Formation Of Liquid Phase Research Articles

Formation, chemical evolution and solidification of the dense liquid phase of calcium (bi)carbonate.

Metal carbonates, which are ubiquitous in the near-surface mineral record, are a major product of biomineralizing organisms and serve as important targets for capturing anthropogenic CO2 emissions. However, pathways of carbonate mineralization typically diverge from classical predictions due to the involvement of disordered precursors, such as the dense liquid phase (DLP), yet little is known about DLP formation or solidification processes. Using in situ methods we report that a highly hydrated bicarbonate DLP forms via liquid-liquid phase separation and transforms into hollow hydrated amorphous CaCO3 particles. Acidic proteins and polymers extend DLP lifetimes while leaving the pathway and chemistry unchanged. Molecular simulations suggest that the DLP forms via direct condensation of solvated Ca²+⋅(HCO3-)2 complexes that react due to proximity effects in the confined DLP droplets. Our findings provide insight into CaCO3 nucleation that is mediated by liquid-liquid phase separation, advancing the ability to direct carbonate mineralization and elucidating an often-proposed complex pathway of biomineralization.

Enhancing strength and ductility of CuCrZr high-conductivity alloy via lamellar heterostructures on grain boundaries

Heterogeneous lamellar structure materials have attracted extensive attention due to their exceptional strength and ductility. In this study, Y element was introduced into CuCrZr alloys to adjust the liquid phase formation temperature of the CuZrY phase during the solution annealing process. By employing cold rolling deformation prior to annealing to elongate the grains, the liquid phase was promoted to wet the elongated grain boundaries during the annealing process, ultimately forming lamellar CuZrY heterostructures distributed along the grain boundaries. The heterogeneous lamellar structure, the grain boundary distribution characteristics, and the effect of Y on stacking fault energy enhanced the hetero-deformation induced working hardening, thereby improving both the strength and ductility of the CuCrZrY alloy. Besides, the investigated CuCrZrY alloy achieved an excellent combination of tensile strength, uniform elongation, electrical conductivity and thermal conductivity, with values of 527 MPa, 10.66%, 83% IACS and 335.5 W/(m·K), respectively. Therefore, the method of controlling liquid phase temperature through composition adjustment and liquid phase infiltration path through grain deformation offers new possibilities for the design of heterogeneous lamellar structure materials.

Immobilization of heavy metals with chlorine and liquid phase formation during thermal treatment of MSWI fly ash

Due to effective detoxification, thermal treatment is a preferred treatment technology of municipal solid waste incineration (MSWI) fly ash. However, immobilization behavior of heavy metals during thermal treatment is unclear. In this work, a circulated fluidized bed fly ash with SiO2 addition and a grate furnace fly ash with high silica-aluminum coal ash addition were used to investigate combined effect of active chlorine content, liquid polymerization degree, temperature of initial liquid phase formation and liquid phase formation rate on the immobilization ratios of Zn, Pb and Cd by principle component analysis (PCA). The results show that the decrease in active chlorine content favors the immobilization of Zn, Pb and Cd because chlorination volatilization is reduced. Both the increase in liquid polymerization degree and the formation of initial liquid phase at low temperature promote the immobilization of Zn, Pb and Cd for physical encapsulation. However, a rapid formation of liquid phase is not favorable for the immobilization of Zn, Pb and Cd, because transfer of heavy metals between crystals and liquid phase is impeded by high viscosity of liquid phase during fusion. The results can provide a reference for how to achieve the immobilization of heavy metals by adjusting the chemical composition of MSWI fly ash during thermal treatment.

Phase evolution, microstructure and properties of glass-ceramics derived from municipal solid waste incineration bottom ash and molybdenum tailings

Municipal solid waste (MSW) incineration bottom ash (BA) and molybdenum tailings (MTs) are bulk solid wastes that have low added value and is of a serious environmental concern. Hence, it is imperative to develop technology that potentially as convert these wastes into potential products that are safe to handle. In the present work, the goal is to synthesize glass-ceramics from BA and MTs without addition other supplement materials. The study attempts to assess the influences of raw material ratio and sintering temperature on the phase transformation, microstructure and properties of glass-ceramics. The synthesized product shows that diopside ferroan and anorthite were the dominant crystals, and the content of diopside ferroan and anorthite increased with an increase in the proportion of MTs. It was observed that the presence of Fe2O3 and TiO2 inside solid wastes promote nucleation facilitating growth of crystals. Diopside ferroan and anorthite distribute uniformly and are well interweaved, densifying the structure with favorable properties of glass-ceramics. At the optimal processing temperature the presence of Na2O and K2O in the raw materials act as fluxing agents that facilitate formation of liquid phase, that enhance diffusion and rate of crystallization. The optimal mass ratio of BA to MTs was 45:55 and the sintering temperature of 1000 °C, exhibited the best comprehensive properties of the glass ceramics. At the optimal conditions the flexural strength, Vickers hardness, bulk density and water absorption were observed to be 76.00 MPa, 5.77 GPa, 2.69 g/cm3 and 0.32 %, respectively. The leaching test proved stability of the glass ceramics, and hence can serve to be a potential way of utilizing the waste into a valuable product benefiting the environment and promoting sustainable growth.

The impact of chelating agent pH on the stability and viscosity of CO2 foam under harsh reservoir conditions

The injection of CO2 foam into the carbonate reservoir for enhanced oil recovery (EOR) has attracted special interest in the last decades; nevertheless, the understanding of the effect of liquid solution chemistry on foam stability at high temperatures and salinities is limited. Hence, this paper fully investigates the effect of chelating agents L-glutamic acid-N, N-diacetic acid (GLDA) pH, and hydrochloric acid (HCl) on the stability and viscosity of generated CO2 foam for heterogeneous carbonate formation under reservoir conditions. In this paper, Duomeen TTM and Armovis VES surfactants were utilized due to their capabilities to produce viscous CO2 foam under harsh conditions. The foamability, foam stability, and foam structure were studied at 100 °C and 1000 psi using a high-temperature and high-pressure (HPHT) foam analyzer. The measurement of CO2 foam viscosity was determined at 100 °C, 1000 psi, and 70 % foam quality using the HPHT foam rheometer. Rheology experiments and dynamic light scattering investigated the micelle’s size or aggregation behavior of surfactants. The obtained results showed that the Duomeen TTM generated unstable foam; however, foam stability and foamability improved with the decrease in GLDA pH. Armovis VES showed excellent CO2 foam performance, where the foam half-life time of Armovis VES systems was 240 min. The liquid drainage and bubble coarsening were delayed due to the formation of the viscoelastic liquid phase. The foamability of Armovis VES was improved as the GLDA pH decreased. Furthermore, the addition of HCl to Armovis VES solution presented the highest foamability. The outcomes of the HPHT foam analyzer and HPHT viscometer proved that as the pH of Armovis VES solution decreased, higher foamability was produced. The highest foam viscosity was obtained using the synergic effect of 0.5 wt% Duomeen TTM and 0.5 wt% Armovis VES (39 cp at 100/s). In comparison, 1 wt% Armovis VES presented the lowest foam viscosity (30 cp at 100/s). The outcomes of this research can provide insight into the effect of chemistry on CO2 foam and extend its application in oilfield development. This work broadens the design of novel CO2 foam formulation, leading to the improvement of sweep efficiency in CO2-EOR methods and enhance the gas trapping in carbon storage.

Cooling Air Velocity on Iron Ore Pellet Performance Based on Experiments and Simulations

During the pellet cooling process, cooling air velocity is crucial for optimizing the cooling rate, evaluating the utilization rate of cooling heat energy, and improving pellet performance. As the simulated cooling air velocity increased, the gas temperature at the cooling endpoint decreased from 87 °C to 51 °C, and the solid temperature decreased from 149 °C to 103 °C. The total enthalpy of the recovered gas initially reduced and then increased while the heat recovery rate gradually increased. During the experiment, the inhomogeneity of pellet quality gradually increased with the rise in cooling air velocity. The effect of cooling air velocity on pellet properties is primarily reflected in the formation of cracks and low-melting liquid phases (FeO and fayalite). As the cooling air velocity increases, the softening onset temperature of the pellet decreases significantly. The melting zone decreases from 193 °C to 105 °C, and the permeability of the adhesive zone increases.

Evolution of liquid phase during homogenous non-equilibrium melting of Ta at superheating temperature.

Homogenous melting at superheating temperature is commonly described by classical nucleation theory (CNT), but the atomic mechanism of the formation and development of critical liquid nuclei is still unclear. Molecular dynamics simulations were conducted to analyze the melting process of Ta. It is found that the process of subcritical liquid clusters evolving into critical liquid nucleus occupies most of the melting time, and merging between neighboring liquid clusters is the main path for subcritical liquid clusters to grow in size. Total melting time is strongly affected by the distribution of formation sites of subcritical liquid clusters, which has been considered random in homogenous melting. This work depicts a clear picture of the formation and development of liquid phase during the homogeneous melting process at superheating temperature and suggests an internal factor of melting mechanism.

Experimental investigation and thermodynamic modelling of WC-Fe-Ni-Co-Cr cemented carbides

This work investigates the effect of Cr addition into the FeCoNi binder phase of the cemented carbides (WC-FeCoNi) using experimental and computational techniques. Liquid phase formation temperatures and C contents of WC-Fe-Ni-Co-Cr alloys were used as experimental results. Based on this, a thermodynamic modelling was conducted on the W-C-Fe-Ni-Co-Cr system using the CALPHAD (CALculation of PHAse Diagrams) approach. Taking into account the experimental and theoretical results, it was shown that the error in the solidus and liquidus temperatures were lower in the database generated in this work in comparison to the commercial thermodynamic databases for steels and cemented carbides. Using the database developed in the present work, the experimental data can be well reproduced.In addition, the maximum solubility of Cr to avoid the formation of Cr-rich carbides was also deduced from this study.

Effect of Organic Solvent on the Mass Transfer Mechanism of Coumarin 102 in a Single Octadecylsilyl Silica Gel/Organic Solvent-Water System by Laser Trapping and Fluorescence Microspectroscopy.

Understanding mass transfer kinetics within individual porous particles is crucial for theoretically explaining the retention and elution behaviors in chromatography and drug delivery. Using laser trapping and fluorescence microspectroscopy, we investigated the diffusion mechanism of coumarin 102 (C102) into single octadecylsilyl particle in acetonitrile (ACN)/water, N,N-dimethylformamide (DMF)/water, and 1-butanol (BuOH)/water solutions. The intraparticle diffusion behavior of C102 was evaluated using the spherical diffusion equation, allowing us to determine the intraparticle diffusion coefficients (Dintra): (8-10) × 10-9 cm2 s-1 for ACN, (10-16) × 10-9 cm2 s-1 for DMF, and (4-6) × 10-9 cm2 s-1 for BuOH. The obtained Dintra values were further analyzed using a pore and surface diffusion model. Thus, we revealed that the diffusion mechanism of C102 differed depending on the organic solvent: surface diffusion for ACN and DMF and pore and surface diffusions for BuOH were observed. This difference is attributed to the formation of a concentrated liquid phase of ACN and DMF at the interface of the alkyl chain and the bulk solution in the pore.

Effect of SiO2/MgO ratio on the properties of diopside-based ceramics

Diopside-based ceramics were successfully synthesized by utilizing recovered extracted titanium slag, asbestos tailings, and quartz tailings as raw materials. The objective of this approach is to explore novel sources of raw materials for ceramic production and optimize the utilization of industrial solid waste. The effects of SiO2/MgO mass ratio (S/M) on the properties of the ceramics were studied by investigating the bulk density, bending strength, water absorption and corrosion resistance. The microstructure and crystallization process of the ceramics were analyzed by SEM-EDS and XRD. The results revealed that the increase of S/M is beneficial to the formation of low viscosity liquid phase, the promotion of ion migration and crystallization process, the decrease of sintering temperature, the decrease of water absorption and the increase of bulk density and bending strength of ceramics. In addition, the increase of S/M helps to increase the acid resistance of ceramics. The most optimal parameters (bulk density of 2.97 g·m−3, bending strength of 118.73 MPa, water absorption of 0.29 %, and acid resistance of 98.98 %, respectively) were achieved at the S/M of 2.50 and the sintering temperature of 1175 °C. The increase of S/M ratio also affects the phase reconstruction process. At lower S/M (1.75–2.08), Melilite is transformed into diopside, and at higher S/M (2.50–4.71), Melilite is transformed into diopside and anorthite. The present study aims to optimize the utilization of industrial solid waste (100 %), which not only protects the environment, but also provides a novel approach for resource recovery from such wastes.

Inhibiting the Accretion in the Coal-Fired Rotary Kiln of High-Silica Iron Ore Pellets Application by Reducing Fines Generation and Liquid Phase Formation

Inhibiting the Accretion in the Coal-Fired Rotary Kiln of High-Silica Iron Ore Pellets Application by Reducing Fines Generation and Liquid Phase Formation

Sintering behaviors, microstructure and properties of CaO–B2O3–SiO2 glass-ceramics for LTCC applications

The aim of this work was to investigate the impacts of MgO on the crystalline behaviors, microstructure, and properties of CaO–B2O3–SiO2 (CBS) glass-ceramics. In the study, the CBS samples with various MgO contents were developed via the melting and quenching route. Subsequently, a CBS casting tape and a multi-layered LTCC microcircuit module were created by using the tape casting method. Results indicated that MgO could break the glass network and promote the formation of liquid phase during the sintering process. A suitable amount of MgO additive promoted densification during firing process and improved the properties of the CBS materials. The CBS sample with 1.5 wt% MgO fired at 875 °C exhibited outstanding properties, including a dielectric constant (εr) of 6.5 (at 10 GHz), a dielectric loss (tan δ) of 8 × 10−4, a flexural strength of 167 MPa, a coefficient of thermal expansion (CTE) of 6.8 ppm/°C, and a thermal conductivity (λ) of 2.2 W/mK. In addition, this LTCC material demonstrated good co-firing compatibility with silver electrodes and superior temperature stability, showing its great potential for microelectronic applications.

Enhancing the mechanical and insulation properties of CF/BPR composites by adding hollow silicate glass microspheres as an Interlaminar reinforcement

Improving the ablation and mechanical properties of ablative thermal protection composites by introducing modified fillers which simultaneously with an unavoidable increase in density. Balancing this increase in density while achieving lightweight properties is crucial for the development of effective ablative composites. In this paper, different contents of the hollow silicate glass microspheres (HSMs) are incorporated into MoSi2/mica-modified CF-BPR composites to investigate the impact of HSMs. The results show that HSMs play a positive role in reducing the density and thermal conductivity of the composite. The ablation and insulation properties of the 30 vol.% HSMs composites exhibit a mass ablation rate of 0.035 g/s and a linear ablation rate of 0.015 mm/s, alongside the lowest backside temperature. A significant improvement in flexural strength after static ablation at 1500 °C reached 82.59 MPa and maintained a relatively high level after 1600 °C. HSMs act as interlaminar skeletons, enhancing the shearing strength of the composite and facilitating the formation of a protective liquid phase around the carbon fibers to prevent oxidation. The increasing toughness of carbon fibers further enhances the mechanical strength of the composites.

Intermetallic phase evolution and strengthening mechanisms of the titanium and stainless steel lap joints welded by interrupted pulsed arc welding

The study is focused on analyzing the intermetallic phase evolution and strengthening mechanisms of the titanium alloy and stainless steel (Ti-SS) seam-welded joints using interrupted pulsed arc welding (IPAW). The precise adjustment of welding parameters for the IPAW technique allowed for the successful creation of two different joining modes for Ti-SS joints: contact reactive brazing and fusion modes. The homogeneous composition in the brazing joints was achieved by the formation of a diffusion-driven eutectic liquid phase at the joining contact, resulting in an unusual eutectic structure consisting of β-Ti and TiFe. The molten pool at high temperatures caused an uneven distribution of composition and energy throughout the fusion joints. The fusion joints consisted of a Ti-rich layer, containing β-Ti and TiFe phases near the TC4 side, and a Fe-rich layer, containing TiFe2/TiCr2 and α-Fe phases near the 304SS side. The shear-bearing capacity of the joints exhibited an initial increase and subsequent decrease as the heat input increased. The low heat input resulted in the formation of the unwelding zone, which significantly reduced the shear resistance of the joints. With the increase of the heat input, a reduction in shear strength occurred due to the accumulation of TiFe2 brittle phases associated with the shift of the joining mode from the brazing to the fusion. The shear force decreased after reaching its maximum value, despite the joints being fully joined and the joining area expanding.

Effects of WC/TiC addition on the thermodynamic behavior of TiB2-based cermet during sintering process

The heat absorption, weight change and exhaust behavior of TiB2-based cermet powder mixtures with additions of WC, TiC and WC-TiC were analyzed by a simultaneous thermal analyzer coupled with a mass spectrometer (TG/DSC-QMS). Thermodilatometry was used to investigate the densification behavior due to sintering process of cermets. During the sintering process, the order of degassing is: water vapor, CO2 released by the reduction of adsorbed oxygen in the raw material powder, CO and CO2 released by the reduction of surface oxides of Co and Ni powder, WC powder, TiB2 and TiC powder. The addition of WC, TiC and WC-TiC accelerated the reduction of oxides on the surface of Co and Ni powders, and decreased the temperature point of liquid phase formation in TiB2-based cermet. WC and TiC dissolved in liquid CoNi binder and then precipitated on the undissolved TiB2 particles to form a typical core-rim structure during the sintering. This study is expected to lay a solid foundation for the development of high-performance TiB2-based cermets based on TiB2-CoNi, TiB2-WC-CoNi, TiB2-TiC-CoNi and TiB2-WC-TiC-CoNi cermets in the future.

Spark plasma sintering in the presence of a liquid phase

Spark plasma sintering (SPS) is a modern sintering technique based on the application of pulses of direct electric current and pressure to the powder sample. SPS is often regarded as a solid state sintering technique. At the same time, in many studies, the formation of a liquid phase during SPS was observed as an effect concurrent to the powder consolidation. Furthermore, in some cases, the formation of a liquid phase was intentionally stimulated. In this article, we aim to analyze the origin of the liquid phase formation during SPS and discuss its role in the microstructure development of different materials. Two situations are considered: melting occurring when the whole sample reaches a temperature required for the liquid to appear and melting of local character associated with overheating of the inter-particle contacts. The problems of the description of the SPS processes with liquid phases involved are discussed and possible future research directions in this area are proposed.

Modification of structural, morphological, and dielectric properties of barium calcium titanate ceramics with yttrium addition

Barium calcium titanate (BCT) ceramics with varying yttrium doping concentrations were fabricated using the solid-state compaction process to explore the attributes of dopants. (Ba0.75Ca0.25) TiO3 and (Ba0.75Ca0.25) (YyTi(1-y)) O3 where, y = 0.00, 0.10, 0.15, and 0.20 ceramics were synthesized by pressing isostatically in pellet press apparatus, then sintered at 1250 °C with consequent cooling in furnace ambient. The structural, morphological, and dielectric properties were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), and impedance spectroscopy interpretations, respectively. The XRD analysis revealed that the cubic BCT lattice was transformed into a tetragonal structure with Yttrium doping. Scanning electron microscopy (SEM) disclosed that yttrium doping countered the liquid phase formation of BCT as well as influenced grain development and microstructure, leading to the formation of distinct grain boundaries and improved densification. The average grain size (18–29 nm) of the Y-BCT increases as the doping level rises. At 60 Hz, it was reported that the dielectric constant obtained a maximum value of 70000 with a resistivity of 5 × 108 Ώ-cm for y = 0.15. The manifestation of the secondary phase confirmed from XRD, allocating an easy path for oxygen migration, might be responsible for the rise in oxygen vacancy, higher leakage current, and dielectric loss for y = 0.01. Co-doping of calcium and yttrium in BCT ceramics has modified the basic structure and ameliorated composites' structural stability and dielectric characteristics. The optimized sample, upon demonstrating outstanding efficiency, ought to be employed for specific uses such as energy storage devices and capacitors.

Potential Utilization of Iron Oxidation Reaction Heat for the Generation of SiO2–FeO System Melts

Silicon-containing steel forms an oxide layer within the scale during hot rolling. This layer comprising oxides such as Fe2SiO4 and FeO adversely affect the surface quality of steel owing to strong adhesion between Fe2SiO4 and the steel substrate. A method to melt this silicon-containing oxide layer through the oxidation reaction of iron plates by applying SiO2 powder to the surface is proposed. The aim of this study is to understand the reaction mechanism and identify the optimal conditions for this process. Application of SiO2 coating to the surface of an iron plate at 6.67 × 10–4 g·mm−2 and maintaining the plate at 1423 K, just below the eutectic temperature of Fe2SiO4–FeO system (1450 K), cause the surface oxide scale to melt when exposed to oxidation in an atmospheric environment. Notably, reducing the electric furnace temperature hinders the melting process, whereas excessive application of SiO2 hampers the formation of sufficient liquid phase. On the surface of the iron plate, primarily FeO and Fe2SiO4 are formed. Heat generation is mainly due to the formation of FeO, which leads to the rapid generation of Fe2SiO4. Eutectic reactions within SiO2–Fe2SiO4 or FeO–Fe2SiO4 systems drive the formation of the liquid phase. Once the liquid phase was established, rapid diffusion of iron ions within it resulted in rapid iron oxidation and additional heat generation. Ultimately, a liquid phase in equilibrium with FeO is formed across the entire surface of the iron plate.

Effects of CuO doping on the calcination and hydration performance of alite-belite-ferrite-ye'elimite cement

High-belite calcium sulfoaluminate cement (HBCSA) is a novel low-carbon cement, but the limited reactivity of belite (C2S) leads to gradual strength development. In this study, we developed an alite-belite-ferrite-ye'elimite cement (ABFY) incorporating C3S, and a high C4AF phase based on HBCSA. We explored the effects of CuO doping on the calcination and hydration properties of ABFY clinker. Various analytical techniques, including X-ray diffraction, scanning electron microscopy-energy dispersive X-ray spectroscopy, inductively coupled plasma-optical emission spectroscopy, thermogravimetric analysis and derivative thermogravimetry, and nuclear magnetic resonance, were employed to investigate the effects of CuO doping on the sintering and hydration properties of ABFY clinker. The results indicated that CuO doping preferentially enters the ferrite phase, promotes liquid phase formation, and enhances the sintering of the C3S and C4A3$ phases, thereby improving hydration activity. However, exceeding a CuO content of 0.5% results in the decomposition of C4A3$ into C12A7 and the transformation of C3S into the M-type. Dissolved Cu during hydration combines with SO42‐, affecting the transformation and formation of AFm and AFt, resulting in deteriorated later-stage performance. ABFY with 0.5 % CuO exhibits favorable hydration activity.

Geopolymers: A viable binder option for ultra-low-cement and cement-free refractory castables?

Alternative binders offer an avenue for advancing ultra-low-cement and cement-free castables while reducing carbon emissions and energy consumption. In this study, geopolymer binders partially or fully replaced calcium aluminate cement (CAC) in high-alumina castables. The formulations underwent diverse testing, including flowability, physico-thermo-mechanical measurements, and XRD, ATR-FTIR, and SEM analyses. The findings highlighted the feasibility of utilizing geopolymers to craft innovative refractories. The formulation comprising 2.7 wt% CAC and 1.3 wt% geopolymer (AT-3 C-1 G*) exhibited the most successful performance. At 1400 °C, these samples displayed shrinkage of 1.18%, elastic modulus of 135 GPa, flexural strength of 39.1 MPa, and high thermal shock resistance (∆T∼1000 °C). The interaction between CAC and geopolymer inhibited cement hydration while enhancing the geopolymerization process. Moreover, firing the samples at 800–1400 °C led to liquid phase and nepheline formation from the geopolymeric gel, resulting in viscous sintering and improved ceramic densification. These developments produced refractories with remarkable overall performance, surpassing the reference material.