Lithium Hydroxide Solution Research Articles

Validation of a New Liquid Asymmetric-Electrode Plasma Optical Emission Spectroscopy (LAEP-OES) Method for Measurement of Total Mercury in Tuna.

Mercury intake is caused by eating seafood, such as tuna and other predatory fish species. To reduce the health risks of mercury intake, it is necessary to continuously measure and monitor mercury concentrations at fish farms and markets. We have developed a compact system that can detect multiple heavy metals by liquid asymmetric-electrode plasma optical emission spectroscopy (LAEP-OES). The validity of the LAEP-OES method for total mercury levels was evaluated using standard solutions, certified substances, and specimens of bluefin tuna and other fish species. All specimens were dissolved in 4 M lithium hydroxide solution and then dispensed into a sample reservoir well of the single-use measurement reagent pack. Total mercury levels were automatically measured within 15 min of placement into the dedicated equipment. A total of 102 fish specimens, classified into 10 fish species, were evaluated using the new method and the results were compared to those obtained from validated analytical methods. LOD (0.02 mg/kg), LOQ (0.07 mg/kg), repeatability (4.0%), intermediate precision (9.8%), and trueness (recoveries 107%) of the proposed method were within satisfactory limits for total mercury levels in fish. Additionally, when using various fish species, the method had a strong positive correlation with the results of cold-vapor atomic absorption spectrometry (CV-AAS, the official method) with Spearman rs = 0.984. The LAEP-OES method can be used for measuring total mercury levels in bluefin tuna. Total mercury measurement using this new method has the potential to be applied to other fish species. Total mercury levels in fish were measured using our unique analysis system. Pacific bluefin tuna, southern bluefin tuna, and Atlantic bluefin tuna distributed in the Japanese market were analyzed for total mercury in their wild and farmed fish varieties.

Assessing dead time effects when attempting isotope ratio quantification by time-of-flight secondary ion mass spectrometry.

Time-of-flight secondary ion mass spectrometry (TOF-SIMS) is a quasi-non-destructive technique capable of analyzing the outer monolayers of a solid sample and detecting all elements of the periodic table and their isotopes. Its ability to analyze the outer monolayers resides in sputtering the sample surface with a low-dose primary ion gun, which, in turn, imposes the use of a detector capable of counting a single ion at a time. Consequently, the detector saturates when more than one ion arrives at the same time hindering the use of TOF-SIMS for quantification purposes such as isotope ratio estimation. Even though a simple Poisson-based correction is usually implemented in TOF-SIMS acquisition software to compensate the detector saturation effects, this correction is only valid up to a certain extent and can be unnoticed by the inexperienced user. This tutorial describes a methodology based on different practices reported in the literature for dealing with the detector saturation effects and assessing the validity limits of Poisson-based correction when attempting to use TOF-SIMS data for quantification purposes. As a practical example, a dried lithium hydroxide solution was analyzed by TOF-SIMS with the aim of estimating the 6Li/7Li isotope ratio. The approach presented here can be used by new TOF-SIMS users on their own data for understanding the effects of detector saturation, determine the validity limits of Poisson-based correction, and take into account important considerations when treating the data for quantification purposes.

Influence of chromium of low content on the corrosion behavior of SA106B carbon steels in high-temperature pressurized LiOH medium

The corrosion of carbon steel (CS) pipelines widely troubles the primary circuit system of pressurized heavy water reactors. The element chromium (Cr) plays a crucial role in resisting corrosion. However, the mechanism of oxide film formation and dissolution on low Cr-content CS remains unclear. A comparison study in corrosion behavior between SA106B with 0.02 wt% and 0.36 wt% Cr was carried out with weight loss tests, electrochemical measurements, and morphology observations. Immersion tests were performed in deaerated lithium hydroxide solution at 553 K and 6.3 MPa for 30 days. The results showed that although the content of Cr was as low as 0.36 wt%, it exhibited relatively high corrosion resistance to the SA106B with 0.02 wt% Cr. Two layers of oxide film were formed on both the two CSs and chromium oxide was present in the inner oxide layer of 0.36Cr CS. The possible formation mechanism of oxidation film with low content of Cr in high-temperature water was discussed.

Synthesis of Single Crystal Li2NpO4 and Li4NpO5 from Aqueous Lithium Hydroxide Solutions under Mild Hydrothermal Conditions.

The ternary oxides, Li2NpO4 and Li4NpO5, were synthesized under mild hydrothermal conditions using concentrated LiOH solutions containing NpO2(NO3)2. The reactions resulted in the formation of single crystals of both compounds, enabling the determination of their single crystal structures for the first time. Exploration of the synthetic phase space demonstrates that the resulting neptunate phases are dependent on the concentration of LiOH, transitioning from Li2NpO4, containing a typical octahedral neptunyl geometry with two shorter Np≡O bonds, at lower LiOH concentrations to Li4NpO5 with two long and four short Np-O bonds under saturated solution conditions. Reactions exploring the same synthetic conditions are also reported for uranyl(VI) for comparison. Raman spectra of the compounds were collected and analyzed to evaluate the Np-O bonding in these compounds.

LITHIUM HYDROXIDE FORMATION BY MEMBRANE ELECTROLYSIS

The production of high-purity lithium hydroxide (LiOH) solution by electrochemical conversion of soluble lithium salts (membrane electrolysis) was tested on semi-industrial scale. Stainless steel (cathode) and lead (anode) were used as electrode materials. Lithium sulphate solution was utilised as anolyte and water - as catholyte. During membrane electrolysis, water oxidation takes place in the anode compartment with the formation of gaseous oxygen and protons. Lithium ions permeate through the cationic membrane into the cathode compartment, where gaseous hydrogen and hydroxide ions are formed as the products of water decomposition on the cathode, so lithium hydroxide gets concentrated up to 33-36 g/dm3 with respect to lithium oxide. Electrolysis efficiency is 50-55 % for one process cycle. Sulphuric acid formed in the anode compartment may be then neutralised by adding lithium carbonate, and the formed lithium sulphate may be re-used in membrane electrolysis, which means anolyte recycling. Five successive electrolysis cycles with recycled anolyte allow an increase in the degree of lithium ion transfer from the anode to cathode compartment to 95-98 %. It is established that, in addition to lithium, other metal ions (sodium, potassium, calcium, etc.) and sulphate ions migrate through the cation-exchange membrane into the cathode compartment from anolyte solution. To evaluate the quality of the obtained lithium hydroxide monohydrate (LiOH•H2O), lithium hydroxide solutions obtained both by membrane electrolysis and by the traditional lime causticisation process were evaporated. Comparison between the concentrations of impurity ions in lithium hydroxide monohydrate samples obtained using different methods shows that the product of better purity may be synthesized from lithium sulphate solution by membrane electrolysis.

Effects of Zn injection into boric acid and lithium hydroxide solutions on the corrosion behaviors of 316LN stainless steel in simulated hot functional test high-temperature pressurized water

The effects of Zn injection into boric acid and lithium hydroxide solutions on the corrosion behaviors of 316LN stainless steel (SS) in simulated hot functional test (HFT) high-temperature pressurized water at 573 K were investigated. Low concentration of lithium hydroxide solutions with 20–100 ppb Zn injection are recommended for Zn-injected HFT water chemistry and the beneficial effects of Zn injection into both HFT and primary coolant water chemistry are confirmed in view of the protective properties of the oxide films on 316LN SS. The Zn injection involved corrosion mechanism during HFT is discussed.

Conversion of Lithium Chloride into Lithium Hydroxide by Solvent Extraction

A hydrometallurgical process is described for conversion of an aqueous solution of lithium chloride into an aqueous solution of lithium hydroxide via a chloride/hydroxide anion exchange reaction by solvent extraction. The organic phase comprises a quaternary ammonium chloride and a hydrophobic phenol in a diluent. The best results were observed for a mixture of the quaternary ammonium chloride Aliquat 336 and 2,6-di-tert-butylphenol (1:1 molar ratio) in the aliphatic diluent Shellsol D70. The solvent extraction process involves two steps. In the first step, the organic phase is contacted with an aqueous sodium hydroxide solution. The phenol is deprotonated, and a chloride ion is simultaneously transferred to the aqueous phase, leading to in situ formation of a quaternary ammonium phenolate in the organic phase. The organic phase, comprising the quaternary ammonium phenolate, is contacted in the second step with an aqueous lithium chloride solution. This contact converts the phenolate into the corresponding phenol by protonation with water extracted to the organic phase, followed by a transfer of hydroxide ions to the aqueous phase and chloride ions to the organic phase. As a result, the aqueous lithium chloride solution is transformed into a lithium hydroxide solution. The process has been demonstrated in continuous counter-current mode in mixer–settlers. Solid battery-grade lithium hydroxide monohydrate was obtained from the aqueous solution by crystallization or by antisolvent precipitation with isopropanol. The process consumes no chemicals other than sodium hydroxide. No waste is generated, with the exception of an aqueous sodium chloride solution.Graphical

Nanocrystallized Surface Effect on the Tribocorrosion Behavior of AISI 420

Nanopeening treatment was applied to the AISI 420 steel to decrease its sensitivity to tribocorrosion damage. The microstructural investigation highlighted that the nanopeening treatment led to high plastic deformation and a nanostructured surface layer with a 110 µm depth. In order to study the combined effect of corrosion and mechanical wear, tribocorrosion tests were performed on non-treated and nanopeened samples in boric acid and lithium hydroxide solutions, considering both continuous and intermittent sliding. It was found that the AISI 420 steel is sensitive to the synergy between mechanical friction and electrochemical corrosion with the dominance of abrasive wear. Adhesive wear was also detected in the wear track. Indeed, the mechanical wear was pronounced under intermittent sliding because of hard wear debris generation from the repassivated layer during rotating time. The nanopeening treatment led to enhanced mechanical performance and corrosion properties. Such improvement could be explained by the high plastic deformation resulting in the nano-structuration of grains and the increasing hardness of AISI 420 steel.

Efficient lithium extraction via electrodialysis using acid-processed lithium-adsorbing lithium lanthanum titanate

Increasing demands of lithium (Li) for lithium-ion batteries (LIBs) call for efficient Li extraction methods from natural resources and used LIBs. In this study, we efficiently extract Li from a Li-containing solution via electrodialysis using a fast ion conductor, lithium lanthanum titanate (LLT, Li0.29La0.57TiO3), as a separation membrane. Here, the LLT surface was modified by immersing in a strong acid solution such as hydrochloric acid to adsorb Li ions. For a mixed alkaline solution of lithium hydroxide, sodium hydroxide, and potassium hydroxide with a 0.1-M concentration, the maximum extraction speed of Li reached 3.5 mg/h when 5 V voltage was applied to the ionic conductor membrane with an area of 16 cm2. With the Li-adsorbing LLT, 40 mg of Li was extracted after 72 h from an aqueous solution in which Li was eluted by immersing black powder of used LIBs in water. The result indicates that high alkalinity may play a key role to achieve fast extraction.

Li-Ion Conductive Li1.3Al0.3Ti1.7(PO4)3 (LATP) Solid Electrolyte Prepared by Cold Sintering Process with Various Sintering Additives.

The density, microstructure, and ionic conductivity of solid electrolyte Li1.3Al0.3Ti1.7(PO4)3 (LATP) ceramics prepared by cold sintering using liquid and solid sintering additives are studied. The effects of both liquid (water and water solutions of acetic acid and lithium hydroxide) and solid (lithium acetate) additives on densification are investigated. The properties of cold-sintered LATP are compared to those of conventionally sintered LATP. The materials cold-sintered at temperatures 140–280 °C and pressures 510–600 MPa show relative density in the range of 90–98% of LATP’s theoretical value, comparable or higher than the density of conventionally sintered ceramics. With the relative density of 94%, a total ionic conductivity of 1.26 × 10−5 S/cm (room temperature) is achieved by cold sintering at the temperature of 200 °C and uniaxial pressure of 510 MPa using water as additive. The lower ionic conductivities of the cold-sintered ceramics compared to those prepared by conventional sintering are attributed to the formation of amorphous secondary phases in the intergranular regions depending on the type of additives used and on the processing conditions selected.

Electrodialysis of a Lithium Sulphate Solution: An Experimental Investigation

In the hydrometallurgical recycling of spent lithium-ion batteries, a lithium sulphate solution (Li2SO4) can be obtained as a by-product. Electrodialysis (ED) was employed in this study to split Li2SO4 into lithium hydroxide (LiOH) and sulfuric acid (H2SO4) solutions, which can be reused in the recycling process to create a closed-loop process. A three-compartment ED cell with a dilute channel filled with a Li2SO4 solution and two concentrate channels separately filled with LiOH and H2SO4 solutions was developed. The dilute and concentrate channels were separated by cation-exchange and anion-exchange membranes, respectively. High ion recovery ratios of Li+ and SO4 2− of 94.3 and 87.5%, respectively, were achieved at a current density of 833 A·m−2. The effects of the current density, inlet concentrations, and initial fluid volume on the overall efficiency of the cell were studied. Electro-osmosis played an important role during ED, particularly on the functioning of the cation-exchange membrane. Increasing the initial solution volume in the concentrated compartments can enhance current efficiency and ion recovery. In conclusion, the present study provides insights into the transport of coupled species through an ED cell, and the findings may guide future designs and operations of ED cells for optimal efficiency.

A technology for producing electrode materials for lithium-ion batteries from Kazakhstan spodumene raw materials

This study aims to develop a technology for producing innovative electrode materials for modern lithium batteries. An efficient technology for post-purifying of technical lithium carbonate to reach the level of battery quality (99.95%) was developed. This technology involves causticiziation of technical lithium carbonate, ultrafiltration and ion-exchange sorption of a lithium hydroxide solution, followed by precipitation of lithium carbonate with ammonium carbonate. Cation-exchange resins of the brands Purolite S930Plus, Purolite S940 and Purolite S950 were studied for sorption purification of lithium-containing solutions from calcium and magnesium impurities. Purolite S940 and Purolite S950 can be recommended as the most effective cation exchangers. The kinetic parameters of calcium and magnesium sorption were determined using a Purolite S940 cation exchanger. The bicarbonation mode was set at room temperature and a pressure of 0.3 atm. The synthesized samples of lithium-iron-phosphate studied by the sol-gel method. The structures of the obtained electrode materials corresponding to the standard profile of lithium-iron-phosphate were investigated by X-ray diffraction. The synthesized electrode materials in the structure of lithium half- and button cells confirmed their good electrochemical properties, stable operation of batteries and a high intercalation reversibility of lithium ions in the samples within the potential range of 2.5–4.3 V. The main research results are innovative cathode and anode materials of a new generation for modern lithium-ion batteries with significantly increased capacity and stability of operation, obtained from lithium precursors – battery grade lithium carbonate based on domestic mineral and technogenic raw materials.

Electrochemical method of obtaining copper (II) oxide powders in alkaline electrolyte

Within the framework of these studies, an electrochemical method for the synthesis of highly dispersed powders of copper compounds in aqueous solutions of alkalis is presented. The factors influencing the rate of production of nanoscale copper (II) oxide particles are determined. It is shown that during the anodic oxidation of copper by direct current, the speed of highly dispersed powders formation depends on current density, the nature of alkali cation, and the concentration of electrolyte solution. The mass loss of copper electrodes in NaOH solution is higher than in solutions of potassium hydroxide and lithium hydroxide by 10% and 12%, respectively. This experiment suggests that the studied alkalis act similarly on the anodic behavior of copper and the nature of cation does not significantly affect the speed of anodes destruction. The change in the concentration of alkali solution practically does not affect the mass loss of copper electrodes. The speed of copper oxidation remains almost constant over time, but noticeable weight loss and, accordingly, the speed of copper dissolution is achieved within 15 minutes. The speed of copper oxidation does not depend on current density. It is determined by the amount of electricity that has passed. The current density of 1 A/cm2 can be considered optimal.

Polymeric coordination complex of lithium(I) with aqua and cyanurate ligands.

The polymeric title complex, poly[hexa-μ-aqua-diaquatetra-μ-cyanurato-tetralithium] [Li4(C3H2N3O3)4(H2O)7] n , synthesized at room temperature from an aqueous solution of lithium hydroxide and cyanuric chloride, crystallizes in the triclinic space group P . There are two distinct Li+ cations in the asymmetric unit, one of which, Li1, has distorted trigonal-bipyramidal geometry and is coordinated via oxygen to two cyanurate anions occupying equatorial positions, and three water mol-ecules, two in the axial positions and the third in an equatorial position. One of the axial water ligands and the equatorial water ligand are involved in bridging to a crystallographically equivalent Li1 cation. A centre of inversion lies between the two Li1 cations and the Li1⋯Li1 distance is 3.037 (5) Å. The remaining axial water ligand bridges to the second Li cation, Li2, which is disordered over two crystallographic sites with approximately equal occupancy, and has an Li1⋯Li2 distance of 3.438 (7) Å. The terminal Li2 cation is coordinated to three water mol-ecules and an oxygen atom from a cyanuric anion and has a distorted tetra-hedral geometry. A three-dimensional network of inter-molecular hydrogen bonds involving N-H⋯O, O-H⋯O and O-H⋯N inter-actions serves to hold the structure together. The title compound was further characterized using IR and UV-vis spectroscopy and TG-DTA analysis.

Study of thermo-acoustical properties of Liquid mixtures of Aqueous solution of Lithium Chloride and Lithium Hydroxide at Different Temperatures

Density, viscosity and ultrasonic velocity of the various compositions of liquid mixtures of aqueous solutions of Lithium chloride (LiCl) and Lithium hydroxide (LiOH) have been experimentally measured at 303,308,313 and 318K and at atmospheric pressure. From these experimental measurements the acoustic impedance (Z) and adiabatic compressibility (ad) have been calculated. The variations in these parameters have been correlated to derive the intermolecular interactions taking place between the mixtures of present study.

Concentration-dependent diffusion of lithium, sodium, potassium, and cesium hydroxides in water

The diffusion coefficients of aqueous solutions of lithium, sodium, potassium, and cesium hydroxide in a concentration range of 0 to 3.0 mol/L were obtained at 25 °C and normal pressure. The Fizeau interferometer and the spatial phase-shifting method were used to measure the spatial distribution of concentration of the investigated substances. The concentration dependence of the diffusion coefficient was determined from the Matano-Boltzmann analysis. The experimental setup and techniques, as well as the image and data processing procedure, were tested using an aqueous solution of nitric acid. The comparison made for lithium, sodium, and potassium hydroxides indicated good agreement between the obtained results and the data collected from the literature. The concentration dependence of the diffusion coefficient for cesium hydroxide in water was found experimentally for the first time.

PROSPECTS FOR CREATING A FULL CYCLE OF LITHIUM PRODUCTION IN KAZAKHSTAN – FROM ORE PROCESSING TO LITHIUM BATTERIES

Today, lithium is becoming a new strategic material capable of influencing the sustainable development of the world economy. The results of developments in the production of innovative electrode materials from lithium carbonate on the basis of domestic lithium-containing raw materials with the creation of a full cycle of the technological line of lithium production: from ores to modern lithium batteries are pesented. Analysis of the explored reserves, mineral and material composition of domestic spodumene raw materials and lithium-containing dumps of the Belogorsk GOK indicate the prospects and expediency of their development for the production of the ever-increasing needs of the world market for lithium materials. As a result, the sulfuric acid technology for obtaining high-grade lithium carbonate directly from spodumene was optimized, bypassing the stage of obtaining a technical grade product, in a single technological process for processing spodumene with a reduction in the number of technological operations, excluding the expensive operation of concentrating a lithium sulfate solution by stripping. An efficient technology of purification and post-treatment of technical lithium carbonate to battery quality of 99.95% has been developed, including the processes of causticization of technical lithium carbonate, ultrafiltration and ion-exchange sorption of a solution of lithium hydroxide, followed by precipitation of lithium carbonate by ammonium carbonate. Cathode materials - lithium iron-phosphate , obtained from high-purity lithium carbonate by aerosol pyrolysis (MAP) and the sol-gel method (SGM), showed good electrochemical characteristics. The end result is innovative electrode materials for modern LIBs with significantly increased capacity and stability. The practical implementation of a full cycle of technologies from lithium-containing raw materials to modern lithium batteries opens up prospects for the creation in Kazakhstan of a high-tech lithium cluster according to the Scheme: Spodumene ores → Lithium concentrate → Lithium carbonate → Lithium cathode materials → Batteries.

Recovering Lithium from the Cathode Active Material in Lithium-Ion Batteries via Thermal Decomposition

In this study, calcination tests were performed on a mixed sample of lithium cobalt oxide and activated carbon at 300–1000 C under an argon atmosphere. The tests were conducted to discover an effective method for recovering lithium and cobalt from the cathode active material used in lithium-ion batteries. Additionally, the effect of soluble fluorine on the purification of lithium carbonate was investigated by the addition of lithium fluoride to an aqueous lithium hydroxide solution and a CO2 flow test was performed. The lithium recovery was ≥90% when the calcination occurred at temperatures of 500–600 C. However, the percent recovery decreased at temperatures ≥700 C. It was demonstrated that in order to increase the recovery while maintaining 99% purity of lithium carbonate in the recovered material, it was imperative to increase the temperature of the solution and to limit the F/Li ratio (mass%/mass%) in the solution to a value that did not exceed 0.05.

Deep Purification of Lithium Compounds to Remove Chemical and Radioactive Impurities

Possibility of performing deep purification of lithium hydroxide solutions to remove admixtures of alkaline-earth and transition metals, magnesium, aluminum, uranium, thorium, and radium radionuclides (strontium) by using the sorption and membrane methods has been examined. It was shown that successive procedures of mechanical filtration, ultrafiltration with a ceramic membrane having pore size of 50 nm, and sorption purification on an imine carboxyl cation exchanger make it possible to obtain lithium carbonate with no less than 99.9% main substance. The content of impurities being determined in the sample obtained does not exceed 0.005–0.01 wt %. The specific activity of a sample as regards the sum of alpha- and beta-emitters does not exceed their lower detection limit (less than 0.1 Bq/g).

Pd/C-CATALISED HYDROGENIZATION OF METHYL PYRROLE-3-CARBOXYLATES IN THE DIASTEREOSELECTIVE SYNTHESIS OF α-SUBSTITUTED β-PROLINES

The analysis of synthetic and biological importance of α-substituted β-prolines was conducted. Methods of synthesis of β-prolines and their esters, based on both intra- and intermolecular reactions of formation of functionalized pyrrolidinic cycle, as well as catalytic reduction of corresponding 2,3-substituted pyrroles and their dihydro derivatives, were systematized. The necessity of the hydrogenation process improvement of 2,3-di-substituted pyrroles using cheap catalysts was justified. The approach to α-substituted β-prolines (2-substituted pyrrolidine-3-carboxylic acids) was pro-posed, the first stage of which is N-Boc-protection of 2-substituted pyrrolidine-3-carboxylates with di-tert-butyl dicarbonate (Boc-anhydride) in the dichloromethane solution at the room temperature in presence of catalytic amounts of N,N-dime-thylaminopyridine. Obtained derivatives were subjected to hydrogenation in the autoclave at 45 atm. at 40 oC for 20 hours in presence of 10 % Pd/C catalyst. It was found, that reaction at such conditions proceeds with the full conversion of starting compounds and demonstrates high stereoselec-tivity and leads to the mixture of diastereomeric N-Boc-protected pyrrolidine-3-carboxylates of cis- and trans-configurations with corresponding contents of 84–87 % and 13–16 % according to NMR 1Н and chromato-mass spectra. The mild hydrolysis of isolated reaction mixtures in the water solution of lithium hydroxide followed by neutrali-zation and N-Boc-deprotection with 15 % hydrochloric acid allows isolating pure major diaste-reomers of α-substituted β-prolines with 69–74 % yields. Their trans-configuration was reliably confirmed by NMR 1Н spectroscopy using the NOESY experiment.