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Terbium and rare earths recovery from fluorescent powders of exhausted lamps by acid leaching with hydrochloric acid was the objective of this study. In order to investigate the factors affecting leaching a series of experiments was performed in according to a full factorial plan with four variables and two levels (4 2 ). The factors studied were temperature, concentration of acid, pulp density and leaching time. Experimental conditions of terbium dissolution were optimized by statistical analysis. The results showed that temperature and pulp density were significant with a positive and negative effect, respectively. The empirical mathematical model deducted by experimental data demonstrated that terbium content was completely dissolved under the following conditions: 90 °C, 2 M hydrochloric acid and 5% of pulp density; while when the pulp density was 15% an extraction of 83% could be obtained at 90 °C and 5 M hydrochloric acid. Finally a flow sheet for the recovery of rare earth elements was proposed. The process was tested and simulated by commercial software for the chemical processes. The mass balance of the process was calculated: from 1 ton of initial powder it was possible to obtain around 160 kg of a concentrate of rare earths having a purity of 99%. The main rare earths elements in the final product was yttrium oxide (86.43%) following by cerium oxide (4.11%), lanthanum oxide (3.18%), europium oxide (3.08%) and terbium oxide (2.20%). The estimated total recovery of the rare earths elements was around 70% for yttrium and europium and 80% for the other rare earths., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Consumption of photovoltaic solar panels is expected to increase, so the growing amount of end-of-life (EOL) solar panels will require large spaces for their disposal, which at the moment costs around 200 euros/ton. Thus, a proper treatment technique to recover secondary materials from this waste, which are mainly copper, aluminum, silicon, high-transmittance glass, and plastics, must be developed. The last three components are strongly attached to each other; hence, their detachment is necessary for recovery. To achieve this objective, a chemical route was chosen; in fact, solvent extraction is highly recommended, as it has a high separation efficiency. In this study, D-limonene as a bio-solvent was examined for detaching different components of solar panels from each other. A high efficiency for ethylene vinyl acetate (EVA) dissolution and components' detachment under different conditions was achieved with the help of sonication power. The effects of sonication power, thermal pre-treatment, temperature, and contact time on detachment percentage were examined, and the best conditions (namely, no pre-treatment, medium sonication power of 450 W, temperature of 60 °C, and a contact time of 120 min) were found for total component detachment. Additionally, the recyclability of D-limonene was examined, and it was established that the solvent could carry out 100% component detachment for three cycles. [ABSTRACT FROM AUTHOR]

The disposal of end-of-life (EOL) photovoltaic solar panels has become a relevant environmental issue as they are considered to be a hazardous electronic waste. On the other hand, enormous benefits are achieved from recovering valuable metals and materials from such waste. Eventually, physical and chemical processing will become the most important stages during the recycling process. A physical treatment including crushing, grinding, and screening was achieved, and it was observed that a fine fraction of −0.25 mm had the maximum percentage of the required materials. Moreover, the optimum chemical treatment conditions were adjusted to reach the maximum recovery of silver, aluminum, and silicon. The synthesis of silicon oxide, silver oxide, alunite, and K-Alum from leachant solution was performed through a simple route. The structural and morphological properties of the prepared materials were defined by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and field emission scanning electron microscopy (FESEM). [ABSTRACT FROM AUTHOR]

The main aim of this work is the thermal recovery of manganese and zinc from a mixture of zinc-carbon and alkaline spent batteries containing 40.9% of Mn and 30.1% of Zn after a preliminary physical treatment followed by the removal of mercury. Separation of the metals is carried out on the basis of their different phase change temperatures, in fact the boiling point of mercury and zinc are 357 °C and 906 °C, respectively, and the melting point of Mn3O4, the main Mn-bearing phase in the mixture, is 1564 °C. After wet comminution and sieving to remove the anodic collectors and most of the chlorides contained in the mixture, chemical and X-ray powder diffraction (XRPD) analyses were performed. The mixture was initially heated in an air flow at temperatures ranging from 300 °C to 400 °C to eliminate mercury, then, the flow of air was turned into an inert carbon dioxide atmosphere. The volatilization of metallic zinc starts at a temperature 850 °C. At higher temperature the reduction of zinc oxide and subsequent volatilization of metallic zinc is carried out by the carbon present in the original mixture or in the automotive shredder residue (car fluff) added from the outside. By optimization of temperature, stoichiometric ratio and residence time, a product suitable for production of new batteries after refining was obtained. The treatment residue consisted of manganese and iron oxides that could be used to produce manganese-iron alloys. [ABSTRACT FROM AUTHOR]

Both economic and environmental reasons force research activities to find valid alternatives to the disposal of high quantities of metal containing slags. One of the most promising routes seems to be the exploitation of slags as inert materials for cement conglomerate: to this end a preliminary characterization of slags arising from lead/zinc pyrometallurgical smelting (ISF) and lead batteries recycle (LBR) was made and different slag-Portland cement mixes were prepared with an increasing waste content. Heat evolution has been determined and a series of tests on the final waste forms have been conducted in order to evaluate the mechanical performance and the leaching behaviour. In spite of the acceptable mechanical characteristics for both slag-cement products, a high release of lead represents a serious problem. The conclusion is drawn that if preliminary extraction of the main pollutants from the raw slags is unpractical, just a limited amount of slags can be incorporated in cement. At the same time the adoption of other stabilization techniques should be taken into account. [ABSTRACT FROM AUTHOR]