Research of the thorium purification at monazite refinement processes

This paper is aimed to the research of the thorium purification processes at monazite refinement processes. We have investigated different solution containing thorium with different mix of rare-earth elements. It was found that the application of cation resin is well- recommended if we want to reach the highest yields of thorium purification process

n-Hexane Bromination Using Barium Fluorobromate Ba(BrF[4])[2]

It was observed that Ba(BrF[4])[2] demonstrates a high reactivity towards n-hexane. It was found that the heating the reaction mass proceed with intensive self-heating up to 40 °C and release of elemental bromine. The GC-MS analysis showed that the main product of Ba(BrF[4])[2] interaction with n-hexane is 3-bromohexane. The optimal interaction parameters were found. The heat effect of the reaction was determined by isothermal calorimetric method, it was –1451 kJ/mole. The qualitative composition of solid precipitate was determined by EDXRF and XRD analyses. BaF[2] is formed as only solid product of the reaction between Ba(BrF[4])[2] and n-hexane. It was found that conditions of researched reaction are quite unusual for known free-radical hydrogen substitution processes in case of alkanes. Also we can conclude that Ba(BrF[4])[2] is much more soft reagent is case of interaction with alkanes in comparison with BrF[3] and it can provide more or less selective bromination of alkane unlikely to BrF[3]

Oxidative fluorination of iridium metal for urban mining: Kinetic studies

The process of oxidative fluorination of a compact iridium metal has been studied. For this purpose, tetrafluoridobromates(III) of alkali and alkaline-earth metals were chosen as oxidizing agents with numerous advantages. The main results of this work include the kinetic dependencies for the two following processes: 1) interaction of iridium with molten potassium tetrafluoridobromate; and 2) interaction of iridium with a solution of potassium tetrafluoridobromate in liquid bromine trifluoride. In both cases it has been found out that iridium can be transformed into its soluble fluorinated derivative; the reaction with molten potassium tetrafluoridobromate proceeds almost 50 times faster (in comparison to the interaction in BrF3 solution) and can be potentially applied for the practical purposes

n-Hexane Bromination Using Barium Fluorobromate Ba(BrF[4])[2]

It was observed that Ba(BrF[4])[2] demonstrates a high reactivity towards n-hexane. It was found that the heating the reaction mass proceed with intensive self-heating up to 40 °C and release of elemental bromine. The GC-MS analysis showed that the main product of Ba(BrF[4])[2] interaction with n-hexane is 3-bromohexane. The optimal interaction parameters were found. The heat effect of the reaction was determined by isothermal calorimetric method, it was –1451 kJ/mole. The qualitative composition of solid precipitate was determined by EDXRF and XRD analyses. BaF[2] is formed as only solid product of the reaction between Ba(BrF[4])[2] and n-hexane. It was found that conditions of researched reaction are quite unusual for known free-radical hydrogen substitution processes in case of alkanes. Also we can conclude that Ba(BrF[4])[2] is much more soft reagent is case of interaction with alkanes in comparison with BrF[3] and it can provide more or less selective bromination of alkane unlikely to BrF[3]

Composition, crystallization conditions and genesis of sulfide-saturated parental melts of olivine-phyric rocks from Kamchatsky Mys (Kamchatka, Russia)

Highlights • Parental melts of sulfide-bearing KM rocks have near primary MORB-like composition. • Crystallization of these S-saturated melts occurred in near-surface conditions. • Extensive fractionation and crustal assimilation are not the causes of S-saturation. • S content in melts can be restored by accounting for daughter sulfide globules. Abstract Sulfide liquids that immiscibly separate from silicate melts in different magmatic processes accumulate chalcophile metals and may represent important sources of the metals in Earth's crust for the formation of ore deposits. Sulfide phases commonly found in some primitive mid-ocean ridge basalts (MORB) may support the occurrence of sulfide immiscibility in the crust without requiring magma contamination and/or extensive fractionation. However, the records of incipient sulfide melts in equilibrium with primitive high-Mg olivine and Cr-spinel are scarce. Sulfide globules in olivine phenocrysts in picritic rocks of MORB-affinity at Kamchatsky Mys (Eastern Kamchatka, Russia) represent a well-documented example of natural immiscibility in primitive oceanic magmas. Our study examines the conditions of silicate-sulfide immiscibility in these magmas by reporting high precision data on the compositions of Cr-spinel and silicate melt inclusions, hosted in Mg-rich olivine (86.9–90 mol% Fo), which also contain globules of magmatic sulfide melt. Major and trace element contents of reconstructed parental silicate melts, redox conditions (ΔQFM = +0.1 ± 0.16 (1σ) log. units) and crystallization temperature (1200–1285 °C), as well as mantle potential temperatures (~1350 °C), correspond to typical MORB values. We show that nearly 50% of sulfur could be captured in daughter sulfide globules even in reheated melt inclusions, which could lead to a significant underestimation of sulfur content in reconstructed silicate melts. The saturation of these melts in sulfur appears to be unrelated to the effects of melt crystallization and crustal assimilation, so we discuss the reasons for the S variations in reconstructed melts and the influence of pressure and other parameters on the SCSS (Sulfur Content at Sulfide Saturation)

“Hydrotriphylites” Li1-xFe1+x(PO4)1-y(OH)4y as Cathode Materials for Li-ion Batteries

Lithium iron phosphate LiFePO4 triphylite is now one of the core positive electrode (cathode) materials enabling the Li-ion battery technology for stationary energy storage applications, which are important for broad implementation of the renewable energy sources. Despite the apparent simplicity of its crystal structure and chemical composition, LiFePO4 is prone to off-stoichiometry and demonstrates rich defect chemistry owing to variations in the cation content and iron oxidation state, and to the redistribution of the cations and vacancies over two crystallographically distinct octahedral sites. The importance of the defects stems from their impact on the electrochemical performance, particularly on limiting the capacity and rate capability through blocking the Li ion diffusion along the channels of the olivine-type LiFePO4 structure. Up to now the polyanionic (i.e. phosphate) sublattice has been considered idle on this playground. Here, we demonstrate that under hydrothermal conditions up to 16% of the phosphate groups can be replaced with hydroxyl groups yielding the Li1-xFe1+x(PO4)1-y(OH)4y solid solutions, which we term “hydrotriphylites”. This substitution has tremendous effect on the chemical composition and crystal structure of the lithium iron phosphate causing abundant population of the Li-ion diffusion channels with the iron cations and off-center Li displacements due to their tighter bonding to oxygens. These perturbations trigger the formation of an acentric structure and increase the activation barriers for the Li-ion diffusion. The “hydrotriphylite”-type substitution also affects the magnetic properties by progressively lowering the Néel temperature. The off-stoichiometry caused by this substitution critically depends on the overall concentration of the precursors and reducing agent in the hydrothermal solutions, placing it among the most important parameters to control the chemical composition and defect concentration of the LiFePO4-based cathodes

An Assessment of the diversity in scenario-based tsunami forecasts for the Indian Ocean

This work examines the extent to which tsunami forecasts from different numerical forecast systems might be expected to differ under real-time conditions. This is done through comparing tsunami amplitudes from a number of existing tsunami scenario databases for eight different hypothetical tsunami events within the Indian Ocean. Forecasts of maximum tsunami amplitude are examined at ten output points distributed throughout the Indian Ocean at a range of depths. The results show that there is considerable variability in the forecasts and on average, the standard deviation of the maximum amplitudes is approximately 62% of the mean value. It is also shown that a significant portion of this diversity can be attributed to the different lengths of the scenario time series. These results have implications for the interoperability of Regional Tsunami Service Providers in the Indian Ocean