Preparation and characterization of nano-structured lead oxide from spent lead acid battery paste

Rapid recovery of high pure PbO from spent lead acid battery without desulfation and chemicals consumption method

The direct recovery of high-purity PbO from spent lead paste without a pre-desulfation process has significant industrial promise. Herein, we propose a recyclable, ultra-fast, and high value-added closed-loop of high-purity PbO recovery process by intensive multidentate coordination of histidine with crude 2PbO·PbSO4 by a rotating liquid-film (RLF) reactor and CO2 carbonation-dissociation. Parameter optimizations and kinetic calculations show the leaching time is shortened from 40 min to 60 s with 99.14 % leaching rate and 99.99 % PbO purity by internal diffusion control, where the RLF reactor promotes mass transfer and reaction rates by instantly renewing the surface of crude 2PbO·PbSO4. Furthermore, all 5 batches reveal that the separation of SO42- ions from the regenerated mother liquid with Ba(OH)2 significantly improves the recycling rate of the mother liquid and high-purity PbO product. This new strategy reveals a bright prospect of a highly efficient, high value-added, and environmentally friendly recycling route for solid waste resources.

Recycling lead from copper plant residue (CPR) using brine leaching - Precipitation - Calcination process

Copper plant residue (CPR) is a hazardous industrial by-product possessing both high toxicity and valuable metal content, necessitating its high value-added utilization. Traditional practices in smelters involve stockpiling and landfilling of CPR, leading to substantial land occupation and water contamination. This study focused on the preparation of PbO and Pb3O4 using the HCl-NaCl leaching-conversion-thermal decomposition process, employing CPR as the primary raw material. The effect of various leaching process conditions on the metal leaching rate was explored. A maximum lead leaching rate of 87.65% was achieved under optimal conditions including leaching temperature, liquid-solid ratio, leaching time, HCl molar concentration, NaCl mass concentration, and particle size. The lead content in the leachate was 15.85 g/L. Experimental data indicated that ash diffusion control served as the rate-limiting step in the HCl-NaCl leaching process. The apparent activation energy was determined to be 18.374 kJ mol-1, with a reaction order of 0.8986 concerning the HCl concentration and an L/S ratio of 0.8124. Additionally, response surface methodology enabled the determination of technological parameters for refining PbCl2 into PbCO3 precursors, yielding a conversion rate exceeding 96.50%. Moreover, the technical indicators of PbO and Pb3O4 obtained through low-temperature thermal decomposition of PbCO3 were investigated. The fabricated PbO and Pb3O4 exhibited purities of 99.65% and 99.26%, respectively, effectively transforming CPR from hazardous waste residue into valuable products. The process ensures the efficient recovery of lead to its maximum extent and promotes residue recycling.

Recycled and Nickel- or Cobalt-Doped Lead Materials from Lead Acid Battery: Voltammetric and Spectroscopic Studies

The active mass of the plates of aspent car battery with higher wear after an efficient desulfatization can be used as sources of a new electrode. This paper proposes the recycling of spent electrodes from a lead acid battery and the incorporation of NiO or Co₃O₄ contents by the melt-quenching method in order to enrich the electrochemical properties. The analysis of X-ray diffractograms indicates the gradual decrease in the sulfated crystalline phases, respectively, 4PbO·PbSO₄ and PbO·PbSO₄ phases, until their disappearance for higher dopant concentrations. Infrared (IR) spectra show a decreasing trend in the intensity of the bands corresponding to the sulfate ions and a conversion of [PbO₃] pyramidal units into [PbO₄] tetrahedral units by doping with high dopant levels, yielding to the apparition of the PbO₂ crystalline phase. The observed electron paramagnetic resonance (EPR) spectra confirm three signals located on the gyromagnetic factor, g~2, 2.2 and 8 assigned to the nickel ions in higher oxidation states as well as the metallic nickel nanoparticles. This compositional evolution can be explained by considering a process of the drastic reduction in nickel ions from the superior oxidation states to metallic nickel. The linewidth and the intensity of the resonance lines situated at about g~2, 2.17, 4.22 and 7.8 are attributed to the Co⁺² ions from the EPR data. The best reversibility of the cyclic voltammograms was highlighted for the samples with x = 10 mol% of NiO and 15 mol% of Co₃O₄, which are recommended as suitable in applications as new electrodes for the lead acid battery.

Exploring specific biomarkers regarding neurobehavioral toxicity of lead dioxide nanoparticles in medaka fish in different water matrices

Nano-scale lead dioxide (nPbO₂) is an industrial metal oxide nanoparticle that can be also formed as a corrosion by-product from chlorination of Pb-containing plumbing materials. nPbO₂ governs release of toxic lead ion in drinking water and receiving organisms; however, its modes of toxic action regarding neurobehavioral toxicity remain unclear. This study evaluated the toxicity mechanism of nPbO₂ (10 and 20 mg/L) versus its released Pb(II)_aq (100 μg/L) in terms of aqueous chemistry, bioavailability and neurobehavioral toxicity to medaka fish in different water matrices. In very hard water (VHW), dissolved salts enhanced the aggregation and sedimentation of nPbO₂, resulting in higher bioavailability and altered locomotion of treated fish than those fish exposed to nPbO₂ in soft water with humic acid (SW + HA). Transcriptomic results identified six differentially expressed genes with greater altered expression with nPbO₂ than the control or Pb(II)_aq exposure. With VHW exposure, nPbO₂ caused greater altered expression of genes involved in cell adhesion (nlgn1 and epd), cell cytoskeleton (α1-tubulin), and relevant apoptosis (c-fos, birc5.1-a and casp3), as compared with SW + HA or Pb(II)_aq exposure. This study provides novel molecular mechanistic insights into the neurobehavioral nanotoxicity using nPbO₂ and medaka fish as surrogates, suggesting nPbO₂ promotes neurobehavioral dysfunction, leading to adverse outcomes from gene alteration to the organismal level. The identified biomarkers responded specifically to the nPbO₂-induced neurotoxicity in different water matrices can be used for evaluating toxicity risks of small metal oxide particulates on human or aquatic life under environmentally relevant exposures.

Lead recovery from spent lead acid battery paste by hydrometallurgical conversion and thermal degradation

Spent lead paste is the main component in lead-acid batteries reaching end of life. It contains about 55% lead sulphate and 35% lead dioxide, as well as minor amounts of lead oxide. It is necessary to recycle spent lead paste with minimal pollution and low energy consumption instead of the conventional smelting method. In this study, a novel approach involving hydrometallurgical desulphurisation and thermal degradation is developed to recover lead as PbO products from spent lead acid batteries. First, the desulphurisation effects and phase compositions of products with different transforming agents were compared, and the optimum conditions using (NH₄)₂CO₃ as a transforming agent were determined. And then, the thermal degradation processes of both precursors lead carbonate and lead dioxide were investigated to prepare α-PbO, Pb₃O₄, and β-PbO products in argon and air atmospheres, respectively. Both the desulphurisation precursors and the calcination products were characterised by thermogravimetry and differential scanning calorimetry, X-ray diffraction, and scanning electron microscopy. The results showed that the lead oxide products were prepared, including α-PbO at 450°C in argon, Pb₃O₄ and β-PbO at 480°C and 620°C in air, respectively.

A green recycling process of the spent lead paste from discarded lead-acid battery by a hydrometallurgical process

In this study, a green recycling process of discarded lead-acid battery paste, which could avoid both the smelting and electro-winning route has been developed. Leaching reagents containing sodium citrate, acetic acid and hydrogen peroxide were reacted with spent lead paste in aqueous media at the pH of 5-6. Lead paste was leached and formed into lead citrate precursor, which was recrystallized and separated from the solution. The optimal conditions for the leaching process at room temperature were found to be the: concentration of acetic acid solution of 0.92 mol L^-1; concentration of sodium citrate solution of 0.478 mol L^-1; initial mass ratio of solid spent lead paste to liquid (solid/liquid ratio) of 1/5 g/mL; and reaction time of 2 hours. The results showed that the desulphurization efficiency of lead paste was up to 99.9%. The optimal conditions for lead citrate re-crystallization from the leaching mixed solution were found to be the re-crystallization temperature of 55^oC for 5 hours in a water bath. The lead citrate precursor synthesized from discarded lead-acid battery pastes was the chemical formula of Pb₃(C₆H₅O₇)₂·3H₂O with columnar shape in the length of 30-50 μm, which was easily separated from the leaching solution. The results of kilogram-scale experiments made progress easier for obtaining the ultrafine lead oxide product (PbO and Pb) from discarded lead-acid battery paste.

Identification of management strategies and generation factors for spent lead acid battery recovery plant wastes in Turkey

The recovery of spent or waste lead acid batteries is important both for the management of lead input to the environment and to meet the lead demand of the market in a more energy and cost effective manner than primary production. As an important producer of lead acid batteries for the Middle Eastern and Eastern European market, Turkey seems to meet 22%-52% of its total lead demand by waste lead acid battery recovery. In this study, the wastes from Turkish waste lead acid battery recovery plants are identified and management strategies that are both technically sufficient and economically feasible for each of these wastes are complied. Furthermore, ranges of the amount of each waste generated per mass of final lead produced in these plants are estimated. Some of the most significantly generated wastes are lead containing dusts, wash water treatment sludges and slags from smelting furnaces with generation rates between 5-250, 1-150 and 5-100 kg t^-1 of product lead, respectively. Many of these can be fed back to the recovery process inside the plants except a subset of slags that are called 'final slag' and have low (5%-6%) lead content. Final slags can either be recovered for the production of cement, road-filling materials or abrasives proven that they are in a non-leachable, stable state or should be stored at hazardous waste landfills. For improved environmental performance, newly emerging techniques that eliminate the generation of such slags are also discussed and suggested.

Toward sustainable and systematic recycling of spent rechargeable batteries

A comprehensive and novel view on battery recycling is provided in terms of the science and technology, engineering, and policy.

A novel heterometallic compound for design and study of electrical properties of silver nanoparticles-decorated lead compounds

A novel Ag-NPs decorated on hexagonal-like PbCO₃ was constructed with a novel heterometallic compound (AgPb(C₂O₄)(NO₃)) through thermal heating at 523 K.

Spent lead-acid battery recycling in China - A review and sustainable analyses on mass flow of lead

Lead is classified to be one of the top heavy metal pollutants in China. The corresponding environmental issues especially during the management of spent lead-acid battery have already caused significant public awareness and concern. This research gives a brief overview on the recycling situation based on an investigation of the lead industry in China and also the development of technologies for spent lead-acid batteries. The main principles and research focuses of different technologies including pyrometallurgy, hydrometallurgy and greener technologies are summarized and compared. Subsequently, the circulability of lead based on the entire life cycle analyses of lead-acid battery is calculated. By considering different recycling schemes, the recycling situation of spent lead-acid battery in China can be understood semi-quantitatively. According to this research, 30% of the primary lead production can be shut down that the lead production can still ensure consecutive life cycle operation of lead-acid battery, if proper management of the spent lead-acid battery is implemented according to current lead industry situation in China. This research provides a methodology on the view of lead circulability in the whole life cycle of a specific product and is aiming to contribute more quantitative guidelines for efficient organization of lead industry in China.

Reduction of lead dioxide with oxalic acid to prepare lead oxide as the positive electrode material for lead acid batteries

Sponge-like lead oxides prepared from PbO₂can discharge a capacity of 115.2 mA h g⁻¹after 50 cycles at 100 mA g⁻¹.

The effect of barium sulfate-doped lead oxide as a positive active material on the performance of lead acid batteries

Barium sulfate (BaSO₄) is a common impurity in recycled lead paste, and the effect of this impurity in positive active materials on the performance of recycled lead acid batteries was investigated.

Preparation of high-purity lead oxide from spent lead paste by low temperature burning and hydrometallurgical processing with ammonium acetate solution

Lead sulfate, lead dioxide and lead oxide are the main components of lead paste in a spent lead-acid battery.

Recycling lead from spent lead pastes using oxalate and sodium oxalate and preparation of novel lead oxide for lead-acid batteries

A sustainable method, with minimal pollution and low energy cost in comparison with the conventional smelting method, is proposed for treating components of spent lead acid batteries with oxalate and sodium oxalate.

Leaching of spent lead acid battery paste components by sodium citrate and acetic acid

A sustainable method, with minimal pollution and low energy cost in comparison with the conventional smelting methods, is proposed for treating components of spent lead-acid battery pastes in aqueous organic acid(s). In this study, PbO, PbO2, and PbSO4, the three major components in a spent lead paste, were individually reacted with a mixture of aqueous sodium citrate and acetic acid solution. Pure lead citrate precursor of Pb3(C6H5O7)2 · 3H2O is the only product crystallized in each leaching experiment. Conditions were optimized for individual lead compounds which were then used as the basis for leaching real industrial spent paste. In this work, efficient leaching process is achieved and raw material cost is reduced by using aqueous sodium citrate and acetic acid, instead of aqueous sodium citrate and citric acid as reported in a pioneering hydrometallurgical method earlier. Acetic acid is not only cheaper than citric acid but is also more effective in aiding dissolution of the lead compounds thus speeding up the leaching process in comparison with citric acid. Lead citrate is readily crystallized from the aqueous solution due to its low solubility and can be combusted to directly produce leady oxide as a precursor for making new battery pastes.