Valorisation des déchets d'équipements électriques et électroniques (DEEE) par différentes approches bio/hydrométallurgiques : application au cas du cuivre et de l’or

The well-being of the society depends on a number of metals, including base metals, precious metals and increasingly rare earth elements (REE). The usage of these metals increased in numerous applications, including electrical and electronic equipment (EEE), and their interrupted supply is at stake. There is an increasing interest in the secondary sources of these metals, particularly waste electrical and electronic equipment (WEEE) in order to compensate their potential supply deficit. This PhD thesis demonstrates the advantages and bottlenecks of biological and chemical approaches, as well as the advances and perspectives in the development of sustainable processes for metal recovery from WEEE. Furthermore, a novel process for the recovery of metals from WEEE is described, and a techno-economic assessment is given. Discarded printed circuit boards (PCB) from personal computers (PC), laptops, mobile phones and telecom servers were studied. Following an extensive literature review, a novel characterization and total metal assay method is introduced and applied to waste board materials. Discarded PCB contained metals in the range of (%, by weight): copper (Cu) 17.6 - 39.0, iron (Fe) 0.7 - 7.5, aluminum (Al) 1.0 - 5.5, nickel (Ni) 0.2 - 1.1, zinc (Zn) 0.3 - 1.2, as well as gold (Au) (in ppm) 21 - 320. In addition, multi-criteria analysis (MCA) using the analytical hierarchical process (AHP) methodology is applied for selection of the best-suited technology. A proof-of-concept for a two-step bioleaching extraction was given, in which 98.4% and 44.0% of the Cu and Au, respectively, were extracted. The two-step extraction concept was applied to the chemical leaching of metals from PCB. Cu leaching was carried in an acidic oxidative mixture of H2SO4 and H2O2, whereas Au leaching for carried out by S_2 O_3^(2-) in a NH_4^+ medium, catalyzed by CuSO4. Under the optimized parameters, 99.2% and 96.6% of Cu and Au, respectively, were extracted from the board material. Selective recovery of Cu from the bioleaching leachate using sulfidic precipitation and electrowinning was studied. Cu was selectively recovered on the cathode electrode at a 50 mA current density in 50 minutes, with a 97.8% efficiency and 65.0% purity. The techno-economic analysis and environmental sustainability assessment of the new technology at an early stage of development was investigatedLe bien-être de notre société dépend directement de plusieurs métaux tels que les métaux communs, les métaux précieux et, de plus en plus, les terres rares (TR). L’utilisation de ces métaux s’est développée dans de nombreuses applications, notamment pour les équipements électriques et électroniques (EEE), et leur approvisionnement interrompu est un enjeu majeur. Les appareils électroniques modernes contiennent jusqu’à 60 métaux différents. Il y a un intérêt grandissant pour les sources secondaires de ces métaux, en particulier les déchets d’équipements électriques et électroniques (DEEE), afin de compenser des potentiels manques d’approvisionnement. Cette thèse de doctorat montre les avantages et les inconvénients des approches biologiques et chimiques, ainsi que des avancées et perspectives dans le développement de procédés viables for la récupération des métaux des DEEE. Un nouveau procédé for la récupération des métaux des DEEE est décrit et une évaluation économique est fournie. Les cartes de circuits imprimés (CCI) des ordinateurs de bureau, des ordinateurs portables, des téléphones mobiles et des serveurs de télécommunications ont été étudiées. Les CCI jetées contenaient des concentration en métaux dans la gamme (% du poids) cuivre (Cu) 17,6 - 39,0 / fer (Fe) 0,7 - 7,5 / aluminium (Al) 1,0 - 5,5 / nickel (Ni) 0,2 - 1,1 / zinc (Zn) 0,3 - 1,2 , ainsi que de l’or (Au) (en ppm) 21 - 320. Une analyse multicritère (AMC) utilisant la méthodologie du processus d’analyse hiérarchique (PAH) a été appliquée pour la sélection de la technologie de récupération des métaux la plus adaptée. Une preuve du concept d’extraction par une double étape de biolixiviation est fournie, dans laquelle 98,4% et 44,0% de cuivre et d’or, respectivement, ont été extrait. Cette procédure d’extraction à deux étapes a aussi été appliquée pour la lixiviation chimique des métaux des CCI. La lixiviation du Cu a été effectuée dans un mélange acide d’H2SO4 et d’H2O2, alors que l’Au a été extrait par du S2O32− dans un milieu NH4+, catalysé par CuSO4. Avec les conditions opératoires optimales, 99,2% et 92,2% de Cu et d’Au, respectivement, ont été extrait de ces matériaux. La récupération sélective du Cu du lixiviat de biolixiviation a été étudiée en utilisant la précipitation sulfurée et l’extraction électrolytique (electrowinning). Le Cu a été récupéré de manière sélective en 50 min sur la cathode à une densité de courant de 50 mA, avec une efficacité de 97,8% et une purité de 65,0%. L’analyse technico-économique et l’évaluation de la viabilité environnementale de la nouvelle technologie à un stade précoce de développement ont été étudiée

Decentralized is a thesis developed to correspond the emerging climate crisis in coastal ecosystems with resistant and alternative housing solutions

LAUREA MAGISTRALEDecentralizzata è una tesi sviluppata per corrispondere alla crisi climatica emergente negli ecosistemi costieri. Il progetto si trova nel delta del Gange in India, dove l'ecosistema delle mangrovie è soggetto a perturbazioni dovute all'inquinamento che ne deriva. Anche l'innalzamento del livello del mare sta minacciando la migrazione di molte famiglie. Il progetto mira a imitare il sistema di difesa costiera degli alberi di mangrovie nativi e sviluppare rifugi modulari e resistenti alle inondazioni per proteggere l'ecosistema fornendo al contempo un centro comunitario resistente.Decentralized is a thesis developed to correspond to the emerging climate crisis in Coastal Ecosystems. The project is located in the Ganges Delta of India, where the Mangrove ecosystem is subjected to disturbance by the arising pollution. Sea level rises are also threatening many families to migrate. The design aims to mimic the Coastal Defence System of the native Mangrove Trees and develop flood-resistant and modular shelters to protect the ecosystem while providing a resistant community center

Metal recovery from electronic waste: Biological versus chemical leaching for copper and gold recovery

Waste electrical and electronic equipment (WEEE) generation is a global problem. Despite the growing awareness and deterring legislation, most of the WEEE is disposed improperly, i.e. landfilled or otherwise shipped overseas, and treated in sub-standard conditions. Informal recycling of WEEE has catastrophic effects on humans and the environment. WEEE contains considerable quantities of valuable metals such as base metals, precious metals and rare earth elements (REE). Metal recovery from WEEE is conventionally carried out by pyrometallurgical and hydrometallurgical methods. In this PhD research, novel metal recovery technologies from WEEE are investigated. Using acidophilic and cyanide-generating bacteria, copper and gold were removed from crushed electronic waste with removal efficiencies of 98.4 and 44.0%, respectively. The leached metals in solution were recovered using sulfidic precipitation and electrowinning separation techniques. Finally, a techno-economic assessment of the technology was studied. This research addresses the knowledge gap on two metal extraction approaches, namely chemical and biological, from a secondary source of metals. The essential parameters of the selective metal recovery processes, scale-up potential, techno-economic and sustainability assessment have been studied

Radiation-induced mutagenicity and lethality in Salmonella typhimurium

The mutagenic and lethal effects of ionizing radiation on histidine-deficient auxotrophs of Salmonella typhimurium were studied to improve the understanding of radiation damage to DNA. The auxotrophs were divided into two groups - one which is sensitive to base-pair substitutions and another sensitive to frameshifts. These groups were composed of parent-daughter pairs in which the chemical mutagenicity enhancing plasmid, pKM101, is absent in the parent strain and present in the daughter. Co-60 ..gamma..-radiation and 250 kV x-rays were used to irradiate the bacteria. Irradiation of the frameshift - sensitive strains which carry the pKm101 plasmid doubled the absolute number of induced revertants whereas irradiation of the base-pair substitution sensitive strain which also carries the pKm101 plasmid produced nearly no change in the number of induced revertants. A nearly negligible effect on the mutation rate was observed for all parent strains. (ACR

The Sustainable strategy for small and medium sized enterprises: The relationship between mission statements and performance

The study aims to contribute to the literature by empirically examining the relationship between small and medium sized enterprises’ (SMEs) mission statements and their performance in sustainable strategy formulation. Although it seems that there is a relatively vast amount of research with regard to mission statements of companies, very few studies have focused on the relationship between mission statements and performance. When these few studies are taken into consideration, it is difficult to reach any overall conclusion since their findings are mixed and inconclusive. To achieve this aim, 3034 SMEs operating in organized industrial zones in Turkey were examined via a survey approach. In order to investigate the relationships among the variables, nine categories of mission statements as independent variables and four performance indicators (financial, market, production, and overall) as dependent variables were analyzed through logistic regression. This study identified three mission components, (1) survival, growth, and profit; (2) philosophy and values; and (3) public image, as the common independent variables in explaining the performance of SMEs. Survival, growth, and profit is the most frequently observed mission component regardless of the subsector differentiation in the entire sample, which reflects the significance of business sustainability for SMEs in the Turkish manufacturing context. Besides, among all performance indicators, SMEs’ market performance was found to be the lowest when compared to other performance indicators (financial, production, overall). Although the firms were placed in different manufacturing subsectors, similar mission statements were highlighted so that the discourse similarity might be considered as evidence of isomorphism characteristics for SMEs