Chloride Salt Mixtures Research Articles

Effect of NaCl replacement by other salt mixtures on myofibrillar proteins: Underlining protein structure, gel formation, and chewing properties.

The protein structure, gel changes, and chewing properties of low-sodium myofibrillar protein (MP) prepared by compound chloride salts (KCl/MgCl2, KCl/CaCl2, and KCl/MgCl2/CaCl2) and different substitution degrees (10%, 25%, and 40%) at same ionic strength (0.6M) were investigated. The results revealed that the low-sodium MP gels containing CaCl2 manifested more liquid loss and less moisture content accompanied by obvious morphological shrinkage, while KCl/MgCl2 contributed to the gel juiciness. At high substitution degree of 40%, KCl/CaCl2 substitution rendered the gel with dense structure and highest strength, but worse water retention capacity. Using other compound chloride salts influenced the chewing efficiency, and CaCl2 substitution made the gel relatively hard to chew. The inhomogeneous structure accompanied by cluster blocks in KCl/CaCl2-substituted MP gel accelerated the overall fracture rate. During heating process, more proteins in CaCl2-substituted MP did not participate in gel formation, intervening the final gel properties. The chloride salt mixtures containing MgCl2, rather than CaCl2, avoided or alleviated the liquid loss and shrinkage of low-sodium MP gel within the substitution degree of 10%-40%, and substitution degree not exceeding 25% was more reasonable for the controlled qualities.

Heterogeneous Structure, Mechanisms of Counterion Exchange, and the Spacer Salt Effect in Complex Molten Salt Mixtures Including LaCl3.

Complex molten chloride salt mixtures of uranium, magnesium, and sodium are top candidates for promising nuclear energy technologies to produce electricity based on molten salt reactors. From a local structural perspective, LaCl3 is similar to UCl3 and hence a good proxy to study these complex salt mixtures. As fission products, lanthanide salts and their mixtures are also very important in their own right. This article describes from an experimental and theory perspective how very different the structural roles of MgCl2 and NaCl are in mixtures with LaCl3. We find that, whereas MgCl2 becomes an integral part of multivalent ionic networks, NaCl separates them. In a recent article (J. Am. Chem. Soc. 2022, 144, 21751-21762) we have called the disruptive behavior of NaCl "the spacer salt effect". Because of the heterogeneous nature of these salt mixtures, there are multiple structural motifs in the melt, each with its particular free energetics. Our work identifies and quantifies these; it also elucidates the mechanisms through which Cl- ions exchange between Mg2+-rich and La3+-rich environments.

Partial Replacement of NaCl by KCl, MgCl2 and CaCl2 Chloride Salts in the Production of Sucuk: Effects on Volatile Compounds, Lipid Oxidation, Microbiological and Sensory Properties.

The effects of different chloride salt mixtures (I-control: 100% NaCl, II: 50:50-NaCl:KCl, III: 50:30:20-NaCl:KCl:MgCl2, IV: 50:30:20-NaCl:KCl:CaCl2, V: 50:30:10:10-NaCl:KCl:MgCl2:CaCl2) on the quality properties of sucuk (a dry fermented beef sausage) during ripening were investigated. Lactic acid bacteria reached 8 log cfu/g in the 3 days of fermentation in all treatments. However, salt mixtures including MgCl2 caused an increase in Micrococcus/Staphylococcus. The control group showed the lowest mean aw value at the end of ripening. The salt mixture with 20% CaCl2 showed the lowest mean pH value of 4.97. The mean TBARS value varied between 6.34 and 6.97 µmol MDA/kg but was not affected by the salt mixtures (p > 0.05). According to the results of PCA, salt mixtures I, II and III had a positive correlation in PC1, and PC1 also separated salt mixtures with CaCl2 (IV and V) from other groups. In addition, a strong positive correlation between the control and III group (50:30:20-NaCl:KCl:MgCl2) for sensory properties was determined by heatmap clustering analysis. In addition, the principal component analysis showed that the control, II, and III groups had a stronger correlation with each other for volatile compounds.

Corrosion of superheater materials by alkali chloride salt mixtures – The role of the presence of molten phase

In biomass combustion, the presence of alkali chlorides will lower the ash deposit melting temperature. It is also known that aggressive corrosion of superheater materials may occur in the presence of melt in contact with the steel. Therefore, the first melting temperature (T0) has been used as a guideline for the maximum superheater temperature. However, the impact of the share – or percentage - of molten phase in the salt deposit on corrosion has not been systematically investigated. In this work, the role of the share of molten phase on the corrosion of two stainless steel qualities, AISI 347 and 310, was studied. The salt mixtures used (NaCl-Na2SO4 and KCl-K2CO3) were prepared to produce different amounts of melt at the higher test temperature. The steels were exposed for one week to a salt mixture in a tube furnace, at temperatures both below and above T0. After the exposure, the samples were cut to reveal the cross-sections. The cross-sections were analysed by means of SEM-EDX. Remarkable differences in the corrosion tendencies of the materials were observed depending on the percentage of molten phase. The work revealed that for a certain steel quality a given minimum percentage of molten phase was required before observing severe corrosion. For the NaCl-Na2SO4 salt mixtures, around 3 wt% molten phase was sufficient to significantly accelerate the corrosion rate for AISI 347, while the corresponding value was 14 wt% for AISI 310. The criterion of first melting temperature T0 being the critical limit for severe superheater corrosion requires modification. The amount of liquid phase at T0 is also essential.Thecriticalamount of liquid phaseat T0for severe corrosion is steel specific.

Early-stage corrosion of IN 740H alloy in eutectic NaCl-KCl molten salt at high temperatures

The next generation concentrated solar power plants are expected to operate at temperatures above 700 °C and this would necessitate heat storage media such as chloride salt mixtures to be used for better heat transfer and energy storage. In this perspective, the corrosion behaviour of a commercial grade IN 740H alloy is being investigated in the eutectic equimolar NaCl-KCl salt mixture, at 700 °C and 800 °C. To evaluate and understand the early stages of corrosion of IN 740H, electrochemical and gravimetric tests were carried out after exposure to molten eutectic NaCl-KCl salt mixture for 1.5 and 24 h, respectively. The quantitative outcomes of the gravimetric studies suggest that IN 740H corrodes at 0.29 ± 0.03 and 0.59 ± 0.17 mg cm−2 day−1 at 700 °C and 800 °C, respectively. Tafel measurements reveal corrosion rates similar to those measured by gravimetric method. Electrochemical impedance spectroscopy analysis indicated the diffusion-controlled corrosion behaviour, but the passive layer does not inhibit corrosion at early stages. A correlation between the underlying mechanism and the oxide scale microstructure has been presented using electrochemical and cross-sectional studies.

Density and Electrical Conductivity of Molten Beryllium Fluoride–Alkali-Metal Chloride Salt Mixtures

Density and Electrical Conductivity of Molten Beryllium Fluoride–Alkali-Metal Chloride Salt Mixtures

Impact of iodide ions on the speciation of radiolytic transients in molten LiCl-KCl eutectic salt mixtures.

The fate of fission-product iodine is critical for the deployment of next generation molten salt reactor technologies, owing to its volatility and biological impacts if it were to be released into the environment. To date, little is known on how ionizing radiation fields influence the redox chemistry, speciation, and transport of iodine in high temperature molten salts. Here we employ picosecond electron pulse irradiation techniques to elucidate for the first time the impact of iodide ions (I-) on the speciation and chemical kinetics of the primary radiation-induced transient radicals generated in molten chloride salt mixtures (eS- and Cl2˙-) as a function of temperature (400-700 °C). In the presence of I- ions (≥ 1 wt% KI in LiCl-KCl eutectic), we find that the transient spectrum following the electron pulse is composed of at least three overlapping species: the eS- and the Cl2˙- and ICl˙- radical anions, for which a deconvoluted spectrum of the latter is reported here for the first time in molten salts. This new transient spectrum was consistent with gas phase density functional theory calculations. The lifetime of the eS- was unaffected by the addition of I- ions. The newly observed interhalogen radical anion, ICl˙-, exhibited a lifetime on the order of microseconds over the investigated temperature range. The associated chemical kinetics indicate that the predominate mechanism of ICl˙- decay is via reaction with the Cl2˙- radical anion. The iodine containing product of this reaction is expected to be ICl2-, which will have implications for the transport of fission-product iodine in MSR technologies.

Multi-cationic molten salt electrolyte of high-performance sodium liquid metal battery for grid storage

Multi-cationic molten chloride salt mixtures such as LiCl–KCl–NaCl are promising molten salt electrolytes for sodium liquid metal batteries (Na-LMBs). In this work, the melting temperature of LiCl–KCl–NaCl was determined with Differential Scanning Calorimetry (DSC), assisted by FactSage™ simulation and confirmed by a melting point apparatus OptiMelt™. It is founded that the eutectic LiCl–KCl–NaCl can be considered as a pseudo-binary system with LiCl–KCl eutectic (59.2–40.8 mol.%) as the solvent and NaCl as the solute. When NaCl is not more than 9 mol.%, the eutectic LiCl–KCl–NaCl salt mixture has a melting temperature of ∼350 °C as that of LiCl–KCl eutectic. In addition, the exchange reactions between anode Na metal with LiCl–KCl–NaCl molten salt electrolyte were studied at the temperature of 400–500 °C quantitatively. The equilibrium constants of the exchange reactions were determined by chemical analysis on the salt and metal phases with Ion Chromatography (IC). A one ampere-hour (Ah) Na-LMB test cell shows promising energy storage performance. Moreover, the phenomena in the cell test can be explained convincingly, combining the results of exchange reactions and the pseudo-binary-system theory. The findings on the multi-cationic molten salt electrolytes for Na-LMBs in this work could support further development of other liquid metal batteries.

Adsorptive carbons from pinewood activated with a eutectic mixture of molten chloride salts: Influence of temperature and salt to biomass ratio

The current market searches for technologies allowing for efficient and sustainable production of biomass-based activated carbons for their further application in the adsorption of pollutants. Chemical activation of biomass in a bed of molten salts is a novel and promising technology in that regard. However, an in-depth understanding of the process mechanism is low and optimal production conditions must be substantiated. Therefore, this study investigates the relationship between molten bed process conditions and properties of derived activated carbons. Pinewood shavings (ca. 1 mm) were mixed with three different ratios of an eutectic mixture of ZnCl2–KCl–NaCl (60:20:20 mol %) and subsequently treated at 400, 500 and 600 °C under an inert atmosphere. After washing, the properties of activated carbons were characterised with elemental and proximate analysis, FTIR, gas adsorption (N2, CO2) and adsorption of iodine and methylene blue. The pore size distribution of activated carbons indicates that the presence of molten salts during conversion enhances micropore and mesopore formation. At 400 °C with a salt to biomass ratio of 5, the optimal structural properties of activated carbon with a specific surface area of 844 m2/g, was obtained. Its adsorption capacity of methylene blue (144 mg/g) and iodine (725 mg/g) were also satisfactorily high. This study confirms that optimum parameters for chemical activation with molten salts (temperature and salt to biomass ratio) towards functional materials can be achieved. Further process development may lead to a novel and efficient technology for the production of bio-based activated carbons.

Behavior of Glass-like and Mineral-like Phosphate Compounds with an Immobilized Chloride Mixture in Hydrogen Peroxide Solutions

A new type of high-level waste (HLW) is generated during pyrochemical reprocessing of mixed nitride spent uranium–plutonium nuclear fuel. Such waste is a spent electrolyte, which is a mixture of chloride salts containing approximately 25.7 wt.% LiCl + 31.6 wt.% KCl + 4.1 wt.% CsCl + 5.1 wt.% BaCl2 + 3.8 wt.% SrCl2 + 29.7 wt.% LaCl3, and its immobilization in reliable matrices is an actual radiochemical problem. The structure and hydrolytic stability of sodium aluminoironphosphate (NAFP) glass and a low-temperature mineral-like magnesium potassium phosphate (MPP) matrix, which are promising for spent electrolyte immobilization in the presence of hydrogen peroxide solutions simulating natural water radiolysis products, were studied in this work. The structure of the samples was studied using the SEM-EDS method. It was shown that the initial samples of NAFP glass after leaching in hydrogen peroxide solutions are prone to precipitation of crystalline phases on the surface, which are mainly represented by a mixture of sodium–iron–aluminum pyrophosphates. It was established that the leaching rate of structure-forming components of NAFP and MPP matrices generally increase, but remain at a low level, meeting modern requirements for HLW immobilization. This confirms the effectiveness of the studied matrices for the industrial use of the spent electrolyte.

Electrochemical Corrosion Studies in Molten Chloride Salts

This study investigates corrosion of Fe–(Cr)–Ni model alloys in eutectic molten chloride salt mixtures that broadly simulate the heat transfer circuits of molten salt cooled nuclear reactors. The primary focus is impurity-driven corrosion and selective dissolution of electrochemically reactive element(s) (dealloying), which are known degradation modes for Fe– and Ni-based alloys in molten salts. This study demonstrates that a Mg rod performs close to a true Mg∣Mg2+ reference electrode system in a MgCl2 containing mixture. Mg dynamic reference electrodes validated the performance of the ordinary Mg reference electrode. The residual moisture content in molten salts is measured by cathodic polarization of Pt, which showed that convection of molten salts, after step-wise heating, through a bundle of Mg ribbons dropped the moisture content by 30-fold. The effect of impurities in the molten salt mixture, moisture and NiCl2, on dealloying was also investigated at low homologous temperature. It was found that the universal parting limit for dealloying is decreased to a value of approximately 32 at% Fe when Ni from the parent alloy is close to equilibrium with Ni2+ ions added to the eutectic molten salts. Results support the percolation/surface diffusion concept for dealloying in molten salts at low homologous temperature.

A sodium liquid metal battery based on the multi-cationic electrolyte for grid energy storage

Sodium-based batteries are very promising for large-scale applications in near future, thanks to the great abundance and low cost of sodium. Herein, a high-performance liquid metal battery with a negative electrode of metallic sodium is developed. As the metallic sodium has a low melting point (∼ 98°C) and weak corrosion to ceramic seals, the sodium liquid metal batteries (Na-LMBs) offer the merits of low operating temperature, low cost, long lifespan and high safety. However, sodium metal has a high solubility in the electrolyte of single-cationic molten sodium halide mixtures such as NaF-NaCl-NaI due to a high melting point above 500°C, resulting in high self-discharge and low coulombic efficiency. In this work, a multi-cationic ternary molten chloride salt mixture LiCl-NaCl-KCl (59:5:36 mol %) with a melting point lower than 400°C was designed as the electrolyte, which effectively inhibits the dissolution of sodium in the electrolyte. Further, by adopting a dual-active Bi9Sb alloy positive electrode, the active material utilization was improved. At 100 mA cm−2, the battery ran stably over 700 cycles at 450°C with a coulombic efficiency of 97%, and active material utilization of about 80%. The battery also exhibited decent rate performance within the current densities of 100-1000 mA cm−2. The calculation based on a 1 MW/5 MWh demo energy storage plant indicates that the estimated Levelized Cost of Storage (LCOS) of the Na-LMB is lower than 0.029 $/kWh. These results demonstrate the Na-LMB as a promising technology for grid-scale energy storage applications.

Effect of partial substitution of NaCl by KCl , CaCl 2 , and MgCl 2 on properties of mixed gelation from myofibrillar protein and Flammulina velutipes protein

The effects of substitution of sodium chloride (NaCl) by chloride salt mixtures (KCl, CaCl2, and MgCl2) with different formulas on quality characteristics of mixed protein system containing 80% myofibrillar protein (MP) and 20% Flammulina velutipes protein (FVP) were investigated in this study. The addition of chloride salts (KCl, CaCl2, and MgCl2) into a reduced-sodium (0.3 M NaCl) mixed gel system, increased the gel properties, and network structure of the MP-FVP gel, which might be attributed to the increase in protein solubility and rheological properties. The examination of the turbidity, particle size, zeta potential, UV spectroscopy, and Fourier transform infrared spectroscopy indicated that the protein molecules were obviously aggregated, that the electrostatic interaction was weakened, that the hydrophobic interaction and β-sheet content was increased. The results showed that when KCl, CaCl2, and MgCl2 were used to replace NaCl at 35, 10, and 5%, respectively, the gel properties reached the maximum. Practical applications This study evaluated the effects of different types of sodium salt substitution on the structural properties of proteins and the structural properties of mixed myofibrillar protein and Flammulina velutipes protein gels. The results revealed that the mixed protein molecules apparently aggregated under different replacement of KCl, CaCl2, and MgCl2 (i.e., 35, 10, and 5%). The hydrophobicity and β-sheet content significantly increased, while the electrostatic interaction decreased, leading to enhanced mixed gel properties. The results indicated the different replacements of sodium salts could improve the gels characteristics, which may be a guide for the future production of low-salt meat products.

Pinewood Activation with Eutectic Mixture of Chloride Salts Towards High Adsorptive Carbons: Influence of Temperature and Salt to Biomass Ratio

Pinewood Activation with Eutectic Mixture of Chloride Salts Towards High Adsorptive Carbons: Influence of Temperature and Salt to Biomass Ratio

Perspective Compounds for Immobilization of Spent Electrolyte from Pyrochemical Processing of Spent Nuclear Fuel

Immobilization of spent electrolyte–radioactive waste (RW) generated during the pyrochemical processing of mixed nitride uranium–plutonium spent nuclear fuel is an acute task for further development of the closed nuclear fuel cycle with fast neutron reactors. The electrolyte is a mixture of chloride salts that cannot be immobilized directly in conventional cement or glass matrix. In this work, a low-temperature magnesium potassium phosphate (MPP) matrix and two types of high-temperature matrices (sodium aluminoironphosphate (NAFP) glass and ceramics based on bentonite clay) were synthesized. Two systems (Li0.4K0.28La0.08Cs0.016Sr0.016Ba0.016Cl and Li0.56K0.40Cs0.02Sr0.02Cl) were used as spent electrolyte imitators. The phase composition and structure of obtained materials were studied by XRD and SEM-EDS methods. The differential leaching rate of Cs from MPP compound and ceramic based on bentonite clay was about 10−5 g/(cm2·day), and the rate of Na from NAFP glass was about 10−6 g/(cm2·day). The rate of 239Pu from MPP compound (leaching at 25 °C) and NAFP glass (leaching at 90 °C) was about 10−6 and 10−7 g/(cm2·day), respectively. All the synthesized materials demonstrated high hydrolytic, mechanical compression strength (40–50 MPa) even after thermal (up to 450 °C) and irradiation (up to 109 Gy) tests. The characteristics of the studied matrices correspond to the current requirements to immobilized high-level RW, that allow us to suggest these materials for industrial processing of the spent electrolyte.

Effects of calcium, magnesium, and strontium chlorides in determining the total acid number using potentiometric titration

The most widely used method for determining the total acid number (TAN) in crude oils is American Society for Testing and Materials (ASTM) D664, which is subject to interference from hydrolyzable salts. This study investigated and determined at which salt concentration NaCl, CaCl2, MgCl2, and SrCl2 significantly interfere with the determination of the TAN in crude oil using the ASTM D664 method. To evaluate the influence of salts on the titration solvent of ASTM D664 and crude oil, pure chloride salts, and two mixtures of these salts, were added to the titration solvents (at 1500–8000 mg kg−1) and water-in-oil emulsions (alpha and gamma). Precipitation was observed during the titrations of these solvents. Analysis of the precipitates via gravimetric analysis, X-ray diffraction, and attenuated total reflection Fourier transform infrared spectroscopy demonstrated that they were composed of Ca(OH)2, Mg(OH)2, and Sr(OH)2. The alpha oil exhibited an increase in acidity from 0.28 up to 2.47 mg KOH g−1 with the chloride salt mixtures, whereas gamma oil exhibited an increase in acidity from 2.26 up to 4.17 mg KOH g−1 with the chloride salt mixtures. One hundred milligrams of CaCl2, MgCl2, or SrCl2 remaining in the oil was sufficient to interfere with the in TAN determination using the ASTM D664 method.

Cyclotetrabenzil-Based Porous Organic Polymers with High Carbon Dioxide Affinity

Porous organic polymers (POPs) incorporating macrocyclic units have been investigated in recent years in an effort to transfer macrocycles' intrinsic host–guest properties onto the porous networks to achieve complex separations. In this regard, highly interesting building blocks are presented by the family of cyclotetrabenzoin macrocycles with rigid, well-defined, electron-deficient cavities. This macrocycle shows high affinity towards linear guest molecules such as carbon dioxide, thus offering an ideal building block for the synthesis of CO2-philic POPs. Herein, we report the synthesis of a POP through the condensation reaction between cyclotetrabenzil and 1,2,4,5-tetraaminobenzene under ionothermal conditions using the eutectic zinc chloride/sodium chloride/potassium chloride salt mixture at 250 °C. Notably, following the condensation reaction, the macrocycle favors three-dimensional (3D) growth rather than a two-dimensional one while retaining the cavity. The resulting polymer, named 3D-mPOP, showed a highly microporous structure with a BET surface area of 1142 m2 g−1 and a high carbon dioxide affinity with a binding enthalpy of 39 kJ mol−1. Moreover, 3D-mPOP showed very high selectivity for carbon dioxide in carbon dioxide/methane and carbon dioxide/nitrogen mixtures.

Tribological behavior of ceramic-alloy bearing contacts in molten salt lubrication for concentrating solar power

Molten salts are considered as candidate heat transfer fluids and thermal energy storage media for next generation concentrating solar power (CSP). A molten salt circulates inside the piping and heat exchanger and also functions as a lubricant for the sleeve bearings of the CSP pump. Wear- and corrosion-resistant high-temperature bearing materials are critical for the pump efficiency and durability. This study evaluated the tribological performance of candidate bearing materials in lubrication of a molten chloride salt mixture (20% NaCl + 40% MgCl2 + 40% KCl) at 750 °C in an inert argon gas (a simulative CSP pump environment). Six ceramic-alloy pairs were tested, zirconia and silicon nitride against Haynes 244, Hastelloy C276, and Tribaloy T900 alloy, and ranked by the friction coefficient and wear loss. Characterization of worn surfaces suggested the wear mechanism as a combination of abrasion, adhesion, and tribocorrosion. Results from this study provide fundamental insight for the development and selection of bearing materials for molten salt powered CSP pumps.

Effects of Particle Size and Concentration of Magnesium Oxide on the Lubricating Performance of a Chloride Molten Salt for Concentrating Solar Power

One engineering challenge for the next-generation concentrating solar power (CSP) is to identify appropriate heat transfer and thermal energy storage media. A chloride salt mixture (20 wt % NaCl + 40 wt % MgCl₂ + 40 wt % KCl) in a molten phase is proposed as a potential fluid for carrying the heat as well as lubricating the CSP pump bearings. Due to the hygroscopic nature of MgCl₂, the presence of magnesium oxide (MgO) particles is inevitable. In order to understand the impact of MgO particles, this study investigated the tribological behavior of the molten chloride salt mixture containing MgO of various particle sizes and concentrations. Tests were conducted at 750 °C in a dry Ar environment using a zirconia ball sliding against a Haynes 244 alloy disc lubricated by the molten salt. There was a clear trend of the increased friction coefficient and wear loss for a larger particle size and/or a higher concentration of MgO. Distinct wear mechanisms were identified for the ceramic ball and alloy disc. Results provide fundamental insights for this new research avenue of molten salt lubrication for CSP.

Progress in Research and Development of Molten Chloride Salt Technology for Next Generation Concentrated Solar Power Plants

Concentrated solar power (CSP) plants with thermal energy storage (TES) system are emerging as one kind of the most promising power plants in the future renewable energy system, since they can supply dispatchable and low-cost electricity with abundant but intermittent solar energy. In order to significantly reduce the levelized cost of electricity (LCOE) of the present commercial CSP plants, the next generation CSP technology with higher process temperature and energy efficiency is being developed. The TES system in the next generation CSP plants works with new TES materials at higher temperatures (> 565 °C) compared to that with the commercial nitrate salt mixtures. This paper reviews recent progress in research and development of the next generation CSP and TES technology. Emphasis is given on the advanced TES technology based on molten chloride salt mixtures such as MgCl 2 /NaCl/KCl which has similar thermo-physical properties as the commercial nitrate salt mixtures, higher thermal stability (> 800 °C), and lower costs (< 0.35 USD∙kg −1 ). Recent progress in the selection/optimization of chloride salts, determination of molten chloride salt properties, and corrosion control of construction materials (e.g., alloys) in molten chlorides is reviewed.