Hazardous compounds from used batteries pose a great threat to the environment. To prevent pollution and to recover critical materials from battery waste, efficient recycling is required. Until now, battery recycling has focused on the recovery of valuable metals from cathode materials, while organic fractions have often been neglected due to their low material value. New approaches to battery recycling are therefore necessary, where recycling methods based on supercritical carbon dioxide (SC-CO2) extraction show great potential. In this work, a SC-CO2 method was implemented to extract electrolyte solvents for the purification and recovery of a separator waste material (SWM) sorted out from lithium-ion battery (LIB)-based black mass. In addition, two other separation routes (ultrasonic washing and thermal treatment) were used for comparison. Based on the results from the three routes, mass balances revealed the gravimetric composition of the SWM, which includes separator, electrolyte, and electrode powder. The composition of electrolyte solvents was determined via Gas Chromatography-Mass Spectroscopy analysis. Furthermore, the polymeric separator was analyzed using Fourier Transform Infrared Spectroscopy, Thermogravimetric Analysis, and Differential Scanning Calorimetry analysis to evaluate the effects of SC-CO2 extraction on the physicochemical properties. The recovery of electrolyte by the SC-CO2 route is more efficient than the others, with extraction yields of 162 mg of electrolyte per gram of SWM. Moreover, no changes are observed in the analyzed properties of the polymeric separator material due to the SC-CO2 extraction. Thus, the SC-CO2 process proves to be a promising method for an efficient and sustainable recycling of electrolyte solvent and purifying of separator material from LIB waste.

The Cupper Indium Gallium diSelenide (CIGS) Photovoltaic (PV) technology is well established in the market and considered as a good candidate for incorporation in other, more recently developed and complex PV technologies (e.g. tandem). Despite its popularity, little research has been done on the recycling of its materials, which contain valuable, critical and toxic elements. In this paper, the possibility of recovering in solid form the valuable CIGS material from CIGS solar cells, through first selectively leaching the Mo layer deposited underneath and subsequently liberating the unsupported CIGS by mechanical means, was explored. Different NaOH concentrations, process temperatures and means of mechanical liberation of the unsupported CIGS were investigated. The results showed that although a range of the tested NaOH concentrations could efficiently dissolve the Mo even at ambient temperature, for 0.1-0.5 M NaOH, some of the CIGS reacted with the NaOH and the compositional elements of the former ended up scattered in various phases. This was not the case when using a dilute NaOH solution of pH = 11 at 50 degrees C with an automatic titration system for keeping the pH constant. More specifically, after the application of these conditions for 8 h and a subsequent mechanical brushing of the substrate, the composition and crystalline structure of the recovered CIGS had remained practically unaffected, compared with the untreated material. Complete recovery of the CIGS was then achieved, with a purity of about 95 wt%. Simultaneously, 82 wt% of the Mo was recovered in the leachate.

The large scale deployment of Si PV panels presents significant end-of-life challenges due to their limited lifespan. Effective recycling strategies are crucial to reduce the environmental impact and recovering valuable metals. This study presents a simple yet highly efficient two-stage chemical process to preserve Si purity by sequential extraction of Al and Ag from discarded Si solar cells. In the first stage, Al was dissolved with sodium hydroxide (NaOH) and then precipitated by adjusting the pH with sulfuric acid (H2SO4). In the second stage, the Ag was extracted with nitric acid (HNO3), precipitated with sodium chloride (NaCl), and then reduced to metallic Ag with a glucose. Under optimized conditions, the recovery efficiency for Al and Ag was over 99 %, while the resulting Si substrate reached a purity of >99.9 %. ICP-OES, XRF, XRD, and SEM-EDS confirmed the recovered materials' high selectivity and negligible impurities, highlighting their potential for high-value industrial applications.

The recycling of polyvinylidene fluoride (PVDF) from spent lithium-ion battery black mass was investigated using supercritical carbon dioxide (SCCO2) combined with dimethyl sulfoxide (DMSO) as a co-solvent. Experiments were conducted at 70 degrees C and 80 bar for 15 min, varying the DMSO volume. Thermogravimetric analyses revealed that utilizing 4 mL of DMSO enabled the cumulative recovery of 55.6 wt% of PVDF. Thermogravimetric analysis confirmed a significant enhancement in PVDF extraction compared to atmospheric pressure (1 atm), where minimal PVDF was removed even after extended periods of solvent mixed black mass up to 18 days at room temperature and 24 h at 70 degrees C. Scanning electron microscopy revealed particle size reduction from approximately 93 mu m to 43 mu m and decreased agglomeration in treated samples, demonstrating improved particle homogeneity due to binder removal. Fourier-transform infrared spectroscopy and X-ray diffraction analyses confirmed that the chemical structure and crystalline phases of recovered PVDF remained intact. Despite its significance, PVDF recycling has not yet been established at an industrial scale. This study demonstrates the potential of the SCCO2-DMSO system as a rapid, sustainable, and scalable approach for the efficient recovery of PVDF from industrial lithium-ion battery waste.

Electrolyte recovery from spent Li-ion batteries remains a significant challenge in the current recycling process. Li-ion battery waste streams containing electrolyte residues are classified as hazardous waste and entail a financial and workplace safety burden for the recycling industry. Recent studies show the potential use of supercritical CO2 extraction for the recovery of electrolyte solvents. In this study, the extraction behavior of electrolyte solvents from Li-ion battery black mass using supercritical CO2 process under pressures of 100 and 140 bar at 40 degrees C was investigated. The extraction yield of dimethyl carbonate, ethyl methyl carbonate, and diethyl carbonate exceeded 99 % at both pressures. Ethylene carbonate, biphenyl, and propylene carbonate were successfully extracted with an extraction yield exceeding 95 % using 140 bar and 40 degrees C. The extraction rates of biphenyl, ethylene carbonate and propylene carbonate at 140 bar and 40 degrees C in the linear extraction regime of the extraction curve were determined to be 0.18 mg/g CO2, 1.9 mg/g CO2 and 0.4 mg/g CO2, respectively. The research demonstrates that supercritical COQ processing is a highly promising method not only for recycling electrolytes but also for mitigating the hazardous risks associated with battery waste.

Considerable effort has been put over the last few decades into clarifying the correct design and analysis of split-plot factorial experiments. However, the information found in the literature is scattered and sometimes still not easy to grasp for non-experts. Because of the importance of split-plots for the industry and the fact that any experimenter may need to use them at some point, a detailed and step-by-step guide collecting all the available information on the fundamental methodology in one place was deemed necessary. More specifically, this paper discusses the simple case of an unreplicated split-plot factorial experiment with more than one whole-plot (WP) factors and all factors set at two levels each. Explanations on how to properly design the experiment, analyze the data, and assess the proposed model are provided. Special attention is given to clarifications on the calculations of contrasts, effects, sum of squares (SS), parameters, WP and sub-plot (SP) residuals, as well as the proper division of the proposed model into its sub-designs and sub-models for calculating measures of adequacy correctly. The application of the discussed theory is showcased by a case study on the recycling of molybdenum (Mo) from CIGS solar cells. Factors expected to affect Mo recovery were investigated and the analysis showed that all of them are significant, while the way they affect the response variable was also revealed. After reading this guide, the reader is expected to acquire a good understanding of how to work with split-plots smoothly and handle with confidence more complex split-plot types.

This study investigates the dissolution mechanisms of black mass by employing oxalic acid as a leaching agent at different temperatures. The concentration of oxalic acid and the solid-to-liquid ratio of the leaching are maintained at a fixed molar ratio of 1:2.5. This work aims to study the impact of the leaching temperature on the kinetics and the leaching residue composition or morphology. The findings confirm that increasing the temperature significantly enhances the rate of lithium dissolution from the black mass; 6 h is needed to reach a dissolution equilibrium at 30 degrees C against less than 30 min at 80 degrees C. The dissolution rate is shown to be chemically controlled, with a pseudo-homogeneous model of 2nd and 3rd order, and the Avrami model best fitting the experimental data. The energy of activation was determined via the Avrami model to be at 76 kJ/mol. Additionally, this study identifies the anionic oxalate complexes formed in the aqueous solution during the leaching process, which is essential to developing an adequate purification method for the leachate. Finally, residues are characterized using various techniques, including XRD, SEM-EDS, and particle size analysis, which revealed that oxalate precipitate is formed majorly in the bulk of the solution as a disordered (Co,Ni,Mn)C2O4 & sdot;2 H2O phase.

Ethylene carbonate is, among other applications, used in Li-ion batteries as an electrolyte solvent to dissociate Li-salt. Supercritical CO2 extraction is a promising method for the recycling of electrolyte solvents from spent batteries. To design an extraction process, knowledge of the solute solubility is essential. In this work, the solubility of ethylene carbonate at different pressure (80–160 bar) and temperature (40 °C, and 60 °C) conditions is studied. It is shown that the solubility of ethylene carbonate increased with pressure at both temperatures, ranging from 0.24 to 8.35 g/kg CO2. The retrieved solubility data were fitted using the Chrastil model, and the average equilibrium association number was determined to be 4.46 and 4.02 at 40 °C and 60 °C, respectively. Scanning electron microscopy, Fourier-transform infrared spectroscopy, and X-ray diffraction analysis of the collected ethylene carbonate indicated that the crystal morphology and structure remained unchanged. A proof-of-principle experiment showed that EC can be successfully extracted from Li-ion battery waste at 140 bar and 40 °C.

The primary challenge in recycling crystalline silicon (c-Si) photovoltaic (PV) modules is separating the polymeric fractions, including back sheets, from the module structure. Thermal treatment, commonly used for this purpose, adversely affects the environment by releasing harmful gases and degrading polymers. With this in mind, this study introduces a novel hot knife method to efficiently separate and recover the back sheet layer from c-Si PV modules, a primary source of toxic gases during thermal treatment. A thin and highly conductive knife was selected for the hot knife-cutting process. The heating of the knife was accomplished by connecting it to a hot air gun, which offers complete parameter control, enabling precise adjustments to maintain the knife at the required temperature. Experimental tests were conducted to determine the best conditions for separating the back sheet from solar cells. The effectiveness of this method was evaluated using FTIR, TGA, and SEM-EDS. The findings reveal that the proposed hot knife technique effectively separate the back sheet layers from c-Si PV panels without breaking their integrity. The recovered back sheet can significantly reduce environmental pollution risks by preventing polymer material depletion. As a result, the production gases that arise from the degradation of back polymers can be eliminated.

The increasing global market size of high-energy storage devices due to the boom in electric vehicles and portable electronics has caused the battery industry to produce a lot of waste lithium-ion batteries. The liberation and de-agglomeration of cathode material are the necessary procedures to improve the recycling derived from spent lithium-ion batteries, as well as enabling the direct recycling pathway. In this study, the supercritical (SC) CO2 was innovatively adapted to enable the recycling of spent lithium-ion batteries (LIBs) based on facilitating the interaction with a binder and dimethyl sulfoxide (DMSO) co-solvent. The results show that the optimum experimental conditions to liberate the cathode particles are processing at a temperature of 70 °C and 80 bar pressure for a duration of 20 min. During the treatment, polyvinylidene fluoride (PVDF) was dissolved in the SC fluid system and collected in the dimethyl sulfoxide (DMSO), as detected by the Fourier Transform Infrared Spectrometer (FTIR). The liberation yield of the cathode from the current collector reaches 96.7% under optimal conditions and thus, the cathode particles are dispersed into smaller fragments. Afterwards, PVDF can be precipitated and reused. In addition, there is no hydrogen fluoride (HF) gas emission due to binder decomposition in the suggested process. The proposed SC-CO2 and co-solvent system effectively separate the PVDF from Li-ion battery electrodes. Thus, this approach is promising as an alternative pre-treatment method due to its efficiency, relatively low energy consumption, and environmental benign features.

Recovery of manganese as high purity MnSO4H2O from purified NMC111 lithium-ion battery leachate using solvent extraction and evaporative crystallization was investigated. Bis(2-ethylhexyl) phosphoric acid (D2EHPA) was used for Mn extraction. Operational parameters for extraction, scrubbing, and stripping (e.g. pH, number of stages, phases composition) were determined based on the results of batch equilibrium experiments. Counter-current extraction in bench-scale mixer settlers (VMSU=120 mL) was carried out with 35% v/v (1.05 M) D2EHPA in Isopar L operated at an average pH of 2.9 and theta = 1. More than 98% of the Mn was extracted in three counter-current stages together with 4%, 5% and 3% of Co, Li and Ni respectively. The distribution of impurities such as Zn, Ca, and Al was monitored during counter-current operations. Satisfactory removal of Co, Ni and Li from the loaded organic phase was achieved after contact with a solution of Mn 4 g/L (70 mM) in two stages at theta = 1. A solution with a Mn concentration of 8.7 g/L (160 mM) was recovered after stripping with 0.5 M H2SO4 at theta = 1 in two stages. Evaporative crystallization of the product allowed the recovery of high purity (99.6%) MnSO4H2O. A flowsheet for Mn recovery from LIBs is proposed, and the advantages and challenges related to it are discussed.

While the share of solar energy harvesting by photovoltaic (PV) systems in electricity production increases, their recycling still remains mainly at an early stage. Therefore, valuable and critical elements like silver (Ag) and indium (In) are lost along with production and end-of-life waste, highlighting the need for simple and sustainable recycling solutions which could be easily implemented by the industry. In this paper, we suggest a simple environmentally friendly method for selective recovery of Ag and Indium Tin Oxide (ITO) particles from flexible Copper Indium Gallium diSelenide (CIGS) solar cells, using two-step ultrasonic (US) leaching with low nitric acid (HNO3) concentration of 0.1 M. The first step aimed at the selective liberation of ITO through the selective dissolution of the zinc-rich layer underneath, using low US power for 3 min. In the second step, the same conditions as in the first step were applied, but now using high US power for 15 min for removal of the Ag grid lines. Both the ITO and the Ag grid particles were subsequently recovered by filtration and there was no loss of Ag observed in the leachates. By this method, a complete separation of ITO and Ag from the solar cell was achieved, with no changes in their crystal structure and promising purities of about 70.5 wt% and 95.0 wt%, respectively. This new approach opens up a new path for possible direct reuse of these materials in the manufacturing of new PVs, after further purification, with an impressively low need for chemicals.

Precious and scarce silver (Ag) is used as a front electrical contact in silicon solar panels. With massive amounts of solar panel waste coming to end-of-life, it is imperative to recover all the Ag from these modules. In this paper, we propose a novel method to easily reclaim Ag from end-of-life silicon solar cells using low concentration sulfuric acid (H2SO4) leaching followed by ultrasonication. Our process simplifies the Ag recycling procedure by directly recovering the Ag contacts from solar cells, eliminating the need for secondary precipitation/electrodeposition. First, scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy (EDX) and Xray photoelectron spectroscopy (XPS) was used to study the leaching and ultrasonication process on rejected solar wafers. Next, a solar panel from landfill was heated in a furnace to burn off the polymer encapsulant. The silicon wafers were then collected from the burning process and leached in 2 M H2SO4 at two different shaking speeds for 48 h at room temperature. Finally, the end-of-life silicon wafer pieces were collected, sonicated in water, and then the sonication water was centrifuged to show a proof-of-concept to recover the Ag contacts. Inductively coupled plasma optical emission spectroscopy (ICPOES) is used to monitor dissolved elements in the leachate as a function of time and shaking speed. XPS is used to evaluate the composition of the silicon cell wafer surface before and after H2SO4 leaching. SEM is used to image the recovered Ag contacts morphology and EDX confirms the recovered particles contain high amounts of Ag. A proposed schematic illustrates the authors' hypothesis for the peeling mechanism.

The electrolyte in spent Li-ion batteries is prone to cause a high risk of hazardous emissions (HF, etc.) in the state-of-the-art recycling processes. It is the main source of fire risks and represents a significant burden for the recyclers due to the safety. Still, extended research to fully recycle the electrolyte without its destruction at elevated temperature is scarce. This study focuses on the electrolyte extraction from spent LiBs using sub- and supercritical carbon dioxide to fill this gap. The effects of the critical process parameters, pressure (60–120 bar), temperature (15–55 °C) and extraction time (1–50 min) from spent pouch cells were investigated. The results showed that the CO2 density, which is related to pressure and temperature, is significant for the recovery of the non-polar electrolyte solvents. The most important outcome is that dimethyl carbonate, and ethyl methyl carbonate were fully selectively extracted at the studied conditions, whereas the polar ethylene carbonate was extracted only in trace amounts. As results indicated, LiPF6 did not decompose in the proposed process whereby the toxic-gas emissions were dramatically minimized compared to the state-of-the-art recycling processes.

Silicon solar panels are often overlooked in e-waste recycling technology, even though they contain precious silver (Ag). In order to help meet future global Ag demands and prevent contamination of the environment, all the Ag from end-of-life modules must be recovered instead of landfilled. The most mature Ag recycling recipes use high concentration nitric acid (HNO3) solutions often in combination with heating and agitation. After the Ag is leached, chemical precipitation or electrochemistry is used to recover metallic Ag. However, the process of Ag leaching in the HNO3 system with competing elements from silicon solar cells is not well understood. In this paper, we investigate the thermodynamics governing Ag leaching in low-concentration HNO3 without agitation or heating to expand fundamental knowledge in support of Ag recovery efforts from end-of-life solar panels. ICPOES is used to quantify the amount of Ag leached in the HNO3 solution over time. Scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS) are used to study the changes on the silicon solar cell surface. Our results suggest when trace tin (Sn) is used in solar cell fingers, it causes Ag to cement in dendritic form.

The chemical forms of zinc in fly ash from municipal solid waste incineration (MSWI) crucially affect ash management, influencing both material recovery options and the risk of unwanted leaching into ecosystems. The zinc speciation was investigated in fly ash samples sourced from full-scale MSWI plants, including four grate fired boilers (GB) and one fluidized bed boiler (FB). We applied X-ray Absorption Spectroscopy (XAS), and the spectra were analyzed against a unique library of over 30 relevant compounds, tailored to the nuances of zinc chemistry of fly ash. Nano-XANES and sequential leaching were employed as complementary analytical methods. Multiple chemical forms of zinc were found in the ash, whereof potassium zinc chloride salts (K2ZnCl4) 2 ZnCl 4 ) emerged as the predominant form in GB fly ash representing 41-64 % of the zinc content, while less for FB fly ash (19 %). The mere exposure to humidity in the air during storage resulted in hydroxylation of the alkali zinc chlorides into Zn5(OH)8Cl2 center dot H2O. 5 (OH) 8 Cl 2 center dot H 2 O. Other forms of zinc in the ash were Zn4Si2O7(OH)2 center dot H2O, 4 Si 2 O 7 (OH) 2 center dot H 2 O, ZnFe2O4, 2 O 4 , ZnAl2O4, 2 O 4 , surface adsorbed zinc, and Zn5(CO3)2(OH)6. 5 (CO 3 ) 2 (OH) 6 . Notably, the proportion of zinc in spinel forms (ZnFe2O4 2 O 4 and ZnAl2O4) 2 O 4 ) increased threefold in FB ash compared to GB ash, representing 60 % and 10-20 % of the zinc, respectively.

XRD measurements of RaCO3 revealedthat it isnot isostructural with witherite, and direct-space ab initio modeling showed that the carbonate oxygens are highly disordered.It was found that the solubility of RaCO3 is unexpectedlyhigher than the solubility of witherite (log(10) K (sp) (0) = -7.5 and -8.56,respectively), supporting the disordered nature of RaCO3. EXAFS data revealed an ionic radius of Ra2+ of 1.55 & ANGS;. Radium is the only alkaline-earth metal which forms disorderedcrystals in its carbonate phase. Radium-226 carbonate was synthesized from radium-bariumsulfate ((Ra0.76Ba0.24SO4)-Ra-226) at room temperature and characterized by X-ray powder diffraction(XRPD) and extended X-ray absorption fine structure (EXAFS) techniques.XRPD revealed that fractional crystallization occurred and that twophases were formed the major Ra-rich phase, Ra(Ba)CO3, and a minor Ba-rich phase, Ba(Ra)CO3, crystallizingin the orthorhombic space group Pnma (no. 62) thatis isostructural with witherite (BaCO3) but with slightlylarger unit cell dimensions. Direct-space ab initio modeling shows that the carbonate oxygens in the major Ra(Ba)CO3 phase are highly disordered. The solubility of the synthesizedmajor Ra(Ba)CO3 phase was studied from under- and oversaturationat 25.1 & DEG;C as a function of ionic strength using NaCl as thesupporting electrolyte. It was found that the decimal logarithm ofthe solubility product of Ra(Ba)CO3 at zero ionic strength(log(10) K (sp) (0)) is-7.5(1) (2 & sigma;) (s = 0.05 g & BULL;L-1). This is significantly higher than the log(10) K (sp) (0) of witheriteof -8.56 (s = 0.01 g & BULL;L-1), supporting the disordered nature of the major Ra(Ba)CO3 phase. The limited co-precipitation of Ra2+ within witherite,the significantly higher solubility of pure RaCO3 comparedto witherite, and thermodynamic modeling show that the results obtainedin this work for the major Ra(Ba)CO3 phase are also applicableto pure RaCO3. The refinement of the EXAFS data revealsthat radium is coordinated by nine oxygens in a broad bond distancedistribution with a mean Ra-O bond distance of 2.885(3) & ANGS;(1 & sigma;). The Ra-O bond distance gives an ionic radius ofRa(2+) in a 9-fold coordination of 1.545(6) & ANGS; (1 & sigma;).

Electrolyte recovery is seldomly considered in state-of-art lithium-ion battery recycling methods but rather evaporates and decomposes uncontrolled during the pre-treatment steps. However, controlled and safe removal of the electrolyte is inevitable and of high importance to the recycling industry to min-imize the environmental impact of the recycling processes by preventing severe threats produced by the inflammable, toxic and hazardous components of the electrolyte. This study investigated the effects of temperature and process time of a low temperature thermal treatment process on electrolyte recovery. The process exhaust gases and recovered products were analyzed by In-Situ Fourier-transform infrared spectroscopy (FT-IR) and gas chromatography-mass spectrometry (GC-MS) to determine the effective-ness of the significant process parameters. The results show that the electrolyte solvents, which are dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), and ethylene carbonate (EC), were successfully recovered for 80 minutes of processing time at 130 degrees C. The LiPF6 decomposition products hydrogen flu-oride (HF) and phosphoryl fluoride (POF3) were detected in the exhaust gas stream and recovered as acidic solutions. Thermal treatment below 150 degrees C is a promising approach for the recovery of the elec-trolyte solvents prior to the metal recycling stage due to its simplicity, feasibility, and environmental benefit.(c) 2022 The Authors. Published by Elsevier B.V. on behalf of The Korean Society of Industrial and Engi-neering Chemistry. This is an open access article under the CC BY license (http://creativecommons.org/ licenses/by/4.0/).

Solar electricity from photovoltaics (PV) contributed to about 4.5 % of the global electricity production in 2022 and is expected to continue increasing by 2050 [1]. Therefore, both manufacturing waste and end of life waste are expected to reach a considerable volume in the upcoming decade. However, recycling methods for this type of waste are still at a very early stage of development. The thin film CIGS PV technology achieves high energy conversion efficiencies [2] and it is also used in promising newer technologies, namely multijunction solar cells. However critical elements like indium (In) and gallium (Ga), and often valuable silver (Ag) as conductive grid, are essential for the achievement of such efficiencies. Therefore, environmental, economic and resource depletion reasons demand the recovery of these elements. In industrial scale, there is currently no established recycling activity on CIGS containing materials. In lab scale, research mainly focuses on recycling of pure CIGS material production waste, which are free of any other element except for their 4 constituent elements in contrast to the real solar cells or PV. However, monitoring and controlling the impurity levels in the recycling of complex waste is of outmost importance, since the higher the purity of the recovered materials, the more economically viable their recycling business becomes. At the same time, the existing literature on the recycling of pure CIGS waste suggests the use of strong mineral acid solutions and high temperatures for the recovery of their elements. The case is similar for Ag, with some studies on its recovery only from another PV technology, namely silicon PV, being available and describing similarly harsh recovery conditions. Although such conditions can be efficient in many cases, they are not environmentally friendly and can be costly for the industry as well. To the best of our knowledge, the only available research work on the recovery of valuable elements from CIGS solar cells (Ag, In and others) using more benign recovery conditions compared to the ones that have been investigated so far (i.e. lower acid concentrations and room temperature), is our recent research work on leaching with nitric acid (HNO3) [3]. In our current work we investigated the leaching of flexible CIGS solar cells with a stainless steel substrate production waste at room temperature and acid concentrations no higher than 2 M. The leaching efficiency of Ag and In was studied under different leaching times, acid leaching agents and concentrations, as well as geometrical surface area to liquid ratios (A:L). The elemental composition of all the elements that were likely to be present in the solar cell was measured in all the leachates with ICP-OES. The solid materials left on the cell’s surface after the treatment were characterized in terms of morphology and elemental composition with SEM-EDS, when necessary. The results proved that the choice of the leaching agent plays an important role in the recovery of the different elements present in the cell. It was also confirmed that higher acid concentrations achieve higher leaching recoveries for the same leaching conditions, as expected. As far as the A:L ratio is concerned, in many cases, higher A:L ratios achieved higher efficiencies, probably due to better oxygenation of the solutions. An example of the efficiency of the method is presented in Fig. 1, in which the Ag grid line of the untreated sample (Figure 1a, b) looks white under SEM due to the presence of Ag particles. After the acid treatment of the cell with 2 M HNO3 for 24h, the Ag particles of the Ag grid lines have disappeared, making the line look black (Figure 1c). In total, two important conclusions were drawn: a) selective leaching of various elements for achievement of higher purity products is possible by adjusting the leaching parameters and b) a complete recovery of Ag is possible within one day with more environmentally friendly conditions than the ones suggested so far. References [1] International Energy Agency; Solar PV, 2023, available at: https://www.iea.org/energy-system/renewables/solar-pv#tracking [2] Fraunhofer institute for solar energy systems; PHOTOVOLTAICS REPORT, 2022, available at: https://www.ise.fraunhofer.de/content/dam/ise/de/documents/publications/studies/Photovoltaics-Report.pdf [3] I. Teknetzi, S. Holgersson and B. Ebin, Valuable metal recycling from thin film CIGS solar cells by leaching under mild conditions, Solar Energy Materials & Solar Cells 252 (2023) 112178, https://doi.org/10.1016/j.solmat.2022.112178 Acknowledgement: This work was funded by the Swedish Energy Agency [49349-1] Figure 1