High Titanium Content Research Articles

РОССЫПИ ЖЕЛЕЗОСОДЕРЖАЩИХ МИНЕРАЛОВ В САХАЛИНСКОЙ ОБЛАСТИ

Ю.А. Билибин неоднократно подчеркивал, что для того, чтобы понять картину образования россыпей, необходимо учитывать полный цикл их превращений. Много внимания было уделено в последнее время проблемам поиска древних погребенных россыпей и россыпей сложного строения. Богатые резервы полезных ископаемых в россыпях объясняются множественностью их генетических типов, позволяющих вовлекать в промышленную эксплуатацию новые месторождения. Актуальность работы обусловлена необходимостью выявления новых источников получения железа, титана и ванадия в условиях сокращения ресурсов минерально-сырьевой базы. Поисковые работы, выполняемые с целью выявления россыпей, наиболее перспективных для разработки, могут проводиться на основании понимания генезиса их формирования. Цель работы: исследование закономерностей распространения россыпей железистых минералов в пределах Сахалинской области, выявление петрогенетических особенностей преобладающих минералов, определение перспектив освоения месторождений железосодержащего сырья, оценка экономической целесообразности его добычи. Методы. Исследованы железо-титан-оксидные минералы из различных по кремнекислотности горных пород островодужных вулканогенных комплексов Большой Курильской гряды. Для исследований были подготовлены шлифы горных пород, отобрана магнитная фракция из протолочек. Шлифы пород изучались под поляризационным микроскопом. Порошок протолочек горных пород и мономинеральных фракций исследовался посредством химических аналитических методов (гравиметрического, титрометрического, спектрофотометрического, рентгенофлуоресцентного, масс-спектрометрического с индуктивно-связанной плазмой). Результаты. Исследованы закономерности формировании железистых россыпей и определены их основные типы. На побережьях Дальнего Востока России встречаются два типа россыпей с различными условиями питания. Одна из них – Курило-Камчатская провинция собственно титаномагнетитовых россыпей – расположена на территории Сахалинской области. На островах Курильской дуги преобладают современные пляжевые россыпи и дюнные отложения низкой террасы. Главная роль в обеспечении минералами россыпей этого типа принадлежит туфопесчаникам, пемзам и пемзово-шлаковым пирокластическим толщам. Кристаллы железосодержащих минералов в горных породах вулканогенных комплексов имеют довольно разнообразные размеры: от мелких, пылеватых до крупных хорошо выраженных кристаллов, размерами более 1–2 мм. Химический состав титаномагнетитов различных вулканических комплексов изменяется в зависимости от кремнекислотности пород. Продуктивные породы характеризуются повышенным содержанием железа, титана и ванадия. Прибрежно-морские, а также древние погребенные россыпи содержат значительные объемы железосодержащих минералов. Изучение технологических схем переработки железосодержащего минерального сырья показало, что некоторые из них позволят провести его переработку с получением востребованных конечных продуктов. При определенных экономических условиях разработка россыпей может быть целесообразной.

Structural, Mineral and Elemental Composition Features of Iron-Rich Saponite Clay from Tashkiv Deposit (Ukraine)

Low-temperature nitrogen adsorption–desorption isotherms, scanning electron microscopy, transmission electron microscopy, X-ray diffraction, as well as infrared spectroscopy were used to characterize structural features of raw and acid-treated saponite from Tashkiv deposit of Ukraine. It was determined that raw saponite is predominantly composed of trioctahedral saponite with an admixture of dioctahedral nontronite and associated minerals such as quartz, hematite, and anatase. Raw saponite clay was characterized by a high content of iron (19.3%) and titanium (1.1%). Iron is present in the form of hematite particles, isomorphic replacements in octahedral and tetrahedral sheets of a clay structure, or as a charge-balancing cation in the interlayer space. Titanium is homogeneously dispersed as submicrometer anatase particles. The porous structure of both saponite forms consists of micro-meso porous system with narrow slit mesopores dominating. As a consequence of the acid treatment, the specific surface area increased from 47 to 189 m2 g−1, the total pore volume from 0.134 to 0.201 cm3 g−1, and the volume of the micropores increased sevenfold. Using the data of our research allowed us to utilize these mineral resources wisely and to process saponite more efficiently.

Screw Track Osteolysis in the Cementless Total Knee Replacement Design

BackgroundThere is a paucity of reports on osteolysis associated with tibial screw fixation in cementless total knee arthroplasty (TKA), and the pathophysiology is not clear. This study aimed to describe the pathology related to screw track osteolysis around the tibia in cementless TKA. MethodsThe study cohort comprised 100 revised cementless TKAs with tibial screw fixation. Screw track osteolysis and various screw angles were analyzed radiologically. Tissue samples from the joint capsule and the osteolytic cavity were investigated for metal/polyethylene wear. The type of tissue response was determined using immunohistochemistry. Retrieved tibial polyethylene inserts were analyzed for screw hole impression and mode of wear. Tissue metal content was measured by inductively coupled plasma optical emission spectrometry. Electrochemical reactions between the tibial tray and the cancellous screws were investigated. ResultsRadiological analysis showed screw track osteolysis predominantly at the medial aspect of the tibial component, and the severity of osteolysis positively correlated with smaller medial proximal tibial screw angles. Osteolysis was associated with high titanium concentrations but not with polyethylene particles. An open circuit potential between the screw and the tibial base plate was measured. Necrosis, osteolytic cyst formation and macrophages, T and B cells, and dendritic cells were present. ConclusionThe present study highlights the risk for screw track osteolysis in cementless TKA with screw fixation. Our data collectively suggest that titanium wear may contribute to screw track osteolysis in the cementless TKA design. The contribution of screw angles is difficult to prove.

In Situ Synthesis of TS-1 on Carbon Nanotube Decorated Nickel Foam with Ultrafine Nanoparticles and High Content of Skeleton Titanium

In this Article, TS-1 was successfully synthesized on carbon nanotubes decorated nickel foam via in situ strategy forming the monolithic TS-1 (MTS-1). To the best of our knowledge, situ synthesis of the MTS-1 has not been reported. Carbon nanotubes decorated nickel foam has many aggregated pores (confined pores formed in aggregated structure) and a large surface area, and TS-1 particles could be dispersed on the surface of CNT@NF. MTS-1 had the characteristics of ultrafine nanoparticle and high content of skeleton titanium. High absorptive property and electrostatic interaction between CNT@NF and gels could accelerate the crystallization rate. The TS-1 particles were solidly immobilized on the CNT@NF, and the conversion rate was almost constant even after multiple reactions. The catalyst is easy to separate from liquid products after reaction, which offers an economical application prospect.

Appropriate titanium slag composition during smelting of vanadium titanomagnetite metallized pellets

The suitable titanium slag composition with high titanium content for electric furnace smelting of vanadium titanomagnetite was investigated through thermodynamics and related phase diagram analysis. According to the thermodynamic results, low-melting-point regions and MgTi2O5 primary phase area in the phase diagrams, the suggested titanium slag composition for the present vanadium titanomagnetite metallized pellets should consist of 50% TiO2, 8%–12% MgO and 13% Al2O3 (mass fraction) with a binary basicity of 0.8–1.2. Finally, the verified smelting experiments were conducted and successful separation of the molten iron from the titanium slag is obtained. The obtained vanadium-containing molten iron contains 0.681% V and 0.267% Ti, and the obtained titanium slag contains 52.21% TiO2 (mass fraction), in which MgTi2O5 is the primary phase. The titanium resource in the final titanium slag production could be used to produce TiO2 pigment by acid leaching methods.

Determination of chromium cobalt nickel gallium niobium scandium and zirconium in the blast furnace slag of vanadium titanium magnetite by inductively coupled plasma atomic emission spectrometry

In order to recover the precious metal elements in vanadium-titanium blast furnace slag, the analytical method that direct determination of the range from 0.001% ~ 0.300% chromium, cobalt nickel, gallium, niobium, scandium and zirconium in the blast furnace slag of vanadium titanium magnetite by inductively coupled plasma atomic emission spectrometry was established. Sample digestion reagent consists of hydrofluoric acid, hydrochloric acid, nitric acid and sulfuric acid, and their ratio, dosage and reaction control condition are all optimized, so make sure that the blast furnace slag of vanadium titanium magnetite can be quickly completely digested. At the same time, the high content of silicon dioxide can be removed by volatilization to simplify the sample solution matrix composition, and because of the titanium ion and sulfate ion complex reaction generating oxygen titanium sulfate ion so as to solve the high concentration of titanium matrix easy hydrolysis problem in low acidity medium, thus it greatly reduce the acidity of sample solution to reduce the matrix effect. That the influence of the spectral interferences and matrix effects in the high concentrations of titanium, iron, vanadium, aluminum, calcium and magnesium coexistence matrix system had been studied, then the test results are classified summary. The influence of substrate composition were eliminated by the matrix matching and synchronous background correction measures, and then the analytical lines, the background correction areas and working conditions of the spectrometer are all optimized according to the spectral interference test. The technical performance reached: calibration curve correlation coefficient of 0.998 or higher, detection limit of element is 0.0001% ~ 0.0003% and the measuring elements content in lower 0.0003% ~ 0.0009%, RSD is less than 15% when the element content in the range from 0.001% to 0.05%, the actual sample testing results are consistent with ICP-MS.

Thermal and microstructural study of slowly cooled Ni-B hard alloys containing Ti

Binary Ni-B alloys containing varied amounts of titanium were prepared and investigated in this study. Differential Thermal Analysis (DTA) was used to study the solidification and transformation behavior of the alloys, while Optical Microscope (OM) and Scanning Electron Microscope (SEM) equipped with Energy Dispersive X-ray Analyzer (EDXA) were used to study the microstructure of the alloys. Microscopic and thermal investigations of the alloys revealed the presence of two major primary phases Ni (α) and τ with other binary and ternary eutectic structures being present in the hard alloys. The addition of titanium to the Ni-B system enhanced the formation of the ternary phase τ, while solid-state eutectoid transformation of the τ phase was observed in alloys with low titanium composition. But such transformation was not detected in alloys with high titanium contents, which enhanced the formation of hard boride phases.

Geology, geochemistry and petrology of basalts from Paraná Continental Magmatic Province in the Araguari, Uberlândia, Uberaba and Sacramento regions, Minas Gerais state, Brazil

This study covers the region between the cities of Sacramento and Araguari/Uberlândia (Minas Gerais State, Brazil), where basalt flows from the Parana Continental Magmatic Province outcrop. The investigated rocks present tholeiitic signature, with high titanium content, and are classified as Pitanga magma-type. The preserved basalt thickness is between 10 and 200 meters and individual flows do not exceed 15 meters thick. Flows were identified as sheet lobes, smaller and thinner flows units — stacked laterally and vertically forming compound lavas —, or frontal, centimetric lobes. The basalt flows show decimetric to metric intercalations of clastic sedimentary rock, with depositional characteristics that can vary from aeolian to lacustrine, and are important markers on prevailing environmental conditions. The plagioclases are dominantly labradorite and pyroxene is augite, whereas olivine can be hyalosiderite or hortonolite/ferrohortonolite. The behavior of the major, minor and trace elements is compatible with the presence of at least two parental magmas, which were subjected to fractional crystallization mainly of plagioclase, clinopyroxene, ilmenite and magnetite. There is a chemistry distinction between basalts from Sacramento to those from Araguari/Uberlândia region, the former one showing more evolved than the last one. The high (La/Lu)N values are indicative of partial melting of a garnet peridotite, while the Rare Earth Elements (REE) values are indicative of fractional crystallization.

Phase formation and strengthening mechanisms in a dual-phase nanocrystalline CrMnFeVTi high-entropy alloy with ultrahigh hardness

A novel equimolar CrMnFeVTi high-entropy alloy (HEA) was synthesized by mechanical alloying (MA) and spark plasma sintering (SPS). The phase formation and microstructure in the milled powders and in the sintered bulk HEA were characterized using a combination of X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). It was found that a body-centered cubic (BCC) phase formed gradually in the milled powders during MA. After SPS, a very small fraction of the BCC phase transformed into a face-centered cubic (FCC) phase. Thus, the sintered bulk CrMnFeVTi HEA exhibits a dual-phase structure of BCC and FCC phases, with an average nano-scale grain size of ∼97 nm. Thermodynamic analysis demonstrates that it is the high concentration of titanium in the bulk CrMnFeVTi HEA that stabilizes this dual-phase microstructure over a single-phase microstructure. Titanium has the largest atomic radius and the highest enthalpy of mixing with the other elements, leading to a phase transformation from the BCC phase to FCC phase during SPS. The bulk CrMnFeVTi HEA exhibits extremely high values of compressive strength (2279.53 MPa) and hardness (835 HV), which are significantly higher than those reported for most single-phase BCC structured HEAs. Calculations performed for the contributions of different strengthening mechanisms in this HEA indicate that dislocation and grain boundary strengthening play the most significant roles, whereas the effect of solid solution strengthening effect is very limited because of the release of lattice distortion energy during the BCC to FCC phase transformation in the SPS process.

Mesoporous/Microporous Titanium Silicalite with Controllable Pore Diameter for Cyclohexene Epoxidation

A mesoporous/microporous titanium silicalite with controllable pore diameter was synthesized in an easy and new route by using cetyltrimethylammonium bromide (CTAB) as a mesoporous template and tetrapropylammonium hydroxide (TPAOH) as a microporous template. This route leads to the formation of mesopores prior to the crystallization of microporous MFI topology. The porosity formation sequence makes the two types of channels, which are micropores with MFI topology and mesopores with wormlike morphology, distribute homogeneously. The pore diameter of the mesopores can be adjusted from the maximum center of 2.6 nm to that of 6.9 nm by tuning the molar ratio of CTAB to silicon from 0.125 to 0.20. The mesoporous/microporous titanium silicalite catalysts were evaluated in the epoxidation of cyclohexene, and showed excellent catalytic activities, with respect to the conventional microporous TS-1, because of the enhanced diffusion property in the mesopores and higher titanium content near the external surface of ...

Effects of titanium content on hydrogen embrittlement susceptibility of hot-stamped boron steels

This study examines the effects of titanium content on hydrogen embrittlement in hot-stamped boron steel, by employing an electrochemical cathodic charging method, slow rate tensile tests, and thermal desorption analyses. With increasing titanium content in hot-stamped boron steel, titanium carbides are precipitated, while the resistance to hydrogen embrittlement improves with a slight reduction in the elongation when stress is applied to the hydrogen-charged specimens. The specimens with a high titanium content exhibit a relatively superior resistance to hydrogen embrittlement due to the presence of small titanium carbide precipitates that act as irreversible hydrogen trap sites with a high binding energy.

Ways to Improve the Quality of Die Steel 5KhNM

There was performed an analysis of influence of the deoxidation technology, hydrogen content and high concentration of titanium in steel 5KhNM (Rus. “5XHM”) on quality of die blanks, evaluated based on the results of the ultrasonic test.The fractographic examinations of fractures and the X-ray microprobe analysis of chemical composition of non-metallic inclusions were conducted, the evaluation of macro- and micro-structure of a die blank with high titanium content was performed.It is demonstrated that defects of dies from steel 5KhNM (Rus. “5XHM”) are cracks from merged flakes and micro-flakes; in most cases large concentrations of sulphides appeared to be hydrogen collectors for formation of flakes and micro-flakes.

Microstructure and Microhardness of Laser Metal Deposition Shaping K465/Stellite-6 Laminated Material

K465 superalloy with high titanium and aluminum contents was easy to crack during laser metal deposition. In this study, the crack-free sample of K465/Stellite-6 laminated material was formed by laser metal deposition shaping to control the cracking behaviour in laser metal deposition of K465 superalloy. The microstructure differences between the K465 superalloy with cracking and the laminated material were discussed. The microstructure and intermetallic phases were analyzed through scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD). The results showed that the microstructure of K465/Stellite-6 laminated material samples consisted of continuous dendrites with a similar structure size in different alloy deposition layers, and the second dendrite arm spacing was finer compared with laser metal deposition shaping K465. The intermetallic phases in the different alloy deposition layers varied, and the volume fraction of carbides in K465 deposition layer of the laminated material was higher than only K465 deposition under the fluid flow effect. In addition, the composition and microhardness distribution of laminated materials variation occurred along the deposition direction.

Sulfur-bearing metallic glasses: A new family of bulk glass-forming alloys

Metallic glasses constitute a class of engineering materials having an enormous potential for many fields of application due to their superior properties. Here, we report on a new family of sulfur-bearing bulk metallic glasses. So far, sulfur was not considered as alloying element for the synthesis of bulk metallic glasses. We observe bulk glass formation in a variety of sulfur-containing systems, including titanium-based bulk glass-forming systems with an extremely high titanium content of 70at.%. These findings allow the development of a whole new class of amorphous metals, having good processability and consisting of alloying elements suitable for industrial applications.

Characterization of Invert Soda Lime Silica Glasses Containing High Titania Content Together with their Glass Ceramics

Collective structural, optical and thermal properties were investigated for some prepared soda lime silicate glasses containing high TiO2 contents (35, 40, 45%). X-ray diffraction and scanning electron microscopic studies of the prepared heat treated glass-ceramic derivatives were carried out to identify the type of separated crystalline phases and their morphological features. FTIR spectral data indicate the identification of vibrational modes due to the silicate network besides the presence of additional interferences in the wavenumber range 500-800 cm−1 of extra conjugated bands related to Ti-O bending vibrations. X-ray diffraction patterns show the separation of two crystalline silicate phases (wollastonite CaSiO3 and combeite Na2Ca2Si3O9) within the prepared glass-ceramics together with some titanate phases (sodium titanate and calcium titanate). Thermal expansion measurements show the decrease of the dilatometric softening temperature with the increase of TiO2 indicating their housing as TiO6 or TiO5 groups. FTIR spectra are analyzed in relation to the combined identified vibrational modes. Crystallization behavior is related to the dual action of TiO2 acting both as a nucleator for silicate phases and sharing for the formation of some crystalline titanates by direct combination with modifier ions and acting as structural building units.

Characterization and Pre-Concentration of Low-Grade Vanadium-Titanium Magnetite Ore

A large number of unexploited low-grade vanadium-titanium magnetite deposits have been found in the Chao-yang area of China in recent years. The reserves are estimated at more than 20 billion tons. A mineralogical study of raw sample indicated that it was a typical low-grade vanadium-titanium magnetite ore with weathering. Most of vanadium-titanium magnetite was replaced by martite and sphene, which would affect the recovery of valuable elements. The intergrowth relationship between vanadium-titanium magnetite and sphene was very complex, and the grain size of sphene was generally fine, and could not be completely liberated even by fine grinding, whereas the content of vanadium and titanium in sphene was higher than that in vanadium-titanium magnetite, resulting in vanadium-titanium magnetite concentrates with characteristics of high vanadium and titanium content. A magnetic separation process was investigated for the pre-concentration of low-grade vanadium-titanium magnetite ore. The results showed that 73.52% of feed ore were directly discarded for reducing the processing capacity of follow-up processing. A vanadium-titanium magnetite concentrate with 1.14% V2O5, 22.22% TiO2, 42.51% Fe and a rough concentrate of ilmenite with 16.05% TiO2, 20.77% Fe were obtained from low-grade vanadium-titanium magnetite ore which contains 0.050% V2O5, 1.67% TiO2 and 8.53% Fe.

A 7000-year history of coastal environmental changes from Mexico’s Pacific coast: A multi-proxy record from Laguna Mitla, Guerrero

The lack of multi-millennial multi-proxy paleoenvironmental reconstructions from Mexico’s Pacific coast has limited our understanding of the regional response to climate change and sea-level rise. A 479-cm core covering the last 6900 years was extracted from Laguna Mitla in the state of Guerrero on Mexico’s Pacific coast. Beginning as a Rhizophora-dominated salt pan ~6900 yr BP, at ~6500 yr BP, the site transitioned to a mangrove swamp dominated by Laguncularia, which lasted about 300 years. The beach barrier formed from ~6200 to 5200 yr BP, during which time, the site existed as an intermittently sheltered bay, the result of large, rapid changes in wave energy associated with the shifting barrier location and changes in stability. After the beach barrier was stabilized at ~5200 yr BP, water level at the coring site became a function of precipitation rather than sea level. Since that time, deposition has alternated between peat, laid down in a mangrove swamp, and clay intervals characterized by high concentrations of titanium and a predominantly regional pollen signal, representing open-water lagoon phases. Seven periods of increased water level, varying in duration, occurred during the backbarrier period, with El Niño-Southern Oscillation (ENSO) likely the main climatic mechanism causing these periodic shifts in the paleo-precipitation levels. We suggest that the deepest water levels detected over the last ~3200 years correlate with periods of increased ENSO activity. The spatial distribution of tropical cyclone rainfall, which represents a significant percentage of total annual precipitation along Mexico’s Pacific coast, may explain the inconsistencies between our record and paleoclimatic records from Mexico’s interior, but more work is needed to test this hypothesis.

Effect of Slag Composition on the Oxidation Kinetics of Alloying Elements during Electroslag Remelting of Stainless Steel: Part-2 Control of Titanium and Aluminum Content

Kinetics of slag/metal reaction were investigated experimentally using 50 kg electroslag remelting (ESR) furnace in order to clarify the effect of slag containing different CaO and TiO2 content on titanium, aluminum and silicon content during the ESR process with 1Cr21Ni5Ti stainless steel. The results obtained show that the more CaO content in slag is, the more aluminum content in ingots increases. The lg([Al]4/[Ti]3) increases with the increase of slag temperature in the first 13 minutes during the ESR process, and after the slag temperature tends to be stable, the lg([Al]4/[Ti]3) decreases with the increase of TiO2 content in the rest process. The penetration and film theories were employed to analyze the rate determining step of slag/metal reaction, and it was found that the rate determining step of the reaction was the mass transfer of aluminum through the molten steel, silica through the slag and titanium on both of the metal and slag sides. The slag containing low CaO content combined with extra titania constantly added into molten slag in the first temperature-rising period is suitable for electroslag remelting of 1Cr21Ni5Ti stainless steel with high titanium and low aluminum content.

Preparation of Rutile from Ilmenite Concentrate Through Pressure Leaching with Hydrochloric Acid

Take into account the fact that the natural rutile utilized for the production of titanium dioxide pigment through chloride process is desperately lacking worldwide especially in China, an attempt was exploited for extracting synthetic rutile from Yunnan ilmenite concentrate with hydrochloric acid pressure leaching process. The leaching parameters for one step leaching process were investigated. The results shown that the optimum condition is leaching temperature of 413 K (140 °C), acid concentration of 20 pct HCl, leaching time of 4 hours and liquid/solid mass ratio of 8:1. A two steps leaching process was also suggested to reutilize the leaching liquor which with a high content of HCl. The results showed that the content of HCl decreased from 135 to 75 g/L, total iron increased from 44.5 g/L to about 87.6 g/L, and the liquid/solid mass ratio decreased to 5:1 with a two steps leaching process. The leaching product produced through a two steps leaching process shows a pure golden red with a high content of titanium (92.65 pct TiO2), a relatively low content of calcium (0.10 pct CaO) and magnesium (0.12 pct MgO), but high content of silicon (5.72 pct SiO2).

Design of friction and wear resistant titanium- and cobalt-modified nickel-base repair alloys by spray forming

Powder injection molding (PIM) is a newly developed method for repairing gas turbine components in recent years. However, the PIM method needs a sacrificial binder, which increases working procedure and cost. To overcome this disadvantage, a new method of maintenance, i.e. spray forming (SF) technique, is put forward in this study. Three kinds of Ni-base repair alloys have been designed and prepared by the SF process. And these alloys were subjected to friction, wear and material analysis tests. Results reveal that the alloy with high titanium and cobalt content has the best friction and wear resistance. The increase in titanium and cobalt content will result in the increase of γ/γ′ misfit, grain size, and coherent γ′ size, and enhance the formation of good oxides lubricants, which leads to a decrease of the coefficient of friction. Moreover, with increasing titanium and cobalt content, the predominant wear mechanism changes from delamination wear to abrasive wear and adhesive wear. The high titanium and cobalt content give a large improvement in wear resistance by strongly hindering dislocations motion and reducing crack growth rate, which resists delamination wear.