Navrotsky International Symposium (2nd Intl. Symp. on Geochemistry for Sustainable Development)

Professor Alexandra Navrotsky has built an extraordinary career asking fundamental questions about how materials form and behave in extreme environments. She combines fundamental thermodynamic principles with elegant thermophysical property measurement techniques to understand and model interesting problems, especially those that are far from equilibrium. [1] Many important industrial processes, for example steelmaking, glassmaking, and petrochemical cracking, are high-temperature processes that occur far from equilibrium, and they rely on refractory ceramics to contain these harsh industrial processes. Because refractories fill a vital role in achieving sustainable manufacturing, improving efficiency, reducing CO2 emissions, adapting to hydrogen fuels, adapting to new high-performance alloy compositions, and more, the refractory industry offers straight-to-the-bottom line opportunities for engineers to impact today’s grand challenges. However, the industry competes for talent with emerging materials science technologies, and it suffers from an outdated perception as a dusty, staid industry. The American Ceramic Society and the Ceramic and Glass Industry Foundation have taken on the challenge of raising the visibility of this “invisible” industry and of presenting the industry as an innovative discipline that solves urgent problems with global impact. As a result, hundreds of thousands of prospective and working ceramic and glass engineers have been presented with Prof. Navrotsky’s challenge to “Think big, bold, and hot!”

High-temperature materials properties are challenging to compute from first principles or machine learning. We demonstrate the feasibility of rapid and large-scale prediction of melting temperature prediction based on integrated density functional theory calculations and deep learning. We employ the method and tool to discover the material with the highest melting temperature in the world, as well as dozens of potential candidates of refractory materials.

We build cyber infrastructure to provide public access to our databases and models. Our application programming interface (API) enables users to swiftly calculate the melting temperatures of as many as 10,000 materials in a single API call, with a processing speed of 0.03 seconds per material. This valuable functionality is accessible to the general public free of charge, with all calculations being handled by our server hosted at the ASU Research Computing Center. An alternative way for users to access our models is by visiting our website through a browser, where they can perform single material calculations.

In order to extend the applicability of our methodology, we have constructed deep learning models for the prediction of various material properties beyond melting temperature, such as bulk modulus, volume, fusion enthalpy, and others. We build the Materials Properties Prediction (MAPP) framework, characterized by a diverse array of materials properties, the potential for iterative enhancement, and the prospect of model integration for systematic improvement.

Radiation-induced processes at and near interfaces are important in applications ranging from space travel to advanced nuclear technologies and environmental remediation of legacy radioactive waste [1]. It is the last of these applications that is the focus of the Department of Energy's (DOE) Energy Frontier Research Center – Interfacial Dynamics in Radioactive Environments and Materials (IDREAM). IDREAM’s mission is to master fundamental chemical phenomena and interfacial reactivity in complex environments characterized by extremes in alkalinity, low-water activity, and ionizing radiation. IDREAM focuses on the fundamental science that underpins the processing of highly radioactive legacy wastes stored in underground tanks at DOE Hanford and Savannah River Sites. These wastes contain large quantities of aluminum in solution and in solid aluminum (oxy)hydroxide phases, along with molar concentrations of sodium hydroxide, nitrate, nitrite, and radioactive materials that provide a continuous supply of transient species. At solid/liquid interfaces in the waste, radiation-induced reactions contribute in poorly understood ways to key processes including dissolution and precipitation. The magnitude of the effect depends on the fundamental details of energy deposition and energy transfer, through both the bulk material and the bulk solution to the interface. Less is known about these phenomena in extreme chemical environments, such as concentrated electrolytes, where low-water activity can create new interfacial structures through confinement of water and clustering of ions. Given the ever-growing nexus of extreme conditions associated with new energy systems and environmental materials, this area of radiation effects, minerals, and concentrated electrolytes is an important emerging frontier. We do not have the capacity to subject all materials and environments to radiation testing, therefore a mechanistic understanding is needed to predict performance. To this end, IDREAM has developed a toolbox of experimental and computational techniques for radiation studies across temporal and spatial scales. Using this toolbox, we have generated new knowledge of “early” events that occur during radiolysis of highly concentrated salt solutions, and at solid/solution interfaces, to inform a mechanistic understanding of processes and timescales. Based on this mechanistic understanding, we can develop strategies for quantitatively evaluating material performance to accelerate waste processing, and to inform generation and treatment of future nuclear waste.

Fusible alloys, and gallium-based liquid metal alloys (Ga-LMA) in particular, have applications in soft robotics, microelectronics, self-healing battery components, and 2D materials synthesis, making the study of their thermodynamic properties critical to improvement and development of hybrid materials. To determine the enthalpies of formation/mixing of the binary Ga-In, the ternary Ga-In-Sn, and the quaternary Ga-In-Sn-Zn eutectics, a novel experimental calorimetric technique based on oxidative solution calorimetry was developed. The experimental results for the binary alloy are consistent with previous data obtained by direct reaction and solution calorimetry, demonstrating the viability and precision of the experimental technique, which is applicable to a large variety system that are liquid at or below room temperature. The heats of mixing in the ternary and quaternary systems represent the first reported experimental values. Both the standard geometrical models and FactSage were used to define enthalpy analogs for these systems which agreed with the experimental data, providing a foundation to analyze the thermodynamics of other unknown Ga-based alloys.

The maximum and effective energies of an atomic structure equal the sum of their entropic energy components. This summation is performed for systems in equilibrium entropic state and following special rules. The spatial-energy parameter is obtained, which numerically equals the most effective energy in structural interactions. The computational and analytical method for evaluating the solubility and phase formation for complex multicomponent metal systems is developed. The calculation results are quite coherent with the experimental data. The technique based on entropic principles for calculating the activation energy of self-diffusion and volumetric diffusion of atoms in solids is presented.

Entropic principles provide the basis for forming functional bonds between many values of chemical kinetics. The equilibrium sum of entropic components of the universal gas constant equal to R/2 has the direct mathematical connection with the geodesic angle tangent. A similar ratio of this parameter is obtained by Arrhenius graphs of reaction rate coefficient dependence on the temperature. When two entropic components move in one format, the equilibrium sum of their energies equals a half of the energy initial value. The established principles are also manifested in other regularities of physical chemistry, for example, by the activation energy in diffusion processes and kinetic energy equation.

The climate change time bomb is waiting to explode its fury with frequent and severe droughts, heatwaves, and rainfall unless we limit the global temperature increase to below 1.5°C above pre-industrial levels. To avert this situation we have to reduce the greenhouse gas emissions by 43% by 2030 [1], and we can if the entire world works together—collaborating and exchanging knowledge and technology. 

Globally, all nations trying to expand their renewable energy portfolio are facing the same problems regardless of their geographic location— 

• NIMBY or not in my backyard—public resistance to renewable energy installations for aesthetic reasons and fear of loss in property value 
• Siting delays for environmental reasons, or inadequate or nonexistent policies on renewable energy installations on government and municipal lands, and inadequately trained workforce 
• Interconnection delays due to inadequate transmission bandwidth to carry renewable electricity 
• Intermittency in renewable power and the need for fossil fuel power to bridge that gap 
• Opposition from the fossil fuel industry and lobby who stand to lose the most in terms of profits and jobs.

In 2019, globally 41 million people were employed by fuel supply & power generation sectors [2], and assuming one dependent per employee makes 82 million (~1%) of the world population supported by the fossil fuel industry in 2023. Moreover, after information technology and the financial sector, energy is the most profitable sector on the global stock market and is a major component of most state-sponsored retirement plans and U.S. social security. Hence going cold turkey on fossil fuel energy is not an option. We need a well-orchestrated transition from the fossil fuel industry that repurposes its manpower, infrastructure, and value chain to the maximum, and ensures continuity and amplification of tax revenue generation from renewable energy.

And through economy of scales, a one-size-fits-all solution can deeply discount the levelized cost of clean energy and green hydrogen as compared to other renewable energy technologies, making it affordable for every nation and expediting its adoption.

I will present how we can expand a network of solar microgrids comprising solar, electrolyzer, fuel cell, and hydrogen & energy storage in New York State to: 

• Produce the cheapest electricity and green hydrogen to collectively end the “Tale of Two Grids” which has resulted in 92.7% zero emissions electric supply (and the remainder from fossil fuel) in upstate New York, and merely 5.5% zero emissions electric supply (and rest from fossil fuel) in downstate due to transmission congestion [3] 
• Build a clean hydrogen network to offset the intermittency in renewable electricity from solar and wind power to deliver weather-resistant electricity in New York State with 6σ reliability without investing in expensive transmission system upgrade 
• Decarbonize hard-to-decarbonize sectors including fertilizer, steel & concrete, ammonia, methanol production, etc. 
• Facilitate expansion of EV charging infrastructure, and 
• Discuss how we can implement this model worldwide to achieve the economic prosperity of every nation through energy independence.

The climate change time bomb is waiting to explode its fury with frequent and severe droughts, heatwaves, and rainfall unless we limit the global temperature increase to below 1.5°C above pre-industrial levels. To avert this situation we have to reduce the greenhouse gas emissions by 43% by 2030 [1], and we can if the entire world works together—collaborating and exchanging knowledge and technology. 

Globally, all nations trying to expand their renewable energy portfolio are facing the same problems regardless of their geographic location— 

• NIMBY or not in my backyard—public resistance to renewable energy installations for aesthetic reasons and fear of loss in property value 
• Siting delays for environmental reasons, or inadequate or nonexistent policies on renewable energy installations on government and municipal lands, and inadequately trained workforce 
• Interconnection delays due to inadequate transmission bandwidth to carry renewable electricity 
• Intermittency in renewable power and the need for fossil fuel power to bridge that gap 
• Opposition from the fossil fuel industry and lobby who stand to lose the most in terms of profits and jobs.

In 2019, globally 41 million people were employed by fuel supply & power generation sectors [2], and assuming one dependent per employee makes 82 million (~1%) of the world population supported by the fossil fuel industry in 2023. Moreover, after information technology and the financial sector, energy is the most profitable sector on the global stock market and is a major component of most state-sponsored retirement plans and U.S. social security. Hence going cold turkey on fossil fuel energy is not an option. We need a well-orchestrated transition from the fossil fuel industry that repurposes its manpower, infrastructure, and value chain to the maximum, and ensures continuity and amplification of tax revenue generation from renewable energy.

And through economy of scales, a one-size-fits-all solution can deeply discount the levelized cost of clean energy and green hydrogen as compared to other renewable energy technologies, making it affordable for every nation and expediting its adoption.

I will present how we can expand a network of solar microgrids comprising solar, electrolyzer, fuel cell, and hydrogen & energy storage in New York State to: 

• Produce the cheapest electricity and green hydrogen to collectively end the “Tale of Two Grids” which has resulted in 92.7% zero emissions electric supply (and the remainder from fossil fuel) in upstate New York, and merely 5.5% zero emissions electric supply (and rest from fossil fuel) in downstate due to transmission congestion [3] 
• Build a clean hydrogen network to offset the intermittency in renewable electricity from solar and wind power to deliver weather-resistant electricity in New York State with 6σ reliability without investing in expensive transmission system upgrade 
• Decarbonize hard-to-decarbonize sectors including fertilizer, steel & concrete, ammonia, methanol production, etc. 
• Facilitate expansion of EV charging infrastructure, and 
• Discuss how we can implement this model worldwide to achieve the economic prosperity of every nation through energy independence.

Ceramic materials based on the RE2O3-HfO2 system are interesting from the standpoint of the development of advanced materials for TBCs. This is due to high strength characteristics, low thermal conductivity and high melting temperatures [1,2]. Yet the data on the thermodynamic properties for the compounds with the pyrochlore structure is quite limited. Thermodynamic properties of pyrochlore compounds RE2Hf2O7 (where RE = La, Pr, Nd – Tb) and solid solutions RE2O3·HfO2 (RE=Dy-Lu) were determined in the temperature range between 2 and 1800 K using relaxation and adiabatic calorimetry and DSC methods. Enthalpies of formation of RE hafnates were determined by high-temperature oxide melt drop-solution calorimetry. The obtained results have been compared with the data for titanates and zirconates and have shown the similar dependence of the formation enthalpy from the ionic radii of the rare-earths.
AKNOWLEDGEMENTS:
The study was supported by Russian Science Foundation project № 18-13-00025.

The Ce-U-O system has gained much attention due to its relevance to the nuclear industry and its unique properties (the Ce and U cations form a complete solid solution in the fluorite structure and can withstand different possible oxidation states). Mixed fluorite oxide powders of Ce_1-xU_xO_2±δ; compositions were also found to be particularly active for H₂ production through thermochemical water splitting. In the present work, we explore the reduction-oxidation properties of the mixed oxides with x=0.1, 0.25, and 0.5. We report a particularly high oxygen Storage capacity (OSC) for x≥0.25 and show that the oxygen extracted from those mixed oxides is of a different origin than that extracted from CeO2. While in ceria, oxygen is extracted from the tetrahedral sites, leading to the formation of oxygen vacancies, the extracted oxygen in Ce_1-xU_xO_2±δ (x≥0.25) is essentially excess oxygen in the fluorite lattice (which penetrates the oxide in ambient or oxidative conditions spontaneously). This property, which is clearly related to the change of valency of the U cations, allows for a higher OSC and lower activation energy for oxygen extraction from the mixed oxides compared to ceria. The mixed oxide powders are shown to be structurally stable, retaining their fluorite structure following reduction under Ar-5%H2 until 1000°C or oxidation in air until 1000°C. The presented results provide new insights into the Ce-U-O system, which may be exploited for future technical applications, for thermochemical water splitting or as a solid electrolyte.

Study area is located in the Aegean region and the Mediterranean climate zone, just north of Akkaya (Muğla, Turkey). In this area, the Jura-Cretaceous-aged carbonate Muğla Marble Formation has been observed. To determine the distribution, geochemical characteristics, and uses of the Terra Rossa formations on these carbonate platforms, Geographic Information System (GIS) applications were used. These applications involved collecting vector and raster data from satellite images, topography, geology, forestry, meteorology, agriculture, and livestock fields using a multi-disciplinary approach. The Terra Rossa formations are commonly found in flat and karstic depressions, associated with NW-SE and less frequently NE-SW fault and fracture systems. They typically occur at slopes below 200. Within the total study area of 478.9 hectares, there is a potential Terra Rossa area of 413.4 hectares with slopes between 0-20o, but only 30.2 hectares of this area (7.3%) actually consists of Terra Rossa formations. Among the Terra Rossa potential area, there is a 23.8-hectare registered land area, and 11.7 hectares of this area are covered by Terra Rossa. Taking into account both the Terra Rossa formations and the registered land areas, a transition zone (GZ) of 371.1 hectares has been calculated, while a massive zone (MZ) of 65.5 hectares with steeper slopes than 20o has been identified. The forested areas cover 366.8 hectares, and the treasury lands cover 88.3 hectares, with nearly all of them being classified as unqualified forest. In the forested areas, 10.3 hectares, and in the treasury lands, 8.2 hectares of new Terra Rossa formations have been identified. A total of 24 geochemical samples have been taken from these different zones. The major oxides and trace elements in these samples have been analyzed and evaluated using geo-statistical methods. Similarities in trace element contents have been observed among all Terra Rossa samples, and the presence of REE (Rare Earth Elements) content has also been revealed. Based on the geological and geochemical characteristics, the studied area has been divided into three groups: Terra Rossa (TR), Transition Zone (GZ), and Massive Zone (MZ). According to GIS applications and geochemical analyses, Terra Rossa areas are suitable for almond, olive, walnut, vineyards, and pasture; Transition Zone includes areas suitable for urban development and pasture, and Massive Zone could potentially remain as a free zone. Furthermore, it has been determined that all these areas can be evaluated together, as they intermingle within the study area.

The measurements, computations, and predictions of high temperature thermodynamic properties are of interest to geoscience, material science, and engineering. The experimental techniques to provide structural and thermodynamic data above 1500 °C were developed in Navrotsky’s group for over 10 years. This resulted in the first demonstration of crystal structure refinements on laser-heated aerodynamically levitated samples using synchrotron X-ray and neutron diffraction and drop calorimetry measurements with splittable nozzle aerodynamic levitator [1]. High temperature diffraction provides experimental data on thermal expansion, atomic displacement parameters, and volume change in phase transformations. Drop calorimetry on levitated samples provides enthalpy of fusion. These data can also be obtained from ab initio molecular dynamic computations. The experimentally benchmarked computations can provide reliable data on high temperature heat capacities [2].
Melting or decomposition temperature is a widely used thermodynamic property. Experimental measurements and ab initio computations require time, resources, and expertise. The machine learning model has been developed and trained on ~10,000 experimental and ab initio values of melting points for congruently melting compounds. It has been applied to predict melting or decomposition temperatures of ~5,000 known mineral species which revealed new correlations with the time of Late Heavy Bombardment event and structural complexity index [3]. The model is publicly accessible via the web interface on Hong’s group website for the prediction of melting temperatures within seconds [4].

Thermodynamics is a science concerning the state of a system, whether it is stable, metastable, or unstable.  The combined law of thermodynamics derived by Gibbs laid the foundation of thermodynamics though only applicable to equilibrium or freezing-in systems.  Gibbs further derived the classical statistical thermodynamics in terms of the probability of configurations in a system, which was extended to quantum mechanics-based statistical thermodynamics by Landau, while the irreversible thermodynamics was derived by Onsager.  The development of density function theory (DFT) by Kohn enabled the quantitative prediction of properties of the ground-state configuration of a system from quantum mechanics.  In this presentation, we will present our theories that integrate quantum, statistical, and irreversible thermodynamics in a coherent framework by utilizing the predicative capability of DFT to revise the statistical thermodynamics (zentropy theory) and by keeping the entropy production due to irreversible processes in the combine law of thermodynamics to derive flux equations (theory of cross phenomena).  It will be demonstrated that the zentropy theory is capable of predicting the free energy landscape as a function of internal degrees of freedom of a system including singularity and instability at critical point and emergent positive or negative divergences of properties, while the theory of cross phenomena can predict the coefficients of internal processes between conjugate variables (direct phenomena) and non-conjugate variables (cross phenomena) in the combined law of thermodynamics, both with inputs from DFT-based calculations only and without fitting parameters.

When synthesizing a new material, one often starts by consulting the thermodynamic phase diagram. There are four main varieties of phase diagrams today: 1) Temperature–Pressure; 2) Temperature–Composition; 3) Ellingham (T, μ_O2); and 4) Pourbaix diagrams (pH, Redox potential). Prof. Navrotsky performed seminal calorimetry work showing that surface energies can drive nanoscale crossovers in phase stability when metastable polymorphs have lower surface energies than the bulk equilibrium phases. In addition to surface energies, many forms of thermodynamic work may further be operative during nucleation and growth—such as  elastic, electromagnetic and electrochemical work. Here, I will describe a geometric process to ‘lift’ 2D phase diagrams into higher dimensions, exposing these additional forms of thermodynamic work on the axes. By properly accounting for these hidden thermodynamic variables, we can reconcile many surprising experimental observations of non-equilibrium intermediates during multistep crystallization. I will conclude with a broader vision for the construction and deployment of high-dimensional phase diagrams, which may serve as a powerful new conceptual framework for the design and synthesis of advanced functional materials. 

Layered oxides NMC (LiNi_xMn_yCo_zO₂), high voltage LMO spinels (Li(M,Mn)₂O₄) and LMFP olivines (LiMFePO₄) are commercially relevant cathode materials for lithium-ion battery design. To investigate their electrochemical thermodynamics we combine various types of calorimetry (DSC, Tian Calvet, Accelerating Rate Calorimetry, ARC) and electrochemical cell analyses with thermal and safety studies, respectively. Additionally, we use computational thermodynamics (CALPHAD approach) for modeling phase stabilities and electrochemical behavior as well as for calculation of related phase diagrams. We prepared samples of the NMC- and LMO-base compositional solid solution series by sol-gel methods and high-temperature calcination in air. High temperature drop solution calorimetry was suitable for determining the enthalpies of formation of all solid solution members. Systematic information on phase stabilities could be provided. Electrochemical investigations of half and full cells involved galvanostatic coulometry (with potential limitations), galvanostatic intermittent titration techniques (GITT), cyclic voltammetry (CV) as well as rate capability and cyclability tests. The presented work focuses on the investigation of such properties to provide quantitative data for better understanding the performances of lithium-ion batteries during their regular use and abuse, respectively, and in case of accidents. Such data are crucial input for the design of batteries thermal management systems. Accelerating Rate Calorimetry (ARC) is applied to quantitatively measure both the non-critical thermal characteristics and thermal runaway behavior of self-made and commercial coin cells, cylindrical cells and pouch cells, respectively. ARC provides quasi-adiabatic test conditions and enables precise temperature, and temperature rate measurements. Critical temperatures and heat effects for various abuse conditions have been studied and compared for different cell type materials as mentioned before. 

Exoplanets orbit stars other than our own sun. Aerosols are a prominent feature of exoplanet atmospheres, sometimes obscuring the spectral determination of atmospheric gas composition [1]. Hot Jupiters are studied because they are the hottest of exoplanets, so emit the most radiation and therefore, give the most spectral information on exoplanets. Because it is not yet possible to definitively determine aerosol composition and formation through astronomical observations, it is important to model aerosol production accurately [2]. A key factor in the determination of nucleation and condensation rate is the surface energy of the nucleating material [3]. High surface energy materials, such as forsterite, will nucleate much more slowly compared to lower surface energy materials, such as sulfides. Despite their importance, few surface energies of rock-forming minerals have been measured [4]. In this work, surface energies were measured using oxide melt solution calorimetry of materials with different surface areas for likely exoplanet atmosphere condensates including zinc sulfide (ZnS) [5] and enstatite (MgSiO3), with other measured surface energies taken from experimental rather than estimated data. This work inputs the accurate measured surface energy data to calculate a model of nucleation rates for each of the proposed cloud species of a hot Jupiter exoplanet with atmospheric metallicity of 10x solar, a total atmospheric pressure of 10 bar and a saturation ratio of 10. These corrected surface energy values show drastically different nucleation rates for a variety of condensates in the atmospheres, which lead to different atmospheric compositions of these exoplanets than previous models.

Carbon is ubiquitous in the Universe, and on Earth it circulates between the atmosphere, land, ocean, biological organisms and plants, and it is subducted from the shallow continental crust to the very deep mantle. Recently, the geological pathway for incorporating carbon into silicates was summarized by Alexandra Navrotsky [1]; this study combined existing geologic hypotheses and observations on carbon-bearing mineralogical assemblages with experimental work on Si-O-C nanoceramics [1]. Here, we present detailed observations on moissanite (SiC) collected from a Miocene volcanic tuff (Yizre’el Valley, Israel) associated with inter-plate alkaline basalt volcanism [2,3] and from metamorphic rocks of Triassic age in Southern Bulgaria [4]. The samples were studied with optical microscopy, Raman spectroscopy, synchrotron X‐ray Laue microdiffraction, scanning electron microscopy, focused ion beam, and transmission electron microscopy.

SiC from volcanic tuff of Israel. The crystals belong to 4H and 6H polytypes of hexagonal symmetry, wurtzite structure, with 4H-SiC as the dominant phase. Larger crystals of SiC (0.2-1.8 mm) contain nanometric inclusions of Si, and metal-silicides. Several metal-silicide phases were found: Si₅₈V₂₅Ti₁₂Cr₃Fe₂, Si₄₁Fe₂₄Ti₂₀Ni₇V₅Zr₃, and Si₄₃Fe₄₀Ni₁₇. Their crystal structure parameters match Si₂TiV₅ (cubic space group Pmm), FeSi₂Ti (orthorhombic space group Pbam), and FeSi₂ (orthorhombic space group Cmca) respectively. Since the silicide inclusions exhibit spherical morphology, this provides evidence of their crystallization from a melt. Our observations suggest that SiC formed because of an interaction of a small volume of reducing fluids (H₂O–CH₄–H₂–C₂H₆) and crustal materials (SiO₂) that were possibly available from the walls of the alkaline basalt reservoir. 

SiC from metamorphic rocks (black shell) of Bulgaria. Moissanite crystals ranging from 10–300 μm in size were found within 0.1–1.2 mm isolated clusters, filled with amorphous carbon and nanocrystalline graphite. They belong to 15R (rhombohedral) and 6H (hexagonal) polytypes. One prismatic crystal was found within them which exhibits an unusual concentric polytypical zoning. The core is polytype 15R with an intermediate zone of 6H and the outer rim is 3C-cubic. SiC crystals formed during the cooling of the metamorphic reservoir from 580 °C to ∼400 °C [4]. The SiC crystals associated with amorphous carbon and nanocrystalline graphite are not in equilibrium with the surrounding mineralogical assemblage, which crystallized under a high oxygen fugacity environment. Moissanites from terrestrial rocks show that their carbon has an organic origin, e.g. δ13 C ‰ = -20 to -30 [5]. Therefore, the geologic Si-O-C pathway suggests that any existing geological or organic carbon source that forms a reducing fluid may interact with Si-bearing rocks providing local “isolated” chemical conditions where SiC, Si, metal silicides, and nanographite can form. These refractory minerals do not equilibrate with other mineralogical assemblages that normally crystallize under high oxygen fugacity. Instead, they remain as indicators of the local reducing fluid/melt environments. 

We present neutron total scattering combined with high-temperature calorimetry as a new strategy for the characterization of radiation effects in materials. Irradiation experiments were performed at the GSI Helmholtz Center with heavy ions of specific energy of 11.4 MeV/u. The use of such ions (penetration depth: ~100 μm) produces the sufficiently large irradiated sample mass (~150 mg) required for bulk structural and thermodynamic analysis. Neutron scattering was performed at the Nanoscale Ordered Materials Diffractometer at the Spallation Neutron Source (Oak Ridge National Laboratory). High temperature oxide melt solution calorimetry and differential scanning calorimetry was utilized to investigate the thermodynamic properties and energetic evolution using the same set of irradiated samples. We studied various ion-induced structural modifications [1-5], such as defect formation (CeO₂), disordering (Er₂Sn₂O₇), and amorphization (Dy₂Ti₂O₇). Our analytical approach demonstrated that irradiation-induced modifications are more complex than previously thought with distinct processes occurring over different length scales and temperature regimes.

Thermodynamics is a science concerning the state of a system, whether it is stable, metastable, or unstable [1]. The combined law of thermodynamics derived by Gibbs laid the foundation of thermodynamics though only applicable to equilibrium or freezing-in systems. Gibbs further derived the classical statistical thermodynamics in terms of the probability of configurations in a system, which was extended to quantum mechanics-based statistical thermodynamics by Landau, while the irreversible thermodynamics was derived by Onsager and Prigogine. The development of density function theory (DFT) enabled the quantitative prediction of properties of the ground state of a system from quantum mechanics. In this presentation, we will present our theories that integrate quantum, statistical, and irreversible thermodynamics in a coherent framework by utilizing the predicative capability of DFT to revise the statistical thermodynamics (zentropy theory) and by keeping the entropy production due to irreversible processes in the combine law of thermodynamics to derive flux equations (theory of cross phenomena). It is demonstrated that the zentropy theory is capable of predicting free energy landscape as a function of internal degrees of freedom including singularity and instability at critical point and emergent positive and negative divergences of properties, while the theory of cross phenomena can predict the coefficients of internal processes between conjugate variables (direct phenomena) and non-conjugate variables (cross phenomena) in the combined law of thermodynamics as discussed in this publication [2]. Furthermore, the author’s perspectives on future development of thermodynamic modeling will be discussed [3].

Redox reactions are fundamental to life and local heterogeneities in the critical zone create gradients in pH, redox and chemical concentrations that support chemical reactions. Among the chemical reactions that act on the transformation of soils, oxidation-reduction reactions have a special place because by acting on the environment, they allow living organisms to recover the energy necessary for their metabolism. 

Layered Double Hydroxide compounds form a large group of minerals, also including green rusts, the natural form of which is fougerite. They can drive self-organizing reactions, including redox reactions, usable for storage and replication of chemical information. LDHs, by their 2D structure, are able to support auto-organization of reactions facilitating chemical reactions, including redox reactions and are good mineral candidates for the storage and replication of information over long-range order both in the plane (a, b) and along the c-axis, perpendicular to the sheets.

These will be illustrated by some results obtained both: (i) by in situ monitoring of water and mineral transformations in soils from the Fougère’s forest (Brittany, France) and from Camargue’s rice fields (South region, France) [1], (ii) in situ sampling of fluids in alkaline hydrothermal vents from Lost City (medio Atlantic ridge) [2] and (iii) experimental data from laboratory and modelling [3].

The frequency and severity of wildfires are increasing throughout much of the world, which pose risks to human health through inhalation of airborne particulate matter less than 2.5 µm in diameter (PM_2.5) in the wildfire smoke. PM_2.5 may originate from ash and soil nanoparticles (NPs), which are often associated with toxic metals such as Cr(VI)  formed by the oxidation of Cr(III) during wildfires.  PM_2.5 is a general term used for any particulate < 2.5 µm; however, a wide variety of particulates with different sizes and physical and chemical properties can be formed in this size range, which are not well studied. The health risks due to exposure to PM_2.5 can be different for various PM_2.5 phases with different sizes, metal content, and crystal chemistries and structures. We studied the size and structure of fire-induced soil NPs and their association with Cr(VI). Soils with different mineralogy (serpentine, greenstone, sandstone, and chert) were collected from the Jasper Ridge Biological Preserve (San Mateo County, CA) and heated to temperatures ranging from 200 to 800 °C for 2 h. The samples were characterized using X-ray diffraction, X-ray fluorescence spectrometry (XRF), scanning and transmission electron microscopy (EM), synchrotron X-ray absorption spectroscopy, and wet chemistry experiments. The concentration of Fe and Cr showed a positive correlation in all the samples, with the highest concentration in serpentine soils; 117 ± 4 mg/g for Fe and 3.90 ± 4 mg/g for Cr.  The primary Fe minerals in all the samples were magnetite which transformed to hematite with increasing temperature. Using Energy dispersive X-ray spectroscopy of EM, we found that Fe (hydr)oxide NPs are associated with Cr, which increased with burning. More than 2.5% of Cr(III) was transformed to exchangeable Cr(VI) with burning up to 600 ^∘C in all the samples. The exchangeable Cr(VI) concentration was slightly higher in chert samples, attributed to their lower concentration of Fe (hydr)oxide NPs. Additionally, EM showed that the size of particles in fresh and burned samples ranges between 5-500 nm, with most particles being less than 100 nm. Our results showed that the size of airborne PM originating from soils could be much smaller than 2.5 µm, which increases their association with wildfire-induced toxic metals such as Cr(VI), and assist their penetration into the human lung and beyond. This information is critical to inform targeted policies and interventions for mitigating respiratory health risks to firefighters, farm workers, and local communities who are disproportionately impacted by wildfire smoke. 

Though the abundances of elements in our galaxy arise from nuclear physics, the materials they form in planetary systems reflect their chemistry, with complex reactions involving gases, liquids, fluids, melts and solids. On Earth we have inherited, from billions of years of geologic processes, mostly at high temperature and pressure, a suite of rocks and minerals which are the source of all materials we make and use. After use, the elements are eventually returned to the Earth as “waste” or “contamination”. This cycle of mining, processing, use, and disposition can be referred to as “cradle to grave” technology. More sustainable technology, involving reuse of “waste” in technology, is sometimes called “cradle to cradle”. In either case, the feasibility of each step is determined by thermodynamics, and its rate by kinetics. Using rare earths and actinides as examples, this lecture addresses thermodynamic constraints on mining, extraction, separation, fabrication, corrosion and disposal. Current interest in space exploration and planetary missions, as well as the discovery of myriads of exotic and highly variable exoplanets, place these thermodynamic questions in a much broader context for materials of the universe.

The thermochemical properties and processes of materials and minerals under extreme temperature and pressure conditions in harsh chemical environments are a current and future concern of understanding their stability in energy production and storage, aerospace transportation, and planetary and space exploration applications. Some examples of these environments include the lower atmosphere and surface of Venus [1], the atmospheres of Hot Rocky Planets [2], the combustor chamber of jet engines [3] and the reactor of nuclear thermal propulsion rockets [4]. Knowledge gained on these properties and processes have important implications for construction materials of future planetary probes and for aerospace propulsion vehicles besides helping us to better understand the history and present-day state of inhospitable and even inaccessible regions of the Earth as well as other solar or extrasolar planets. This presentation provides an overview of our experimental and computational capabilities of the NASA GRC Thermochemistry Laboratory to measure and compute the integral and partial thermodynamic properties of minerals, materials and gases/vapors, and the features and characteristics of the unique Glenn Extreme Environment Rig (GEER) [5] which is capable of accurately reproducing the atmospheric chemical compositions of bodies in the solar system including those with acidic and hazardous elements of the Venus lower atmosphere. It also covers some recent experimental results.

A series of complex oxides have, along the years, raised interest in the field of Martian mineralogy. This includes compounds of the Jarosite, Apatite and Jahnsite large groups of minerals. Whereas some of them, typically F- and Cl-apatites have been identified on the red planet, the presence of some other phases like Jarosites and more recently Jahnsites have been suspected to occur on Mars without actual proofs of their presence. 

Whether for confirming or invalidating the possible presence of such oxide phases on the surface of Mars, or for better assessing their eventual evolution in the Martian atmosphere and surface conditions, it is primordial to have access to thermodynamic data – as much reliable as possible – yet sometimes scarcely available. Thus, in this long run work along the years, we have launched synthesis procedures with the view to prepare relevant compositions of these three families of minerals ore relevance to Mars mineralogy, and explored their thermodynamics through oxide-melt solution calorimetry when possible, and via the ThermAP (Applied Predictive Thermodynamics) simplified predictive approach. 

In this presentation, the main milestones and findings of this research will be reminded, and the main thermodynamic trends will be highlighted with regards to Jarosites, Apatites and Jahnsites.

In order to recover gold from solid waste efficiently，a combined beneficiation and metallurgical test was carried out on gold-bearing tailings. The results of chemical analysis show that the gold content in solid waste is 0.86 g/t. Process mineralogy show that the main gold minerals are tellurite ore，tellurium-gold-silver ore and gold-bearing tellurium-silver ore，followed by natural gold and silver-gold ore. In the original ore sample，gold is mainly produced in the form of sulfide wrapped gold，accounting for 51.72%，followed by bare gold，accounting for 31.03%，a small amount of gold is produced in the form of quartz wrapped gold，accounting for 17.24%.The original ore sample was vibrated to the particle size of -0.074 mm accounted for 98.15%.According to chemical phase analysis，gold is still mainly produced in the form of sulfide wrapped gold，accounting for 50.00%，with little change. Part of gold is produced in the form of bare gold，accounting for 41.86%，and a small amount is produced in the form of quartz wrapped gold，accounting for 8.14%.It can be seen that grinding can obviously improve the leaching rate of gold. If gold is recovered by flotation，the recovery rate of gold can be increased. At the same time，it can also be seen that the recovery rate of gold is less than 50% by direct cyanidation leaching method，and the gold in the ore sample needs to be recovered by the combined process of concentration and smelting. The flotation gold concentrate pretreatment leaching process for gold concentrate should be adopted to recover gold. The closed circuit process of “one roughing-two sweeping-two cleaning” was adopted. Gold concentrate with the yield of 14.23%，gold grade of 5.21 g/t and gold recovery of 86.21% can be obtained. When the gold concentrate is grinded to -0.037 mm accounted for 70.12%，the leaching rate of direct cyanide gold is 41.60%.The main barrier effecting the gold leaching is that most gold is wrapped by pyrite and gold minerals are mainly tellurite，tellurite，gold-bearing silver tellurite，etc. The oxidizing roasting-leaching improved the leaching rate effectively. The suitable conditions for the oxidation roasting cyanidation leaching of gold concentrate are：The temperature of oxidation roasting is 750 ℃，the roasting time is 60 min，and the fineness of the roasting sand is -0.037 mm accounted for 85%，pulp concentration is 33%，pulp pH value is 10.5，sodium cyanide dosage is 10 kg/t，leaching time is 24 h. Under these conditions，the cyanide leaching rate is of gold is 73.76%，compared with the direct cyanide index of gold concentrate（cyanide leaching rate is 41.60%），the cyanide leaching rate of gold is increased by 32.16%.

An electronic databank of the experimental viscosities of oxide melts and glasses being collected and processed will soon be available online. In the meantime, the collected experimental data on viscosities of unary, binary and ternary oxide systems will be extracted and analysed using statistical methods. New insights on the viscosity behaviour in the selected systems revealed during the analysis will be suggested and discussed.
AKNOWLEDGEMENTS:
The authors gratefully acknowledge the financial support of the Program “Chemical Thermodynamics and Theoretical Material Science” (№ 121031300039-1), Lomonosov MSU.