Magnesium Chloride Hexahydrate Research Articles

Research on the Influence of Thermal Decomposition of Magnesium Chloride Hexahydrate on the Preparation of Magnesium Oxide and Hydrated Magnesium Hydroxide

Magnesium chloride hexahydrate is an important intermediate product in magnesite processing. In order to promote the efficient utilization of magnesite resources, based on the pyrolysis interval of magnesium chloride hexahydrate, the relationship between magnesium oxide with different physicochemical properties and the apparent properties of hydrated magnesium hydroxide was studied. The results show that the effect of temperature on magnesium oxide sintering is stronger than that of holding time. With the increase of calcination temperature and the extension of holding time of magnesium chloride hexahydrate, the calcined product magnesium oxide was sintered into large particle size with the characteristic particle size D<sub>50</sub> of 33.89 μm. The crystal was distorted, the chemical activity deteriorated, and the color development time was up to 407 s. When hexahydrate magnesium chloride was calcined at 480 °C with 2 h, it decomposed almost completely. The product, magnesium oxide, consisted of uniformly distributed small coral rod-like particles with strong chemical reactivity and a color development time of 115 s. The particles were small and evenly distributed, with a characteristic particle size D50 of 1.36 μm, and the highest specific surface area reached 7.292 m<sup>2</sup>/g. The hydrated magnesium hydroxide particles had well-defined edges and corners, with a characteristic particle size D50 of 1.59 μm and a uniform particle size distribution.

Environmental Implications of Ionic Liquid and Deep Eutectic Solvent in Geothermal Application: Comparing Traditional and New Approach Methods.

The significant surge of ionic liquids (ILs) research over the past decade has led to the formation of various novel ionic liquid compounds and their diverse applications. Enhanced geothermal systems (EGS) for geothermal power generation are an emerging IL application as a heat extraction fluid. The once widely held belief in the environmentally friendly characteristics of ionic liquids, mainly due to their insignificant vapor pressure, is now being scrutinized. It has become apparent that while ILs do not readily evaporate into the atmosphere, they are not guaranteed to remain entirely isolated from the environment. Recent attention has been directed toward toxicological studies, including ecotoxicity impacts, with the long-accepted assumption of ILs having low toxicity being invalid. This paper aims to shed light on the toxicity of hexylepyradinium bromide (HPyBr) IL and a deep eutectic solvent (DES) comprising choline chloride with magnesium chloride hexahydrate (ChCl:MgCl2·6H2O) to five test species, an algal species (Raphidocelis subcapitata), the water flea (Ceriodaphnia dubia and Daphina magna), the fathead minnow (Pimephales promelas), and the earthworm (Eisenia fetida), to measure acute and chronic toxicity. Additionally, new approach methods (NAMs) are presented using the fathead minnow embryo and the rainbow trout (Oncorhynchus mykiss) gill cell line and the RTgill-W1 assay to compare sensitivity across species. Overall, ChCl:MgCl2·6H2O displayed lower toxicity, while HPyBr demonstrated higher toxicity, highlighting the need for caution in handling it to prevent harm to aquatic ecosystems. Comparative analysis underscored the potential threat of ChCl:MgCl2·6H2O to aquatic life, highlighting the cumulative effects of the environmental components.

A refractories binder derived from modified magnesium chloride hydrate

A modified magnesium chloride hydrate was synthesised using ethanol and magnesium chloride hexahydrate as precursor materials, combined with magnesium oxide to create an enhanced binder. The effectiveness of this modified binder was evaluated through experimental testing on commonly used corundum refractories. Results showed a significant increase in compressive strength compared to a conventional magnesium chloride-based binder, along with superior resistance to hydration. Detailed characterisations revealed that the improved performance stemmed from enhanced adhesive properties and reduced water absorption capacity, attributed to the presence of ethanol. Ethanol molecules replaced water molecules in binding to magnesium ions, contributing to the binder's favorable characteristics. These findings underscore the potential of this modified binder as a superior alternative for binding applications in refractory materials, paving the way for further advancements in refractory binding technology.

Design, fabrication, and hydrogen blocking performance of alumina/zirconia functional gradient coatings

When electrophoretic deposition (EPD) is employed for fabricating alumina (Al2O3)-based hydrogen barrier coatings, it becomes customary to enhance the adhesion strength by subjecting the deposited coating to high-temperature annealing. In this study, a functionally-graded Al2O3/ZrO2 coating was designed by using the thermal stress module of Ansys software. The influence of different gradient composition distribution indices, number of layers, and layer thickness on the distribution of thermal stress was systematically investigated by simulation. Based on simulation results, the gradient parameters of the functionally-graded coating were determined as follows: a transition layer with three layers, each with a thickness of 0.13 mm; the first layer consisted of Al2O3 to ZrO2 ratio of 1:3, the second layer with a ratio of 1:1, and the third layer with a ratio of 3:1. Subsequently, the process parameters for EPD of Al2O3 coating were optimized via experimental exploration. Under conditions of deposition time of 120 s, deposition voltage of 60 V, Al2O3 concentration of 8 g L−1 in the electrophoretic solution, and magnesium chloride hexahydrate concentration of 0.6 g L−1, the as-fabricated Al2O3 coating exhibited optimal hydrogen barrier performance. Finally, different proportions of ZrO2 were sequentially incorporated into the prepared Al2O3 coating to form functionally-graded materials (FGM). Thermal cycling experiments showed that the Al2O3 coating with added ZrO2 exhibited better stability at high temperatures. Regarding hydrogen barrier performance, the functionally-graded coating outperformed the non-functionally-graded coating.

Castable refractory materials from magnesium oxychloride cement-bonded cordierite-mullite

Cordierite-mullite ceramics are well-suited for use as kiln furniture due to their superior mechanical strength and thermal shock resistance. This study explores the development of cordierite-mullite refractory castables bonded with magnesium oxychloride (MOC) cement. These castables were created using calcined kaolin aggregates and a matrix comprised light-burned magnesia, calcined alumina, milled sand, and magnesium chloride hexahydrate. Interaction between light-burned magnesia and magnesium chloride hexahydrate produced a needle-like MOC cement phase, significantly enhancing the green strength of the castables. After firing at 1350 °C for 4 h, the MOC crystals decomposed, forming robust cordierite and mullite phases. The resulting sintered castables demonstrated a modulus of rupture of 14.55 MPa, a bulk density of 1.95 g/cm3, a porosity of 24.84 %, and a thermal expansion coefficient of 2.89x10−6°C−1. These findings indicate the effectiveness of MOC cement bonding for manufacturing high-strength cordierite-mullite refractory castables, making them ideal for kiln furniture applications.

Combined use of chemical dust suppressant and herbaceous plants for tailings dust control.

Tailings dust can negatively affect the surrounding environment and communities because the tailings are vulnerable to wind erosion. In this study, the effects of halides (sodium chloride [NaCl], calcium chloride [CaCl2], and magnesium chloride hexahydrate [MgCl2·6H2O]), and polymer materials (polyacrylamide [PAM], polyvinyl alcohol [PVA], and calcium lignosulfonate [LS]) were investigated for the stabilization of tailings for dust control. Erect milkvetch (Astragalus adsurgens), ryegrass (Lolium perenne L.), and Bermuda grass (Cynodon dactylon) were planted in the tailings and sprayed with chemical dust suppressants. The growth status of the plants and their effects on the mechanical properties of tailings were also studied. The results show that the weight loss of tailings was stabilized by halides and polymers, and decreased with increasing concentration and spraying amount of the solutions. The penetration resistance of tailings stabilized by halides and polymers increased with increasing concentration and spraying amount of the solutions. Among the halides and polymers tested, the use of CaCl2 and PAM resulted in the best control of tailings dust, respectively. CaCl2 solution reduces the adaptability of plants and therefore makes it difficult for grass seeds to germinate normally. PAM solutions are beneficial for the development of herbaceous plants. Among the three herbaceous species, ryegrass exhibited the best degree of development and was more suitable for growth in the tailings. The ryegrass plants planted in the tailings sprayed with PAM grew the best, and the root-soil complex that formed increased the shear strength of the tailings.

Performance and rotational study of solar box cooker utilizing PCM and hybrids deep algorithm approach

The cooking performance of the solar box cooker (SBC) is enhanced by utilizing magnesium chloride hexahydrate (MgSO4·7H2O) with plastic balls (PBs) encasing the phase-change material (PCM). Accurate predictions of SBC efficiency were achieved using an Artificial Neural Network (ANN) simulation and the incorporation of thermal behavior utilizing the tree-seed metaheuristic algorithm (TSA). Therefore, improving ANN performance may be necessary to reap the benefits associated with adopting a variation in engineering design. The design incorporates a copper bar plate (CBP) that is 50% larger than a silver bar plate (SBP), and the Tree-Seed Algorithm (TSA) is used to establish an optimal influence for neurons. For the SBC with CBP design, food cooking efficiency was functional, with R 2, RMSE, MRE, and MAE values of 0.990, 0.0475, 0.228, and 0.050, respectively. Similarly, for SBP, the values are 0.98, 0.086, 0.007, and 0.053, respectively, simulated using the ANN/TSA technique. For the CBP in the training set “R,” testing set “R,” and overall set “R,” the respective values were 0.999, 0.995, and 0.997. Similarly, for the SBP in SBC cooking performance, the values were 1.000, 0.964, and 0.996. The performance of CBP in the SBC design with PCMPBs is found to enhance cooking efficiency, improving the system’s ability to prepare rice and eggs within 2 to 3 h.

Discrimination of hydration states of hydrated salts using terahertz time-domain spectroscopy

Water-sensitive nature of terahertz radiation has been exploited here to discriminate the hydration states of different hydrated salts, such as Cobalt Chloride Hexahydrate (CoCl2.6H2O), Copper Sulfate Pentahydrate (CuSO4.5H2O), Magnesium Chloride Hexahydrate (MgCl2.6H2O), and Calcium Chloride Dihydrate (CaCl2.2H2O). Hydration states of these salts have been prepared by heating them in an oven at different temperature for specific time on the basis of thermo-gravimetric analysis. The prepared samples were analyzed using terahertz time-domain spectroscopy (THz-TDS). The variation in absorption coefficient and refractive indices of these hydrated salts in terahertz spectral regime (0.2–1.6 THz) are linked with the change of hydration states, which has been used for their discrimination. The results have been validated with X-ray diffraction analysis. The present work indicates that THz-TDs can be considered a promising technique to fulfill the ever increasing demand of the analysis of these hydrated salts.

Strength variation and cracking behavior of corundum bricks with modified hydrated magnesium chloride Binders

This work examined differences between modified and non-modified binders regarding corundum brick cracking and strength variations pre and post-modification. Comparing samples treated with magnesium chloride hexahydrate at 200 °C before and after modification highlighted the importance of basic magnesium chloride in filling corundum gaps and aiding dehydration, affecting initial strength. The transformation from the 518 phase (5 Mg(OH)2·MgCl2·8H2O) to magnesium chlorocarbonate phase (Mg2CO3(OH)Cl·2H2O) enlarged grain size, explaining later-stage strength differences in hydration. TEM analysis after FIB fixed-point cutting of the cracked site of the ninth-day hydrated corundum brick sample indicated that the significant mismatch in lattice spacing between the magnesium chlorocarbonate phase and corundum resulted in the generation of a large number of misfit dislocations at the binding site. Additionally, the transformation from the 518 phase to the magnesium chlorocarbonate phase generated numerous dislocations during structural transformation. The internal stress generated by hydration pushes these dislocations to form a stress field, causing the samples to crack.

Experimental research of photovoltaic-valley power hybrid heating system with phase change material thermal storage

The widespread integration of high-ratio distributed photovoltaic (PV) systems in buildings calls for flexible load management to align with municipal power peaks and PV variability. To address the timing and demand mismatches between PV generation and building energy needs, energy storage systems are used to manage PV excess, aid in grid peak shaving, and support building heating. This research develops a Photovoltaic-Valley power complementary phase change energy storage heating system, designed to consume photovoltaic and valley power for the decentralized heating of individual rooms, thus optimizing distributed energy utilization. A CPCM of magnesium chloride hexahydrate, EG, and calcium hydroxide, designed for indoor heating, was created with a phase change temperature around 117.9 °C and an enthalpy of 106.2 kJ/kg. An experimental platform was established to test the system and its control strategy, showing that the PV-powered phase change energy storage heater effectively keeps indoor temperatures above the thermal comfort minimum of 18 °C. As the PV guarantee rate increases, the system improves indoor temperature regulation and significantly reduces fluctuations. Operating costs are over 30% lower than those of traditional heating networks and natural gas systems, underscoring substantial energy savings and emission reductions. This research provides an integrated approach for optimizing building PV consumption, managing grid peaks, and regulating indoor temperatures with phase change energy storage heating systems.

Exploration of Choline Chloride Based Type II and Type III Deep Eutectic Solvents: A Computational and Experimental Approach

AbstractDeep eutectic solvents (DESs) of choline chloride with citric acid (CACC), Maleic acid (MACC) and Magnesium chloride hexahydrate (MAGCC) were synthesized in 1 : 1 molar ratio and investigated experimentally and computationally. For the computational study, density functional theory (DFT) calculation with B3LYP/6‐31 (+, +) G (d,p) level of theory for MACC and CACC and at B3LYP/SDD basis set for MAGCC was employed and the FT‐IR spectroscopy was used for experimental evaluation. For understanding the orientation of bonds and hydrogen bonding present in DESs geometrically optimized structures were used. Through frontier molecular orbital (FMO) theory and HOMO−LUMO values and various quantum chemical parameters, viz., ionization potential (IP), electron affinities (EA), electro negativity (χ), chemical potential (μ), global softness (σ) and hardness (η), electrophilicity index (ω) were calculated for all DESs. These computational values made it clear that MAGCC is the most stable among the three DESs due to the high value of global hardness (η) (3.291 eV) and HOMO−LUMO energy gap (Egap) (6.582 eV) and lowest value of softness (σ) (0.152 eV), CACC shows the moderate values (η=2.452, Egap=4.905 and σ=0.204 eV). While MACC is found to be the least stable and most reactive among three DESs with values of η, Egap and σ, 1.970, 3.940 and 0.254 eV, respectively. Furthermore, MESP analysis gives an idea about the electrophilic and nucleophilic surface region of DESs. This study will give valuable information for a better understanding of DESs and the applicability of computational calculations in the future.

Electrodeposition of Magnesium in Deep Eutectic Solvents Based on Magnesium Chloride Hexahydrate and Choline Chloride with Urea Added

Magnesium (Mg) alloy has small density, large elastic modulus, good heat dissipation and corrosion resistance to organic matter and alkali. At present, magnesium alloy is more and more used in automotive industry, medical devices and aerospace industry. However, the traditional preparation method of Mg has the disadvantages of high investment, high labor intensity and great environmental pollution. Therefore, it is of great significance to develop simple, environment-friendly methods of the magnesium. In this study, urea was added to adjust the electrochemical property of the deep eutectic solvent (DES) mixed by choline chloride (ChCl) and magnesium chloride hexahydrate (MgCl2·6H2O). Cyclic Voltammetry (CV) curves reveals that the addition of urea made the reduction potential of Mg shifted from -0.9 V to -1.3 V. Among the CV curves, one was proposed as the “dividing line”, which shows that the electroactive species in the two DESs, ChCl-MgCl2·6H2O and urea-MgCl2·6H2O, are different due to the changes of the component of the DESs. Fourier transform infrared (FTIR) data shows the type of hydrogen bond had been changed with the increase of urea content. Furthermore, the Raman spectra indicates that Mg2+ was coordinated with urea chains, which did not exist in ChCl-MgCl2·6H2O. Moreover, it was found that urea changed the electrochemical performance of the ChCl-Urea-MgCl2·6H2O by changing the hydrogen bond in the system and coordination form of the electroactive species, rather than adsorbing onto the electrode surface. Combined with geometry calculations at the B3LYP/6-311++G (d, p), the most probable mechanism of electrodeposition process was deduced.

Low-temperature friction experiments on ice–salt mixtures: Implications for the strength of ice plate boundaries on Europa

While recent observational studies have suggested that the ice shell on Europa is undergoing active plate subduction, some theoretical studies have concluded that the high frictional strength of ice would prevent such icy plates from subducting. Constraining the frictional behavior of mixtures of ice and non-ice materials that exist on the surface is therefore key to understanding the frictional strength of plate boundaries on Europa. Here we perform friction experiments on 1 mm thick layers of gouge comprised of mixtures of ice-Ih and magnesium chloride with 0, 17, 29.5 and 47 wt% salt under low-temperature conditions (−40 to −10 °C). The experiments are conducted using a biaxial testing machine with constant normal stresses of either 2.5 or 5.0 MPa, and a constant shear velocity of 3 μm/s. Our experimental results for pure ice and ice–salt mixtures yield steady-state friction coefficients ranging from 0.72 ± 0.02 (−39.2 ± 0.7 °C) to 0.47 ± 0.01 (−16.4 ± 0.2 °C), and 0.51 ± 0.01 (−39.8 ± 1.4 °C) to 0.10 ± 0.02 (−16.9 ± 0.5 °C), respectively. These differences in friction coefficient indicate that non-ice materials can have a significant effect on the friction coefficient along the plate boundaries on Europa. Spatial variations in the frictional strength of plate boundaries are expected to be localized near the base of the conductive layer, as the friction coefficient of the ice–salt mixture exhibits a strong temperature dependence. The observed stick–slip behavior at low temperatures in our experiments indicates the potential for occurrence of intermittent stick–slip along the shallower parts of the plate boundaries, whereas steady-state sliding occurs along the deeper parts.

H2O assisted to improve the electrochemical performance of deep eutectic electrolyte formed by choline chloride and magnesium chloride hexahydrate

Introduction of H2O provides an effective strategy to tailor conductivity and viscosity in the electrolyte based on deep eutectic solvent (DES), as well as customize the energy storage performance. Herein,...

Effect of succinic acid on morphology transformation of the anhydrous magnesium carbonate particles prepared by magnesium chloride hexahydrate and urea

The homogeneous and controllable morphology of anhydrous magnesium carbonate (MgCO3) particles with excellent properties is difficult to obtain because of a variety of synthetic factors. The effect of succinic acid as a crystal modifier on the particle morphology transformation of anhydrous MgCO3 was investigated by the hydrothermal method. The effect of the addition of succinic acid on the particles was similar to that of temperature change. The morphology of particles with a folded diamond-like shape was gradually uniform, and the particle size was between 3.3 and 7.5 μm. Anhydrous MgCO3 particles prepared at pH 9 could easily agglomerate, and the average particle size increased from diamond-like to cube-like as the reaction time increased. The interaction between succinic acid and magnesium ions at different concentrations was the main factor responsible for the morphological changes. The pH, temperature, and time affected the molecular motion rate and crystal growth.

Production and characterization of single-phase diopside sol–gel powder

In this work, diopside powder was synthesized through the sol–gel method aiming at obtaining single-phase fine particles. Tetraethyl orthosilicate, calcium nitrate tetrahydrate and magnesium chloride hexahydrate were used as sources of cations, in ratios specific to diopside. Wet gel was synthesized by hydrolyzing a homogeneous solution consisting of precursors dissolved in ethanol. Ground gel powder was investigated by differential thermal analysis and thermogravimetry (DTA-TGA) to define details of the subsequent heat treatments. Samples calcined at 600, 650, 700, 800 and 1100 °C for 3 h underwent characterization through Fourier-transform infrared spectroscopy, X-ray diffraction analysis and scanning electron microscopy. Diopside was found as the single crystalline phase in the interval 600–1100 °C.

Thermal analysis of PCM magnesium chloride hexahydrate using various machine learning and deep learning models

The heat storage through Phase change material (PCM) is important for sustainable development. Previously a set of experiments were carried out on 14.5 kg of PCM, Magnesium chloride hexa hydrate in a shell and tube heat exchanger. The results are used to build machine learning and deep learning models such as Support vector machine, Random forest, Extreme gradient boost, Catboost and Artificial neural network to replicate the experiment virtually. The input variables are heat transfer fluid’s inlet and outlet temperature and time elapsed while PCM’s temperature is predicted in both charging and discharging cycles. The hyperparameter tuning is done using hyperband. Catboost model outperformed all other models with highest variance in both the cycles (0.9945 and 0.9299) and highest score: 0.993 and 0.9466. It has got the lowest MAPE (0.2% and 0.1 %). Hence this model can be recommended over these other models for doing system simulation of problems involving both charging and discharging cycles of the PCM.

An experimental investigation on the performance of designed closed reactor system on the thermochemical heat storage of magnesium chloride hexahydrate

ABSTRACT In the present study, a lab-scale for closed thermochemical heat storage reactor design is performed for seasonal thermochemical energy storage using magnesium chloride hexahydrate based on dehydration and hydration processes. Firstly, the closed reactor and plate heat exchanger are studied. Then, reactor layout modifications are examined. The dehydration process is performed under 95°C. During hydration, plates’ temperature ranges from 20°C to 30°C. The impact of adding zeolite13X-4A to magnesium chloride hexahydrate is examined. The addition of zeolite13X-4A to magnesium chloride hexahydrate of 1/4 mass ratio improves the hydration process and increases its efficiency.

Biocompatible topical delivery system of high-molecular-weight hyaluronan into human stratum corneum using magnesium chloride

Non-invasive delivery of hyaluronan into the stratum corneum (SC) is extremely difficult because of its high molecular weight and the strong barrier of the SC. We developed a safe method of administering hyaluronan into the human SC and determined its penetration route. The amount of hyaluronan that penetrated into the SC was 1.5–3 times higher in the presence of magnesium chloride hexahydrate (MgCl2) than other metal chlorides. The root-mean-square radius of hyaluronan in water decreased with the addition of MgCl2. Moreover, MgCl2 solutions maintained their dissolved state on a plastic plate for a long time, suggesting that size compaction and inhibition of hyaluronan precipitation on the skin enhanced hyaluronan into the SC. Our results also strongly suggest that an intercellular route contributes to the penetration of hyaluronan from the upper to the middle layer of the SC. No disruption to the SC barrier was observed after continuous use once a day for 1 month, demonstrating the potential of our method for the safe, topical application of hyaluronan.

System scale testing of magnesium chloride hexahydrate for thermal energy storage - A physical and numerical approach

Background•To test bulk quantity (14.5 kg) of Magnesium chloride hexahydrate in a heat exchanger to find optimum flow rate while cooling•To formulate PCM Stefan number that can access the suitability of a material for a particular application•To numerically simulate the process and to formulate Nusselt number and to correlate it with other non dimensional numbers Methods•Experimental setup was fabricated that consist of boiler, heat exchanger and other auxillary parts. The flow rate in cooling was varied in the steps of 500 lit/hr.•Numerical simulation (CFD) was carried out in Ansys using enthalpy-porosity technique. The results were exported and using regression technique in Python, the Nusselt number correlations for charging and discharging were formulated. Significant findings•Optimum flow rate for the discharging process is 1000 lit/hr•Magnesium chloride hexahydrate is suitable for short term storage•Nusselt number correlation will be useful for formulation of design principles in future.