Following its achievement of zero waste to landfill achievement in 2002 and zero waste to incineration in 2008, Toyota’s UK Manufacturing operation continues to focus on resource efficiency as part of its sustainable manufacturing activities.
Toyota, like most other companies, was using metal recycling companies to collect their machining swarf to re-melt into aluminium ingots and transport back as a raw material for engine manufacture. The aluminium ingots, a significant energy intensive resource, are then melted again and cast into engine blocks and components. Toyota wanted to reduce its demand for both virgin and recycled aluminium ingots by improving the aluminium yield and set a target of 20%.
In 2010 over 1,600 tonnes a month of aluminium swarf contaminated with machining coolant was being transported off-site for recycling. After intensive study Toyota decided to take a two stage approach to improve aluminium yield. The first stage in 2010 was to reduce the coolant contamination from 12% to less than 2%. This was achieved by utilising a centrifugal coolant recycling system to wash and then dry the contaminated swarf. This had the additional environmental benefit of recovering 10% of coolant waste.
Stage 2 in 2011 was to re-melt our dry swarf safely in our furnaces. For this we need a moisture content of less than 1%. Toyota used heat recovered from the furnace exhaust to dry the swarf before injecting it into the aluminium melting furnace.
Our aluminium yield increased from 70% to 93% exceeding the original target of 20%. In addition to this and the coolant recovery, Toyota were also able to reduce aluminium deliveries by 10%. The resource efficiency improvements reduced our reprocessing costs by 40%.
