Recycling Of Alkaline Batteries Research Articles

Use of the organic fraction from recycled alkaline batteries in the manufacture of LECAs: Experimental and Environmental Assessment

The industrial alkaline battery recycling process produces an organic fraction (OF) consisting of waste paper, plastic and cardboard. Currently, this OF is used for energy recovery, given the absence of a successful alternative recycling approach, attributed to its contamination and limited economic value. This study explored the valorisation of the organic fraction derived from the recycling of alkaline batteries as a foaming agent in the production of lightweight expanded clay aggregates (LECAs). The OF, was mixed with red stoneware atomized paste (RSAP) in varying proportions (5–30 wt%) and fired at temperatures between 1000 and 1200 °C. The volumetric expansion, density, and compressive strength of the resulting aggregates were determined via mineralogical and microstructural characterization. The results indicate the organic fraction's suitability as an expansion agent, particularly at 1200 °C with 5–15 wt% inclusion, showcasing density (0.65–0.75 g/cm3) and compressive strength (1.34–1.39 MPa) comparable to commercial expanded clays. The microstructural analysis revealed the formation of rounded pores, influenced by the firing temperature and OF content. A Life Cycle Assessment (LCA) compared the environmental impacts of this process with traditional LECA manufacturing, highlighting the potential environmental benefits of using recycled battery waste. This study marks the first incorporation of this battery waste residue into LECA manufacturing, providing valuable insights into its environmental implications and paving the way for sustainable waste management practices.

Characterization of Fe-based sediments received from chemical pre-treatment of hydrometallurgical waste leachate from the recycling of alkaline batteries

The waste leachate from the hydrometallurgical recycling of spent batteries contains a significant amount of undesirable iron that needs to be precipitated before the recovery of target metals. The produced Fe-sediments are usually disposed of or stored at the treatment site as waste and are often poorly managed. This work estimates the environmental stability and application potential of Fe-sediments produced from highly acidic hydrometallurgical leachate during the recycling of spent alkaline batteries. After pH neutralization of the leachate by Na2CO3, a primary Fe-sediment (PFS), mainly composed of highly unstable metal (i.e., Fe, Zn, and Mn) sulfates, was obtained. The subsequent rinsing of this unstable PFS sediment led to the production of a secondary Fe-sediment (SFS), which was composed of an amorphous-phased ferric iron sulfate hydrate – Fe16O16(SO4)3(OH)10·10H2O. The results of single extraction using chemical reagents and biological dissolution by iron-transforming bacteria confirmed that despite most of the ions in PFS were dissolvable, the processed SFS was environmentally safe. The sorption efficiency of SFS towards Pb(II) and As(V) (up to ~ 99% and 94%, respectively, with an initial concentration of 100 mg/L) was found to be promising, suggesting the high potential for economical reuse of SFS.

Recycling of Alkaline Batteries via a Carbothermal Reduction Process

Primary battery recycling has important environmental and economic benefits. According to battery sales worldwide, the most used battery type is alkaline batteries with 75% of market share due to having a higher performance than other primary batteries such as Zn–MnO2. In this study, carbothermal reduction for zinc oxide from battery waste was completed for both vacuum and Ar atmospheres. Thermodynamic data are evaluated for vacuum and Ar atmosphere reduction reactions and results for Zn reduction/evaporation are compared via the FactSage program. Zn vapor and manganese oxide were obtained as products. Zn vapor was re-oxidized in end products; manganese monoxide and steel container of batteries are evaluated as ferromanganese raw material. Effects of carbon source, vacuum, temperature and time were studied. The results show a recovery of 95.1% Zn by implementing a product at 1150 °C for 1 h without using the vacuum. The residues were characterized by Atomic Absorption Spectrometer (AAS) and X-ray Diffraction (XRD) methods.

Luminescence and gas-sensing properties of ZnO obtained from the recycling of alkaline batteries

The great amount of wasted alkaline batteries produced nowadays constitutes a driving force for obtaining valuable materials from the recycling process. Zn is one of the major components of the batteries residues; hence, the possibility to obtain good quality ZnO appears very attractive. In this work, we have characterized ZnO obtained by different synthesis routes from the black mass produced during the mechanical recycling process. The luminescent behaviour has been studied and compared to that of the commercial ZnO. Chromaticity has been analysed through the corresponding CIE [Commission Internationale d’Eclairage (CIE) 1931] coordinates, obtained from the emission spectra. The possible response to gases from the ZnO obtained from the different sources has been also investigated. While ZnO from recycling does not show an appreciable gas sensitivity, the possibility to follow different calcination routes and hence obtaining ZnO with different defect structures and luminescent behaviour open the way to tailor the colour of the emitted light.

Synthesis and microstructural properties of zinc oxide nanoparticles prepared by selective leaching of zinc from spent alkaline batteries using ammoniacal ammonium carbonate

Two different precursors of zinc oxide were prepared via the ammoniacal ammonium carbonate leaching of the black mass obtained during the recycling of alkaline batteries. For a concentration of 0.1 mol/L of ammonium in the leaching solution, zinc basic carbonate, was obtained, while for higher ammonium concentrations (0.5 and 1 mol/L), zinc ammonium carbonate was the final product. These precursors were characterised by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Thermogravimetric analysis (TGA/DTG) and Scanning electron microscopy (SEM), and calcined to obtain ZnO. Raman spectroscopy, X-ray diffraction and Transmission electron microscopy (TEM) analysis of the resulting zinc oxide samples indicated a wurtzite hexagonal lattice with a parameter values ranging from 3.23 Å to 3.30 Å, and c parameter values from 5.18 Å to 5.21 Å (values close to typical). The room temperature photoluminescence spectra of the zinc oxide samples showed two main bands: a high energy UV-blue band centred at either 412 or 382 nm (depending on the NH3 concentration of the leaching solution used), and a green band centred at 527 nm. These emission bands are comparable to those reported for pure zinc oxide.

Leaching properties of Mn‐slag from the pyrometallurgical recycling of alkaline batteries: standardized leaching tests and influence of operational parameters

In the present study, different complementary leaching tests were applied to a Mn‐rich slag sample that was not thoroughly studied until now, in order to understand the potential mobility of the elements (Mn, Si, Fe, Ca, K, Mg, Al) within it. Several standard leaching tests (EN 12457‐1 and ‐2, and TCLP) were carried out in order to compare results to regulatory values: the Mn‐rich slag studied could be considered as ‘inert’ waste with respect to the release of the main trace metallic elements (Cu, Ni and Zn). In order to have a better understanding of the environmental behaviour of the Mn‐rich slag constituents, other tests were performed. These experiments revealed that the dissolution of the Mn‐rich slag was favoured for pH ≤ 6. The mobility of the major elements was governed by the solubility of the primary solid phases and the precipitation of secondary minerals. The Visual MINTEQ modelling allowed the leaching results to be completed. From an environmental point of view, the reuse of this slag in acidic conditions has to be rejected due to the dissolution of the main solid phase.

Leaching experiments on a Mn-rich slag from the recycling of alkaline batteries – Solid phase characterization and geochemical modeling

Square sections of a Mn-rich slag from an alkaline battery recycling plant were submitted to 6-month batch leaching procedures. High-Purity Water (HPW), acidic (pH 4) and alkaline (pH 12) conditions were used in order to observe the behavior of primary solid phases as well as the constituent elements (Mn, Mg, Al, Si, Ca). The experiments were coupled with both KINDIS(P) modeling and mineralogical study (SEM-EDS). Experimental results showed that the Mn-rich slag was sensitive to acidic conditions which induced the dissolution of primary phases. Moreover, pH 4 conditions did not result in the formation of newly formed solid products, leading to the greatest mobilization of metallic elements (especially Mn). Alkaline conditions favored the precipitation of secondary phases, especially rhodochrosite, calcite and Mg-saponite, inducing low mobilization of the contained elements. The KINDIS(P) modeling allowed the stability of primary phases and newly formed products to be predicted. Although the modeled results have to be considered with caution, they allow the assessment and understanding of future environmental behavior of the solid material in given conditions. In this case, the reuse of Mn-rich slag in acidic conditions has to be avoided because of the acidic dissolution of the primary phases.