What’s this about? One of the most compelling facts about aluminium is that it takes only 5 percent of the original energy used to produce it to recycle it. In today’s resource-constrained world, recycling takes on even greater importance in reducing the world’s energy diet and addressing climate change.
But one of the most complex challenges in the future of recycling is how to process un-separated material, i.e., ‘contaminated aluminium scrap’ (post-consumer waste) that usually has other material attached to it. This is driving the need for more advanced remelting technologies to deal with issues such as charge preparation, melting rate, metal yield and melt quality, which become as important as the casting process itself.
A prime concern for all remelting activities is the composition and amount of organic material attached to the metal. Scrap with more than 5 percent organic contamination usually cannot be ‘charged’ in big portions into a melting furnace without preliminary treatment. The organic content has to be diluted by less contaminated material in order not to exceed the capacity of the gas handling and afterburning equipment and to avoid an unutilized heat surplus in the furnace. Furthermore the generation of toxic emissions have to be avoided by complete combustion inside the furnace.
At the heart of the challenge The main problem occurs shortly after charging, when instant gasification from a big scrap surface takes place and the furnace volume is too small and the heat created too large. Consequently only a small portion of the calorific value of the pyrolysis gas can be used for heating.
Central to your solution is creating a pyrolysis process significant enough to maximize removal of organic material from the aluminium scrap while being controllable enough to capture the heat coming off the process.
Click here to download the full brief for Challenge 3: Life-cycle challenge
