H2O Crystallization Research Articles

Low temperature resistant flexible zinc-ion hybrid supercapacitor

Zinc-ion hybrid supercapacitors (ZIHS) have high capacity and power density, as well as safety and stability. However, ZIHS are susceptible to electrolyte solidification and deactivation under low temperatures, resulting in rapid capacity degradation. Consequently, their practical use in cold environments is limited. In this study, solid organic hydrogels were prepared as electrolytes using ZnCl2 in a solution of ethylene glycol (EG) and deionized water (H2O), incorporating polyvinyl alcohol (PVA). The hydrogen bonding between PVA and EG effectively suppresses ice crystal formation and promotes the growth of PVA crystal domains. In addition, EG can also form hydrogen bonds with H2O molecules, further preventing H2O crystallization, thereby improving the low temperature resistance of the ZIHS. The results show that the specific capacitance of ZIHS prepared with MnO2 as cathode electrode material and active carbon (AC) as anode electrode material can reach 60 mF cm−2 at −30 °C, and the capacity retention rate can reach 81.2 % after 8000 cycles. In addition, it was found that ZIHS still had good stability after bending at different angles at −30 °C. The development of ZIHS with excellent flexibility and low-temperature resistance is crucial for advancing electronics capable of operating in cold environments.

Determination and analysis of solid–liquid equilibria for ternary systems Na2SO4–H2O2–H2O and Na2CO3–H2O2–H2O at 5 °C

To develop a better process for synthesizing sodium percarbonate and getting separation of the sodium salt, the equilibrium of the ternary system Na2SO4–H2O2–H2O and Na2CO3–H2O2–H2O at 5 °C was determined using the isothermal method, and the appropriate synthesis conditions for sodium carbonate from a theoretical perspective was discussed. The Na2SO4–H2O2–H2O system phase diagram contains one co-saturated point of Na2SO4·0.5H2O2·H2O and Na2SO4·10H2O. The Na2CO3–H2O2–H2O system phase diagram contains three crystal zones: Na2CO3·10H2O crystallization field, 0Na2CO3·1.5H2O2·H2O crystallization field and Na2CO3·2H2O2·H2O crystallization field. According to the phase diagram, the suitable raw material ratio of sodium percarbonate synthesis was obtained, to get the maximum of product yield, the optimal mass ratio of Na2CO3 to 30% H2O2 is 0.609.

Conditioning of simulated cesium radionuclides in NaOH-activated fly ash-based geopolymers

The growing nuclear safety concerns call for better solutions than traditional Portland cement-based materials to retain radionuclides especially Cesium (Cs). This work explored engineering process development and characterization of low-cost sustainable NaOH-activated fly ash-based geopolymers (FA-GP) as a conditioning matrix for non-radioactive equivalent of Cs (133Cs+). The effects of processing parameters on the FA-GP microstructure, porosity, in-situ zeolite crystallization, and Cs immobilization performance (quantified as the Leachability Index LX) were investigated and compared with literature data. The immobilization of non-radioactive equivalent of Cs (133Cs+) in NaOH-activated FA-GP was investigated using factorial design of experiments. The Cs leachability index (LX) was evaluated according to ANSI/ANS-16.1. FA-GP were characterized using SEM, XRD, and N2 adsorption-desorption isotherms. The results revealed that the main factors influencing Cs immobilization were the curing temperature and the interaction between Cs dosage and curing temperature. LX ≥12 and effective diffusion coefficient De ≤10−12 cm2/s was obtained for FA-GP cured at 90 °C. The effective diffusivity was about 5–7 orders of magnitude lower than for the conventional Portland cement-based encapsulation materials. Enhanced immobilization of Cs (LX = 14.6, De = 2.5 × 10−15 cm2/s), not reported hitherto, was further achieved by in-situ pollucite (Cs,Na)2Al2Si4O12.2H2O crystallization within FA-GP via one-step synthesis route at 90 °C. In addition, leaching studies on powdered FA-GP demonstrated encouraging performance and reliability of FA-GP under extreme mechanical conditions. It therefore appears that FA-GP could be a promising nuclear waste immobilization material, especially for the waste containing high concentration of Cs.

An exceptionally stable and widespread hydrated amorphous calcium carbonate precipitated by the dog vomit slime mold Fuligo septica (Myxogastria)

Biogenic amorphous calcium carbonate (ACC) is typically metastable and can rapidly transform through aging, dehydration, and/or heating to crystalline calcium carbonate. Gaining insight into its structure and properties is typically hampered by its tendency to crystallize over short time periods once isolated from the host organism, and also by the small quantities that are usually available for study. Here we describe an exceptionally stable hydrated ACC (HACC) precipitated by the cosmopolitan slime mold Fuligo septica (L.) F.H. Wigg. (1780). A single slime mold can precipitate up to a gram of HACC over the course of one night. Powder x-ray diffraction (XRD) patterns, transmission electron microscopy images, infrared absorption spectra, together with the lack of optical birefringence are consistent with an amorphous material. XRD simulations, supported by thermogravimetric and evolved gas analysis data, are consistent with an intimate association of organic matter with ~ 1-nm-sized ACC units that have monohydrocalcite- and calcite-like nano-structural properties. It is postulated that this association imparts the extreme stability of the slime mold HACC by inhibiting loss of H2O and subsequent crystallization. The composition, structure, and thermal behavior of the HACC precipitated by F. septica collected over 8000 km apart and in markedly different environments, suggests a common structure, as well as similar biochemical and biomineralization mechanisms.

Selective lithium recovery and integrated preparation of high-purity lithium hydroxide products from spent lithium-ion batteries

The current paper presents an innovative route for selective lithium extraction, followed by production of battery grade LiOH·H2O via reductive hydrogen roasting, water leaching and LiOH·H2O crystallization. The results suggest that during the initial hydrogen reduction stage, almost 98% of Li can be transformed into soluble LiOH·H2O with H2 reduction at 500 °C within 15 min, while Ni, Co, Mn all transform into their corresponding insoluble metals or their oxides. Consequently, almost all of Li present in the roasted material can be effectively separated from other impurities by 10 min of water leaching at 25 °C with liquid-solid (L/S) ratio of 2, such that the extraction of other metals like Ni, Co, Mn are < 0.1%. Subsequent stages allow high purity LiOH·H2O (99.92%) to be obtained directly through evaporation and crystallization. In addition, high nickel battery cathode materials (LiNi0.8Co0.1Mn0.1O2) are prepared from the recycled LiOH·H2O products and these demonstrate good electrochemical performance. Overall, this newly developed hydrogen reduction-based process may provide a more simple, efficient and environmental friendlier method for the recovery of valuable metals from spent LIBs, as well as offering great potential for straightforward industrial-scale recycling.

Phase Equilibria for the Reciprocal Aqueous Quaternary System Li+, Rb+//Cl−, Borate–H2O at 323.2 K

The isothermal dissolution equilibrium method was applied for the solid–liquid equilibria experiments of the reciprocal aqueous quaternary system Li+, Rb+//Cl−, borate–H2O at 323.2 K, and the relevant diagrams (phase diagram, water content diagram, density/refractive index against composition diagram) were plotted. It was found that there are two commensurate type quaternary invariant points with three-salt cosaturated, five univariant curves, and four crystallization fields corresponding to four single salts, rubidium chloride (RbCl), lithium chloride monohydrate (LiCl·H2O), lithium tetraborate trihydrate (Li2B4O7·3H2O), and rubidium pentaborate tetrahydrate (RbB5O8·4H2O), respectively. LiCl·H2O has a salting out effect on other coexisting salts and the size of the LiCl·H2O crystallization field is the smallest. Li2B4O7·3H2O has the largest crystallization field, which demonstrates that Li2B4O7·3H2O can be more easily separated from the solutions.

Compositions and formation conditions of primitive magmas of the Karymsky volcanic center, Kamchatka: evidence from melt inclusions and trace-element thermobarometry

This paper reports the results of a study of naturally and experimentally quenched melt inclusions in magnesian olivine (Fo77–89) from a basalt sample from the Karymsky volcanic center, which is located in the middle segment of the Eastern Volcanic Front of Kamchatka. The conditions of parental magma formation were estimated using modern methods of trace-element thermometry. Based on direct H2O measurements in inclusions and thermometry of coexisting olivine and spinel, it was shown that the parent melts contained at least 4.5 wt % H2O and crystallized at a temperature of 1114 ± 27°C and an oxygen fugacity of DQFM = 1.5 ± 0.4. The obtained estimates of H2O content and crystallization temperature are among the first and currently most reliable data for the Eastern Volcanic Front of Kamchatka. The primary melt of the Karymsky volcanic center was derived from peridotitic material and could be produced by ~12–17% melting of an enriched MORB source (E-DMM) at ~1230–1250°C and ~1.5 GPa. Our estimates of mantle melting temperature beneath Kamchatka are slightly lower than values reported previously and up to 50°C lower than the dry peridotite solidus, which indicates the influence of a slab-derived hydrous melt. The combined approach to the estimation of the initial H2O content of melt employed in this study can provide a more reliable data in future investigations, and its application will probably to decrease the existing temperature estimates for the mantle wedge above subduction zones.

Compositions and Formation Conditions of Primitive Magmas of the Karymsky Volcanic Center, Kamchatka: Evidence from Melt Inclusions and Trace-Element Thermobarometry

This paper reports the results of a study of naturally and experimentally quenched melt inclusions in magnesian olivine (Fo77–89) from a basalt sample from the Karymsky volcanic center, which is located in the middle segment of the Eastern Volcanic Front of Kamchatka. The conditions of parental magma formation were estimated using modern methods of trace-element thermometry. Based on direct H2O measurements in inclusions and thermometry of coexisting olivine and spinel, it was shown that the parent melts contained at least 4.5 wt % H2O and crystallized at a temperature of 1114 ± 27°C and an oxygen fugacity of ΔQFM = 1.5 ± 0.4. The obtained estimates of H2O content and crystallization temperature are among the first and currently most reliable data for the Eastern Volcanic Front of Kamchatka. The primary melt of the Karymsky volcanic center was derived from peridotitic material and could be produced by ~12–17% melting of an enriched MORB source (E-DMM) at ~1230–1250°C and ~1.5 GPa. Our estimates of mantle melting temperature beneath Kamchatka are slightly lower than values reported previously and up to 50°C lower than the dry peridotite solidus, which indicates the influence of a slab-derived hydrous melt. The combined approach to the estimation of the initial H2O content of melt employed in this study can provide a more reliable data in future investigations, and its application will probably decrease the existing temperature estimates for the mantle wedge above subduction zones.

Inorganic Crystallization Engineered by the Dynamic Adsorption of Linear and Particulate Polyelectrolytes

For most of natural hybrid materials, the shape of mineral crystals is controlled by natural polymers (e.g., proteins) to provide designated and unique physical properties and functions. Synthetic hybrid materials, which show comparable performance to the natural ones, require well-controlled crystal growth. In particular, the dynamic process including adsorption of the polymers on the crystal surface plays a significant role. We investigated CaSO4·0.5H2O crystallization in the presence of linear or particulate charged macromolecules, which can interact electrostatically with the crystals. Not only the static factors such as concentration and charge fraction but also the diffusion dynamics of the charged macromolecules were found crucial to involve the complete inhibition of growth and the subsequent shape transition of the crystals. This leads to the elucidation of semiquantitative relationships between dynamic factors such as the diffusion of macromolecules and the rate of crystal growth to the growth i...

Crystallization conditions of peraluminous charnockites: constraints from mineral thermometry and thermodynamic modelling

Most igneous charnockites are interpreted to have crystallized at hot and dry conditions, i.e. at >800 °C and <3 wt.% H2O and with an important CO2 component in the system. These charnockites are metaluminous to weakly peraluminous and their formation involves a significant mantle-derived component. This study, in contrast, investigates the crystallization conditions of strongly peraluminous, metasediment-sourced charnockites from the Qinzhou Bay Granitic Complex, South China. To constrain the temperature-melt H2O crystallization paths for the studied peraluminous charnockites, petrographic characterization was combined with fluid inclusion compositional data, mineral thermometry, and thermodynamic modelling. The uncertainties of the thermodynamic modelling in reconstructing the crystallization conditions of the granitic magmas have been evaluated by comparison between modelled and experimental phase relations for a moderately evolved, peraluminous granite (~70 wt.% SiO2). The comparison suggests that the modelling reproduces the experimentally derived phase saturation boundaries with uncertainties of 20–60 °C and 0.5–1 wt.% H2O for systems with ≤1–2 wt.% initial melt H2O at ~0.2 GPa. For the investigated natural systems, the thermometric estimates and modelling indicate that orthopyroxene crystallized at relatively low temperature (750–790 ± 30 °C) and moderately high to high melt H2O content (3.5–5.6 ± 0.5 wt.%). The charnockites finally solidified at relatively “cold” and “wet” conditions. This suggests that thermodynamic modelling affords a possible approach to constrain charnockite crystallization as tested here for peraluminous, moderately low pressure (≤0.3 GPa), and overall H2O-poor systems (≤1–2 wt.% H2O total), but yields results with increasing uncertainty for high-pressure or H2O-rich granitic systems.

Nature of influence exerted by Na2SiF6 on REE recovery from orthophosphoric acid solution in the course of CaSO4·0.5H2O crystallization

Chemical and X-ray phase analyses were used to study the influence exerted by Na2SiF6 on the isomorphic inclusion of cerium into the structure of CaSO4∙0.5H2O precipitates formed from solutions of phosphoric acid hemihydrate (38 wt % P2O5). The poorly soluble suspensions of CaSO4∙0.5H2O precipitates can serve as adsorbents for cerium compounds, with CaSO4∙0.5H2O–NaCe(SO4)2∙H2O and CaSO4∙0.5H2O–CePO4∙0.5H2O solid solutions formed. The introduction of Na2SiF6 makes the sorption properties CaSO4∙0.5H2O several times better because the Na2SiF6 phase is a source of sodium cations and creates the necessary Na: Ce ratio of 1: 1 for extracting cerium from the liquid phase into a precipitate in the form of a CaSO4∙0.5H2O–[NaCe(SO4)2∙H2O + CePO4∙0.5H2O] solid solution. Under the industrial conditions in which extraction phosphoric acid is manufactured, a similar isomorphous capture of rare-earth elements of the cerium group (La–Sm) may occur in joint precipitation of CaSO4∙0.5H2O and Na2SiF6.

Studies on the transformation of calcium sulphate dihydrate to hemihydrate in the wet process phosphoric acid production

Studies on the transformation of calcium sulphate dihydrate to hemihydrate in the wet process phosphoric acid production The influence of the process temperature from 85°C to 95°C, the content of phosphates and sulphates in the wet process phosphoric acid (about 22-36 wt% P2O5 and about 2-9 wt% SO4 2-) and the addition of αCaSO4·0.5H2O crystallization nuclei (from 10% to 50% in relation to CaSO4·2H2O) on the transformation of calcium sulphate dihydrate to hemihydrate has been determined. The wet process phosphoric acid and phosphogypsum from the industrial plant was utilized. They were produced by reacting sulphuric acid with phosphate rock (Tunisia) in the DH-process. The X-ray diffraction analysis was used to determine the phase composition and fractions of various forms of calcium sulphates in the samples and the degree of conversion of CaSO4·2H2O to αCaSO4·0.5H2O and CaSO4. It was found that the transformation of CaSO4·2H2O to αCaSO4·0.5H2O should be carried out in the presence of αCaSO4·0.5H2O crystallization nuclei as an additive (in the amount of 20% in relation to CaSO4·2H2O), at temperatures 90±2°C, in the wet process phosphoric acid containing the sulphates and phosphates in the range of 4±1 wt% and 27±1 wt%, respectively.

Non-isothermal kinetics of thermal decomposition of NH4ZrH(PO4)2·H2O

Nanocrystalline NH4ZrH(PO4)2·H2O was synthesized by solid-state reaction at low heat using ZrOCl2·8H2O and (NH4)2HPO4 as raw materials. X-ray powder diffraction analysis showed that NH4ZrH(PO4)2·H2O was a layered compound with an interlayer distance of 1.148 nm. The thermal decomposition of NH4ZrH(PO4)2·H2O experienced four steps, which involves the dehydration of the crystal water molecule, deamination, intramolecular dehydration of the protonated phosphate groups, and the formation of orthorhombic ZrP2O7. In the DTA curve, the three endothermic peaks and an exothermic peak, respectively, corresponding to the first three steps' mass losses of NH4ZrH(PO4)2·H2O and crystallization of ZrP2O7 were observed. Based on Flynn–Wall–Ozawa equation and Kissinger equation, the average values of the activation energies associated with the NH4ZrH(PO4)2·H2O thermal decomposition and crystallization of ZrP2O7 were determined to be 56.720 ± 13.1, 106.55 ± 6.28, 129.25 ± 4.32, and 521.90 kJ mol−1, respectively. Dehydration of the crystal water of NH4ZrH(PO4)2·H2O could be due to multi-step reaction mechanisms: deamination of NH4ZrH(PO4)2 and intramolecular dehydration of the protonated phosphate groups from Zr(HPO4)2 are simple reaction mechanisms.

Conditions of Magma Storage, Degassing and Ascent at Stromboli: New Insights into the Volcano Plumbing System with Inferences on the Eruptive Dynamics

Stromboli is known for its persistent degassing and rhythmic strombolian activity occasionally punctuated by paroxysmal eruptions. The basaltic pumice and scoria emitted during paroxysms and strombolian activity, respectively, differ in their textures, crystal contents and glass matrix compositions, which testify to distinct conditions of crystallization, degassing and magma ascent. We present here an extensive dataset on major elements and volatiles (CO2, H2O, S and Cl) in olivine-hosted melt inclusions and embayments from pyroclasts emplaced during explosive eruptions of variable magnitude. Magma saturation pressures were assessed from the dissolved amounts of H2 Oa nd CO2 taking into account the melt composition evolution. Both pressures and melt inclusion compositions indicate that (1) Ca-basaltic melts entrapped in high-Mg olivines (Fo89^90) generate Stromboli basalts through crystal fractionation, and (2) the Stromboli plumbing system can be imaged as a succession of magma ponding zones connected by dikes. The 7^10 km interval, where magmas are stored and differentiate, is periodically recharged by new magma batches, possibly ranging from Ca-basalts to basalts, with a CO2-rich gas phase.These deep recharges promote the formation of bubbly basalt blobs, which are able to intrude the shallow plumbing system (2^4 km), where CO2 gas fluxing enhances H2O loss, crystallization and generation of crystal-rich, dense, degassed magma. Chlorine partitioning into the H2O^CO2-bearing gas phase accounts for its efficient degassing (� 69%) under the open-system conditions of strombolian activity. Paroxysms, however, are generated through predominantly closed-system ascent of basaltic magma batches from the deep storage zone. In this situation crystallization is negligible and sulfur exsolution starts at � 170 MPa. Chlorine remains dissolved in the melt until lower pressures, only 16% being lost upon eruption. Finally, we propose a continuum in explosive eruption energy, from strombolian activity to large paroxysmal events, ultimately controlled by variable pressurization of the deep feeding system associated with magma and gas recharges.

Decompression and H2O exsolution driven crystallization and fractionation: development of a new model for low-pressure fractional crystallization in calc-alkaline magmatic systems

Magma ascent, decompression-induced H2O exsolution and crystallization is now recognized as an important process in hydrous subduction zone magmas. During the course of such a process calculations suggest that the ascent rate of a degassing and crystallizing mafic magma will be greater than crystal settling velocities. Thus, any crystals formed as a consequence of volatile exsolution will remain suspended in the magma. If the magma erupts before the percentage of suspended crystals reaches the critical crystallinity value for mafic magma (~55 vol.%) it will produce the commonly observed crystal rich island arc basalt lava. If the magma reaches its critical crystallinity before it erupts then it will stall within the crust. Extension of compaction experiments on a 55 vol.% sand-Karo syrup suspension at different temperatures (and liquid viscosities) to the likely viscosities of interstitial andesitic to dacitic liquid within such a stalled magma suggest that small amounts (up to ~10%) can be expelled on a time scale of 1–10 years. The expelled liquid can create a new intermediate to silicic body of magma that is related to the original mafic magma via fractional crystallization. The short time scale for liquid expulsion indicate that decompression-induced H2O exsolution and crystallization can be an important mechanism for fractional crystallization. Based on this assumption a general model of decompression-induced crystallization and fractionation is proposed that explains many of the compositional, mineralogical and textural features of Aleutian (and other andesites).

Luminescence effects accompanying Ba(BrO3)2 ⋅ H2O crystallization from solution

Kinetics of the Ba(Br2O3)2 ⋅ H2O precipitation from aqueous solution and the accompanying luminescence effects are studied. Specific features of appearance of luminescence during grinding of Ba(Br2O3)2 ⋅ H2O crystals are also examined. The origin of luminescence effects is interpreted as the result of electric discharge accompanying cracking of crystals during their growth or grinding.

Partition of Microamounts of Some M2+ Ions During MgSO4.7H2O Crystallization

Partition coefficients (D) of trace amounts of Ni2+, Co2+, Zn2+, Cd2+, Cu2+, Mn2+, Ca2+, and Fe2+ have been determined during crystallization of MgSO4.7H2O. Their dependences on the ionic radii of the M2+ ions, solubilities and structures of the corresponding sulfates, as well as the abilities of the microcomponents to form solid solutions with MgSO4.7H2O have been analysed. The D values are in the range from &lt;0·005 (DCa) to 1·13 (DNi) and depend mainly on the ionic radii of the M2+ ions, as well as the structures of the corresponding sulfates and the ability to form solid solutions with the macrocomponent.

Distribution of Cocrystallized Microamounts of Some M+ ions during NiSO4.(NH4)2SO4.6H2O Crystallization.

Distribution of Cocrystallized Microamounts of Some M+ ions during NiSO4.(NH4)2SO4.6H2O Crystallization.

Optimization of the cascade crystallizers

AbstractFor the cascade crystallization process a set of technological optimization conditions was established. The possibility of succesful application of proposed optimization conditions was pointed out by comparison with a mathematical model of Na2SO4 · 10 H2O crystallization in multichamber crystallizer presented in the literature. The method has a general applicability and can be used for the optimization of any cascade‐linked system, provided that the mathematical model was detailed enough to permit the operation of numerical derivation.