile is related to the HPF 6 amount in the dipping sol. The reason is ascribed to the existence of CaF 2 at the interface, which provides more oxygen for rutile formation by forming hydrogen bonding (F⋯HO).

High-Q factor frequency-temperature compensated sapphire Bragg distributed resonator

A new sapphire TE10δ resonator was constructed with a novel support structure made from sapphire and rutile (patent pending). The amount of rutile was chosen to act as Bragg reflectors to reduce conductor losses while simultaneously annulling the temperature coefficient of frequency. The resonator was confirmed to have an annulment temperature of −8°C and Q-factor of 65 000 limited by the dielectric loss tangent.

Characterisation of a heavy mineral-bearing sample from India and the relevance of intrinsic mineralogical features to mineral beneficiation

Iscor has developed a standard method to deal with heavy mineral-bearing sand samples in order to characterise and evaluate such samples. The aim of this paper is to present the methodology of the standard method, using a sample from a heavy mineral-bearing beach sand deposit in India as a case study. The first stage of the standard method involves preparation of the original sample to produce fundamental data, as well as to provide suitable samples for mineralogical investigation. During sample preparation the sample was deslimed, sink-floated and subjected to magnetic separation to produce four fractions, namely high susceptible magnetics, magnetics, magnetic-others and non-magnetics. Stage 2 of the method involves mineralogical investigations of these fractions in order to characterise the original sample. The investigation includes the systematic analyses and descriptions of the samples, using techniques such as XRF and XRD analyses, microscopic descriptions of the minerals and semi-quantitative analyses. Finally, based on results obtained in the previous stages, the sample is then evaluated to decide whether the specific deposit merits furthers interest or not. Applying the methodology of this standard method to characterisation of the Indian sample, some important aspects were revealed. It became evident that the mineralogical and chemical compositions of the high susceptible magnetic, magnetic and magnetic-other fractions are similar in that these fractions consist mainly of ilmenite with the high susceptible magnetic fraction also containing appreciable amounts of hematite. Detailed microcopy revealed that the widespread occurrence of ilmenite in all three these fractions can be explained by variations in weathering and textural properties resulting in heterogeneous grains with varying magnetic susceptible properties. Furthermore, it was found that zircon is the main valuable mineral present in the non-magnetic fraction while considerable amounts of rutile are also present. Unfortunately, the presence of undesirable amounts of sillimanite increases the impurity levels of this fraction. However, with this being known beforehand, proper beneficiation flowline design can “clean-up” the fraction to acceptable levels. Characterisation of these intrinsic mineralogical features plays an important role in understanding the behavior of the minerals during beneficiation and the designing of optimal beneficiation routes. Finally, semi-quantitative mineralogical data were used to calculate the mineral composition of the sample, and together with chemical analyses, supplied a very useful and practical data set to use in evaluation of the original sample.

Effect of rutile/anatase ratio on catalytic properties of Co−TiO2 catalysts for fischer-tropsch synthesis

CO hydrogenation on Co−TiO2 catalysts with similar cobalt dispersity and rutile amount within f=0–1·0 in a rutile-anatase mixture has been studied. The highest activity and selectivity to liquid hydrocarbons is observed for the catalyst with f=0.7.

Rutile fibers in surface waters of northern New Jersey

Transmission electron microscope (TEM) analyses of surface water samples from the northern New Jersey (USA) area indicate that rutile (TiO2) is a consistent contaminant, with fiber concentrations ranging from 0.2 to 1.5 million fibers per liter (MFL), and averaging 0.7 MFL. Concentrations of rutile fiber were comparable to or somewhat higher than asbestos concentrations in ambient surface water samples. Rutile is a component of bedrock in the drainage areas studied, and is also widely used commercially. The data favors a bedrock origin for most of the rutile observed. Analysis of hydraulic parameters indicates that rutile in the surface water samples is entirely in the Wentworth clay range, with Stokes' diameter of less than 2 microns, and suggests a high degree of sorting control over suspended particles. Since the samples were all from actual or potential sources of drinking water, the results suggest that a substantial amount of rutile is ingested via surface water supplies by the general population. The health effects of such ingestion are unknown.

Analysis of titanium pigments in human lung tissue

Methods are described for the unequivocal identification of mineral deposits in lung tissues obtained during the autopsy of a titanium dioxide-exposed worker who died of an undifferentiated malignant tumor. The methods included scanning and transmission electron microscopy, electron and X-ray diffractometry, and atomic absorption spectroscopy. The presence of considerable amounts of rutile was revealed. Despite this heavy loading, no lung tissue reaction was evident. Within the limits imposed by the period since the first exposure (6 years), this finding lends support to the supposition that the rutile crystal modification of titanium dioxide is biologically inert.

The Geiger counter x-ray diffractometer for determining the rutile content of heavy mineral separations of beach sands

Utilizing NaF as an internal standard and MgO as a diluent, quantitative evaluation of the amount of rutile can be obtained by x-ray diffraction of beach sands with a Geiger detection method. The percentage obtained by the x-ray method was checked with chemical determination of TiO 2 content and found to be in good agreement. Beach sand from Moana, South Australia, was used for the investigation.

EFFECT OF SIZE AND SHAPE OF TITANIUM OXIDE CRYSTALS ON SPECTROPHOTOMETRIC PROPERTIES OF TITANIUM‐BEARING PORCELAIN ENAMELS*

AbstractColor changes of three titanium enamels given varied firing treatment were investigated. The size and shape of titanium oxide particles were studied with the electron microscope, the relative amounts of anatase and rutile were determined from X‐ray analyses, and spectrophotometric curves of the fired panels were made.Electron micrographs showed that rutile particles recrystallized as needles or “sticks,” whereas anatase appeared as ill‐defined, irregularly shaped, rounded particles. With increasing firing temperature or firing time (1) rutile particles showed a greater increase in size than anatase particles, (2) the amount (by weight or volume) of anatase crystals decreased and the amount of rutile crystals increased, and (3) a color change from blue‐white to cream‐white was observed.The change in color seemed to be related to the scattering of blue light by small particles at lower temperatures or shorter periods of firing. As the size of opacifying particles increased, the scattering of blue light decreased, and the characteristic absorption of visible light in the shorter wave lengths was more apparent. In enamels containing both anatase and rutile, the smaller anatase crystals were predominant at lower and the larger rutile crystals at higher temperatures, so that sharp changes of color were observed as the firing temperature was increased.

MINERALOGY OF TYPICAL NORTH CAROLINA CLAYS AND SHALES*

A microscopic examination was made on those clays and shales of North Carolina which gave most promise of future development in the structural clay products industry. The more common minerals were determined rather than the rare ones which did not occur in sufficient quantity to affect the quality of the clay. The work showed clay substance to be the most abundant material present, followed by quartz, red and yellow iron oxides, muscovite through sericite to hydromica, and epidote, with smaller amounts of rutile, biotite, titanite, tourmaline, and zircon. Diatoms were found in two cases and kaolinite in one.