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The Gurvunur apatite-magnetite deposit is located within the Ozerny ore cluster in Western Transbaikalia. A peculiarity of this object is the presence of rare-earth mineralization in the ores. The main REE concentrator minerals include monazite, allanite, apatite, and epidote. One of the main concentrators of REE is apatite, where the content of REE sum reaches 2.6 wt. %. The REE are mainly represented by light lanthanides, with La up to 1.8 wt. % and Ce up to 2.08 wt. % predominating. Monazite-(Ce) is formed in the process of apatite refining, leading to the monazite fine-grained dissemination and veinlets occurring. Epidote is found in nests and vein-like formations of skarn aggregates. The mineral mainly contains light lanthanides (La up to 5.11 wt. %, Ce up to 2.47 wt. %) and forms gradual transitions to allanite that, in its turn, is also found in the form of isolated segregations or as a part of aggregates of epidote-allanite composition. Light lanthanides with Ce up to 14.35 wt. % and La up to 9.16 wt. % predominate in the allanite composition. The study of the mineral composition and distribution of REE in ores and minerals allows us to conclude that rare-earth mineralization in the ores of the Gurvunur apatite-magnetite deposit was formed as a result of skarning of the carbonate-bearing volcanogenic-sedimentary rocks, and the source of rare-earth mineralization was granodiorites of the Vitimkan intrusive suite.

Calcium phosphate coatings containing brushite, calcite, and apatite were obtained by electrochemical deposition on titanium plates at room temperature, pH 5, constant current density 30 mA/cm2, from CaCO3/Ca(H2PO4)2 suspension electrolyte. A layer of amorphous apatite was deposited by the biomimetic method, by keeping the coatings in a concentrated modeling solution of Simulated Body Fluid. As a result of heat treatment at 800°C, apatite crystallized into hydroxyapatite, calcite decomposed to calcium oxide, and titanium was covered with a layer of titanium (IV) oxide. Preclinical studies on rats in vivo for 3 months showed increased osseointegration of plates with calcium phosphate coatings compared to uncoated titanium. Titanium implants with calcium phosphate coatings enriched with hydroxyapatite are promising for use in neurosurgery, dentistry, orthopedics due to the absence of inflammatory reactions from the body and increased osseointegration.

Calcium phosphate composite powders consisting of brushite and calcite were obtained in an aqueous medium from a CaCO3/Ca(H2PO4)2 suspension at Ca/P ratios of 1,33, 1,50, 1,67, pH 5–7, and maturation time of 21-50 days. Prolonged maturation (up to 68 days) of composite calcium phosphate powders led to a hydrolytic transition of brushite to octacalcium phosphate, the amount of which increased with increasing duration of the maturation stage. Drying calcium phosphate powders at 37°C for 24 h contributed to the partially transition of the metastable phase of octacalcium phosphate to apatite represented by amorphous calcium phosphate. The presence of vibrations of О–Н at 633 cm-1 as the shoulder on the IR spectra indicates the presence of apatite in calcium phosphate powders. The use of an electric current (20 mA/cm2, 3–20 min) for a local increase of the pH value made it possible to increase the amount of octacalcium phosphate in the composition of the composite powder, which has a characteristic rosette morphology of thin lamellar crystallites.

Relevance of the study is determined by the decisions taken to increase the production volume of certain commercial products from mineral raw materials. The scale, impact and consequences of the projects on developing the resource-saving technologies for beneficiation of mineral raw materials are socially significant, and the economic growth of mining production complies with the sustainable development goals. The aim of the study is to develop the flotation circuit and mode that improve the technological performance of beneficiation of apatite-nepheline ores of the Khibiny Massif in the Kola Peninsula. The scientific idea of ​​the work is to develop the flotation circuit, the movement of beneficiation products in which ensures a major increase in the content of the recovered component in the rougher flotation procedure with a simultaneous increase in dressability of the material. The above condition is met when mixing the feedstock with rough concentrate. Recovery of the valuable component from the resulting mixture is accomplished in a mode differing from the known ones in that the heat of steam condensation is used to increase water temperature in the interphase film between the particle and the bubble. For pulp aeration during flotation, a mixture of air and hot steam is used as the gas phase. A high recovery of the valuable component in ore flotation according to the developed circuit and mode is facilitated by increasing water temperature in wetting films due to the steam condensation heat. A high selectivity of flotation with a steam-air mixture can be explained using the concepts of a phonon component of disjoining pressure, the value and sign of which are associated with a difference in the dynamic structure of liquid in the wetting film and bulk liquid.

In this paper we present the results on apatite fission-track dating, which was first performed at the Schmidt Institute of Physics of the Earth, Russian Academy of Sciences, using the laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS, Dobretsov Geological Institute, Siberian Branch of the Russian Academy of Sciences) for two intrusions of the Siberian Permian-Triassic large igneous province: Magan alkaline-ultramafic pluton (two samples) and Kontay intrusion (one sample). The obtained AFT ages are 217.6±18.6 and 238.8±35.8 Ma (95% confidence) for the Magan intrusion and 150.0±23.0 Ma for the Kontay intrusion and mark the time since they have been cooled below 120 °C. The distributions of track lengths in apatite grains from the studied samples indicate their rapid cooling to near-surface temperatures. We provide a detailed description of the method used, and also demonstrate that the results of fissiontrack analysis performed on the "sample-to-sample" principle by the classical external detector method (EDM) and the LA-ICP-MS method in the modification of the zeta calibration coincide within the age uncertainty.

The paper presents and analyzes new and previously published data on track dating of detrital apatite grains isolated from different-age structural complexes of Eastern Kamchatka. The investigations were carried out in areas with different geodynamic settings. These were the Kronotskii Peninsula which is situated in the zone of convergence of the Kamchatka margin with the relatively warm and light oceanic crust of the Pacific plate with the Obruchev Rise, the Kamchatkii Mys Peninsula which is situated in the area of collision of the Commander block of the Aleutian volcanic arc and the continental margin of Kamchatka, and the the Kumroch Ridge complexes of which belong to the Ozernovsky-Valaginskii and Vetlovskii terranes. The analysis allows distinguishing several exumation events: 29.9–34.9, 19.3–24.1, 10.2–15.4, 6.2–8.6, and 3.3–5.1 Ma. The highlighted age intervals correlate well with the main tectonic events and allow us to conclude that accretionary and collisional processes in Eastern Kamchatka continued from the Oligocene to the Late Miocene-Pliocene.

Calcium phosphate coatings on titanium plates were obtained by electrochemical deposition at room temperature in a two-electrode cell at a constant current density of 30 mA/sm^2 and a deposition time of 10 min, and brushite coatings from Ca(NO3)2 / NH4H2PO4 system at pH=4, and composite (brushite/calcite/apatite) coatings from the CаCO3 / Ca(H2PO4)2 system at pH=5. The apatite-forming ability (bioactivity) was determined by soaking both types of calcium phosphate coatings in a model SBF solution during month. The newly formed amorphized apatite layer after heat treatment at 800°С crystallized into β–tricalcium phosphate/hydroxyapatite on brushite coatings and hydroxyapatite on composite coatings due to the presence of calcite, whose carbonate ions initiate formation of hydroxyapatite, as well as apatite nanoparticles in the initial coating. The obtained calcium phosphate coatings are promising as biocoatings capable to increase osseointegration of metal implants.

Unlike conventional X-ray fluorescence spectrometry, the total-reflection X-ray fluorescence spectrometry is not a widespread and routine method for analyzing solid samples with mineral matrix, but it has a great potential for geochemical, geological, and archaeological studies. Rapid multi-elemental analysis of very small sample amounts can be performed by the internal standard method which does not require the matrix-matched reference materials. This is an undoubted advantage of the TXRF method over the conventional X-ray fluorescence method, especially if there is a limited available sample amount and a lack of well-characterized reference materials. This paper presents our experience with the application of TXRF spectrometry in the elemental analysis of apatite, ceramics, sediments, ores, and nodules. Special attention has been paid to the sample preparation procedure because it is one of the main sources of errors in the analysis. Preparing thin homogeneous specimen from the solid sample with a complex mineral matrix is not easy. Sample preparation strategy should be chosen considering the features of an analytical object, the content of the elements to be determined, and the accuracy required for a reliable interpretation. Consideration is being given to the examples of the preparation of a suspension for rapid analysis of ores and sediments, and to the original techniques of chemical decomposition for apatite and ceramics.

Research subject. The geological structure and rock composition of the Nizhne-Sinyachikhinsky plagiogranite massif, which is part of the Alapaevsk-Sukholozhsky zone, is promising for the Cu(Au,Mo)-porphyric mineralization type, were studied. The aim was to determine the formation features of these rocks and compare them with the productive granitoids of Ural porphyry deposits of similar age. Materials and methods. The mineral composition of the rocks was determined using a JEOL JSM 6790LV scanning electron microscope with an INCA Energy 450 X-Max 80 EDS spectrometer and a CAMECA SX-100 electron microprobe analyser. The rock composition was obtained by X-ray fluorescence spectrometry on a SRM-35 and XRF-1800 spectrometers with the titrimetric determination of FeO. The concentrations of rare and rare-earth elements were determined on an ELAN 9000 inductively coupled plasma mass spectrometer at the Geoanalitik Center for Collective Use of the Ural Branch of the Russian Academy of Sciences. Results. For the first time, an early tonalite-plagiogranite series was identified in the structure of the massif. This series is represented by tonalites of the hypabyssal appearance, broken through by the dikes of plagiogranite-porphyry. It was shown that the separation of plagiogranite-porphyry melts from magmas of the mafic composition occurred at the base of the island-arc construction, and their crystallisation was carried out in an intermediate chamber at a pressure of 1.8–2.3 kbar. In contrast, the plagiogranites of the main phase of the massif were separated from the parent melt in an intermediate chamber located at the level of the upper crust, and their crystallisation occurred at a pressure of 1.5–2.0 kbar. Conclusions. A comparison of the main phase plagiogranites and the isolated early-series plagiogranite-porphyry indicates their similar composition, as well as their similarity in age with the granitoids of the Southern Urals, productive in terms of the porphyry mineralisation type. The concentrations of F, Cl and S in the apatites and amphiboles of the rocks under study is an argument in favour of their belonging to andesitoid formations that are productive in terms of the Cu (Au)-porphyry mineralisation type. The absence of the sulphide mineralisation of this type can be explained by a more significant depth of rock formation and their erosion section.

We present the first results of fission-track dating of apatite monofractions from two rock samples taken from the Southern carbonatite massif of the world’s largest alkaline ultrabasic Guli pluton (~250 Ma), located within the Maymecha-Kotuy region of the Siberain Traps. Based on the apatite fission-track data and computer modeling, we propose two alternative model of the Guli pluton's tectonothermal history. The models suggest (1) rapid post-magmatic cooling of the studied rocks in hypabyssal conditions at depth about 1.5 km, or (2) their burial under a 2-3 km thick volcano-sedimentary cover and reheating above 110°C, followed by uplift and exhumation ca. 218 Ma.

Research subject. In this research, we carried out a series of mineralogical, petrological and geochemical studies to investigate ore zones present in the Kusa ilmenite-magnetite deposit located within the boundaries of a similarly-named laminated gabbro massif. Here, ore bodies occur at various intrusion horizons among laminated apogabbroid amphibolites of a different basicity. In the intrusion section, the composition of halogens (Cl, F) in co-existing fluid-bearing minerals (apatite, am-phibole, staurolite) was analyzed.Materials and methods. In order to investigate the composition of mineral samples, their polished sections were examined using an electronic-microprobe analyzer JXA-5. The content of petrogenic and microelement components (CRF and ICP-MS methods) in the rock and ore samples was determined using the facilities of the Laboratory of Physical and Chemical methods, UBRAS Institute of Geology and Geochemisty.Results. It is established that the content of Cl and F in the apatite, amphibole and staurolite under study, as well as the chemical composition of ilmenite, magnetite, and hombombite components, depend on the position of the ore bodies in the intrusion. Thus, the apatites from the near-ore rocks in the central part of the deposit showed the highest Cl concentrations of up to 4.1%, while those located in the near-contact parts of the intrusion demonstrated a much lower Cl content of 2%. The central ore-bearing zone having the maximal Cl content features the largest formation of ore bodies, which (including magnetite) contain higher amounts of Fe2O3, Cr and V The presence of fluid-bearing minerals (apatite, scapolite, etc.) with high chlorine concentrations of up to 2.44% is this deposit is established.Conclusions. The identified peculiarities of halogen distribution in the apatite of bipyroxene gabbro, as well as the inheritance of relations TiO2/FeO in bipyroxene gabbro, in massive magnetite-ilmenite ores and in near-ore rocks point to a single magmatic source of these formations.

Granitoid massifs of the northern part of the West Tagil structural-formational zone previously had not a reliable geochronological substantiation of age however, some of them are connected with skarn-magnetite deposits. One of such ones is the Yuzhno-Pomursky massif, to which the dedicated copper-iron ore deposit - Tretii Severnyi Rudnik. Authors performed the geological research of the massif, studied the composition of intrusive rocks, and accessory minerals of granitoids. There were determined the contents of petrogenic oxides and petrological-informative elements by ICP-MS; the age of magmatic rocks was determined by U-Pb LA-ICP-MS method in zircons and titanites. Using the microprobe SX-100 it was performed the analyses of the compositions of apatites, amphiboles, magnetites and ilmenites, feldspars and zircons. The studies showed that the Yuzhno-Pomursky massif consists of igneous rocks belonging to the two Silurian complexes - diorite-granodiorite Petropavlovsky and diorite-granite Severorudnichnyi. The characteristic of petrographic features and chemical composition of the intrusive formations is given, the data of their age is provided. The study of the evolution of the fluid regime that accompanied the crystallization of the melt, showed that in the early stages of the fluid has been enriched with chlorine, and the later - fluorine; so accordingly changed the metallogenic orientation of fluid-hydrothermal processes: from skarn-magnetite to gold and rare metal systems. In exocontact aureole of the massif are known ore manifestations and deposits of skarn copper-magnetite ores, mineralized gold-sulfide zones, some points with high content of tungsten. The conclusion about the possibility of the presence at the exocontact of Yuzhno-Pomursky massif not only copper-skarn-magnetite deposits similar to the known Tretii Severnyi, but the gold mineralized zones too is inferred.

We have studied mineral and chemical composition of lamproites from Kalymbaevsky Complex the Middle Trias. These lamproites were developed in Magnitogorsk and Eastern-Urals megazones of the Southern Urals. We have established the presence of olivine, phlogopite, diopside phenocrysts. We have registered the presence of globular structures, consisting of sanidine and interstitial glass. We have also shown the presence in the base of rocks microlites of aluminous diopside-augite and alkaline pyroxenes of aegirin-augite series, which previously were taken for alkaline and sub-alkaline amphiboles. We have established high sulfur concentration in the apatite which, without magmatic sulfides in the rocks, witnesses for oxidation of lamproite magmas. For the first time precise geochemical data for microelemental and isotopic Sr, Nd composition of rocks are given. It was found that the South Urals rocks have a intermediate composition between lamproites and potassium alkaline basalts. Their source was the enriched mantle with the value εNdi = +0.7-+3.9. We have shown uncertainty of geochronological data, according to which lamproite magmatism could be initiated 197-240 or 300-310 Ma.

Case study of the differentiated subvolcanic porphyritic intrusion underlying Magnitogorsk skarn-magnetite deposit revealed regular relations between petrochemistry features of the rocks and composition of halogens (Cl and F) in the accessory apatite. During the process of intrusion formation in terms of general trend of differentiation from the pyroxene-porphyrites its base to atachites (trachyandesites, phonotephrites) its upper part, several autonomous fluid-magmatic systems (FMS), which differ in major and trace elements distribution as well as halogen composition in apatites, are formed. In the uppermost part of the atachite section, mostly saturated by alkalis and volatile components, through a further fluid-magmatic stratification were formed two atachite strata: sodium, enriched in Na, Ca, Sr, and with a higher Cl content in apatite and potassium “ore-bearing” located at a higher hypsometric level and enriched in K, Rb, Fe, V, Ti, P, with a higher content of F in apatite. Formation of subvolcanic intrusion was accompanied by repeated occurrences of explosive phenomena. These data indicate the features of magmatism in Magnitogorsk megazone in D3-C1, at the change the island-arc stage by accretionary-collision (island arc-continent) one

Copyright of Metallophysics & Advanced Technologies / Metallofizika i Novejsie Tehnologii is the property of G.V. Kurdyumov Institute for Metal Physics, N.A.S.U 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 Journal of Nano- & Electronic Physics is the property of Sumy State University 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.)

In most cases, it is impossible to study and describe the structure and properties of samples using a single method. That is why in our studies two research methods were used and compared – X-Ray diffraction (XRD) and scanning electron microscopy (SEM) with electron diffraction (ED). Each method has certain advantages. In the case of the XRD – usability and more complex evaluation of the sample structural parameters. The advantages of the second one are the direct estimation of nanoparticle sizes and insignificant amount of the sample needed for the analysis. The main direction of our work is the studies and the analysis of the structural and substructural parameters of composite biomaterials based on an apatite and presented in the shape of fine-dispersed powders, pastes and gels. Certain dependences of the sample structure and substructure on the initial agents and synthesis conditions were determined. [ABSTRACT FROM AUTHOR]

The causes of Ca / P ratio deviation in biological apatites from stoichiometric one were discussed. By the simple model evaluation Ca / P ratio was shown to deviate from stoichiometric one because of small sizes of crystals, and peculiarities in chemical composition of their facets. Also size effect is noted to be unsufficient for explanation of wide variations of Ca / P ratio in biological apatites. It proves the significant contribution of lattice isovalent and heterovalent substitution into variability of Ca / P ratio. The problem of revealing the predominant causes of Ca / P deviation from stoichiometric one and estimation of their relative contribution is related to determination of the functional role of the structural imperfections in biological apatites of different origin. [ABSTRACT FROM AUTHOR]

The paper represents the results of the study on the structure and phase composition of bone apatite and fragments of calcified aorta of the same experimental animal with model osteoporosis. Examination by the X-ray and electron diffraction, electron microscopy and infrared spectroscopy reveals that pathological calcification of rabbit aorta with model osteoporosis in crystal-chemical terms is the imperfect calcium apatite Ca10(PO4)6(OH)2. Temperature growth of ectopic apatite crystals during annealing at 900°C is similar to bioapatite of bone. [ABSTRACT FROM AUTHOR]

Biological apatite is the main mineral phase of bone tissue and of numerous calcified pathological deposits. Mg, Na, and K are usually absent in the structure of pure apatite and are present in such biominerals in significant concentrations. In present work the approach was tested for the determination of predominant location of these elements through separation of apatite and non-apatitic components of bone tissue mineral. The preparation procedures include the annealing and subsequent ultrasonication of powdered material in aqueous medium; concentrations of elements were determined by atomic spectrum analysis. The results suggest that Mg and Na in bone apatite can be both in the structurally bounded (substituting calcium in lattice) and in the labile state (being localized on the crystal surface), while K is not able to join the apatite structure in significant amount or be chemically bounded to it. [ABSTRACT FROM AUTHOR]