Burçak Ebin

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.

Pyrometallurgical Processes for the Recovery of Metals from WEEE

After reaching its useful physical life, electrical and electronic equipment is collected and recycled, depending on the type, through various techniques. Besides environmental concerns, recycling of this equipment is attractive and also viable since it contains significant amounts of precious metals. Pyrometallurgy has proven itself to be a versatile approach for the efficient recovery of the metallic fractions from waste electrical and electronic equipment (WEEE). In this context, the main pyrometallurgical methods-smelting, incineration, combustion, pyrolysis, molten salt, and pyrochemical processes-are reviewed. The pyrometallurgical treatment of WEEE varies worldwide with respect to the type of the WEEE, physical shape and size of the fed materials, and the plant operating parameters. With simplified flowcharts included, the available processes are discussed on a thermodynamic and kinetic basis. The limitations, challenges, and environmental issues associated with currently used methods and developing techniques are summarized with the aim of providing a better understanding of the topic.

Preparation and magnetic characterization of Fe/metal oxide nanocomposite particles by means of hydrogen reduction assisted ultrasonic spray pyrolysis (USP-HR)

Abstract Fe/metal oxide nanocomposite particles were produced by means of hydrogen reduction assisted ultrasonic spray pyrolysis. Fe/Fe0.761Mg0.239O and Fe/MgO nanocomposite particles were obtained at 600 and 800 °C, respectively. The thermodynamics of the formation reactions were investigated. Increasing the reaction temperature allowed efficient reduction of the precursor to metallic iron that induces the formation of pure MgO phase. The crystallite sizes of the Fe in the composite structures slightly increased, and also the crystallite sizes of the oxides decreased with elevating temperature. The nanocomposite particles exhibited spherical morphology and their particle sizes were slightly different. All of the samples showed ferromagnetic characteristics and the results indicate that the amount of metal and metal oxide phases most affected the saturation magnetizations of the composite particles which were lower than pure iron.

Simple preperation of CuO nanoparticles and submicron spheres via ultrasonic spray pyrolysis (USP)

Abstract Copper oxide nanoparticles and submicron size spheres were produced via the ultrasonic spray pyrolysis method using copper nitrate without any additives. The effects of the process temperature and solution concentration on the copper oxide particles were investigated. HSC software, differential scanning calorimetry and thermal gravimetric analysis were used for the thermodynamic investigation of the CuO formation by the decomposition reaction. Particle characterization studies were performed using X-ray diffraction, energy dispersive spectroscopy, scanning–and transmission–electron microscopy. The results show that spherical CuO nanoparticles having around 80 nm particle size were prepared at 400 °C and the submicron size CuO spheres were obtained by the aggregation of nanoparticles at elevated temperatures. The crystallite sizes of the particles ranged between 21 and 46 nm.

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.