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Aluminium Industry Trend & Analysis, Technology Review, Event Rundown and Much More …

AL Circle Secondary Aluminium

What does a Sustainable Aluminium World Look Like?

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We can hardly imagine the technological advances that may take place in next ten years, let alone thirty years. But, our visions for the future, our dreams, can drive us to innovate and to take new paths towards sustainability in a technologically advanced world. While attending the AluSolutions 2016 conference and exhibition in Abu Dhabi from May 10-11, I was inspired by the many and varying views of future sustainable practices. These views have been extrapolated and expanded in the following vision of a truly sustainable aluminium industry in the year 2050.

In 2050, the world is a different place: no longer can we consume more resources than we can replace, and nothing is “waste”. The community, regulators and industry have adopted the UN Global Sustainability Goals and International Circular Economy practices as essential for human progress with the population at 9.5 billion. The aluminium industry continues to play its part by reducing its carbon footprint and utilising resources responsibly.

In 2050, Bauxite is sourced from lands suitable for mining and rehabilitation with approval and involvement of indigenous peoples. The “stripping ratio” is less than 0.5:1 for all approved bauxite deposits, to ensure low impact on the land. Fully automated mining and haulage equipment is 90% remanufactured from used machinery. Solar power is used solely for electrical demands due to efficiencies in daylight operations. In cases where the refinery is not at the mine site, shipping is continuous in 40,000 tone auto-piloted solar powered vessels. Rehabilitated land is handed back to its traditional owners for farming and is assessed and continually monitored to optimise its utilization.

In 2050 Alumina is refined with zero odour, air and water emissions with all vapours and liquids captured and recycled within the process. Coordination with smelters has optimised alumina properties for efficient HF capture and electrolytic reduction. Co-generation of power is optimised in steam production, and co-current heating is practised within the plant to eliminate wasted heat. Solar power with Aluminium-Ion battery storage is used for lighting, computing and small electrical motors. Sonic agglomeration methods have eliminated thickeners. Bauxite pre-treatment is undertaken to reduce red mud generation. Red mud generated is processed to remove all toxic compounds and re-use these compounds in other industries, with high-value metals (eg Scandium) extracted to pay for the processing. The final by-product is non-hazardous and is used in construction (brick-making) and industrial processes such as heap leaching and anthracite production, as well as large volumes being used as a filtration agent in water treatment.

In 2050, Aluminium Smelting has reached the pinnacle of energy efficiency in the electrolytic conversion of alumina to aluminium metal for both inert and conventional anode technologies. Inert anode reduction cells finally became commercialised in 2025, exactly 200 years after aluminium was first made in the laboratory. The inert anodes are not easily retrofit-able: it is more efficient for new “mini-smelters” to be constructed to optimise production. The inert anode cells are smaller, more energy-efficient drained-cathode “launder cells” with low-temperature electrolyte and direct TiB2-bonded iron cathodes. Conventional anode smelters are operating at around  10kWh/kg of aluminium produced and 97% current efficiency, with improved alumina and electrolyte engineering, better refractory lining, cell feeder and busbar design and individual anode sensors linked to automatic height control. All smelters are mandated to operate with minimum +/- 20% amperage modulation to assist in optimisation of demand in the renewable power grid. Management of energy input is facilitated by pot-shell heat exchangers which allow control of isotherms in the lining. In peak demand times smelters can make more money from power than aluminium!

Smelters still on non-renewable power have retrofitted modern cell designs and continue to operate by purchasing carbon credits. Improved cell hooding and automated anode change practices means there are almost zero fugitive emissions, with 99.9% of HF captured by dry scrubbers due to improved alumina contact methods and pore geometry. Anode effects have been eliminated. Anodes are rodded immediately on exiting the fuel-efficient vertical baking furnace, and are set in the cells while still hot. Anode butts and spent potlining are both recycled on site – the SPL is processed to remove the hazards and either made into sub-cathodic cell lining or sold to cement clinker plants. Together with other beneficial re-use pathways there is now zero smelter waste going to landfill. Compressed air use on site has been minimised by use of wireless, solar-powered sensors and valve actuation. Some smelters practice siphon casting directly from the pots into mobile alloying ingot casters, due to close control of metal purity in each reduction cell.

In 2050, End-Use of Aluminium is now regulated by recycled metal content. Most affordable electric cars contain minimum 80% recycled aluminium alloys with 3D-printable body panels. Household appliances can only be made using recycled aluminium. 3D printers in homes and businesses make aluminium items for one-off use with immediate recycling into the next item required, such as foils which have replaced plastics in food wrapping. All buildings are run by solar power stored in Aluminium-Ion battery walls. Buildings are constructed with aluminium components that are designed to be easily separated in automated sorting warehouses for recycling and/or re-manufacturing. Thermally transforming sandwich alloys allow ultra-thin, modular façade and wall construction techniques that are stronger, safer and which optimise energy consumption.

Back in 2016, aluminium smelting production was at a crossroads. While the Hall-Heroult process was the most recent of the major metal recovery processes (US patent filed 1886), it had progressed exceptionally by efficiency, health and safety standards. But resistance to mining in Jamaica, Iceland and India, along with smelter closures in the West indicated problems with the existing model. The aluminium industry had to rapidly develop and achieve sustainability objectives while promoting its “infinitely recyclable” message clearly to meet the rising demand for responsible metal production. Certification to the Aluminium Stewardship Initiative (ASI) voluntary sustainability standard helped to achieve these goals. Without establishing the important sustainability targets and celebrating their success, aluminium may have been superseded by other emerging materials in many applications. The industry evolution over the complete supply chain to 2050 has been challenging but has been essential to enable the aluminium industry to thrive during the “resource revolution” of the last 30 years.

(Phil Black has more than 20 years’ experience in process engineering including lead roles in waste valorization, EPCM projects, smelting operations and R&D. He has high-level skills in Aluminium environmental and reduction technology, process development and implementation, front-end engineering design, project management and commissioning. Phil currently utilises all of these skills in consulting to industry on environmental and process solutions for efficient and sustainable production. Read more at www.blackindustrialsolutions.com )


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