Electronic waste is usually processed by means of classical methods, i.e. in pyro-and hydrometallurgical processes. However, new solutions for more economically and ecologically efficient recovery of metals are constantly being searched for. Biohydrometallurgy can become a promising technology of recovering metals from industrial waste. Bioleaching-one of the methods applied in that technology-is the subject of particular interest of many scientific centres. The paper presents the results of laboratory tests of bacterial leaching of metals from electronic scrap. It describes the mechanisms of this process and the factors influencing the chemical reaction. The paper also presents preliminary results of experimental studies on the copper bioleaching from electronic waste with the participation of Acidithiobacillus ferrooxidans bacteria.
The objective of this work was to evaluate the influence of static, stirring and shaking conditions on copper, zinc, nickel and aluminium dissolution from printed circuit boards (PCBs) using the mixed acidophilic bacterial culture of Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans. The results revealed that static conditions were the most effective in zinc and aluminium dissolution. Zinc was removed almost completely under static conditions, whereas maximum of nickel dissolution was reached under the stirring conditions. The highest copper recovery (36%) was reached under stirring conditions. The shaking conditions appeared to be the least suitable. The relative importance of these systems for the bioleaching of copper and nickel decreased in the order: stirring, static conditions, shaking.
Automotive catalytic converters have a limited life time, after which the catalyst must be replaced or regenerated. The spent catalytic converters contain small amount of precious metals. Recovery of these metals is essential for environmental and economic reasons. The waste electronic equipment is also an attractive source for recovery of precious metals. Precious metals in electronic scraps are concentrated mainly in printed circuits and integrated circuits -so generally in elements that are the most diverse in their composition. Material heterogeneity of these elements is the reason why there is no universal method for processing this type of scrap. Methods used in the world for recovery of precious metals from spent auto catalytic coverters and electronic wastes by pyrometallurgical and hydrometallurgical methods were mentioned in this paper. The results of simultaneous melting of electronic waste with spent automotive catalysts were presented. The printed circuit boards were used as the carrier and as a source of copper. The precious metals present in the catalyst were collected in copper.Keywords: electronic waste, copper, platinum, metal collector, pyrometallurgical methods Samochodowe konwertory katalityczne mają ograniczony czas życia, po czym katalizator ten należy wymienić lub poddać regeneracji. Zużyte katalizatory zawierają niewielkie ilości metali szlachetnych, a możliwość odzysku tych metali jest istotna ze względów ekonomicznych i ekologicznych. Równie atrakcyjne źródło metali szlachetnych stanowi wycofany sprzęt elektroniczny. Metale szlachetne w płytkach elektronicznych są zlokalizowane głównie w obwodach drukowanych układów scalonych, które są najbardziej zróżnicowane pod względem składu. Niejednorodność materiałowa tych elementów powoduje, że nie ma uniwersalnego sposobu przetwarzania tego rodzaju złomu. W artykule zwrócono uwagę na metody pirometalurgiczne i hydrometalurgiczne stosowane na świecie do odzysku metali szlachetnych ze zużytych katalizatorów samochodowych oraz odpadów elektronicznych. Przedstawiono wyniki badań próby wspólnego przetopu odpadów elektronicznych z odpadami zużytych katalizatorów samochodowych. Odpady elektroniczne w postaci drukowanych płytek obwodowych zostały wykorzystane jako nośnik i główne źródło miedzi, metalu pełniącego rolę metalu zbieracza platynowców, obecnych w katalizatorach. Otrzymano stop Cu-Fe-Au-Pt odzyskując w ten sposób platynę na poziomie około 78%.
The article draws attention to the problem of the presence of metals: germanium (Ge), tellurium (Te), thallium (Tl), and others (Cd, Ba, Co, Mn, Cr, Cu, Ni, Pb, Sr, and Zn) in selected waste of electrical and electronic equipment (WEEE). As a result of the growing demand for new technologies, the global consumption of TECs has also been increasing. Thus, the amount of metals in circulation, of which the impacts on the environment have not yet been fully understood, is constantly increasing. Due to the low content of these metals in WEEE, they are usually ignored during e-waste analyses. The main aim of this study was to determine the distribution of Ge, Te, and Tl (and other elements) in ground sieve fractions (1.0, 0.5, 0.2, and 0.1 mm) of selected electronic components (solar lamps, solar cell, LED TV screens, LCD screens, photoresistors, photodiodes, phototransistors) and to determine the possible tendency of the concentrations of these metals in fractions. This problem is particularly important because WEEE recycling processes (crushing, grinding, and even collection and transport operations) can lead to dispersion and migration of TCE pollutants into the environment. The quantitative composition of e-waste was identified and confirmed by ICP-MS, ICP-OES and SEM-EDS, and XRD analyses. It was found that Ge, Te, and Tl are concentrated in the finest fractions of ground e-waste, together with Cd and Cr, which may favor the migration of these pollutants in the form of dust during storage and processing of e-waste.
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