High-purity Production Research Articles

High-efficiency recovery of valuable metals from spent lithium-ion batteries: Optimization of SO2 pressure leaching and selective extraction of trace impurities

The recovery of valuable metals from spent lithium-ion batteries (LIBs) is crucial for environmental protection and resource optimization. In the traditional recovery process of spent LIBs, the leaching of high-valence metals has the problems of high cost and limited reagent utilization, and some valuable metals are lost in the subsequent purification process of the leaching solution. To reduce the cost of reagents, this study proposes the use of low-cost SO2 as a reagent combined with pressure leaching to efficiently recover high-valence metals from delithiated materials of spent LIBs, while selective solvent extraction is used to remove trace impurities in the leaching solution to avoid the loss of valuable metals. Experimental results demonstrated that by optimizing the conditions to 0.25 MPa SO2 partial pressure and 60 min reaction time at 70 °C, the leaching efficiencies for Ni, Co, and Mn reached 99.6%, 99.3%, and 99.6%, respectively. The kinetic study indicated that the leaching process was diffusion-controlled. Furthermore, the delithiated materials were used to completely utilize the residual SO2 in the solution to obtain a high concentration Ni–Co–Mn rich solution. Subsequently, Fe and Al impurities were deeply removed through a synergistic extraction of Di-2-ethylhexyl phosphoric acid (D2EHPA) and tributyl phosphate (TBP) without loss of valuable metals, achieving a high-purity Ni–Co–Mn solution. The process developed based on this work has the characteristics of environmental friendliness, high valuable metal recovery, and high product purity, providing a reference technical method for the synergistic treatment of waste SO2 flue gas with spent LIBs and the deep purification of impurities in spent LIBs.

Efficient electrocatalytic nitrate reduction using 3D copper foam-supported Co hexagonal nanoparticles in a membrane electrode assembly

Electrocatalytic nitrate reduction reaction (NO3RR) provides a promising route for nitrate recycling and ammonia production. In this work, Co nanoparticle catalyst was developed on a copper foam substrate (CoNPs/CF) by electrodeposition. The CoNPs/CF catalysis exhibits a Faradaic efficiency (FE) of 92.0% at −0.2 V vs. RHE and an NH3 yield rate of 14328.65 μg h−1 cm−2 at −0.5 V vs. RHE. In-suit Raman spectroscopy and theoretical calculations demonstrated that the 3D copper foam structure of the substrate enhances the electron exchange capacity, which promotes the adsorption of nitrate on the cobalt (Co) surface. Moreover, Membrane Electrode Assembly (MEA) is employed with CoNPs/CF, contributing to 98.43 mg h−1 with FE over 80%. Coupled with an air stripping process, this configuration has enabled the successful production of high-purity gaseous NH3 products. This work suggests a practical and viable approach for the conversion of wastewater nitrate into valuable ammonia products.

Multinary Tetrahedrite (Cu12-x-yMxNySb4S13) Nanoparticles: Tailoring Thermal and Optical Properties with Copper-Site Dopants.

Tetrahedrite (Cu12Sb4S13) is an earth-abundant and nontoxic compound with prospective applications in green energy technologies such as thermoelectric waste heat recycling or photovoltaic power generation. A facile, one-pot solution-phase modified polyol method has been developed that produces high-purity nanoscale tetrahedrite products with exceptional stoichiometric and phase control. This modified polyol method is used here to produce phase-pure quaternary and quintenary tetrahedrite nanoparticles doped on the Cu-site with Zn, Fe, Ni, Mn, or Co. This is the first time that Cu-site codoped quintenary tetrahedrite and Mn-doped quaternary tetrahedrite have been produced by a solution-phase method. X-ray diffraction shows phase-pure tetrahedrite, while scanning and transmission electron microscopy show the size and morphology of the nanomaterials. Energy dispersive X-ray spectroscopy confirms nanoparticles have near-stoichiometric elemental compositions. Thermal stability of quintenary codoped tetrahedrite material is analyzed using thermogravimetric analysis, finding that codoping with Mn, Fe, Ni, and Zn increased thermal stability while codoping with cobalt decreased thermal stability. This is the first systematic study of the optical properties of quaternary and quintenary tetrahedrite nanoparticles doped on the Cu-site. Visible-NIR diffuse reflectance spectroscopy reveals that the quaternary and quintenary tetrahedrite nanoparticles have direct optical band gaps ranging from 1.88 to 2.04 eV. Data from thermal and optical characterization support that codoped tetrahedrite nanoparticles are composed of quintenary grains. This research seeks to enhance understanding of the material properties of tetrahedrite, leading to the optimization of sustainable, nontoxic, and high-performance photovoltaic and thermoelectric materials.

Novel Study on Cryogenic Distillation Process and Application by Using CHEMCAD Simulation.

The purpose of this study was to examine the cryogenic separation process used in air separation plants with the CHEMCAD simulation program. A preliminary analysis was carried out with the literature about the operation of the process. In light of the technical information, the simulation of the cryogenic separation process was utilized with the program. While no changes were analyzed in the basic parts of the process, the filtration of the air and separation from moisture and carbon dioxide were not included in the simulation. The simulation showed the three basic components of air, nitrogen, oxygen, and argon obtained as a product of the desired purity rather than a one-to-one demonstration of the applications in the industry. In addition, the low-temperature separation process of an air separation unit was studied to obtain high-purity products (99.49-99.99%) achieving the expected separation efficiency. As a result, the production of all three substances in desired purity was achieved successfully.

Optimization of Process for Enzymatic Resolution of Racemic Amines using Continuous Flow Bioreactor

The optimization of enzymatic process for the resolution of chemically and pharmaceutically important racemic amines is described using a continuous flow bioreactor. Also described are the isolation and purification methods of the reaction products and the various parameters affecting the optimal reaction conditions for the enzymatic resolution to afford the products in high chemical purity and enantiomeric excess (ee) of over 90%.

Assessment of human factor contribution to risk analysis of chemical cargo shortage incidents by using intuitionistic fuzzy integrated fault tree analysis

A shortage of chemical cargo on tanker ships refers to a situation where the declared cargo amount by the shipper is lower than the declared terminal cargo amount, or the amount specified in the Bill of Lading. As the chemical cargoes are high purity and expensive products, any shortage claims may cause high commercial loss even in small amounts. Despite the chemical transportation industry conducting some technical researches on shortage prevention, no systematic, academic and methodological study has yet been proposed which is capable of comprehensively revealing the underlying causes, their contributions to the risk of shortage. In this study, contribution of all human factor-related structural, technical and operational root causes to risk of shortage are identified. Their failure probabilities are determined by utilising Intuitionistic Fuzzy Integrated Fault Tree Analysis (IFFTA). Accordingly, the probabilistic risk of chemical cargo shortage is obtained and found to be 0.0731 and this number is validated with two different methods. It is found that direct or indirect human factors lead to cargo shortages, accounting for approximately 84% of all factors. It is believed that the proposed model provides an effective solution to mitigate the related risk by systematically revealing notable underlying human related causes.

Abstract 680: Leveraging an RNA-targeting platform for the discovery of cell-active c-MYC mRNA-binding small molecules

Abstract The MYC gene, with its oncogenic potential, has long been a formidable challenge in conventional drug discovery efforts, and its critical role in cancer progression and resistance has underscored the need for innovative therapeutic strategies. Here we demonstrate the capabilities of the Ribometrix RNA-targeting platform to modulate the c-MYC mRNA with small molecules with the aim of reducing c-MYC protein levels. Using our comprehensive platform of RNA-targeting drug discovery tools and analyses including chemical probing, structure modeling, high-purity RNA production, high-throughput screening, and biophysical characterization, we evaluated the potential to directly target c-MYC mRNA using small molecules. Our analysis revealed six high-confidence structured elements throughout the c-MYC mRNA expected to harbor tertiary structures amenable to drug-like ligand binding. Leveraging the multifaceted chemical probing and structure modeling components of our platform, we confirmed that our in vitro-transcribed RNA screening constructs adopt the same structures found in endogenous cellular c-MYC transcripts. After large-scale in vitro RNA preparation, we subjected four of these RNA elements to high-throughput screens of chemically diverse drug-like libraries using mass spectrometry affinity-selection that identified multiple chemical series with sub-micromolar affinity. We validated binding affinity using orthogonal methods including isothermal titration calorimetry and NMR. To eliminate pan-binding ligands, we evaluated of selectivity against a panel of non-target mRNA structures. Importantly, these compounds lead to rapid (4 hr) reduction of MYC protein levels in a small cell lung cancer cell line, DMS-273, with no cellular toxicity at 72 hr suggesting an on-target effect. Employing our suite of chemical probing tools, we confirmed that compounds from multiple series engage the c-MYC mRNA in cells. Medicinal chemistry efforts are ongoing to increase potency and define the precise mechanism of action in clinically relevant models. The discovery of these c-MYC mRNA-binding small molecules not only validates the utility of the Ribometrix RNA-targeted small molecule discovery platform but also showcases its potential in tackling traditionally 'undruggable' targets and provides a promising avenue for developing novel anti-cancer therapies. As we learn more about the intricacies of c-MYC mRNA biology and further refine effective small molecules, our results provide practical insights into previously-unknown vulnerabilities of MYC and present tangible opportunities for advancing targeted cancer therapies. Citation Format: Matthew J. Smola, Krista Marran, Sarah E. Thompson, Brittani Patterson, Roheeth K. Pavana, Caleb Sutherland, Jessica A. Sorrentino, Katherine D. Warner. Leveraging an RNA-targeting platform for the discovery of cell-active c-MYC mRNA-binding small molecules [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 680.

Recovery of rare earths and lithium from rare earth molten salt electrolytic slag by lime transformation, co-leaching and stepwise precipitation

The rare earth molten salt electrolytic slag (REMSES) has recently attracted significant attention due to its potential environmental hazards and high content of rare earths and lithium, leading to a surge in recycling efforts. In this study, we propose and demonstrate a novel and straightforward process for the simultaneous extraction of rare earths and lithium from REMSES through lime transformation and sulfuric acid leaching at low temperatures. Firstly, during the lime transformation process, REMSES is converted into hydroxides that can be easily dissolved in acids. Secondly, REEs and Li present in the slag are co-extracted using a conditional sulfuric acid leaching method, resulting in 95.72% REEs leaching efficiency and 99.41% Li leaching efficiency under optimal conditions. Finally, REEs and Li in the solution are precipitated using oxalic acid and trisodium phosphate with precipitation efficiencies of 99.02% for REEs and 94.85% for Li respectively. This innovative process enables the conversion of REEs and lithium from REMSES into high-purity products (a mixture of REOs with 99.31% purity; Li<sub>3</sub>PO<sub>4</sub> with 98.93% purity), thereby facilitating their valuable utilization.

Design and Numerical Study of Induction-Heating Graphitization Furnace Based on Graphene Coils

Induction-heating graphitization furnaces are widely used to produce high-purity graphite products due to their high heating rate, high-limit temperatures, safety, cleanliness, and precise control. However, the existing induction-heating systems based on copper coils have limited energy efficiency. This paper proposes a new induction-heating graphitization furnace based on graphene coils. Due to the excellent high-temperature resistance of the macroscopic graphene material, the coil can be placed closer to the graphite heater, which improves the electromagnetic efficiency; the coil itself does not need to pass cooling water, which reduces the heat loss of the furnace and ultimately results in a higher energy efficiency of the induction furnace. In this paper, a numerical model of the induction-heating process is established and verified, the temperature-field and electromagnetic-field distributions of the heating process are analyzed by using the model, and the energy balance calculations are performed for the original furnace and the new furnace. Through a comparison, it was found that the new furnace possesses an electromagnetic efficiency of 84.87% and a thermal efficiency of 20.82%, and it can reduce the energy consumption by 33.34%, compared with the original furnace. In addition, the influence of the coil parameters on the performance of the induction furnace is discussed. By changing the coil conductivity, the induction furnace can achieve an energy efficiency of 17.76%–18.11%. This study provides new ideas for the application of macroscopic graphene materials in high-temperature induction heating.

Pr doped CeO2 for chemical looping air separation at ultra-low temperatures

Chemical looping air separation (CLAS) represents a promising approach to use thermal energy for high-purity oxygen production. CeO2 represents a class of material that uncouples oxygen using thermal energy, but the required temperature is usually very high (>1400 °C). This limits the potential use for CeO2-based materials in CLAS. This study reports a Pr doped CeO2 oxygen sorbents for chemical looping air separation at ultra-low temperatures. The as-formed Ce1-xPrxO2 solid solution can uncouple oxygen effectively, achieving a redox oxygen capacity of 0.88 wt% at isothermal condition as low as 500 °C. The redox oxygen capacity can be further enhanced to 1.63 wt% in temperature-swing cycles between 400 °C and 900 °C. Moreover, oxygen partial pressure-swing cycles show that the Ce1-xPrxO2 solid solution maintains 95% of its redox oxygen capacity at oxygen partial pressure as low as 0.02 atm, indicating its potential applications in oxygen separation from diluted air. DFT calculations and other physio-chemical characterizations indicate that Pr doping can effectively reduce the oxygen vacancy formation energy, and gaseous oxygen is uncoupled when Pr4+ and Ce4+ are reduced in the Ce1-xPrxO2 solid solution. Overall, this study highlights the novel performance of CeO2 with Pr doping and could offer insights into CeO2 modification strategies for thermal chemical applications.

Численное моделирование водородопроницаемости с концентрационной зависимостью коэффициента диффузии

The paper presents a nonlinear mathematical model of alloys hydrogen permeability for membrane technologies of high-purity hydrogen production. Diffusion processes in the material bulk are taken into account as well as physical and chemical phenomena at the surface: adsorption, desorption and relatively fast dissolution. The iterative computational algorithm and software in Scilab have been developed to model the hydrogen permeability with dynamic boundary conditions and concentration-dependent diffusion coefficient.

Selective recovery of high purity aluminium phosphate from incinerated sewage sludge ash with Zr-modified biochar

Phosphorus recovery from incinerated sewage sludge ash (ISSA) is critical for the sustainable development of phosphorus resources due to its non-renewable nature. An innovative strategy based on a Zr-modified rice-husk biochar (Zr-RB) adsorbent has been proposed for the selective recovery of high-purity AlPO4 products from ISSA. 0.1 mol/L H2SO4 was chosen to extract phosphorus from ISSA with a phosphorus extraction of 54.5 ± 1.6 mg/g. Phosphorus was selectively adsorbed by the Zr-RB adsorbent with a maximum adsorption capacity of 53.1 ± 0.6 mg/g according to the Langmuir isotherm model. The adsorption kinetics of phosphorus in the leachate followed the pseudo-second order model, suggesting phosphorus adsorption by chemisorption processes. After 5 phosphorus adsorption-desorption cycles, the Zr-RB adsorbent still showed good adsorption performance for phosphorus, indicating its high stability. Electrostatic attraction and ligand exchange on the Zr-RB adsorbent were mainly responsible for the adsorption of phosphorus from the leachate. The simulation and experimental results demonstrated the production of high-purity AlPO4 products at the pH = 3.0 without the addition of exogenous substances, indicating the application potential of recovering high-value AlPO4 products from ISSA based on the Zr-RB adsorbent.

Highly efficient crystallization for sustainable azeotrope separation of formic acid-Water

The cost-effective separation of azeotropes poses a shared challenge. In this work, we utilized a green technique: layer melt crystallization (LMC), to separate the formic acid and water. Characterized by the lower energy consumption and high selectivity, LMC is welcome in high-purity production preparation. Firstly, we discussed the effects of temperature, cooling and heat rates, and time on the separation performance. We discovered that temperatures were important in the solute distribution and impurity migration. Then, the stirring technique is coupled to optimize the separation performance. Under the optimal trajectory, the product purity exceeds 99.7%. Next, to better understand the crystallization process, several theoretical models are established to clarify the intrinsic correlations of process variables and target parameters. Kinetic models are established to clarify the crystal layer growth, and sweating melt flow with the temperature difference-based driving force. Interfacial solute distribution factor and mass transfer coefficient are introduced to give the solute distribution rule and impurity migration mechanisms. At last, a dimensionless number is used to evaluate the sweating intensity, and we also correlated this coefficient with the separation performance of LMC qualitatively. In conclusion, LMC provides a viable approach for separating azeotropes, and the proposed theoretical models can offer valuable support for crystallization design.

Design of proton-beam degrader for high-purity 89Zr production

This work investigated the most suitable type of degrader (Cu, Al or Nb) and its thickness, taking into consideration the salient aspects of concrete activation for high-purity 89Zr production by 89Y(p,n)89Zr nuclear reaction. The MCNP and FISPACT codes were used to determine the optimal degrader thickness and the radioactivity of shielding concrete by neutron activation, respectively. The results showed that the optimal thickness of the beam degraders was 1.16, 3.19, and 1.33 mm for Cu, Al, and Nb, respectively. The neutron production rate per proton and the energy and angular distributions of neutrons varied depending on the type of degrader. Considering the radioactivity of the target-room concrete and the amount of radioactive waste expected to be generated, the use of a 1.33-mm-thick Nb degrader for 89Zr production was determined to be the best choice.

A New Method for Selective Extraction of Torularhodin from Red Yeast Using CO2-SFE Technique.

Torularhodin is a dark pink colored carotenoid belonging to the xanthophylls group that can be biologically synthesized by red yeasts, especially by Rhodotorula and Sporobolomyces genera. The growing interest in this molecule is due to its biological activities such as antioxidant, anticholesterolemic, anti-inflammatory, antimicrobial, and anticancer. To satisfy potential commercial markets, numerous methods have been proposed to develop a cost-effective and environmentally friendly downstream process for the purification of torularhodin. However, obtaining high purity products without resorting to the use of toxic solvents, which can leave residues in the final preparations, remains a major challenge. In this context, the present study aimed to develop a new efficient method for the isolation of torularhodin from the red yeast Rhodotorula strain ELP2022 by applying the extraction technique with supercritical CO2 (CO2-SFE) in two sequential steps. In particular, in the first step, the dried lysed biomass of yeast was subjected to the action of CO2 in supercritical conditions (CO2SC) as sole solvent for extraction of apolar carotenoids. In the second step, the residual biomass was subjected to the action of CO2SC using ethanol as a polar co-solvent for the extraction of torularhodin. Both steps were carried out at different operating parameters of temperature (40 and 60 °C) and pressure (from 300 to 500 bar) with a constant CO2 flow of 6 L min-1. Regardless of the operating conditions used, this method allowed to obtain an orange-colored oily extract and a red-colored extract after the first and second step, respectively. In all trials, torularhodin represented no less than 95.2% ± 0.70 of the total carotenoids in the red extracts obtained from the second step. In particular, the best results were obtained by performing both steps at 40 °C and 300 bar, and the maximum percentage of torularhodin achieved was 97.9% ± 0.88. Since there are no data on the selective recovery of torularhodin from red yeast using the SFE technique, this study may be a good starting point to optimize and support the development of industrial production of torularhodin by microbial synthesis. This new method can significantly reduce the environmental impact of torularhodin recovery and can be considered an innovation for which an Italian patent application has been filed. In a circular bioeconomy approach, this method will be validated up to a pilot scale, culturing the strain Rhodotorula spp. ELP2022 on low-cost media derived from agri-food wastes.

Pleiotropic beneficial cardiometabolic actions of a high-purity eicosapentaenoic acid product in high cardiovascular risk individuals.

The ideal approach to the secondary dyslipidemia goal of lowering triglycerides (TG) is not well established. The available ω-3 fatty acid products differ from each other in composition and content. The purpose of the present study was to investigate the effect of a highly purified eicosapentaenoic acid (EPA) formulation on cardiometabolic biomarkers in high cardiovascular (CV) risk patients. The study included 226 subjects with high TG and ≥1 of the following CV risk factors: arterial hypertension, diabetes mellitus, ultrasound-documented atheromatosis, peripheral artery disease, previous myocardial infarction, or ischemic stroke. Participants received 2 g EPA twice daily for 3 months, along with typical nutritional counseling. Cardiometabolic hematological parameters (TG, low-density lipoprotein [LDL], high-density lipoprotein [HDL], non-HDL, total cholesterol [TChol], apolipoprotein A1 [Apo A1], apolipoprotein B [Apo B], glucose, glycated hemoglobin [HbA1c], and C-reactive protein [CRP]) were measured at baseline and at 3 months. The mean patients' age was 61.1 ± 1.4 years and the mean baseline TG was 2.97 ± 0.15 mmol/L. Apart from Apo A1, all other biomarkers significantly (p < 0.05) improved at 3 months, regardless of sex (except Apo B) and age: TG 1.75 ± 0.09 versus 2.97 ± 0.15 mmol/L, LDL 2.46 ± 0.08 versus 3.05 ± 0.13 mmol/L, HDL 1.22 ± 0.03 versus 1.11 ± 0.03 mmol/L, non-HDL 3.29 ± 0.10 versus 4.14 ± 0.16 mmol/L, TChol 4.55 ± 0.10 versus 5.15 ± 0.13 mmol/L, Apo A1 26.8 ± 9.3 versus 22.5 ± 8.6 μmol/L, Apo B 1.25 ± 0.23 versus 1.29 ± 0.23 μmol/L, glucose 5.66 ± 0.11 versus 5.99 ± 0.17 mmol/L, HbA1c 5.83 ± 0.1 versus 5.97 ± 0.1% and CRP 1.92 ± 0.2 versus 5.26 ± 2.8 mg/L. In conclusion, adding highly purified EPA product (4 g daily) on nutritional counseling leads to a significant TG reduction. In addition, this treatment appears to have pleiotropic beneficial cardiometabolic actions.

Thermo-oxidative degradation of carbon nanotubes and related nanostructures: role of acidic environment and chloride ions

It is shown that acid activation of ultralong carbon nanotubes synthesis products increases their reactivity during subsequent thermochemical treatment in air at 480 °C. Such an integrated approach of CNTs processing provides high purity and maximum yield of the target product. For example, the non-CNT fraction decreases by 3.2 times, while the residual iron content decreases by 17–24 times in comparison with thermochemical treatment without acid. Raman spectroscopy and low-temperature nitrogen adsorption showed that acid activation does not lead to extra surface defects, which could initiate further oxidation of carbon matrix in air. It is suggested that the increased reactivity of CNT synthesis products after acid activation during thermo-oxidative degradation may be due to the formation of an “adduct” of carboxyl groups on the surface of nanotube carbon matrix with hydrogen chloride. It was shown by thermogravimetric studies coupled with mass-spectra investigation of gas evolved, that under the constant heating, at the temperatures of the beginning of intensive oxidation (500–600 °C), the decomposition of the “adduct” occurs, bypassing the stage of formation of more temperature-resistant phenolic groups, which can inhibit further oxidation. Water released during the decomposition of the “adduct” can also accelerate the process of thermal oxidation.

Enviro-economic investigation of Novel heat-integrated configurations for pressure swing distillation

Pressure Swing Distillation is a widely adopted solution for the separation of pressure-sensitive azeotropic mixtures in various chemical industries. While this method yields high-purity products, it comes with inherent challenges such as elevated operating costs and energy consumption. However, the temperature differential between the two columns involved presents a compelling opportunity for heat integration. In this study, 18 distinct heat integration scenarios were systematically evaluated using a process simulation software to identify the optimal column configuration for minimizing the Total Annualized Cost. These scenarios span five categories: the Conventional Method, Partial Heat Integration, Full Heat Integration, Internal Heat Integration Distillation Column, and External Heat Integration Distillation Column. The Vapor Recompression Column and Divided Wall Column schemes were applied to each method. Genetic Algorithm served as the optimization tool to determine the best arrangement with TAC as the objective function. Additionally, the environmental impact, assessed through CO2 emissions, was considered. Results indicate that the most economically and environmentally friendly solution is the I-HIDiC with divided wall columns, incorporating VRC systems in both columns. This approach offers a remarkable 66.5% cost savings and a substantial 96.3% reduction in CO2 emissions.

A sustainable process for electrochemical production of 2-Iodosylbenzoic acid

Herein, an environmentally friendly, scalable and highly efficient process for production of 2-iodosylbenzoic acid, a well-established hypervalent iodine oxidant is reported. It is based on anodic oxidation of 2-iodobenzoic acid in anhydrous AcONa-AcOH electrolyte followed by simple work-up of solid product. In particular, a benefit of the developed electrochemical process is absence of any chemical oxidant, application of environmentally benign solvent, high Faradaic efficiency and product yield. The process on the anode side combines anodic oxidation of reactant to the desired product with separation process, i.e. removal of Na+ cation from the anolyte through a cation-exchange membrane leading to drop of AcONa concentration. Consequently, the product of high purity can be obtained simply by filtering the anolyte solution followed by drying the filtration cake. Interestingly, no washing by organic solvents is required. Moreover, both anolyte filtrate and catholyte can be reused multiple times. Energy and material balance and cost and environmental footprint analysis showed benefits of the developed process and suggested clear strategy towards further reduction of the product cost and, in particular, significant decrease of a generated waste amount.

Recovery of lithium resources from salt lake brines using a novel low dissolution loss extractant of DEHEHP with FeCl3

Lithium is becoming one of the most eye-catching metal elements in modern industry, mainly because of its crucial role in manufacturing lithium-ion batteries. The demand for lithium in the new energy market is burgeoning significantly, while enormous lithium resources reserved in salt lakes in northwest China are not exploited effectively, due to the high Mg/Li mass ratio. Although the TBP extraction system has been applied in lithium extraction from salt lake brines, there are still some problems to be solved, such as its high solubility, easy degradation, and so on. In this work, a novel low dissolution loss extraction system was developed, with DEHEHP and FeCl3 serving as extractant and co-extractant, respectively. A real brine from Da Qaidam Lake was used to prove its practicality and effectiveness. After studying the detailed conditions of each process, a whole countercurrent process was performed, including eight stages of extraction, two stages of scrubbing, three stages of stripping, and regeneration. It was found that 99.4% of Li+ was successfully recovered from the brine, and the stripping liquor contained 22.74 g/L Li+, 0.51 g/L Mg2+, and 3.16 g/L B. The concentration of Li+ increased approximately 20-fold while the Mg/Li mass ratio decreased by a factor of 3900, from real brine to stripping liquor. High-purity (>98.5%) lithium carbonate products were prepared from the stripping liquor by precipitation. The dissolution loss of the organic phase in the raffinate was only 22.5 ppm, much lower than published works. Finally, the mechanism of extraction and co-extraction were systematically studied and the structure of the complex formed during extraction was revealed as LiFeCl4·2DEHEHP.