Search results for "Sähkö-"
showing 10 items of 12 documents
Porous 3D Printed Scavenger Filters for Selective Recovery of Precious Metals from Electronic Waste
2018
Selective laser sintering (SLS) 3D printing is used to fabricate highly macroporous ion scavenger filters for recovery of Pd and Pt from electronic waste. The scavengers are printed by using a mixture of polypropylene with 10 wt% of type‐1 anion exchange resin. Porosities and the flow‐through properties of the filters are controlled by adjusting the SLS printing parameters. The cylinder‐shaped filters are used in selective recovery of Pd and Pt from acidic leachate of electronic waste simply by passing the solution through the object. Under such conditions, the scavenger filters are able to capture Pd and Pt as anionic complexes with high efficiency from a solution containing mixture of dif…
Surfactant-based enrichment of rare earth elements from NdFeB magnet e-waste: Optimisation of cloud formation and rare earths extraction
2023
Appropriate waste and resource management are essential for a sustainable circular economy with reduced environmental impact. With critical resources, e-waste may serve as indirect raw material. For example, with NdFeB permanent magnets, Neodymium (Nd) and the co-present Dysprosium (Dy) are critical rare earth elements (REEs). However, there exists no economically viable technology for recycling them from electronic waste (e-waste). Here, a method is presented based on cloud point extraction (CPE). The work involves basic complexation chemistry in a cloud medium with pure REE salts, as well as, with real NdFeB-magnets (nearly 28% REE content by weight) from an old hard disk drive (5.2 g mag…
Into the world of e-waste: mobility among e-scrappers in Nigeria
2017
AbstractIn the management of e-waste, mobility of e-scrappers plays a pivotal role, especially in e-waste acquisition and sales of extracted materials. This research examines the relationship between e-scrappers and the locations of their work by analysing the influence of environmental and social factors on their mobility behaviour in Nigeria. A qualitative analysis of video material collected from 29 male e-scrappers in Nigeria between 2014 and 2015 reveals that e-waste has inherent properties that intermittently mobilise e-scrappers to search for recyclable and valuable electronic trash. Applying the new mobilities paradigm and the new materialism theory, we present that e-scrappers’ mob…
Kullan talteenotto sähkö- ja elektroniikkaromusta
2017
Tutkielman kirjallisessa osassa käydään läpi yleisesti kiertotaloutta ja metallien osuutta kiertotaloudessa. Lisäksi kirjallisessa osassa keskitytään sähkö- ja elektroniikkaromun kasvavaan määrään ja sen kierrätyksen tärkeyteen sekä kierrätyksen ongelmiin. Työssä käydään läpi yleiset kullan talteenottotavat, hydrometallurgia, pyrometallurgia sekä fysikaalinen ja mekaaninen erottelu, joita on tutkittu sähkö ja elektroniikkaromun kierrätykseen. Myös yleisimmät kullan analysoinnissa käytetyt menetelmät käydään läpi kirjallisen osan loppuvaiheessa. Kullan talteenotolle kehitettiin menetelmä, jonka avulla kulta pystyttiin ottamaan talteen jopa yli 99 % puhtaudella ja 60–70 % saannoilla liuotetus…
Elektroniikkaromun ja kuparipitoisen romun näytteenotto, -valmistus ja analytiikka
2008
Moving forward sustainably : material and social conditions of electronic waste management in Nigeria
2018
This dissertation focuses on understanding the social material interaction between e-waste and e-scrappers for sustainable management of e-waste. Previous studies mainly concentrate on the detrimental environmental impact of e-scrappers activities, the economic and political influences of e-waste on the e-scrappers, the material flow of e-waste and the exportation of valuable e-waste extracts from highly industrialized countries to less industrialized countries. The aim of the dissertation is therefore to extend the scope of the previous studies by investigating the social material interaction between e-scrappers and e-waste. To achieve this aim, this study examines the following research q…
Precipitation of potassium as hazenite from washing water of spent alkaline batteries
2022
Hazenite (KNaMg2(PO4)2 × 14 H2O), a new type of struvite mineral, was precipitated from the potassium-rich washing water of spent alkaline battery black mass. Hazenite can be used as a fertilizer, which would be an additional benefit derived from the sustainable recovery of battery materials. Precipitation experiments were performed using different pH values (9.5–12), Mg:K:PO4 ratios ((1.0–1.5):1:(1.0–1.5)) and temperatures (10–40 °C). Based on the results, hazenite precipitated in a wide pH range under alkaline conditions. The precipitation kinetics were fast, and the purity of the hazenite was high. Overall, hazenite can be precipitated at room temperature without the addition of excess c…
Robots responding to care needs? : A multitasking care robot pursued for 25 years, available products offer simple entertainment and instrumental ass…
2020
Twenty-five years ago, robotics guru Joseph Engelberger had a mission to motivate research teams all over the world to design the ‘Elderly Care Giver’, a multitasking personal robot assistant for everyday care needs in old age. In this article, we discuss how this vision of omnipotent care robots has influenced the design strategies of care robotics, the development of R&D initiatives and ethics research on use of care robots. Despite the expectations of robots revolutionizing care of older people, the role of robots in human care has remained marginal. The value of world trade in service robots, including care robots, is rather small. We argue that the implementation of robots in care is n…
Effective Recovery Process of Copper from Waste Printed Circuit Boards Utilizing Recycling of Leachate
2020
AbstractThis study presents an optimized leaching and electrowinning process for the recovery of copper from waste printed circuit boards including studies of chemical consumption and recirculation of leachate. Optimization of leaching was performed using response surface methodology in diluted sulfuric acid and hydrogen peroxide media. Optimum leaching conditions for copper were found by using 3.6 mol L−1 sulfuric acid, 6 vol.% hydrogen peroxide, pulp density of 75 g L−1 with 186 min leaching time at 20°C resulting in complete leaching of copper followed by over 92% recovery and purity of 99.9% in the electrowinning. Study of chemical consumption showed total decomposition of hydrogen pero…
Elektroniikkajätteen typpihappoliuotus ja metallien talteenotto
2017
Tämän pro gradu -tutkielman kirjallisessa osassa käsitellään elektroniikkajätettä ja metallien talteenottoa. Erityisesti talteenottomenetelmissä keskitytään typpihappoliuoksiin, sillä kokeellisessa osassa tutkimuksen kohteena oleva liuos on typpihappo. Näiden lisäksi tarkastellaan tutkimuksen kannalta merkittävien metallien; kuparin (Cu), nikkelin (Ni), lyijyn (Pb), tinan (Sn), hopean (Ag), sinkin (Zn) sekä palladiumin (Pd) fysikaalisia ja kemiallisia ominaisuuksia. Tutkielmassa tuodaan myös esille elektroniikkajätteen ympäristövaikutukset sekä sen taloudellinen merkitys maailmassa. Elektroniikkajäte on maailman nopeinten kasvava jätefraktio. Tämä on saanut useat tahot heräämään tähän kasva…