scholarly journals STABLE TETRAEDR OF LiF-LiCl-Li2SO4-NaCl

2017 ◽  
Vol 60 (5) ◽  
pp. 57
Author(s):  
Sabina M. Omarova ◽  
Nadinbeg N. Verdiev ◽  
Alibek B. Alkhasov ◽  
Ukhumaali G. Magomedbekov ◽  
Vasiliy I. Dvoryanchikov ◽  
...  
Keyword(s):  
Phase Transitions ◽  
Cross Section ◽  
Lithium Chloride ◽  
Eutectic Composition ◽  
Renewable Energy Sources ◽  
Eutectic Point ◽  
Physicochemical Analysis ◽  
Thermal Method ◽  
Thermal Batteries ◽  
Mutual System

With differential-thermal method of physicochemical analysis; using the General rules of the projection-thermographic method; the surface was studied of the liquidus stable tetrahedron LiF–LiCl–Li2SO4–NaCl of quaternary mutual system Li;Na//F;Cl;SO4. As a result of researches it was established that the system implements the quadruple eutectic point melting at 410 °C. Increased interest in involvement in the global energy balance of renewable energy sources (RES); encourages research to identify the eutectic salt mixtures capable of accumulating heat energy. Research undertaken with the aim of developing nizkodubova; eutectic composition; which can be used in thermal batteries as coolant of accumulators. As research object the stable tetrahedron LiF – LiCl – Li2SO4 – NaCl four-component mutual system was selected. This system was formed from the halides and sulfates of lithium and sodium. The choice of the research object is due to the fact that its composition includes lithium salt with large values of enthalpies of phase transitions. For planning of experimental researches; analysis of systems with lower dimensionality within free of the system under study was carried out. The results revealed that the most informative section for an experimental study in the system LiF –LiCl – Li2SO4 – NaCl is a cross-section of selected volume of the crystallization of lithium chloride. Based on these considerations; in a volume of the crystallization of lithium chloride the two-dimensional polythermal cross section ABC was choosen. The phase diagram of the section MN located at the cross-section ABC was DTA experimentally investigated. It allows determining the ratio of lithium fluoride and sodium chloride in the quaternary eutectic. Further; consistent analysis of DTA-dimensional polythermal sections- В – а –Ē□; (LiCl)2 – Ē□ – E□ - the ratio of sulfate and lithium chloride in the quaternary eutectic was determined. The revealed by such a way the eutectic contains (LiF)2 – 10.4%; (LiCl)2 – 38%; Li2SO4 -23.6%; (NaCl)2 – 28%. The crystallization temperature was 410 °C. Taking into account that all components of eutectic have relatively large values of enthalpies of phase transitions; it can be assumed that the identified eutectic composition will have sufficient value of ΔНпл. Therefore; the composition can be recommended as a coolant for devices of thermal energy storage. For citation:Omarova S.M.; Verdiev N.N.; Alkhasov A.B.; Magomedbekov U.G.; Dvoryanchikov V.I.; Nekrasov D.A. Stable tetraedr of LiF-LiCl-Li2SO4-NaCl. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2017. V. 60. N 5. P. 57-62

scholarly journals LiF – NaF – KCl SYSTEM

2018 ◽  
Vol 59 (5) ◽  
pp. 37 ◽  
Author(s):  
Nadinbeg N. Verdiev ◽  
Patimat A. Arbukhanova ◽  
Alibek B. Alkhasov ◽  
Ukhmaali G. Magomedbekov ◽  
Zaira N. Verdieva ◽  
...  
Keyword(s):  
Cross Section ◽  
Eutectic Composition ◽  
Solid Phase ◽  
Ternary Systems ◽  
X Ray ◽  
Mutual System ◽  
Solid Phase Reactions

The stable cross section of LiF - NaF - KCl quadruple mutual system Li, Na, K // F, Cl was studied with the differential thermal (DTA) and X-ray fluorescence (XRF) methods. It was established that in a system the eutectic composition crystallizing at 591 ° C is realized.  Temperatures of starting solid-phase reactions were revealed in the ternary systems mutual Na, K // F, Cl and Li, Na // F, Cl, (715 and 650 °C, respectively) corresponding to the conversion of reactants of metastable diagonals into products of stable diagonals.

scholarly journals RESEARCH OF STABLE TETRAHEDRON OF LiF-LiVO3-NaBr-NaVO3 QUATERNARY MUTUAL SYSTEM OF Li,Na||F,Br,VO3

2018 ◽  
Vol 59 (4) ◽  
pp. 47
Author(s):  
Ivan K. Garkushin ◽  
Inna N Samsonova ◽  
Tatiana V. Gubanova
Keyword(s):  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Phase Equilibria ◽  
Quaternary System ◽  
Eutectic Point ◽  
Analysis Method ◽  
Thermal Analysis Method ◽  
Mutual System

Phase equilibria of quaternary system LiF-LiVO3-NaBr-NaVO3 were studied with differential thermal analysis method. The temperature and composition of eutectic point was determined: Е 458 ºС: 11.2% LiF, 57.2% LiVO3, 16% NaBr, 15.6% LiVO3.

Glass-forming ability of Pr–(Cu,Ni)–Al alloys in eutectic system

2003 ◽  
Vol 18 (3) ◽  
pp. 664-671 ◽  
Author(s):  
Y. Zhang ◽  
H. Tan ◽  
H. Z. Kong ◽  
B. Yao ◽  
Y. Li
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Eutectic Composition ◽  
Solidus Temperature ◽  
Eutectic Point ◽  
Glass Forming Ability ◽  
Al Alloys ◽  
Eutectic System ◽  
Glass Forming

A eutectic point in Pr-rich Pr-(Cu,Ni)-Al alloys was experimentally determined by measuring the solidus temperature (Tm) and liquidus temperature (T1). It was found that Pr68(Cu0.5Ni0.5)25Al7 (at.%) is at the eutectic composition in the pseudoternary Pr–(Cu0.5Ni0.5)–Al alloys. The alloy Pr68(Cu0.5Ni0.5)25Al7 exhibits better glass-forming ability (GFA) than the ternary eutectic alloy Pr68Cu25Al7. However, the best GFA was obtained at an off-eutectic composition (Pr54[Cu0.5Ni0.5]30Al16) in the Pr–(Cu0.5Ni0.5)–Al alloys, which can be formed in fully amorphous rods with diameter of 1.5 mm by copper mold casting. Moreover, the glass-transition temperature Tg increases quickly (from 367 to 522 K) with the increasing of the Al content (from 3 to 27 at.%). The deviation of the best GFA composition from the eutectic point [Pr68(Cu0.5Ni0.5)25Al7] was explained in terms of the asymmetric coupled eutectic zone, the competition between growth of crystalline phase and formation of amorphous, and the higher glass-transition temperature Tg on the hypereutectic side.

scholarly journals RESEARCH IN THE FIELD OF GLASS FORMATION IN THE ASS-ERS SYSTEM

2021 ◽  
Vol 7 (8(62)) ◽  
pp. 35-38
Author(s):  
DUNIA TALEH HASANOVA
Keyword(s):  
Glass Transition ◽  
Physicochemical Properties ◽  
Cooling Rate ◽  
Transition Region ◽  
Glass Formation ◽  
Eutectic Composition ◽  
Physicochemical Analysis ◽  
Glass Transition Region ◽  
X Ray

In order to determine the region of glass formation between the AsS and ErS compounds, we studied the methods of physicochemical analysis: differential thermal (DTA), X-ray phase (XRD), microstructural (MCA), as well as by measuring microhardness and density. The eutectic composition between the AsS and ErS compounds is 10 mol. % ErS and temperature 280oC. At a cooling rate v = 102 K / min, the glass transition region based on AsS reaches 10 mol. % ErS. Some physicochemical properties of alloys from the region of glass formation have been investigated. The area of homogeneity based on AsS reaches up to 1.5 mol. % ErS.

scholarly journals Production of Solid Fuel by Torrefaction Using Coconut Leaves As Renewable Biomass

2016 ◽  
Vol 5 (3) ◽  
pp. 187-197 ◽  
Author(s):  
Lola Domnina Bote Pestaño ◽  
Wilfredo I. Jose
Keyword(s):  
Renewable Energy ◽  
Crude Oil ◽  
Solid Fuel ◽  
Energy Demand ◽  
Renewable Energy Sources ◽  
Combustion Characteristics ◽  
Thermal Method ◽  
Process Conditions ◽  
Renewable Biomass ◽  
Torrefied Biomass

The reserves of non-renewable energy sources such as coal, crude oil and natural gas are not limitless, they gradually get exhausted and their price continually increases. In the last four decades, researchers have been focusing on alternate fuel resources to meet the ever increasing energy demand and to avoid dependence on crude oil. Amongst different sources of renewable energy, biomass residues hold special promise due to their inherent capability to store solar energy and amenability to subsequent conversion to convenient solid, liquid and gaseous fuels. At present, among the coconut farm wastes such as husks, shell, coir dust and coconut leaves, the latter is considered the most grossly under-utilized by in situ burning in the coconut farm as means of disposal. In order to utilize dried coconut leaves and to improve its biomass properties, this research attempts to produce solid fuel by torrefaction using dried coconut leaves for use as alternative source of energy. Torrefaction is a thermal method for the conversion of biomass operating in the low temperature range of 200oC-300oC under atmospheric conditions in absence of oxygen. Dried coconut leaves were torrefied at different feedstock conditions. The key torrefaction products were collected and analyzed. Physical and combustion characteristics of both torrefied and untorrefied biomass were investigated. Torrefaction of dried coconut leaves significantly improved the heating value compared to that of the untreated biomass.  Proximate compositions of the torrefied biomass also improved and were comparable to coal. The distribution of the products of torrefaction depends highly on the process conditions such as torrefaction temperature and residence time. Physical and combustion characteristics of torrefied biomass were superior making it more suitable for fuel applications.Article History: Received June 24th 2016; Received in revised form August 16th 2016; Accepted 27th 2016; Available onlineHow to Cite This Article: Pestaño, L.D.B. and Jose, W.I. (2016) Production of Solid Fuel by Torrefaction Using Coconut Leaves As Renewable Biomass. Int. Journal of Renewable Energy Development, 5(3), 187-197.http://dx.doi.org/10.14710/ijred.5.3.187-197

PHASE EQUILIBRIUM IN SYSTEM (LiF)2 – Li2CO3 – Li2SO4

2018 ◽  
Vol 62 (1) ◽  
pp. 20-25
Author(s):  
Zaira N. Verdieva ◽  
Alibek B. Alkhasov ◽  
Nadinbeg N. Verdiev ◽  
Gadzhi A. Rabadanov ◽  
Patimat A. Arbukhanova ◽  
...  
Keyword(s):  
Lithium Fluoride ◽  
Theoretical Calculations ◽  
Liquidus Surface ◽  
Experimental Studies ◽  
Polythermal Section ◽  
Lithium Carbonate ◽  
Physicochemical Analysis ◽  
Crystallization Field ◽  
Thermal Method ◽  
Carbonate Decomposition

The liquidus surface of the system (LiF)2-Li2SO4-Li2CO3 was studied by the calculated and differential thermal method of physicochemical analysis. An analysis of the systems of lower dimensionality of the facets of the investigated object showed that the most informative, for the experimental study, is the sections located in the crystallization field of lithium fluoride. A study of the DTA of a number of compositions located at the initially chosen polythermal section in the lithium fluoride crystallization field, the ratios of lithium sulfate and carbonate in the eutectic are determined. The composition of the triple eutectic was revealed by studying a non-invariant cut from the vertex of the triangle (LiF), through a point showing a constant ratio of sulfate and lithium carbonate in the eutectic, to the fusion of the thermal effects of the primary and tertiary crystallizations. The complexity of the study was that lithium carbonate is the most fusible component in the system, and according to the literature, after the melting of lithium carbonate, decomposition begins, which greatly complicates the interpretation of research results. In order to avoid the decomposition of lithium carbonate, each experimentally studied composition was heated to the melting temperature of lithium carbonate and kept in isothermal mode, at a temperature below its melting. Thus, the theoretical melting calculations and the region of location of the non-invariant composition have been extrapolated, allowing to limit the number of experimentally studied samples, and the subsequent experimental investigation of DTA of two polythermal sections revealed a eutectic composition crystallizing at 476 ° C and containing LiF-20 eq.%, Li2SO4 - 51 eq.%, Li2CO3 – 29 eq.%. The discrepancies between theoretical calculations and experimental studies are 8.3% in temperature and 5.05% in composition.  

scholarly journals Clay Composites for Thermal Energy Storage: A Review

Molecules ◽  
2020 ◽  
Vol 25 (7) ◽  
pp. 1504
Author(s):  
Denis V. Voronin ◽  
Evgenii Ivanov ◽  
Pavel Gushchin ◽  
Rawil Fakhrullin ◽  
Vladimir Vinokurov
Keyword(s):  
Phase Transitions ◽  
Thermal Energy ◽  
Phase Change Materials ◽  
Renewable Energy Sources ◽  
Construction Materials ◽  
Cost Effective ◽  
Modern Material ◽  
Practical Applications ◽  
Functional Additives ◽  
Flame Retardant Properties

The development of novel materials and approaches for effective energy consumption and the employment of renewable energy sources is one of the current trends in modern material science. With this respect, the number of researches is focused on the effective harvesting and storage of solar energy for various applications. Phase change materials (PCMs) are known to be able to store thermal energy of the sunlight due to adsorption and release of latent heat through reversible phase transitions. Therefore, PCMs are promising as functional additives to construction materials and paints for advanced thermoregulation in building and industry. However, bare PCMs have limited practical applications. Organic PCMs like paraffins suffer from material leakage when undergoing in a liquid state while inorganic ones like salt hydrates lack long-term stability after multiple phase transitions. To avoid this, the loading of PCMs in porous matrices are intensively studied along with the thermal properties of the resulted composites. The loading of PCMs in microcontainers of natural porous or layered clay materials appears as a simple and cost-effective method of encapsulation significantly improving the shape and cyclic stability of PCMs. Additionally, the inclusion of functional clay containers into construction materials allows for improving their mechanical and flame-retardant properties. This article summarizes the recent progress in the preparation of composites based on PCM-loaded clay microcontainers along with their future perspectives as functional additives in thermo-regulating materials.

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