Dross is skimmed off the surface to leave the clean metal. Dross is generated in primary production, casting, recycling and anywhere in the chain where Aluminium is melted. Dross is primarily a mixture of metallic aluminium and oxides. It is estimated that worldwide over 3 million tonnes of dross are produced annually with currently an estimated 50% being recycled.
Over the past 30 years aluminium dross recycling has gained importance due to several reasons including environmental concerns and economic drivers. Correct processing of dross can add significant cost benefits and avoid costly landfill which may cause environmental issues.
For the lower grade drosses which contain small amounts of free Aluminium we generally process this through our bespoke dross mill to separate any residual aluminium from the aluminium oxides. It’s a process that improves the recovery of aluminium in tilt furnaces and means we can turn all grades of dross into a variety of end products. For drosses that contain a higher percentage of aluminium we will process these directly in our tilt rotary furnace (TRF).
The TRF is considered to be the most effective way to process dross as it maximises energy efficiency whilst at the same time giving maximum recovery. TRFs are available in a number of sizes and at Tandom we employ two; a 13 tonne and 6 tonne capacity, both fired with the latest technology oxygen-gas burners. The TRF has the distinct advantage over a fixed axle furnace as it only uses approximately 25% of the salt by comparison, which results in lower slag volumes and higher metal yields.