Since the recycling of tantalum bearing post-consumer waste is practically not existent, metallurgical residues are the most important feed for the tantalum recycling. Most tin ores naturally contain significant quantities of refractory metals. During the smelting process in primary tin production these elements are enriched in the slag phase. This slag is a highly valuable raw material for tantalum production due to its considerable concentration of tantalum and its functioning as an additional slag former in further pyrometallurgical treatment. In this paper the first process stage of an existing pyrometallurgical process for tantalum recovery, mainly from low grade pyrometallurgical residues, is discussed. Smelting trials were carried out in a pilot-scale electric arc furnace to analyse the effect of feeding on the activity of carbon as a reducing agent. Therefore, blowing petroleum coke through an iron lance and the manual adding of coke into the melting bath were tested. During the pyrometallurgical treatment elements with a high affinity to carbon were reduced to their carbide form and enriched in the molten iron-based metal phase. The objective of the process was to reduce the oxidic tantalum completely and to enrich it into the metal phase. Furthermore, the transfer of unwanted elements such as titanium into the metal phase was aimed to be avoided. Spoon test specimens were taken from the liquid mineral melt to follow the evolution of the reduction process. The cooled down solidified melting bath was investigated by using the XRD and EDX method to characterise the slag system and to identify relevant mineral phases.
The economic decline brought on by the Covid-19 pandemic and resultant lockdown has exacerbated the already problematic culture of non-payment in South Africa.
A lack of commercially viable alternatives means that landfilling remains the only option for the safe and cost-effective disposal of waste. However, there is a dire shortage of airspace on existing landfill sites.
The collapse of a tailings dam at Vale’s Corrego do Feijao mine in Brazil in early 2019, which left 270 people dead, highlights the vital importance of good mine waste management. Dry tailings, a newer alternative to traditional wet tailings storage, offer many advantages.
With 90% of South Africa’s annual waste ending up in landfills across the country, unlocking the energy potential of waste may help alleviate our national power crisis.
With unemployment likely to worsen as a result of the Covid-19 pandemic, it is important to explore possibilities to revive entrepreneurship in the waste management sector, especially among the youth.
When it comes to waste management, we need a greater focus on the waste hierarchy: first reduce, then reuse, and only then recycle.
In pursuit of reducing greenhouse gas emissions, various countries have adopted the practice of carbon trading, while others – like South Africa – have implemented a carbon tax as a corrective means to make carbonintensive industries more environmentally conscious.
My introduction to waste management took place in Durban in the early 1990s. I was fortunate to know and learn from some of the pioneers of modern waste management in South Africa, and particularly all things landfill, as we know them today.
The Covid-19 pandemic has seen an unprecedented increase in medical and hazardous waste generation. To protect human health and the environment, it is impor tant to ensure the safe handling and disposal of such waste.
South Africa’s leading electrical and electronics producers are committed to growing the circular economy, but are consumers and landfills ready? Alastair Currie speaks to Keith Anderson, CEO, eWaste Association of South Africa, about the quest to implement effective diversion and recycling strategies.
The Covid-19 pandemic has had a tremendous impact, not only on the economy but also on the waste management sector. As lockdowns were imposed around the world, municipal waste operators had to rapidly adapt their waste management systems to better accommodate increased household waste and a decreased workforce.
The City of Cape Town’s Solid Waste Management Department identified the need for another materials recovery facility (MRF) to service the South Peninsula area in the early 2010s, following the success of the Kraaifontein MRF.
South Africa generates approximately 108 million tonnes of waste per year. As much as 90% of this waste (with an estimated value of more than R25.2 billion) is dumped or disposed of in landfill sites across the country that are rapidly filling up and approaching closure.
Die P-Ruckgewinnung aus Teilstromen mit erhohten P-Gehalten kann direkt in den Klaranlagenbetrieb integriert werden und fuhrt dort in vielen Fallen zu betrieblichen und okonomischen Vorteilen. Sie ist in der Regel auf Bio-P-Klaranlagen beschrankt, da hier die anaerobe P-Rucklosung initiiert und genutzt werden kann. Durch die reine P-Rucklosung durch Schaffung anaerober Bedingungen ist allerdings das Potential der Ruckgewinnung auf 5 bis 15 Prozent der Zulauffracht limitiert. Die meisten Klaranlagen in Deutschland werden mit einer chemischen Phosphor-Fallung betrieben. Diese Anlagen konnen aus dem Klarschlamm Phosphat in ausreichend hoher Konzentration nur zuruckgewinnen, indem zusatzlich anorganische Sauren wie Schwefelsaure zugefuhrt werden oder ein Aufschluss mit flussigem Kohlendioxid stattfindet. Es wird angenommen, dass sich mit diesen Verfahren mehr als 50 Prozent der Zulauffracht einer Klaranlage zuruckgewinnen lassen. Der Aufschluss von Klarschlamm mit Schwefelsaure geht aber mit vergleichsweise hohen Umweltwirkungen sowie mit hoheren Kosten im Vergleich zu anderen Phosphor-Ruckgewinnungsverfahren einher. Ein sehr hohes Potential der Ruckgewinnung von Phosphor (P) ist bei allen Verfahren gegeben, die als Rohstoff die Asche aus der Monoverbrennung verwerten. Der Aufschluss mit anorganischen Sauren ermoglicht die sichere Phosphor-Ruckgewinnung von mehr als 80% Prozent des Klaranlagenzulaufs. Die Verfahren sind zum Teil grostechnisch umgesetzt oder es befinden sich grostechnische Anlagen im Bau. Auch thermochemische Verfahren wurden entwickelt und deren Einsatzbereitschaft im grostechnischen Masstab erfolgreich demonstriert. In dem nachfolgenden Beitrag werden unterschiedliche praxiserprobte Verfahren zur Phosphor-Ruckgewinnung unter technischen und wirtschaftlichen Aspekten vorgestellt.
Global warming, climate change and increased competition for natural resources are likely to make many of the types of jobs occupied by today’s workforce obsolete within the next 15 years. In their place, new opportunities will emerge, driven by the need to implement renewable energy, find power storage solutions and integrate smart technology seamlessly with existing systems.
Waste disposal to landfill is one of the contributors in greenhouse gas (GHG) emissions, through the generation of methane landfill gas (LFG) during landfill operations. South Africa is a signatory of the Kyoto Protocol, and the CoJ has set targets for GHG emissions reduction in its Climate Change Strategy. The city’s mechanism for recovering energy from waste at selected landfills will contribute significantly towards the GHG emission reduction strategy of the city. The city identified five of its landfill sites – Robinson Deep, Marie Louise, Linbro Park, Goudkoppies and Ennerdale – to implement the LFG-to-electricity Clean Development Mechanism (CDM) project. Through the implementation of a CDM project, the city will contribute to the country’s realisation of the Kyoto Protocol commitments and simultaneously generate revenue through the sale of Certified Emission Reductions (CERs) and sale of electricity generated from the project. The project was initiated in 2007, with the main aim of mitigating the harmful GHGs from landfills. Another aim is the generation of renewable energy, which will be fed into the municipal grid, thus largely offsetting coal-derived electricity.
A lack of awareness about the health hazards related to healthcare waste coupled with enforcement challenges are among the biggest problems plaguing the local healthcare and hazardous waste sector. South Africa and its neighbours face more complex and challenging problems than those encountered by developed countries. In places like the USA and UK, regulation makes the sheer volume of healthcare waste a challenge when it comes to management, logistics and disposal. Closer to home, issues such as sorting waste and finding safe disposal methods are more primary challenges, with waste volumes being secondary.
