NaCl KCl Research Articles

Comparison of Hot Corrosion Behavior of Ni36Fe34Al17Cr10Mo1Ti2 and Ni34Co25Fe12Al15Cr12W2 Alloys in NaCl–KCl–Na2SO4 Salt

Comparison of Hot Corrosion Behavior of Ni36Fe34Al17Cr10Mo1Ti2 and Ni34Co25Fe12Al15Cr12W2 Alloys in NaCl–KCl–Na2SO4 Salt

Effect of aggregation on thermal conduction in ternary molten salt-based nanofluids: insights from a multiscale coupled MD–LBM method

Molten salts serve as primary heat transfer and storage media in thermal energy storage systems. Adding nanoparticles to molten salt to create nanofluids is known to significantly improve the thermal conductivity of the molten. However, nanoparticle agglomeration is inevitable and substantially affects the thermal conductivity of molten salts. Moreover, the mechanisms whereby agglomeration influences thermal conductivity remain unclear. This paper presents an innovative multiscale coupling model that combines molecular dynamics (MD) simulations with the lattice Boltzmann method (LBM) to investigate the thermal conductivity of CuO nanoparticles in ternary NaCl–KCl–LiCl molten salt-based nanofluids. Both nonaggregated and aggregated states were considered. After conducting MD simulations at the microscale to examine the thermal contact resistance at the interface between nanoparticles, we employed the LBM to determine the effective thermal conductivity of the nanofluids at the mesoscale. The findings reveal the formation of significant heat flow channels in nanofluids containing nanoparticles. However, an increase in the thermal contact resistance reduces these channels in agglomerated particles, potentially reducing the thermal conductivity compared with that in the nonaggregated nanofluids. In cluster-like structures, fewer nanoparticles are positioned within heat flow channels, in contrast to chain-like arrangements. This reduction limits the enhancement in the thermal conductivity and minimizes variations in the thermal conductivity due to differences in the aggregate particle number and orientation. Furthermore, the thermal conductivity exhibited notable variations with varying agglomerated nanoparticle diameters at identical mass fractions. Both smaller and larger particles can increase the level of contact thermal resistance, ultimately reducing the thermal conductivity.

Effect of grain size on high-temperature corrosion performance of laser cladding inconel 625 coating

As the calorific value of waste-to-energy incineration continues to rise, the corrosion damage to boilers becomes increasingly severe. The impact of the grain size on the high-temperature corrosion resistance of Inconel 625 coating was investigated. The results indicated that the corrosion performance of the coating in 1:1 NaCl–KCl salts at 700 °C for 120 h was highly dependent on the grain size of the coating. The coating fabricated with a laser power of 1800 W and an overlapping distance of 1.5 mm had an average grain size of 13.7 μm and highest hardness, exhibiting the best corrosion performance, with a corrosion weight loss of 1.4 mg/cm2. Coatings processed under different conditions all formed a three-layered structure, with a NiO outermost layer, a Cr2O3 intermediate layer, and an innermost Cr-depletion zone. Coatings with finer grains formed a continuous and dense protective oxide layer of NiO and Cr2O3 due to the rapid diffusion of alloy elements, effectively preventing the invasion of corrosive media and protecting the substrate from corrosion.

Microstructure and thermal properties of ternary chloride eutectic salts for high temperature thermal energy storage

Chloride molten salts are attractive candidate materials used for effective thermal energy transfer and storage in renewable energy system as concentrating solar power, but associated thermal properties at high temperature are still insufficient in research. In this work, eutectic point verification, microstructure and thermal properties of NaCl–KCl–ZnCl2 eutectic salts with four different contents are investigated by molecular dynamics simulation based on Born-Mayer-Huggins potential and experimental measurement. The density, specific heat capacity, viscosity, self-diffusion coefficient and thermal conductivity of four ternary eutectic salts are predicted with experimental validation and their correlations with different temperature and composition are proposed, and the mechanism of desirable thermal performance variation is revealed from the microscopic point of view. As ZnCl2 content increases, the thermal conductivity and specific heat capacity increase significantly, and eutectic salt #4 (18.6 %NaCl: 21.9 %KCl: 59.5 %ZnCl2) has maxima of density, specific heat capacity and thermal conductivity. The above phenomena can be attributed to the increase in potential energy and Columbic energy for more charge of Zn2+, which strengthens the interaction between atoms in the system and intensifies the collision. This work is expected to provide effective guidance on the design and application of molten salts for high temperature thermal energy storage.

Thermal performance of MgCl2–NaCl–KCl eutectic salt for the next generation concentrated solar power and correlation between structure and thermophysical properties: Insights from atomic and electronic levels

MgCl2–NaCl–KCl (MgNaK) eutectic salt has emerged as a highly promising candidate for concentrated solar power (CSP), with extensive research conducted in recent years. However, the thermal property data for the MgNaK eutectic salt are still very limited. Here, we present a novel and accurate many-body potential trained by machine learning (ML) for MgNaK eutectic salt (with mole fractions of 45.4 %, 33 %, and 21.6 % respectively), developed using energies and forces extracted from first-principles molecular dynamics calculations (FPMD). The performance of the potential is well tested. We conduct a detailed investigation on the temperature-dependent structural and corresponding thermal properties, analyzing them from both the atomic and electronic perspectives. The introduction of Na+ or K+ ions disrupts the net structure formed by corner-joint and edge-joint MgClx units, thereby affecting the transport properties. The calculated density (ρ) and constant pressure specific heat capacity (CP) exhibit agreement with experimental data within a margin of 2 %. We observe and discuss the typical λ of negative linear temperature correlation, which is similar to other molten alkali chloride salts. Finally, based on the simulated and experimental values, we provide reliable recommendations for the λ and viscosities (η) of MgNaK eutectic salt across its entire operating temperature range.

Online monitoring of solubility of Li2CO3 in the NaCl–KCl–Na2SO4 system

ABSTRACT The solubility and thermodynamics of lithium carbonate (Li2CO3) play an important role in industrial crystal production. The solubility of Li2CO3 in H2O, NaCl, KCl, Na2SO4 and mixed NaCl–KCl–Na2SO4 solutions is measured, respectively, at temperatures ranging from 293.15 K to 368.15 K using the gravimetric method and immersion infra-red probe. The results suggested that the solubility of Li2CO3 exhibits a decreasing trend with increasing temperature. The impurity composition such as NaCl, Na2SO4 and NaCl–KCl–Na2SO4 can significantly affect the solubility of Li2CO3. It is higher than that in pure water, and the addition of KCl decreases its solubility in the temperature ranging from 293.15 K to 313.15 K. The Van’t Hoff and modified Apelblat models are further employed to correlate the solubility data of Li2CO3 in different systems. In addition, the thermodynamic data of Li2CO3 are calculated, which shows a non-spontaneous exothermal process and entropy reduction.

Effects of sodium chloride intake on urea-N recycling and renal urea-N kinetics in lactating Holstein cows

The effects of high (2.5% of DM) versus normal dietary sodium chloride (NaCl) intake on renal urea-N kinetics and urea-N metabolism were investigated in 9 rumen-cannulated and multi-catheterized lactating dairy cows in a crossover design with 21-d periods. It was hypothesized that urinary urea-N excretion would be greater, and blood urea-N concentration lower in response to greater diuresis induced by high NaCl intake. Also, urea-N transport across ruminal and portal drained viscera (PDV) tissues was hypothesized to be affected by dietary sodium intake. A second experiment was conducted using 8 lactating cows in a crossover design with 14-d periods to test high NaCl (2.5% of DM) versus high KCl (3.2% of DM) intake on milk yield and milk urea-N concentrations. Experiment 1 showed that despite greater diuresis there was no effect of high NaCl intake on urinary urea-N excretion or blood urea-N concentration. The high NaCl intake did not affect rumen ammonia concentrations, total rumen VFA concentrations, ruminal venous - arterial concentration differences for ammonia, or ammonia absorption indicating that high NaCl did not adversely affect ruminal fermentation and microbial protein synthesis. High NaCl intake did not affect the total amount of urea-N transport from blood to gut, but ruminal venous - arterial concentration differences for urea-N were lower with high NaCl and ruminal extraction of arterial urea-N was numerically smaller, indicating that the ruminal epithelial urea-N transport was lower with high NaCl. Energy corrected milk yield was greater with high NaCl (3.2 ± 1.5 kg/d); however, milk urea-N concentrations were not affected by treatment. In experiment 2, ECM was greater with NaCl (1.4 ± 0.31 kg/d) compared with KCl (30.2 and 28.8 ± 0.91 kg ECM / d, respectively). Milk urea-N concentration was lower with KCl, suggesting a urea-N lowering effect in milk not evident with high NaCl intake. In conclusion, the present data show that dietary Na intake of 12-13 g/kg DM was followed by greater diuresis but did not impact urea-N excretion or blood urea-N concentration. High NaCl intake did not affect the total amount of urea-N transfer across PDV tissues. Energy corrected milk yield was greater with high NaCl compared with both control and feeding KCl, however, with KCl milk urea-N decreased.

Preparation and heat storage characteristics of high-temperature phase change macrocapsules of chloride eutectic salt

Chloride salts, as high-temperature phase change materials (PCMs), have advantages in terms of high application temperature and high latent heat, but the intrinsic disadvantages such as high corrosiveness and easy leakage have seriously limited their development. Employing the NaCl–KCl binary salt as PCM, a double-shell cladding strategy with an inner layer of expanded graphite and an outer layer of ceramic was proposed, thereby, the chloride phase change macrocapsule with good thermal storage performance was successfully prepared. The double-shell capsules exhibited better leakage resistance and cycling stability. On this basis, the preparation process of double-shell eutectic salt macrocapsules was simplified by using an in-situ melting method, employing the mixed NaCl and KCl as raw materials directly that were transferred to eutectic binary salt inside the capsules during sintering. It is also proposed to improve the heat storage density of the capsules by increasing the capsule size and isostatically pressing the capsule. The NaK-20-200MPa sample indicated the largest heat storage density in the temperature range from 600 °C to 700 °C, with a mass heat storage density of 190.38 J/g, which was 2.85 % higher than that of the NaK-20-0MPa capsules and 36.99 % higher than that of the NaK-5-0MPa capsules. Additionally, the volume heat storage density of the NaK-20-200MPa capsules was 339.19 J/cm3, which was 14.69 % higher than that of the NaK-20-0MPa capsules and 21.52 % higher than that of the NaK-5-0MPa capsules. The good thermal performance and low cost of chloride PCM could ensure the encapsulated salt for use in high-temperature heat storage.

A low-temperature molten salt synthesis strategy of Eu2Ti2O7 ceramic enabling ultra-durable glass-ceramic waste forms

The conventional solid-phase sintering method for the preparation of Ln2Ti2O7 ceramics using oxides as reactants generally requires higher temperature, larger pressure, and greater energy consumption. In this paper, we synthesize a Eu2Ti2O7 ceramic powder in relatively low-temperature molten salt (KCl–NaCl) using Eu2O3 powder and TiO2 powder as reactants at 1000 °C. The results of XRD, SEM, and element mapping indicate that the product have high phase purity, good crystal morphology and uniform chemical composition. Moreover, Eu2Ti2O7-based glass-ceramics are obtained by sintering with different contents of borosilicate glass. The SEM images of glass-ceramic show that almost no obvious defects or voids are found on the surface of the samples. The values of water absorption for all glass-ceramic waste forms are less than 0.5 %. With the increase of ceramic embedding rate, the hardness of the glass-ceramics first increases and then decreases, while the density gradually increases. When the embedding rate increased to 30 wt%, the hardness of glass-ceramic reaches a maximum of 19.53 GPa. The glass-ceramic waste form embedded with 30 wt% Eu2Ti2O7 exhibits very stable chemical durability with a low leaching rate of 1.42 × 10−8 g m−2 d−1 at 90 °C even after 28 days.

Electrochemical Behavior of Pb(II) in NaCl–KCl Molten Salts

Electrochemical Behavior of Pb(II) in NaCl–KCl Molten Salts

Machine learning model to efficiently predict the structure and properties of MgCl2–NaCl–KCl melts

MgCl2–NaCl–KCl ternary melts hold great promise as thermal energy storage and heat transfer fluid for the next generation of concentrating solar power (CSP), offering major advantages such as high-temperature storage capacity, adjustable temperature ranges, and renewable usability. However, a critical challenge is the lack of an accurate model to analyze the structural and property aspects of this complex melt. In response, a machine learning-based model with high accuracy and applicability has been developed for this purpose. Based on DPMD techniques, the trained model is used to investigate the structure information, transport and thermal properties of the melt. Temperature and composition effects are introduced. Radial distribution functions, coordination numbers, and angular distribution functions are applied to investigate the microscopic ionic environment within the melt. Transport properties studied include density, self-diffusion coefficient, ionic conductivity, and viscosity, while thermal properties include heat capacity at constant pressure and volume and thermal conductivity. Our model accurately reproduces the results obtained from FPMD simulations and accurately predicts the macroscopic properties of the melt through validation. The high stability of the Mg2+-Cl- interactions is introduced, which remains relatively unaffected by temperature and concentration changes. The presence of MgCl53− species in the melt was observed. We are devoted to the development of AI for the CSP science field. Due to the application of machine learning strategies, our models have proven to have exceptional accuracy and ease of study for MgCl2–NaCl–KCl ternary melts, and they can provide valuable insights into their properties and ionic behaviors.

Corrosion behaviour of FeCoNiCrAl high-entropy alloy in molten NaCl–KCl–MgCl2 chloride salt

Molten NaCl–KCl–MgCl2 is becoming a potential heat transfer fluid (HTF) and thermal energy storage (TES) material in the third generation of concentrated solar energy power (CSP) stations due to its excellent heat storage-capacity and thermal stability. However, the strong corrosion of the molten chloride salt at high temperature limits its industrial application. In this study, the corrosion behaviour of FeCoNiCrAl HEA with BCC + FCC phase structure in molten NaCl–KCl–MgCl2 (24.5–20.55–54.95 wt-%) at 650 °C under argon was investigated by a combination of weight loss and electrochemical methods. The results show that, the corrosion of FeCoNiCrAl HEA in molten chloride salt mainly manifests as the selective dissolution of Fe and Cr. With the further increase of immersion time, oxides gradually crack and slightly flake, resulting in large weight loss of FeCoNiCrAl HEA.

Enhanced preparation of dendritic metallic vanadium in recyclable NaCl–KCl–VCl2 molten salt by V2CO electrolysis

Enhanced preparation of dendritic metallic vanadium in recyclable NaCl–KCl–VCl2 molten salt by V2CO electrolysis

Formation of Porous Gold Electrodeposits by Pulse Technique in AlCl<sub>3</sub>–NaCl–KCl Molten Salt Containing AuCl

Formation of Porous Gold Electrodeposits by Pulse Technique in AlCl<sub>3</sub>–NaCl–KCl Molten Salt Containing AuCl

Al2O3 nanoparticles for enhanced thermal performance in NaCl–KCl–Na2CO3 system: From thermodynamic prediction to system level assessment

With the introduction of the Brayton cycle technology, molten salts have become one of the most promising thermal storage materials in thermal energy storage (TES) systems. In this study, a novel eutectic salt (ES) NaCl–KCl–Na2CO3 was used as the base salt and Al2O3 nanoparticles (NPs) as additives to prepare Nano-ES. Both thermal analysis and molecular dynamics results showed that the doping of Al2O3 NPs improved the thermophysical properties of the ES. In particular, the TES density and liquid-state thermal conductivity of the ES increased by 11.60 % and 28.62 %, respectively, when the content of NPs was 2.0 wt%. The improvement in thermophysical properties was attributed to the NPs-induced change in the microstructure of the ES. However, the doping of NPs led to inevitable increase in the viscosity of the ES, which directly affected the strength of natural convection. This study further analyzed the melting process of ES and Nano-ES in shell-tube TES system, and the results showed that the melting rate of TES materials was affected by natural convection and thermal conductivity. The ES with lower viscosity and thermal conductivity exhibited a melting rate close to that of Nano-ES at 420–540 s stage. The viscosity of the TES materials should not be neglected during the application of TES systems. This study provides an important guiding significance for the selection of molten salts and additives for high-temperature TES systems.

Study of the electrochemical behavior of Ni(II) impurity in MgCl2–KCl–NaCl melt

Study of the electrochemical behavior of Ni(II) impurity in MgCl2–KCl–NaCl melt

Membrane behavior of clay under mixed solution conditions

Compacted clay is employed as the buffer material for landfills, and multiple ions are dissolved in the leachate restricted by the compacted clay layer. The membrane efficiency is an important indicator to assess the barrier properties of the compacted clay layer and is measured through membrane tests. However, most membrane tests are currently conducted with a single solute solution, which does not reflect the mixed solution characteristics of leachates. To assess the membrane efficiency of compacted clay under mixed solution conditions, 13 membrane tests were conducted on a bentonite-amended soil using KCl–NaCl mixed solutions, KCl–CaCl2 mixed solutions, and KCl–AlCl3 mixed solutions with different mixing ratios at a total concentration of 20 mM. Nuclear magnetic resonance (NMR) tests were conducted on the soil specimen after the membrane tests to investigate the micromechanism of the membrane behavior under mixed solution conditions. Results indicate that the membrane efficiency increased with the mixing ratio of Na+ but decreased with the mixing ratio of Ca2+ or Al3+. In the 13 membrane tests, the lowest membrane efficiency was achieved when the specimen was tested with pure AlCl3 solution. The relationship between the membrane efficiency and mixing ratio was also investigated at the microscopic scale. As the ion valence increases, the diffuse double layer thickness is smaller and the proportion of macropores is larger, as verified by NMR tests.

Coagulation/Floculation Of Slaughter Effluent Using Moringa Oleifera Lam as A Coagulant

Objective: In view of the growing need for low-cost, easily accessible alternative wastewater treatments, this study aimed to evaluate the influence of a natural product (Moringa oleifera lam), when used as a coagulant, on the removal of turbidity and color from a pig slaughterhouse effluent. Method/design/approach: The coagulant was prepared in saline solution (NaCl - 1M) and saline solution (KCl - 1M), all the coagulant solutions were prepared at the time of the test. In order to assess the effect of the coagulant on the effluent, coagulation/flocculation tests were carried out using the Jar- test apparatus, evaluating the effects of dosages of 200, 500, 1000, 1500 and 2000 mg/L of Moringa in saline solution (NaCl and KCl). The parameters analyzed were color and turbidity. Results and conclusion: According to the results of the statistical analysis, the optimum dosages obtained for the coagulants Moringa NaCl and Moringa KCl were 1000 and 1500 mg/L, respectively. With these dosages, removal of 63.9% for turbidity and 56.3% for color was observed when using NaCl saline solution and removal of 57.4% for turbidity and 45.2% for color when using the coagulant in KCl saline solution. Implications of the research: The main implication of the study is a proposal to evaluate the efficiency of the coagulation/flocculation/decantation process of pig slaughterhouse effluent, using natural coagulants, in the removal of organic matter. Due to the many problems caused by the use of chemical coagulants, such as aluminum sulfate and aluminum polychloride, which are used worldwide, there is a great demand for an alternative coagulant that is mainly natural. Originality/value: The study seeks to contribute to improving the management of water resources, in terms of local management. The use of natural coagulants, produced locally and at a low cost, can alleviate the problems linked to the discharge of untreated wastewater into receiving water bodies and the consumption of non-potable water.

A biphase coupled cathode enables all-organic rocking-chair lithium ion batteries based on crystalline AB-stacked covalent triazine-based frameworks

Crystalline AB-stacked CTFs were synthesized in the AlCl3–NaCl–KCl ternary eutectic salt system, and a CTF-based biphase coupled cathode (BPCC) has been proposed and proved to show significantly enhanced electrochemical performance.

Molten salt synthesized La- substituted CaTiO3 thermoelectric ceramics

Benefiting from molten salts as reaction media, molten salt synthesis (MSS) offers advantages such as control of local reaction conditions to tailor material characteristics, the production of uniform and homogeneous crystallites, as well as reduced energy consumption and emissions. In this study, we successfully synthesized regular polyhedral La-substituted CaTiO3 with an orthorhombic perovskite structure under molten salt conditions, utilizing a NaCl–KCl eutectic mixture at 1073 K for 6 h. The phase compositions of the prepared samples were determined through powder X-ray diffraction (XRD), and their morphologies were characterized via scanning electron microscopy (SEM). Our investigation of the thermoelectric properties reveals that the substitution of La3+ ions significantly enhances electrical conductivity and simultaneously introducing defects that substantially reduce lattice thermal conductivity. We achieved a maximum thermoelectric figure of merit (ZT) of approximately 0.27 at about 1200 K for the sample with a nominal composition of Ca0.8La0.2TiO3. This study is intended as a reference to experimentalists working in MSS for synthesizing CaTiO3-based ceramics and discloses the transport properties of La-doped CaTiO3-based ceramics.