Inorganic Melts Research Articles

Interpretable machine learning for understanding compositional and testing condition effects on refractive index, density, dielectric constant, and loss tangent of inorganic melts and glasses

Artificial intelligence (AI) and machine learning (ML) have enabled property-targeted design of glasses. Several machine learning models and open-source tools in the literature allow researchers to predict the optical, physical, mechanical, and electrical properties of glasses as a function of their chemical compositions. However, these properties also depend on testing conditions. In this paper, we train machine learning models by considering composition and wavelength, temperature, and frequency to predict the refractive index, density, and the two electrical properties, i.e., dielectric constant and loss tangent of glasses, respectively. The predictions of trained models are explained using SHAP analysis, revealing that testing conditions, such as wavelength and temperature, interact majorly with network formers while predicting refractive index and density. In the case of electrical properties, network formers and frequency have the highest interactions, followed by network modifiers and intermediates, and hence govern predictions of dielectric constant and loss tangent. Overall, AI/ML models that can predict the properties of glasses as a function of their composition and testing conditions, coupled with SHAP plots, provide a practical tool to develop a range of glasses for application under varying conditions.

Revealing of rich living radicals in oxide melts via weak magnetic effect on alumina dissolution reaction

Oxide melts are basic media in materials preparation, high-temperature processing and hot corrosion. The melt structure is essential to understand oxide melt properties and plays a fundamental role in ceramic preparation and tailoring. In this work, the rich living radicals in oxide melts were discovered and verified by the variation in the dissolution reaction rate of alumina ceramic in oxide melts with the magnetic flux density, as well as the ESR test results. The radical-rich coexistence structure and forming path of radicals were proposed beyond the traditional inorganic melt structure theory; the weak magnetic effect and associated controlling threshold on free radical reaction in high-temperature inorganic chemical process was revealed. It provides new thoughts on smelting and purification of metals, preparation of ceramic materials, corrosion resistance of refractories and high temperature inorganic reaction-related research.

Facile modified synthesis and intermediate temperature electrical properties of Sn0.95Al0.05P2O7/KSn2(PO4)3 composite electrolyte

In this study, Sn0.95Al0.05P2O7 and a novel dense Sn0.95Al0.05P2O7/KSn2(PO4)3 composite electrolytes were synthesized. The structural characterization of X–ray diffraction (XRD) and microstructual properties of scanning electron microscopy (SEM) were carried out. The XRD results indicated that an in-situ reaction between Sn0.95Al0.05P2O7 and inorganic melt salt take place to form the Sn0.95Al0.05P2O7/KSn2(PO4)3 composite. The intermediate temperature electrical properties were determined by using impedance spectroscopy, oxygen concentration cell and hydrogen concentration discharge cell. Finally, the H2/O2 fuel cell using the Sn0.95Al0.05P2O7/KSn2(PO4)3 as electrolyte membrane was constructed and the obtained maximum power output densities were 67.7mWcm−2 and 142.1mWcm−2 at 650°C and 700°C, respectively.

A study on fragmentation behavior, inorganic melt phase formation, and carbon loss during high temperature gasification of mineral matter rich fraction of Pittsburgh No. 8 coal

Computational models are being developed to determine the fate of organic and inorganic matter during gasification to improve operational reliability and carbon conversion in entrained flow gasifiers. Current models being developed to simulate entrained flow gasifiers assume homogeneity of the coal phase. However, coal is not homogeneous, and various size and density fractions behave differently during gasification. Therefore, a more accurate model can be developed by determining the behavior of various size and density fractions of coal. From that perspective, two particle size distributions (75–106µm and 212–425µm) of the mineral matter rich fraction of Pittsburgh No. 8 coal obtained using the float and sink method were gasified in a laboratory-scale entrained flow reactor at 1773K. Char-ash particles from the two size fractions were characterized using Scanning Electron Microscope-Energy Dispersive X-ray Spectroscopy (SEM-EDS), X-ray Diffraction (XRD), Mossbauer spectroscopy, thermogravimetric analysis, and a micro-sifter for particle size distribution (PSD). The char-ash sample derived from the coarser-sized fraction (212–425µm) showed limited fragmentation (∼8%), while the finer-sized fraction showed no fragmentation. On the other hand, agglomerates were seen for both the particle size fractions with the finer-sized fraction having more melt phase and agglomerates than the coarser-sized fraction. The melt phase composition in the agglomerates is linked to the presence Fe2+-glass and fayalite for both the particle size fractions. The data also confirm that the mineral matter rich particles form melt phase and initiate slagging in the gasifier even at a lower conversion level (<30%). The melt phase thus formed covers the carbonaceous matter in the particle and contributes substantially to the unburnt carbon in the slag.

Discovery-Synthesis, Design, and Prediction of Chalcogenide Phases.

The discovery of new materials and their efficient syntheses is a fundamental goal of chemistry. A related objective is to identify foundational and rational approaches to enhance the art of synthesis by combining the exquisite predictability of organic synthesis with the high yields of solid-state chemistry. In contrast to so-called solid-state methods, inorganic syntheses in liquid fluxes permit bond formation, framework assembly, and crystallization at lower temperatures because of facile diffusion and chemical reactions with and within the flux itself. The fluxes are bona fide solvents similar to conventional organic or aqueous solvents. Such reactions can produce a wide range of materials, often metastable, from oxides to intermetallics, but typically the formation mechanisms are poorly understood. This article discusses how one can design, perform, observe, understand, and engineer the formation of compounds from inorganic melts. The focus is also design concepts such as "dimensional reduction", "phase homologies", and "panoramic synthesis", and their broad applicability. When well-defined building blocks are present and stable in the reaction, prospects for increased structural diversity and product control increase substantially. Common structural motifs within these materials systems may be related to structural precursors in the melt that may be controlled by tuning reaction conditions and composition. Stabilization of a particular building block is often accomplished with tuning of the flux composition, which controls the Lewis basicity and redox potential. In such tunable and dynamic fluxes, the synthesis can be directed toward new materials. Using complementary techniques of in situ X-ray diffraction, we can create time-dependent maps of reaction space and probe the mobile species present in melts. Certain thoughts toward the ultimate goal of targeted materials synthesis by controlling inorganic melt chemistry are discussed.

Stable colloids in molten inorganic salts.

A colloidal solution is a homogeneous dispersion of particles or droplets of one phase (solute) in a second, typically liquid, phase (solvent). Colloids are ubiquitous in biological, chemical and technological processes, homogenizing highly dissimilar constituents. To stabilize a colloidal system against coalescence and aggregation, the surface of each solute particle is engineered to impose repulsive forces strong enough to overpower van der Waals attraction and keep the particles separated from each other. Electrostatic stabilization of charged solutes works well in solvents with high dielectric constants, such as water (dielectric constant of 80). In contrast, colloidal stabilization in solvents with low polarity, such as hexane (dielectric constant of about 2), can be achieved by decorating the surface of each particle of the solute with molecules (surfactants) containing flexible, brush-like chains. Here we report a class of colloidal systems in which solute particles (including metals, semiconductors and magnetic materials) form stable colloids in various molten inorganic salts. The stability of such colloids cannot be explained by traditional electrostatic and steric mechanisms. Screening of many solute-solvent combinations shows that colloidal stability can be traced to the strength of chemical bonding at the solute-solvent interface. Theoretical analysis and molecular dynamics modelling suggest that a layer of surface-bound solvent ions produces long-ranged charge-density oscillations in the molten salt around solute particles, preventing their aggregation. Colloids composed of inorganic particles in inorganic melts offer opportunities for introducing colloidal techniques to solid-state science and engineering applications.

The origin of the conductivity maximum in molten salts. II. SnCl2 and HgBr2.

The phenomenon of electrical conductivity maxima of molten salts versus temperature during orthobaric (closed-vessel) conditions is further examined via ab initio simulations. Previously, in a study of molten BiCl3, a new theory was offered in which the conductivity falloff at high temperatures is due not to traditional ion association, but to a rise in the activation energy for atomic ions hopping from counterion to counterion. Here this theory is further tested on two more inorganic melts which exhibit conductivity maxima: another high-conducting melt (SnCl2, σmax = 2.81 Ω(-1) cm(-1)) and a low-conducting one (HgBr2, σmax = 4.06 × 10(-4) Ω(-1) cm(-1)). First, ab initio molecular dynamics simulations were performed and again appear successful in reproducing the maxima for both these liquids. Second, analysis of the simulated liquid structure (radial distributions, species concentrations) was performed. In the HgBr2 case, a very molecular liquid like water, a clear Grotthuss chain of bromide transfers was observed in simulation when seeding the system with a HgBr(+) cation and HgBr3 (-) anion. The first conclusion is that the hopping mechanism offered for molten BiCl3 is simply the Grotthuss mechanism for conduction, applicable not just to H(+) ions, but also to halide ions in post-transition-metal halide melts. Second, it is conjectured that the conductivity maximum is due to rising activation energy in network-covalent (halide-bridging) melts (BiCl3, SnCl2, PbCl2), but possibly a falling Arrhenius prefactor (collision frequency) for molecular melts (HgBr2).

Sol\u2013gel carbons from ionothermal syntheses

Inorganic salt melts are used for the preparation of ceramics. It turns out that such ionothermal syntheses can also be employed in the chemistry of carbon. Carbon materials with improved application-relevant properties such as high surface area and large pore volume can be obtained. The way these properties are obtained strongly reminds on classic sol–gel synthesis, which displays a comparably easy approach toward such porous carbons. The central role of the solvent, i.e., the inorganic salt melt allows for variation of the chemical and morphological structure of carbon products. Interestingly, the use of inorganic salt melts may also give insights into the crystallization of carbon, if precursors are directly added to the hot melt, which additionally guarantees reorganizational dynamics to the pyrolysis intermediates.Graphical

Synthesis of ferroelectric Ba0.4Sr0.6TiO3 powders in salt melts at temperatures of up to 1000°C

Powders of barium strontium titanate Ba0.4Sr0.6TiO3 with the particle size smaller than 300 nm were prepared by reactions in inorganic salt melts. The reaction was performed in a melt of a low-melting salt, KNO3. The frequency and capacitance–voltage characteristics of the synthesized powders were studied. The paraelectric state of barium strontium titanate of the examined composition is consistent with published data. The method developed, compared to solid-phase sintering, allows synthesis of complex oxide compounds at considerably lower temperatures and in shorter time.

Study of destructive processing of hydrocarbons in inorganic melts. Influence of control parameters

This article is devoted to the study of the destructive processing of hydrocarbons of different composition in inorganic melts. With the help of established methods of laboratory studies it is obtained reliable experimental data on the basis of which the influence of the main control parameters of the process is defined. it is determined an influence of the chemical composition of the melt temperature (in the range 400-600 °C) and contact times (in the range of 0,09-0,27 sec) on the composition and yield of the products in the processing of crude oil, black mineral oil, fuel oil, straight-run gasoline and n-hexane. Researches were conducted using melts of binary eutectic mixtures of metal chlorides (LiCl-KCl, NaCl-CuCl, CuCl-ZnCl 2 , NaCl-ZnCl 2 , KCl-ZnCl 2 , NaCl-MgCl 2 , CuCl-CaCl 2 , KCl-FeCl 3 ), and also Pb-Sn. The optimal process conditions are virtually identical to the raw material of any composition when the maximum liquid yield temperature of about 500 ° C, contact time – from 0,15-0,20 sec, melts – a mixture of metal chlorides with ZnCl 2 or FeCl 3 . Processing of hydrocarbons in optimal conditions can increase the yield of light oil products for crude oil – by 22,1-23,9 %, for black mineral oil – by 23,7-25,9 %; to increase the octane number of straight-run gasoline by 26 points, mainly due to increase in the yield of isoparaffins; obtain a high yield of isomers in the processing of individual hydrocarbons (to 28,9 % from n-hexane).

Erratum to: Relaxation Processes in Inorganic Melts and Glasses: An Elastic Continuum Model as a Promising Basis for the Description of the Viscosity and Electrical Conductivity

Erratum to: Relaxation Processes in Inorganic Melts and Glasses: An Elastic Continuum Model as a Promising Basis for the Description of the Viscosity and Electrical Conductivity

Relaxation processes in inorganic melts and glasses: An elastic continuum model as a promising basis for the description of the viscosity and electrical conductivity

A brief review is presented of the concepts regarding the nature of α and β relaxation processes in melts and glasses. Experimental data have been used to show that different types of relaxation in oxide systems can be interrelated to each other. The molecular mechanism of viscous flow in inorganic systems has been discussed in detail with the use of continuum theories (elasticity and hydrodynamics) developed in the works by the author in 1967–2007. A rigorous relationship between the volumes of atoms overcoming the activation barrier, the instantaneous shear modulus, and the barrier itself (free activation energy) has been derived. This relationship allows one to calculate the sizes of atoms involved in the viscous flow with a deviation that does not exceed 10% of the values determined by direct structural methods. In this case, empirically chosen constants are absent. Based on the results obtained by Anderson and Stewart (1954) and the author (1974), it has been established that the activation energy for ionic conduction can be calculated using similar notions. It has been demonstrated for the first time that the universal relation between the viscosity and conductivity over a wide range of temperatures (for alkali-containing oxide melts) i.e., the Littleton equation, finds a simple quantitative explanation in the framework of the same models, even though the mechanisms of both processes do not depend on each other.

Quantification of Chemical Striae in Inorganic Melts and Glasses through Picture Processing

Chemical striations occur in various types of inorganic melts like lava and glass melts, and affect the physical properties of materials. This paper reports a quantitative study of the chemical striations in iron-rich aluminosilicate melts and glasses. In this study, an integrated method has been established, which consists of sample preparation, image acquiring, Fourier Transformation, and characteristic value determination. The principle of the established method is illustrated by picture processing-based simulation. The extent of the chemical striations and the diffusion length of the striae can be measured using this method. It is found that the extent of the chemical striations is rather sensitive to the melting technique. Furthermore, the impact of chemical diffusion and stirring on the extent of striations is revealed using the picture processing-based simulation approach. The diffusion process eliminates small striae and reduces the intensity of the larger ones. At a constant temperature, the diffusion determines the transformation rate of an inhomogeneous melt into a homogeneous one. During stirring, the size distribution of the large striae becomes broader, but the overall intensity of the striae becomes smaller.

Measuring Self-Diffusion Coefficients up to 1500 K: A Powerful Tool to Investigate the Dynamics and the Local Structure of Inorganic Melts

Self-diffusion is a fundamental property of liquid dynamics that also provides important structural information. To explore the dynamics in inorganic melts with high liquidus temperature, we propose a new setup based on pulsed field gradient NMR combined with laser heating that makes possible in situ self-diffusion coefficient measurements up to 1500 K. Applied to several corrosive molten fluorides in a wide range of compositions and temperature, we have evidenced the different key parameters of their motion along with their structural characteristics. In alkali fluorides, the self-diffusion coefficient of fluorine depends slightly on the composition compared to the temperature, displaying these systems as an ideal bath of polarizable hard spheres. In contrast, self-diffusion in rare earth and alkali fluorides mixtures presents a complicated balance between temperature and the network-forming process of the ionic long-lived units. These results open wide perspectives in the study of high temperature liquids.

Interpretation of inorganic melts' surface properties on the basis of chemical status and structural relations

Abstract This article is devoted to experimental investigation of the influence of chemical composition on surface properties of inorganic oxidic systems. Through its contents it belongs to a broader area of investigation of systems that form a basis of refining metallurgical slags. The experiment itself was realised on equipment using the sessile drop method modified for high temperatures. The results were compared with theoretical concepts about intrinsic structural relations in melts. Due to the occurrence of anomalies in the temperature dependence of surface tension in the systems investigated and ensuing disagreement with theories, we have used high-temperature X-ray phase analysis. This analysis determined precipitation of individual phases during thermal load and added information for theoretical exploration and consideration about physico-chemical properties of melts working only with binary or ternary systems.

Unmixing of hot inorganic melts

Unmixing of hot inorganic melts

ChemInform Abstract: ELECTROLYTIC LITHIUM CHLORIDE PRECIPITATION FROM LITHIUM CHLORIDE‐POTASSIUM CHLORIDE MELT IN POROUS LITHIUM‐ALUMINUM ANODES

Chemischer InformationsdienstVolume 15, Issue 13 Physical Inorganic Chemistry ChemInform Abstract: ELECTROLYTIC LITHIUM CHLORIDE PRECIPITATION FROM LITHIUM CHLORIDE-POTASSIUM CHLORIDE MELT IN POROUS LITHIUM-ALUMINUM ANODES C. E. VALLET, C. E. VALLETSearch for more papers by this authorD. E. HEATHERLY, D. E. HEATHERLYSearch for more papers by this authorL. JUN. HEATHERLY, L. JUN. HEATHERLYSearch for more papers by this authorJ. BRAUNSTEIN, J. BRAUNSTEINSearch for more papers by this author C. E. VALLET, C. E. VALLETSearch for more papers by this authorD. E. HEATHERLY, D. E. HEATHERLYSearch for more papers by this authorL. JUN. HEATHERLY, L. JUN. HEATHERLYSearch for more papers by this authorJ. BRAUNSTEIN, J. BRAUNSTEINSearch for more papers by this author First published: March 27, 1984 https://doi.org/10.1002/chin.198413023Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume15, Issue13March 27, 1984 RelatedInformation

Electrolysis Reactions in Inorganic Acetate Melts

Electrolysis Reactions in Inorganic Acetate Melts

ChemInform Abstract: CADMIUM CHLORIDE COMPLEXES IN ANHYDROUS CALCIUM NITRATE‐POTASSIUM NITRATE MELTS

Chemischer InformationsdienstVolume 10, Issue 32 Physical Inorganic Chemistry ChemInform Abstract: CADMIUM CHLORIDE COMPLEXES IN ANHYDROUS CALCIUM NITRATE-POTASSIUM NITRATE MELTS I. J. GAL, I. J. GALSearch for more papers by this authorD. STOJIC, D. STOJICSearch for more papers by this authorR. M. NIKOLIC, R. M. NIKOLICSearch for more papers by this author I. J. GAL, I. J. GALSearch for more papers by this authorD. STOJIC, D. STOJICSearch for more papers by this authorR. M. NIKOLIC, R. M. NIKOLICSearch for more papers by this author First published: August 7, 1979 https://doi.org/10.1002/chin.197932016Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume10, Issue32August 7, 1979 RelatedInformation

Vibrational spectra of ionic melts

The status and scope of the vibrational spectroscopy of inorganic melts are reviewed. The melts were grouped in increasing order of phase-rule complexity (as determined by the number of independently variable components). Some aspects and principles of vibrational spectroscopy applied to the qualitative and quantitative interpretation of results are described, and features of experimental work indicating differences from conventional practice are summarized. (P.C.H.)