Recovery of critical metals from EV batteries via thermal treatment and leaching with sulphuric acid at ambient temperature.

In the upcoming years, todaýs e-mobility will challenge the capacity of sustainable recycling. Due to the presence of organic components (electrolyte, separator, casings, etc.), future recycling technologies will combine thermal pre-treatment followed by hydrometallurgical processing. Despite the ongoing application of such treatment, there is still a lack of information on how applied parameters affect subsequent metal recovery. In this study, both oxidative and reductive conditions in dependence on temperature and time were studied. Qualitative and quantitative characterizations of the samples after treatment were performed followed by leaching with 2 M sulphuric acid at ambient temperature to determine the leachability of valuable metals such as Co, Mn, Ni and Li. Moreover, the negative or positive effect of treatment on the leachability of the main impurities (Cu and Al) was determined. Since the presence of carbon affects the degree of active material reduction, it's content after each thermal treatment was determined as well. If all variables, temperature and time of thermal processing are taken into account, pyrolysis at 700 °C for 30 min is the optimal treatment. Under these conditions, full recovery is reached after 2 min for Li, 5 min for Mn and 10 min for both Co and Ni. In the case of the incineration, only processing at 400 and 500 °C promoted higher recovery of metals, while the treatment at 600 and 700 °C led to the formation of less leachable species.

Hydrometallurgical recycling of EV lithium-ion batteries: Effects of incineration on the leaching efficiency of metals using sulfuric acid.

The growing demand for lithium-ion batteries will result in an increasing flow of spent batteries, which must be recycled to prevent environmental and health problems, while helping to mitigate the raw materials dependence and risks of shortage and promoting a circular economy. Combining pyrometallurgical and hydrometallurgical recycling approaches has been the focus of recent studies, since it can bring many advantages. In this work, the effects of incineration on the leaching efficiency of metals from EV LIBs were evaluated. The thermal process was applied as a pre-treatment for the electrode material, aiming for carbothermic reduction of the valuable metals by the graphite contained in the waste. Leaching efficiencies above 70% were obtained for Li, Mn, Ni and Co after 60 min of leaching even when using 0.5 M sulfuric acid, which can be linked to the formation of more easily leachable compounds during the incineration process. When the incineration temperature was increased (600-700 °C), the intensity of graphite signals decreased and other oxides were identified, possibly due to the increase in oxidative conditions. Higher leaching efficiencies of Mn, Ni, Co, and Li were reached at lower temperatures of incineration (400-500 °C) and at higher leaching times, which could be related to the partial carbothermic reduction of the metals.

Incineration of EV Lithium-ion batteries as a pretreatment for recycling - Determination of the potential formation of hazardous by-products and effects on metal compounds.

In several industrial Lithium-ion batteries recycling processes, a thermal treatment with oxidative atmosphere is used to separate the battery components and to remove the organic components. This method is often combined with hydrometallurgical processes with the aim to increase the metal recovery rate or to improve the efficiency of the existing processes. Despite such efforts, the effects of a thermal treatment in an oxidative atmosphere on the microstructure and composition on cathode and anode materials has not been explored. In this manuscript, spent batteries which cathode active material has the composition Li(NixMnyCoz)Oz, i.e. NMC-LiBs, were subjected to thermal treatment at 400˚, 500˚, 600˚, and 700 °C for 30, 60, and 90 min. The microstructure and the composition were studied using XRD and ICP-OES. Thermodynamic calculations were performed to forecast the trend of the carbothermic reduction of active materials. It was observed the formation of gas and organic oil by-products from the decomposition of the polypropylene separator and the polyvinylidene fluoride binder. The identification of the composition of these by-products has great importance since they have a corrosive and toxic behavior. It was observed the fluorine behavior during the thermal treatment and its presence in the oil by-products.

Novel process for decontamination and additional valorization of steel making dust processing using two-step correlative leaching.

Recycling of steel making dusts often targets Zn removal. Other heavy metals such as Mo, W or Cr do not receive as much attention, and the decontamination of the dusts from these constituents is scarcely addressed in the literature. This study presents a novel approach of the selective separation of Mo from steel making dusts using alkaline solutions with low concentrations, before Zn removal using concentrated alkaline medium. Such an approach has never been reported before and can contribute to more efficient decontamination of the steel making dusts and will increase the value of recovered components since Mo can be significantly preconcentrated. Two samples originating from two steel producers were investigated. One sample contained 2.65% of Mo and 1.87% of Zn, and the second sample had 0.61% of Mo and 35.9% of Zn. Temperature was found to have a low impact on the leaching efficiency of Mo, while increased NaOH concentration promoted leaching of Zn. Excellent pre-concentration of Mo was achieved by using a S:L ratio of 1:3. Almost 5170 mg/L Mo, 1000 mg/L W, no Fe and only 2 mg/L Zn were present in the solution after leaching at 30 °C for 30 min. For the samples containing lower concentrations of Mo and high concentrations of Zn, the selectivity of the process was affected when using higher concentrations of NaOH. A final leachate containing 797 mg/L of Mo and only 11 mg/L Zn was obtained after leaching with 0.05 M NaOH. DFT computations showed that the 2D layered structures of MoO3 and WO3 are decisive factors that account for their high solubilites.

Recovery of industrial valuable metals from household battery waste.

The modern community is dependent on electronic devices such as remote controls, alarm clocks, electric shavers, phones and computers, all of which are powered by household batteries. Alkaline, zinc-carbon (Zn-C), nickel metal hydride, lithium and lithium-ion batteries are the most common types of household energy storage technologies in the primary and secondary battery markets. Primary batteries, especially alkaline and Zn-C batteries, are the main constituents of the collected spent battery stream due to their short lifetimes. In this research, the recycling of main battery components, which are steel shells, zinc (Zn) and manganese oxides, was investigated. Household batteries were collected in Gothenburg, Sweden and mechanically pretreated by a company, Renova AB. The steel shells from spent batteries were industrially separated from the batteries themselves and the battery black mass obtained. A laboratory-scale pyrolysis method was applied to recover the Zn content via carbothermic reduction. First, the carbothermic reaction of the battery black mass was theoretically studied by HSC Chemistry 9.2 software. The effect of the amount of carbon on the Zn recovery was then examined by the designed process at 950°C. The recovery efficiency of Zn from battery black mass was over 99%, and the metal was collected as metallic Zn particles in a submicron particle size range. The pyrolysis residue was composed of mainly MnO2with some minor impurities such as iron and potassium. The suggested recycling process is a promising route not only for the effective extraction of secondary resources, but also for the utilization of recovered products in advanced technology applications.

Selective recovery of cobalt from the secondary streams after NiMH batteries processing using Cyanex 301.

Cobalt is considered to be a critical raw material for the European Union. Since it has limited supply, substantial efforts should be made to develop sustainable methods to recover cobalt from alternative sources. Hydrometallurgical processing of spent NiMH batteries generates a concentrated stream containing, preferably, Co (11.8 g/L) and impurities (2.3 g/L Ni, 0.2 g/L Al, 9.3 g/L Mn and 4.6 g/L rare earth elements) in the nitric acid media. In this study, the selective separation of Co from the other ions present was investigated. Co was selectively separated from Al, Mn and REEs using 1 M Cyanex 301 in kerosene. The different kinetic behaviour during extraction with Cyanex 301 was utilized to separate Co and Ni ions selectively. The calculated ΔH for the Co extraction process equals - 11.37 ±â€¯0.5 kJ/mol, which indicates that the extraction of Co in the system tested is an exothermic reaction. The effect of temperature on the Co extraction was used to obtain better selectivity towards Ni. Co was recovered by selective stripping with 4 M HCl at ambient temperature. The final purity of the stripping product was 99.9%.

Investigation of zinc recovery by hydrogen reduction assisted pyrolysis of alkaline and zinc-carbon battery waste.

Zinc (Zn) recovery from alkaline and zinc-carbon (Zn-C) battery waste were studied by a laboratory scale pyrolysis process at a reaction temperature of 950°C for 15-60min residence time using 5%H2(g)-N2(g) mixture at 1.0L/min gas flow rate. The effect of different cooling rates on the properties of pyrolysis residue, manganese oxide particles, were also investigated. Morphological and structural characterization of the produced Zn particles were performed. The battery black mass was characterized with respect to the properties and chemical composition of the waste battery particles. The thermodynamics of the pyrolysis process was studied using the HSC Chemistry 5.11 software. A hydrogen reduction reaction of the battery black mass (washed with Milli-Q water) takes place at the chosen temperature and makes it possible to produce fine Zn particles by rapid condensation following the evaporation of Zn from the pyrolysis batch. The amount of Zn that can be separated from the black mass increases by extending the residence time. Recovery of 99.8% of the Zn was achieved at 950°C for 60min residence time using 1.0L/min gas flow rate. The pyrolysis residue contains MnO and Mn2O3 compounds, and the oxidation state of manganese can be controlled by cooling rate and atmosphere. The Zn particles exhibit spherical and hexagonal particle morphology with a particle size varying between 200nm and 3µm. However the particles were formed by aggregation of nanoparticles which are primarily nucleated from the gas phase.

Production of zinc and manganese oxide particles by pyrolysis of alkaline and Zn-C battery waste.

Production of zinc and manganese oxide particles from alkaline and zinc-carbon battery black mass was studied by a pyrolysis process at 850-950°C with various residence times under 1L/minN2(g) flow rate conditions without using any additive. The particular and chemical properties of the battery waste were characterized to investigate the possible reactions and effects on the properties of the reaction products. The thermodynamics of the pyrolysis process were studied using the HSC Chemistry 5.11 software. The carbothermic reduction reaction of battery black mass takes place and makes it possible to produce fine zinc particles by a rapid condensation, after the evaporation of zinc from a pyrolysis batch. The amount of zinc that can be separated from the black mass is increased by both pyrolysis temperature and residence time. Zinc recovery of 97% was achieved at 950°C and 1h residence time using the proposed alkaline battery recycling process. The pyrolysis residue is mainly MnO powder with a low amount of zinc, iron and potassium impurities and has an average particle size of 2.9µm. The obtained zinc particles have an average particle size of about 860nm and consist of hexagonal crystals around 110nm in size. The morphology of the zinc particles changes from a hexagonal shape to s spherical morphology by elevating the pyrolysis temperature.

Submerged-arc welding slags: characterization and leaching strategies for the removal of aluminum and titanium.

In the present study, submerged-arc welding slags were characterized by applying a variety of methods, including X-ray fluorescence, X-ray diffraction, particle size, Raman spectroscopy, and scanning electron microscope with energy dispersive X-ray analysis. The content of Al proved to be quite similar within neutral and acid slags (10-14%), while that of Ti proved to be much higher in acid slags (approximately 10%) than in neutral slags (<1%). The presence of spinel structures associated with Al species could also be identified in the analyzed samples. This characterization study was accompanied by leaching tests performed under changing operating conditions in an attempt to evaluate to what extent the Al and Ti bearing components could be removed from the slags. The leaching work involved three distinct strategies: (i) NaOH leaching followed by H(2)SO(4) leaching, (ii) acid leaching (HCl and H(2)SO(4)) using oxidizing/reducing agents, and (iii) slag calcination followed by H(2)SO(4) leaching. In the best result, 80% of Al was extracted in one single leaching stage after calcination of the acid slag with NaCl+C at 900 °C. By contrast, the removal of Ti proved to be unsatisfactory.