Yttrium Sulfate Research Articles

NH4Y(SO4)2·H2O and NH4YSO4F2: Two New Ammonium‐Rare Earth Metal Sulfates with Enhanced Optical Anisotropy and Deep Ultraviolet Transmission

AbstractTetrahedral oxygenated groups with large highest occupied molecular orbital‐lowest unoccupied molecular orbital (H gaps such as [SO4] are beneficial for deep ultraviolet (DUV) transmission but usually make against generating sufficient birefringence due to the small polarizability anisotropy. Thus, it is extremely difficult to obtain DUV transmission and large birefringence simultaneously in the search for DUV birefringent materials in sulfates. Herein, two new ammonium‐rare earth metal sulfates, NH4Y(SO4)2·H2O and NH4YSO4F2, with DUV transmission are presented. Meanwhile, both exhibit greatly elevated birefringence through the involvement of NH4+ units, compared to Y2(SO4)3·8H2O. Their optical properties are further investigated by theoretical calculations, and the effect of the introduction of NH4+ into yttrium sulfate on optimizing the structures and properties is discussed. This work may provide a new perspective for further exploration of DUV birefringent materials in tetrahedral oxygenated group sulfates.

The recovery of yttrium sulfate through antisolvent crystallization using alcohols

The rare earth elements are used extensively throughout modern technologies due to their unique electronic properties. However, current recovery methods of these elements from leaching solutions are not economically feasible, therefore ongoing research is being conducted to establish alternative processes. Antisolvent crystallization is one of the proposed techniques where antisolvents such as alcohols are used to recover inorganic salts from aqueous solutions. For this study, yttrium sulfate [Y2(SO4)3] was used as model compound to investigate the effect of different short primary alcohols, i.e., methanol, ethanol, and 1-propanol, as antisolvents on the solubility of the salt under isothermal conditions at 23 °C. This work also featured thermodynamic simulations done by using OLI Studio. Experimental values were compared to the simulated data. All the alcohols investigated in this study were ultimately able to reduce the solubility of Y2(SO4)3 by over 99%. Experimental evaluation showed that the concentration of alcohol needed on molar basis was similar ethanol and 1-propanol, followed by methanol. The solid phase recovered from the suspension was experimentally found to be Y2(SO4)3·8H2O for all the alcohols. Lastly, a theoretical case study was done comparing the simulated data with experimental data extracted from literature for the recovery of REEs, which included Y3+, from a NiMH battery leach solution using alcohol. The Y3+ concentration of 1.3 g/kg, observed in the leach solution, was used for the case study in which ethanol was shown to be the most effective antisolvent needing only 0.89 kg (1.13 L) to achieve the maximum plateau yield of 92% from the 1 kg aqueous feed solution. A possible kinetic limitation for the crystallization of Y2(SO4)3 using ethanol as antisolvent was also identified.

Solubility of neodymium and dysprosium sulfates at different pH and temperature and the effect of yttrium sulfate, sodium sulfate, and ammonium sulfate mixtures: Strengthening the predictive capacities of the OLI software

This study focuses on investigating the solubilities of two rare earth element (REE) sulfate salts, Nd2(SO4)3 (representing light REEs) and Dy2(SO4)3 (representing heavy REEs), under various conditions. Four different systems are studied: 1) binary REE2(SO4)3–H2O system at natural pH and temperatures of 25, 46, 65, and 80 °C, 2) ternary REE2(SO4)3–NaOH–H2O system, covering a pH range from 7 down to neutral, at temperatures of 25, 46, 65, and 80 °C, 3) ternary REE2(SO4)3–Y2(SO4)3–H2O system, involving Y2(SO4)3 concentrations ranging from 0 to 20 g/L, pH values of 3 and 7, all at 25 °C, and 4) quaternary REE2(SO4)3–Na2SO4–(NH4)2SO4–H2O system, encompassing Na2SO4 and (NH4)2SO4 concentrations varying from 0 to 20 g/L, pH values of 3 and 7, and at 25 °C. Solubilities of Nd2(SO4)3 and Dy2(SO4)3 decrease as temperature rises, attributed to the exothermic dissolution reactions. Within pH 2 to 5, solubilities remain relatively constant, but at higher pH, they decrease due to the formation of REE2(SO4)(OH)4(H2O)2 (rare earth sulfate hydroxide hydrate). Addition of Y2(SO4)3 does not significantly affect solubilities because of the relatively low Y2(SO4)3 concentration range (below 0.03 mol/kg of water), but solubilities are lower at pH 7 due to REE2SO4OH4H2O2 formation. For Nd2(SO4)3, solubility decreases with increasing Na2SO4 and (NH4)2SO4 concentrations, especially at pH 3 due to the formation of NaNd(SO4)2(H2O) (sodium neodymium bis(sulfate) hydrate) which is also confirmed by the decrease in Na2SO4 concentration compared with the target value. However, at pH 7, the concentration of Na2SO4 is much closer to the target range. This suggests that the formation of NaNd(SO4)2(H2O) is less significant at pH 7 and most of Nd precipitates as Nd2SO4OH4H2O2. For Dy2(SO4)3, solubility increases with increasing sulfate concentrations again due to the to the formation of REESO4+ and REE(SO4)2− complexes but the solubility is lower at pH 7 due to Dy2SO4OH4H2O2 and DySO4OH formation. The outcomes of this investigation represent a notable augmentation to the existing repository of solubility data for Nd2(SO4)3 and Dy2(SO4)3. These particular systems were deliberately chosen to emulate the process of extracting rare earth elements (REEs) from ion-adsorbed clays. Nonetheless, the implications of this research extend beyond this context and hold relevance for various procedures that involve the handling of REEs in sulfate-based environments. One prominent application of these findings lies in the augmentation of thermodynamic models, notably the MSE model integrated into the OLI software. Through the incorporation of this new dataset, the OLI software is poised to become a more potent tool for forecasting and simulating the chemistry of rare earth sulfate systems. This advancement bears significant promise for forthcoming research endeavors and industrial applications where precise modeling of REE behavior is of paramount importance.

Yttrium speciation in sulfate-rich hydrothermal ore-forming fluids

Rare Earth elements (REE) are gaining importance due to their increasing industrial applications and usefulness as petrogenetic indicators. REE-sulfate complexes are some of the most stable REE aqueous species in hydrothermal fluids, and may be responsible for REE transport and deposition in a wide variety of geological environments, ranging from sedimentary basins to magmatic hydrothermal settings. However, the thermodynamic properties of most REE-sulfate complexes are derived from extrapolation of ambient temperature data, since direct information on REE-sulfate complexing under hydrothermal conditions is only available for Nd, Sm and Er to 250 °C (Migdisov and William-Jones, 2008, 2016).We employed ab initio molecular dynamics (MD) simulations to calculate the speciation and thermodynamic properties of yttrium(III) in sulfate and sulfate-chloride solutions at temperatures and pressures up to 500 °C and 800 bar. The MD results were complemented by in situ X-Ray Absorption Spectroscopy (XAS) measurements. Both MD and XAS show that yttrium(III) sulfate complexes form and become increasingly stable with increasing temperature (≥200 °C). The MD results also suggest that mixed yttrium-sulfate-chloride complexes (that cannot be distinguished from mixtures of chloride and sulfate complexes in XAS experiments) form at ≥ 350 °C. Two structures with two different Y(III)-S distances (monodentate and bidentate) are observed for Y(III)-sulfate bonding. The formation constants, derived via thermodynamic integration, for the Y(III) mono- and di-sulfate complexes parallel the trends for those of Nd, Sm and Er determined experimentally to 250 °C.The derived formation constants were used to fit revised Helgeson-Kirkham-Flowers equation-of-state parameters that enabled calculation of formation constants for Y(SO4)+ and Y(SO4)2− over a wide range of temperatures and pressures. The presence of sulfate increases the solubility of Y(III) under specific conditions. Since the stability of sulfate is redox sensitive, Y(III) solubility becomes highly redox-sensitive, with rapid precipitation of Y minerals upon destabilisation of aqueous sulfate.

Volumetric Properties of the Dilute Aqueous Solution of Yttrium Sulfate from 283.15 to 363.15 K at 101.325 kPa

Volumetric Properties of the Dilute Aqueous Solution of Yttrium Sulfate from 283.15 to 363.15 K at 101.325 kPa

Synthesis of Y2O2SO4 submicron spheres and photoluminescence behaviour with Tb3+ doping

Y2O2SO4 submicron spheres were prepared by facile solid-phase reaction between yttrium sulfate and submicron spherical yttrium oxide for the first time. The influence of the sintering temperature, sintering time on the crystallography and morphology of the Y2O2SO4 submicron spheres were carefully investigated. XRD patterns and SEM images of the as-prepared Y2O2SO4 submicron spheres demonstrated that they had a single monoclinic phase and uniform shapes with an average size of about 300 nm. The formation process of submicron spheres was also discussed. The surface composition, photoluminescence behaviour of Y2O2SO4 submicron spheres were studied by doping with Tb3+. XPS data revealed the samples were composed of Y, S, O, and Tb elements, and the presence of Tb3+ states. The PL results showed that the Y2O2SO4:Tb3+ submicron spheres exhibited the strongest green emission peak at 546 nm on the excitation of 233 nm. It was corresponding to the 5D4→7F5 transition of Tb3+ ions. It may be useful as green-emitting phosphors in the lamps and display devices.

Solid and Aqueous Speciation of Yttrium in Passive Remediation Systems of Acid Mine Drainage.

Yttrium belongs to the rare earth elements (REEs) together with lanthanides and scandium. REEs are commonly used in modern technologies, and their limited supply has made it necessary to look for new alternative resources. Acid mine drainage (AMD) is a potential resource since it is moderately enriched in REEs. In fact, in passive remediation systems, which are implemented to minimize the environmental impacts of AMD, REEs are mainly retained in basaluminite, an aluminum hydroxysulfate precipitate. In this study, the solid and liquid speciation and the local structure of yttrium are studied in high-sulfate aqueous solutions, basaluminite standards, and samples from remediation columns using synchrotron-based techniques and molecular modeling. Pair distribution function (PDF) analyses and ab initio molecular dynamics density functional theory models of the yttrium sulfate solution show that the YSO4+ ion pair forms a monodentate inner-sphere complex. Extended X-ray absorption fine structure (EXAFS) and PDF analyses show that Y is retained by basaluminite, forming a monodentate inner-sphere surface complex on the aluminum hydroxide surface. EXAFS of the column samples shows that more than 72% of their signal is represented by the signal of basaluminite with which YSO4+ forms an inner-sphere complex. The atomic view of the REE configuration in AMD environments could facilitate a deeper research of REE recovery from waste generated in AMD remediation systems.

Yttrium and europium recycling from phosphor powder of waste tube light by combined route of hydrometallurgy and chemical reduction

This paper deals with the recovery of yttrium and europium from waste tube light phosphor powder leach liquor using solvent extraction and chemical reduction route. Hydrochloric acid (2 mol/L) is used as the leachant to generate the leach liquor. From the leach liquor, the separation of Y(III) and Eu(III) is carried out with three types of extractants (acidic, neutral and ionic liquid) with extractant concentration and pH variation. Highest separation factor of 60.6 is achieved with 0.1 mol/L D2EHPA at aqueous phase pH of 2.56. The quantitative extraction of yttrium from the leach liquor is achieved in two counter current stages at O:A ratio of 1:1.5 at pH 2.56. After extraction of yttrium, yttrium oxalate is prepared by precipitation stripping with 0.4 mol/L oxalic acid. The stability and reusability of the extractant is also investigated. The reduction process with zinc helps to reduce 78% of Eu (III) to Eu (II) but 16% Y(III) is precipitated as yttrium sulfate along with Eu(II) precipitation. A tentative flow-sheet is developed for the whole process.

Nanostructured Yttrium Oxide Obtained by Hydrolysis of Yttrium Sulfate

Modern functional metal oxide materials are based upon the use of nanostructured particles. In recent years materials on the basis of yttrium oxide find ever-widening application. The properties of yttrium oxide depend heavily on precursors and synthesis conditions. One of the poorly investigated precursors is yttrium sulfate. The study discusses the products of alkaline hydrolysis of yttrium sulfate obtained by the sol-gel method. The influence of the synthesis pH on morphological, thermal and structural properties of compounds has been examined. Formation of non-stoichiometric compounds occluding counter-ions of the reactant salts in their structure has been revealed. The nanostructured hydrolysis products are formed, which increase their specific surface at annealing and retain their morphology and sizes. The obtained results give grounds to expect using yttrium sulfate as a precursor for synthesis of structured yttrium oxide.

Анализ продуктов гидролиза сульфата иттрия золь-гель методом с различными гидролитическими агентами

Исследовано влияние гидролитических агентов на состав и свойства продуктов гидролиза сульфата иттрия. Установлено, что гидролиз сульфатов иттрия приводит к формированию образцов, содержащих значительные примеси сульфатов. Продукты гидролиза полностью аморфные. Применение водного аммиака в качестве гидролитического агента позволяет получить образцы, содержащие незначительные количества поровой и кристаллизационной воды.

Solvothermal synthesis, crystal structure and properties of three new 1D and 3D organically templated lanthanide sulfates

Three new organic amine templated lanthanide sulfates [(CH3)2NH2]3[Y(SO4)3]·H2O 1 and [(CH3)2NH2]9[Ln5(SO4)12]·2H2O (Ln=La 2 and Ce 3) have been solvothermally synthesized under similar conditions and structurally characterized by single-crystal X-ray diffraction. Compound 1 exhibits 1D anionic chain structure compensated by protonated dimethylamine occluded in the helical [Y–O–S]n chains, while the 3D inorganic frameworks of 2 and 3 contain extra-large 20-membered ring channels. The syntheses of three compounds demonstrates that although yttrium and lanthanide belong to one family, the self-assembly of yttrium sulfate may be different from other rare-earth sulfates because Y is much lighter. The formation of 1–3 also demonstrates that the solvent plays an important role during the synthesis.

Growth and Characterization of Doped TGS Crystals for Infrared Devices

Modified triglycine sulfate (TGS) single crystals have been grown from the aqueous solution by doping with urea, yttrium sulfate, l-serine + cobalt sulfate, and l-alanine + urea in the ferroelectric phase using a temperature lowering technique. The effects of these different dopants on the growth, dielectric, pyroelectric, optical, and mechanical properties have been investigated. TGS doped with urea and l-serine + cobalt sulfate exhibited higher material figures of merit for pyroelectric infrared detecting devices compared with pure TGS crystals. The Vicker's hardness studies at room temperature, carried out on (001) and (010) crystallographic planes using the Leitz Weitzler microhardness tester, show increased hardness of the doped crystals.

Use of rare earth metal salt solutions for corrosion protection of aluminum alloys and mild steel

The rare earth metal salt (REMS) compounds which are non-toxic and inexpensive have been used successfully for the corrosion protection of commercial aluminum alloys as well as of mild steel. The resistance to localized corrosion of aluminum alloys such as Al 2024, Al 6061 and Al 7075 has been greatly improved by immersion in hot cerium salt solutions. Cerium oxides/hydroxides were formed at sites where intermetallic compounds containing copper were located and eliminated the formation of local cathodes. REMS solutions were also used for sealing of anodized layer on Al alloys replacing toxic chromates. In addition to increased corrosion resistance excellent paint adhesion was observed. Cerium nitrate and yttrium sulfate solutions produced the most satisfactory results. Cerium salts were also applied successfully as inhibitors and as pretreatment for the corrosion protection of carbon steel in hot NH3/water solutions used in absorption heat pumps. Factorial design experiments have been used to determine the optimum concentrations of CeCl3 and H2O2 as well as the treatment time used in the cerating process for mild steel. The corrosion protection provided by the cerated layer was further improved by cathodic polarization in cerium chloride. A dual corrosion protection strategy employing cerating and addition of a REMS to the working solution is expected to provide long-lasting corrosion protection of mild steel.

Sealing of Anodized Aluminum Alloys with Rare Earth Metal Salt Solutions

Boric‐sulfuric acid anodized (BSAA) aluminum alloys have been sealed in hot solutions of cerium or yttrium salts. For comparison, sealing has also been performed in the presently used dilute chromate solution, boiling water, and a cold nickel fluoride solution. The corrosion resistance of the sealed BSAA Al alloys Al 2024, Al 6061, and Al 7075 has been evaluated by recording impedance spectra during exposure in 0.5 N NaCl for 7 days. Shorter or longer exposure times have also been used depending on the corrosion resistance obtained by different sealing processes. From the impedance spectra the time dependence of the pore resistance, Rpo, and the specific admittance, As, has been determined. At the end of the exposure the pitted area, Apit, was calculated. The relationship between As and Rpo has been evaluated. Two different sealing mechanisms were detected. For sealing in dilute chromate the pores in the outer oxide layer stayed open, while for hot water sealing or sealing in cold nickel fluoride the pores were closed by an oxide/hydroxide. Sealing of BSAA Al alloys in cerium or yttrium salt solutions occurred according to one of these two mechanisms depending on alloy type and solution composition. Based on the experimental values of Rpo, As, and Apit it was concluded that sealing in cerium nitrate and yttrium sulfate solutions provided corrosion resistance similar to that of chromate‐sealed BSAA Al alloys.

Synthesis of ZrO2 and Y2O3‐Doped ZrO2 Thin Films Using Self‐Assembled Monolayers

Undoped or Y2O3‐doped ZrO2 thin films were deposited on self‐assembled monolayers (SAMs) with either sulfonate or methyl terminal functionalities on single‐crystal silicon substrates. The undoped films were formed by enhanced hydrolysis of zirconium sulfate (Zr(SO4)·4H4O) solutions in the presence of HCl at 70°C. Typically, these films were a mixture of two phases: nanocrystalline tetragonal‐ (t‐) ZrO2 and an amorphous basic zirconium sulfate. However, films with little or no amorphous material could be produced. The mechanism of film formation and the growth kinetics have been explained through a coagulation model involving homogeneous nucleation, particle adhesion, and aggregation onto the substrate. Annealing of these films at 500°C led to complete crystallization to t‐ZrO2. Amorphous Y2O3‐containing ZrO2 films were prepared from a precursor solution containing zirconium sulfate, yttrium sulfate (Y2(SO4)38·H2O), and urea (NH2CONH2) at pH 2.2–3.0 at 80°C. These films also were fully crystalline after annealing at 500°C.

Thermogravimetric study of reduction and sulfurization of Y 2(SO 4) 3 using carbon disulfide

The reaction of Y 2(SO 4) 3 with CS 2 was studied using thermogravimetry. Anhydrous yttrium sulfate Y 2(SO 4) 3 first decomposes to Y 2O 2SO 4 at temperatures which depend upon the heating rate, namely 550–650°C at 1 K min −1 and 550–750°C at 5 K min −1. With increasing temperature, Y 2O 2SO 4 is further deoxidized to Y 2O 2S, and in this step the heating rate exerts a larger effect than in the first step. This reaction is complete at 700 and 875°C at heating rates of 1 and 5 K min −1, respectively. The last step involves the reaction of Y 2O 2S to form δ-Y 2S 3. Single phase Y 2S 3 was formed at ≈ 950°C when the heating rate was as low as 1 K min −1. When the heating rate was increased to 5 K min −1, a small amount of unreacted Y 2O 2S was found in the Y 2S 3 product. The compound YS 2 − x , which was determined as YS 1.85, was stable below ≈ 600°C and decomposed to Y 2S 3 at higher temperatures. The difference of the present reaction from the reaction of Nd 2(SO 4) 3 with CS 2 lies mainly in the decomposition of sulfate to oxysulfate and the sulfurization of oxysulfide to sesquisulfide.

Synthesis of YAG:Cr phosphors by precipitation from aluminum and yttrium sulfate solutions

Luminescent chromium doped yttrium aluminum garnet (YAG:Cr) powders were prepared using yttrium and aluminum (hydrous) oxide precursor particles produced by precipitation from aqueous sulfate solutions in urea. The rate of precipitation of yttrium hydrous oxide particles was observed to be slower than that of the aluminum hydrous oxide particles in the two component solution (yttrium plus aluminum sulfate). However, as single components the yttrium hydroxide nucleation occurred at a faster rate. The pH of the single aluminum and yttrium sulfate solution must be ≥ 2.9 and ≥ 5.5, respectively for precipitation to occur. Precipitation in a two component mixture is controlled by the acidic aluminum sulfate solution and homogeneous co-precipitation was not achieved. We have sped up the reaction by seeding a yttrium sulfate solution with aluminum hydroxide particles to promote rapid heterogenous nucleation of yttrium hydrous oxide. Heat treatment of the resulting precursor powders to 1200°C yielded YAG powders with some unreacted alumina and yttria.

Raman Spectroscopic Studies of Y 2(SO 4) 3 Substitution in LiNaSO 4 and LiKSO 4

Lithium sodium sulfate, LiNaSO 4, and lithium potassium sulfate, LiKSO 4, have been prepared with yttrium sulfate, Y 2(SO 4) 3, as a substituent over a concentration range up to 15 mol%. Raman spectra of the sulfate ion intramolecular modes suggest the formation of a new compound in the substituted materials. The possibility of substitutional stabilization of a higher temperature phase in the parent compounds is ruled out by comparison with the spectrum of the high temperature phase in each pure parent compound. A differential scanning calorimetry study of substituted LiKSO 4 shows an endothermic process at 281°C not present in the pure compound. Powder X-ray diffractograms of the substituted LiKSO 4 compounds indicate the presence of pure LiKSO 4, pure Y 2(SO 4) 3, and new peaks not attributable to either component.

Phase stabilization of sodium sulfate by aliovalent cation substitution

Phase stabilization of sodium sulfate by yttrium sulfate has been studied using laser Raman spectroscopy. Comparison of the spectrum of stabilized sodium sulfate with the spectrum of pure sodium sulfate in both powder and single crystal form reveals that the stabilized phase is phase I, the high temperature phase of pure sodium sulfate. In addition, powder X-ray diffraction measurements have been used to confirm the identification of the stabilized phase as phase I of the pure compound.

Formation of amorphous lanthanide sulfates and their crystallization

The sulfate hydrates of trivalent La, Pr, Nd, Sm, Eu and Gd became amorphous anhydrous salts when dehydrated at about 250 °C. The rest of the lanthanides and yttrium produced anhydrous salts of cubic structure even at low temperature. The amorphous salts crystallized exothermically when heated to about 400 °C. To characterize the amorphous state the heats of crystallization were estimated. They ranged from a few kJ mol −1 for La to 40 kJ mol −1 for Eu. X-ray diffraction and infrared spectral studies were carried out to find the bonding characteristics of the sulfate anion and the crystal structural variation along the series. In addition isothermal kinetic measurements of dehydration for all the lanthanide and yttrium sulfate hydrates were carried out. Discussions are presented on the mechanism of dehydration in connection with the state of the product phases.