Separation Process Research Articles

A Room‐Temperature Lithium‐Restocking Strategy for the Direct Reuse of Degraded LiFePO4 Electrodes

AbstractThe sustainable development of lithium iron phosphate (LFP) batteries calls for efficient recycling technologies for spent LFP (SLFP). Even for the advanced direct material regeneration (DMR) method, multiple steps including separation, regeneration, and electrode refabrication processes are still needed. To circumvent these intricacies, new regeneration methods that allow direct electrode reuse (DER) by rejuvenating SLFP electrodes without damaging its structure are desired. Here, a 0.1 M lithium triethyl borohydride/tetrahydrofuran solution, which has the proper reductive capability to reduce Fe3+ in SLFP to Fe2+ without alloying with the aluminum current collector, is selected as the lithiation/regeneration reagent to restock the Li loss and regenerate SLFP electrodes. By soaking the SLFP electrodes in the lithiation solution, we successfully rejuvenated the crystal structure and electrochemical activity of SLFP electrodes with structural integrity within only 6 minutes at room temperature. When being directly reused, the regenerated LFP electrodes deliver a high specific capacity of 162.6 mAh g−1 even after being exposed to air for 3 months. The DER strategy presents significant economic and environmental benefits compared with the DMR method. This research provides a timely and innovative solution for recycling spent blade batteries using large‐sized LFP electrodes, boosting the closed‐loop development of LFP batteries.

Evaluation of Maize Seed Sieving Performance using Sieves with CassiniOval Shape Openings

The process of preliminary cleaning is a determining factor affecting the standard qualities of the seeds. The grain mass that undergoes primary processing contains significant amounts of impurities, the amount of which is strictly regulated by standards. Sieves with rectangular and round openings are the most widely used for separating maize seeds. In this study, the feasibility and efficiency of using sieves with openings in the Cassini oval shape were proposed and substantiated. Three factors subject to variation during the experiments were selected, each having a crucial influence on the process parameters: rotational speed (n, rpm), specific material feed (Q, kg), and angle of sieve inclination (α, deg.). A regression equation was developed, and the response surfaces of the dependencies of defining characteristics of the process of separation of maize seeds on sieves with openings in the Cassini oval shape were compiled and analyzed. The study showed that the rotational speed has a less significant influence on the mass of the undersize of sieved maize than the inclination angle and feeding rate. A maximum grain passage (2.9 kg) into the openings in the Cassini oval shape is obtained at a rotational speed of 290.35 min-1 and a grain feed rate of 3.06 kg min-1.

Poly(bis(1‐methylpiperazin‐1‐ium‐amide) Nanofilm Composite Membrane with Nanochannel‑Enabled Microporous Structure and Enhanced Steric Hindrance for Magnesium/Lithium Separation

AbstractEfficient lithium/magnesium (Li+/Mg2+) separation attainment is fundamental to the extraction of lithium from brine by nanofiltration membrane separation process, which is essential for resource recovery and a circular water economy. However, for poly(piperazine‐amide) nanofilm composite membranes, the higher electronegativity affects the Mg2+ rejection and consequently Li+/Mg2+ separation performance. Manipulating the positive charge density and pore size regulation of the nanofiltration membranes are determinative of the Li+/Mg2+ separation performance improvement. Here, a new monomer 1,1′‐(hexane‐1,6‐diyl)bis(1‐methylpiperazin‐1‐ium) bromide containing bis‐quaternary ammonium cations is employed as a molecular building block to fabricate polyamide nanofilms via interfacial polymerization. The dual quaternary ammoniums and the rod‐shaped conformation of the monomer confer enhanced electropositivity, steric hindrance, loosely packed microporous network structure (pore diameter∼0.8–1.35 nm), and high free volume. The resultant membrane exhibits high water permeance of 28.34 L m−2 h−1 bar−1 with good Li+/Mg2+ selectivity of up to 76.9. In addition, the membrane also exhibits chlorine stability performance owing to the lack of the chlorine sensitive −NH groups in the formed tertiary amide structures. Computational insights on the structural properties, nanofilm formation, and transmembrane water and ion transport behaviors are provided. This study offers insightful theoretical and technological concepts to design and construct membrane materials for energy‐efficient separations.

Comparative Analyses of Dynamic Characteristics of Gas Phase Flow Field Within Different Structural Cyclone Separators

The gas phase flow field inside a cyclone separator is crucial to the particle separation process. Previous studies have paid attention to the steady-state characteristics of the gas phase flow field, while research on its dynamic characteristics remains insufficient. Meanwhile, cyclone separators often adopt different structural forms according to the process requirements, the evolution laws of the dynamic characteristics flow field within them are still not well understood. Therefore, in this study, a hot-wire anemometer (HWA) was employed to measure the instantaneous tangential velocity of the gas phase flow fields within different structural cyclone separators (cylinder type, cylinder–cone (no hopper), and cylinder–cone (with hopper)). Comparative analyses and discussions were conducted regarding the dynamic characteristic distribution rules of the flow field in the time domain and the frequency domain. The results revealed that the dimensionless tangential velocity distributions of different types of cyclone separators all conformed to the Rankine vortex structure. The instantaneous tangential velocity fluctuated with low frequency and high amplitude, and the low-frequency velocity fluctuation exhibited a transfer behavior along the radial direction. Compared with the cylinder–cone-type cyclone separator, the tangential velocity in the cylinder-type cyclone separator fluctuated more greatly, and its quasi-periodic behavior was also more obvious. The time-averaged tangential velocity, the tangential velocity fluctuation intensity (Sd), and the dominant fluctuation frequency all had obvious attenuation along the axial direction in the cylinder-type cyclone separator, while the above-mentioned parameters had no attenuation along the axial direction in cylinder–cone-type cyclone separators. Additionally, the backflow from the hopper of the cylinder–cone-type cyclone separator (with hopper) led to an increase in the instantaneous tangential velocity fluctuation intensity of the local flow field near the dust outlet, as well as the occurrence of the “double dominant frequencies” phenomenon.

Experimental data and thermodynamic modeling for n-propane + Brazil nut oil at high pressures

This research aimed to uncover essential phase transition data for the pseudo-binary system of n-propane and Brazil nut oil. Over a range of temperatures from 313 to 343 K and pressures up to 3.42 MPa, our study identified various phase equilibria, including liquid-vapor, liquid-liquid, and liquid-liquid-vapor, using the visual synthetic-static variable volume method. The observed phase transitions fall under the type III classification proposed by Scott van Konynenburg. Leveraging the cubic Peng-Robinson equation of state with the van der Waals mixing rule, we were able to construct isopleths for the proposed system. Additionally, we examined the fatty acid profile of Brazil nut oil to accurately quantify its composition and estimate critical properties of the pseudo component in line with Kay's rule. This research provides critical insights into the behavior of phase diagrams for pressurized fluid-based extraction and separation processes, which are crucial for achieving maximum yield and minimizing energy expenditure.

Self-assembled ILs-PVA micelle nanostructure impart the pervaporation membrane with high ethanol dehydration performance

Achieving strong interaction with the targeted composition and constructing abundant transport channels is crucial to obtain the pervaporation (PV) membrane with high selectivity and flux. Here, three ionic liquids (ILs) were screened out based on their relative selectivity and capacity targeting for bioethanol dehydration by COSMO-RS. The interaction energies analysis between ILs, EtOH, and H2O suggests that the ILs can form strong hydrogen bonds with water and disrupt the hydrogen bond in the EtOH–H2O azeotropic mixture, which is beneficial for improving the selectivity. Furthermore, driven by the multiple hydrogen bonds, electrostatic interactions, and van der Waals forces, ILs could self-assemble with polyvinyl alcohol (PVA) to fabricate the PV membrane with well-ordered micelle nanostructure, as its structure was revealed by MD simulations. The formation of the ILs-PVA micelle dramatically influenced membrane surface morphology, roughness, and water contact angle, providing an extra transport channel for the membrane. The optimal membrane (at the cmc point) exhibited a superior ethanol dehydration separation factor of 1627, along with a flux of 684 g/m2h at 50 °C. It can be expected that this novel self-assembled ILs-PVA micelle nanostructure strategy will find promising applications in other azeotropic mixture separation processes, like ethanol-ethyl acetate, water-butanol, etc.

Near‐Unity Photothermal CO2 Hydrogenation to Methanol based on a Molecule/Nanocarbon Hybrid Catalyst

Solar‐driven CO2‐to‐methanol conversion provides an intriguing route for both solar energy storage and CO2 mitigation. For scalable applications, near‐unity methanol selectivity is highly desirable to reduce the energy and cost endowed by low‐value byproducts and complex separation processes, but so far has not been achieved. Here we demonstrate a molecule/nanocarbon hybrid catalyst composed of carbon nanotube‐supported molecularly dispersed cobalt phthalocyanine (CoPc/CNT), which synergistically integrates high photothermal conversion capability for affording an optimal reaction temperature with homogeneous and intrinsically‐efficient active sites, to achieve a catalytic activity of 2.4 mmol gcat‐1 h‐1 and selectivity of ~99% in direct photothermal CO2 hydrogenation to methanol reaction. Both theoretical calculations and operando characterizations consistently confirm that the unique electronic structure of CoPc and appropriate reaction temperature cooperatively enable a thermodynamic favorable reaction pathway for highly selective methanol production. This work represents an important milestone towards the development of advanced photothermal catalysts for scalable and cost‐effective CO2 hydrogenation.

Near-Unity Photothermal CO2 Hydrogenation to Methanol Based on a Molecule/Nanocarbon Hybrid Catalyst.

Solar-driven CO2-to-methanol conversion provides an intriguing route for both solar energy storage and CO2 mitigation. For scalable applications, near-unity methanol selectivity is highly desirable to reduce the energy and cost endowed by low-value byproducts and complex separation processes, but so far has not been achieved. Here we demonstrate a molecule/nanocarbon hybrid catalyst composed of carbon nanotube-supported molecularly dispersed cobalt phthalocyanine (CoPc/CNT), which synergistically integrates high photothermal conversion capability for affording an optimal reaction temperature with homogeneous and intrinsically-efficient active sites, to achieve a catalytic activity of 2.4 mmol gcat -1 h-1 and selectivity of ~99 % in direct photothermal CO2 hydrogenation to methanol reaction. Both theoretical calculations and operando characterizations consistently confirm that the unique electronic structure of CoPc and appropriate reaction temperature cooperatively enable a thermodynamic favorable reaction pathway for highly selective methanol production. This work represents an important milestone towards the development of advanced photothermal catalysts for scalable and cost-effective CO2 hydrogenation.

3D Covalent Organic Framework Membranes for Molecular Separations.

Membrane separation has become an indispensable separation technology in social production, playing an important role in drug production, mineral exploitation, water purification, etc. The key core of membranes lies in achieving efficient and precise sieving between substances. As a result, a typical trade-off arises: highly permeable membranes usually sacrifice selectivity and vice versa. To address this dilemma, long-term research has focused on comprehensive understanding and modelling of synthetic membranes at various scales. A significant advancement in this arena is the advent of three-dimensional covalent organic framework (3D COF) membranes, a novel category of long-range ordered porous organic polymer materials. Characterized by an abundance of interconnected channels, diverse pore wall properties, tunable structures, and robust thermal and chemical resilience, 3D COF membranes offer a promising approach for efficient substance separation. This review undertakes a meticulous investigation of the synthesis and physicochemical properties of 3D COF membranes, accentuating the underlying design principles, fabrication methods, and application attempts. A comprehensive assessment of their research trajectory and current standing in the field of membrane processes is provided. The review culminates in a forward-looking outlook, summarizing future research directions and highlighting the substantial potential of this innovative work to shape the future of efficient membrane separation processes.

Redox-mediated electrochemical separation of boron ions: Cell design, process optimization, adsorption isotherm, kinetics, and thermodynamics

Boron contamination of various water sources has been increasing in recent years and is receiving worldwide attention for its negative effects on the environment, wildlife, and humans; therefore, its removal is of utmost importance. Considering dwindling water sources and the possibility of the world population soon experiencing water scarcity, effective and innovative technologies must be developed to remove boron ions from water sources. The aim of the present study was to assess a sustainable separation process for the removal of boron ions using an electrochemical flow cell with symmetric redox-active polyvinyl ferrocene (PVF) functionalized carbon nanotube (CNT) electrodes using real-time measurements of the boron adsorption performance in continuous-flow mode while varying the flow rate, cell voltage, and boron concentration. A Box–Behnken experimental design (BBD) was used to improve boron adsorption. The adsorption isotherms, kinetics, and thermodynamics were investigated to further describe the adsorption process. The high R2 value, calculated using a linear and nonlinear procedure, demonstrated that the Langmuir isotherm and pseudo-first order models fit quite well. The maximum adsorption of 60.61 mg/g was observed. The thermodynamic results illustrated that the adsorption of boron ions onto the PVF/CNT electrodes was spontaneous and endothermic under continuous flow mode.

Synthesizing high performance robust PSf loose nanofiltration membranes through nanobubble-assisted pore-forming

Loose nanofiltration (LNF) membranes have extensive applications in precision separation processes, however, synthesizing highly permselective LNF membranes is still a considerable obstacle. Nanobubble-assisted pore-forming method was adapted to prepare a highly perm-selective LNF membrane for the first time in this work, using polysulfone (PSf) as the membrane-forming material, azodicarbonamide (AC) as the reactive pore-forming agents, and NaOH solution as the coagulation and immersion baths. By leveraging nano-bubbles produced through the reaction between AC and NaOH without adding other pore-forming agents, the membrane-forming process of PSf was regulated. It was found that the PSf LNF membranes prepared in NaOH-solution coagulation and immersion baths exhibited significantly enhanced permeation performance without compromising the rejection. These results suggested that the coagulation and immersion post-treatment processes under NaOH solution had a great effect upon the structure and the property of the membranes. The LNF membrane prepared from 20 wt% PSf casting solution with 8 wt% AC achieved a permeation flux of 188.7 L m−2 h−1, and a Congo red (CR, Mw =696 Da) rejection of over 99 %, while a rejection of NaCl below 7 %, showing a good separation for the CR/NaCl mixed solution. Additionally, the membrane exhibited favorable mechanical properties, with a tensile strength as high as 6.5 MPa and a fracture elongation reaching as much as 32.3 %. This work provided a novel approach for producing high-performance LNF membranes in treating dye wastewater.

Application of NiS modified WS2/TiO2 heterostructure in photocathodic protection

Stainless steel, as a popular corrosion resistant material, is still vulnerable to pitting corrosion in the marine environment. Therefore, in order to ensure the safety of stainless steel in the marine environment, it is necessary to implement corresponding protective measures. Titanium dioxide (TiO2), as an N-type semiconductor with excellent photoelectric properties, is widely used in the field of cathodic protection. However, as a photogenerated cathodic corrosion protection material, TiO2has the disadvantages of low conductivity and high carrier recombination rate. Therefore, WS2and NIS were introduced in this paper to modify it. TiO2/WS2/NiS (TWN) composites with Type-Ⅱ heterojunction structure were prepared by hydrothermal method and titration method. The results reveal TWN5 showed the best photoelectrochemical (PEC) performance, and the photocurrent density was 69% higher than that of a pure TiO2photoanode, and the photochemical and photocathodic protection performance was significantly better than that of pure TiO2. Under simulated ocean conditions, the self-corrosion potential of 304ss combined with TW5 and TWN5 photoanodes is reduced to -0.64 V and -0.7 V, respectively. The main reason is that the contact surfaces of WS2and TiO2formed a Type II heterostructure, which accelerates the separation and diffusion processes of photoinduced carriers. In addition, the plasmon resonance effect of NiS improves the ability to absorb visible light, and the metallic-like feature of NiS also promotes charge separation.

Energy Efficiency Analysis of Hydrate and Ionic Liquid-Based Binary Gas Separation Processes

Energy Efficiency Analysis of Hydrate and Ionic Liquid-Based Binary Gas Separation Processes

Octopus-inspired flocculant for oily wastewater decontamination: Hydrophilic-hydrophobic convertibility and auto-separation characters

Unilateral hydrophobic flocculant and unsatisfactory floc separation constrained the efficacious purification of oil-containing wastewater. Illumined by the hunting behavior of mimic octopus, a biomimetic flocculant (CNSDA) with temperature-sensitive chains (color pouch) and hollow silica cores (mantle) was manufactured to derive hydrophilic-hydrophobic convertibility and auto-separation capabilities. Physical-chemical information of CNSDA was elucidated through characterization analysis. The flocculation behaviors of temperature-sensitive chains and hollow silica cores were evaluated by flocculation experiments. Results indicated that the configuration of CNSDA molecular chains varied from extension to constriction and revealed hydrophobicity as the temperature crossed 29.6 ℃. Compared with 20 ℃, the flocculation efficiencies rocketed at 40 ℃ by CNSDA, and excess flocculants were adsorbed by as-formed flocs through nonpolar interactions (the residual was low to 2.27 % at 160 mg/L). Concomitantly, the contracted molecular chains were contributed to generating dense flocs with low moisture content that flocked into large ones and expedited the solid-liquid separation process (60 % shorter than cationic polyacrylamide) with the auxiliary of low-density cores. The hydrophobic adsorption mechanism actuated by temperature-sensitive character was the decisive factor for high-efficiency flocculation. This study can provide meaningful references for the conception and exploitation of oily wastewater disposal agents.

Fabrication and separation performances of composite membranes containing copper ferrite photocatalysts on graphene oxide nanosheets

An innovative approach thatintegrates photocatalysis, adsorption, and membrane separation processes was presented to degrade pollutants simultaneously during the filtration process. Firstly, a one-pot method was employed to prepare 3D graphene oxide/carbon quantum dot/copper ferrite (G/CFQ) photocatalysts. Then, the M−G/CFQ membrane was fabricated by intercalating 3D G/CFQ photocatalysts between 2D graphene oxide (GO) nanosheets using a negative pressure filtration technique. The time-dependent flux and MB residual rate results revealed that the M−G/CFQ membrane exhibited superior photocatalytic capabilities, particularly in alkaline environments. Furthermore, M−G/CFQ, when used without reaching adsorption saturation and under illumination, displayed outstanding long-term operational catalytic degradation capabilities. For a 5 ppm methylene blue (MB) solution at pH of 7, 10, and 12, the filtrate residue rates were only 8.63 %, 4.44 %, and 1.61 % respectively within 6 h. The versatility, stability, and exceptional properties of M−G/CFQ make it a promising candidate for large-scale water treatment applications, contributing significantly to the conservation of clean water resources and environmental sustainability.

Investigating novel thin-film nanocomposite membranes for sustainable water recovery using fertilizer-driven forward osmosis – Experimental and machine learning approaches

Water recovery from municipal wastewater can augment freshwater resources to meet increasing demand. An osmotic-driven membrane separation process- forward osmosis (FO) is currently being explored as a sustainable technology. This work proposes to address the challenges associated with FO namely (i) robust membrane and (ii) draw solute (DS) recovery. Robust thin-film nanocomposite membranes incorporating a) nickel ferrite or b) nitrogen-enriched nanoporous polytriazine (NENP-1) covalent organic framework were fabricated with enhanced hydrophilicity, surface roughness and anti-fouling properties. The optimum membranes M2 and C2 displayed a pure water flux of 4.86 ± 0.11 and 5.4 ± 0.2 L/m2h respectively and a specific reverse solute flux (SRSF) <<1 when using 1 M NaCl solution as the DS (feed solution – DI water). Fertilizer-driven FO (FDFO) was proposed as the diluted DS need not be recovered but could be used directly for irrigation. The pure water flux for both M2 and C2 membranes were in the following order for the fertilizers used as DS (1 M) - (NH4)2SO4 + (NH₄)₂HPO₄ > (NH4)2SO4 > (NH₄)₂HPO₄ which indicates that the mixed ions in the DS enhanced the water permeance. In all cases, the SRSF was < 1 g/L indicating the feasibility of the process. The membranes exhibited a TOC removal of > 90 % from synthetic municipal wastewater containing persistent organic pollutants and personal & pharmaceutical care products and the membranes could be regenerated after washing with a 10 mM solution of SDS for 5 cycles of operation. Further, ANN was used to develop a predictive model for water flux in FO membranes and the optimized architecture of 7–5–50–40–1 displayed a remarkable overall R2 value of 0.98 (MSE= 0.027). The FDFO process using the fabricated thin-film nanocomposite membranes holds enormous potential to be investigated in larger-scale studies.

Mechanically robust MOF beads for efficient ethylene/ethane separation with fast adsorption kinetics

Shaping of metal-organic frameworks (MOFs) without obvious mass transfer resistance is crucial for scaled-up adsorption separation process. Herein, mechanically robust ultramicroporous MOF (ZU-901, also termed CPL-1-CH3) beads with hierarchical porosity were structured through the calcium alginate (CA) method, which preserved the adsorption separation performance and demonstrated fast gas diffusion rates. The highly crosslinked networks of CA contributed to the excellent mechanical properties of 95 % ZU-901@CA beads with Young’s modulus up to 1.81 MPa and a low abrasion rate of 0.32 %, superior to that of 95 % ZU-901@HPC extrudates (1.13 %). Compared with powder of ZU-901, the C2H4 capacity of ZU-901@CA beads showed only 3 % loss at 298 K. The C2H4 diffusion time constant of 95 % ZU-901@CA beads (7.06 × 10−3 s−1) was comparable to that of the powders (7.61 × 10−3 s−1) and higher than that of ZU-901@HPC extrudates (2.95 × 10−3 s−1). Breakthrough experiments confirmed that ZU-901@CA beads performed well in the dynamic separation of C2H4/C2H6 binary mixture, and could be easily regenerated at room temperature. In addition, after post modification on the exterior of ZU-901 beads, the water contact angle increased from 0° to 119°. Therefore, the mechanically robust ZU-901@CA beads showed great potential in energy-efficient C2H4/C2H6 separation.

Interfacial and mass transport phenomena in the tri-ethylene glycol-methane system at process conditions of natural gas dehydration

AbstractUnderstanding the phase and interphase behavior at equilibrium and during the mass transfer between two adjacent fluid phases is relevant for optimizing and designing efficient separation processes. This study experimentally investigates the interfacial and transport behavior of systems comprising tri-ethylene glycol (TEG) and methane (CH4) under conditions relevant to the gas dehydration process. A comprehensive review of the interfacial tension (IFT) and diffusivity of systems involving non-polar and polar compounds at elevated pressures was studied. However, a research gap exists, particularly concerning the interfacial tension of systems involving TEG, TEG + water, and different types of gases as well as the diffusivity of CH4 in TEG. To address this gap, this study presents new data on mixture densities, interfacial tension, and drop volumes of TEG and TEG + water in CH4 and CH4 + CO2 mixtures at temperatures ranging from 20 to 50 °C and pressures up to 250 bar using the oscillating U-tube and pendant drop methods, respectively. Additionally, time-dependent fluid mixture densities and TEG droplet volumetric expansion, coupled with an analytical approach for the binary diffusion were applied to determine the CH4 solubility and diffusivity in TEG. The results show that IFT and drop volume of TEG and TEG + water in CH4 and CH4 + CO2 mixtures decrease with increasing pressure. The presence of water increases the IFT of TEG-CH4 up to $$\sim$$ ∼ 5mN/m, while CO2 reduces it by $$\sim$$ ∼ 2mN/m. Interestingly, the IFT and drop volume of TEG-CH4 show no significant change at elevated pressures when temperatures rise from 20 to 50 °C. IFT remains relatively constant over time at moderate pressures but decreases by $$\sim$$ ∼ 3mN/m at an elevated pressure of 150 bar, suggesting methane solubilization into TEG to have a significant influence which is confirmed by TEG drop volume expansion. The diffusivity of CH4 in TEG at 150 bar and 50 °C is determined to be in the range of 10–10 m2/s, which is in agreement with the diffusivity of CH4 in liquids of similar viscosity, i.e. according correlations may be applied as good engineering practice. To the best of our knowledge, there is no such comprehensive work on the properties of fluid mixtures relevant in gas dehydration processes published up to date.

Research on the Hierarchical Separation of Rare Earths and Lithium from Rare Earth Molten Salt Slag

Lithium is an important non-renewable resource, and the study of the tiered separation of rare earths and lithium from rare earth molten salt slag is an important approach to solving the current global resource shortage. This article adopts a sulfuric acid leaching process and a lithium-containing solution iron lithium extraction separation process to recover lithium from rare earth molten salt slag. The method systematically investigates the impact of sulfuric acid concentration, liquid-to-solid ratio, leaching temperature, leaching time, pH, P507 concentration, phase ratio, extraction temperature, and extraction time on the lithium extraction effect and iron lithium separation effect in rare earth molten salt slag. The results show that under the conditions of a sulfuric acid concentration of 0.9 mol/L, a liquid-to-solid ratio of 8:1 mL/g, a leaching temperature of 70 °C, a leaching time of 90 min, a pH of 0.9, a P507 concentration of 50%, a phase ratio of 5:3, an extraction temperature of 30 °C, and an extraction time of 20 min, the lithium leaching rate reaches 97.8%, and the separation of iron and lithium is fully achieved. This method can efficiently recover the valuable element lithium from rare earth molten salt slag, which is of great significance for the subsequent preparation of lithium products and the realization of a closed-loop production of rare earth alloys by molten salt electrolysis.

Separation of adhesive joints of pouch cells in the context of battery module disassembly

The increase in demand for electric vehicles due to the transformation to electromobility will lead to a large number of batteries reaching the end of life and needing to be disposed of. Direct recycling of batteries requires disassembly down to cell level. However, adhesive bonds present a major obstacle to mechanical disassembly. In this work, adhesive bonds between pouch cells are characterised and possible separation processes are identified. Based on this, an industrial system concept for cutting the adhesive bonds, particularly with a rope cut, is developed and tested. A stable and safe process parameter space was identified. The separation process can enable further circular economy strategies such as remanufacturing or reusing the battery cells.