How do we know if an aluminum coil is made from recycled material or not?

Determining if an aluminum coil is made from recycled material can be challenging without specific testing, as recycled and virgin aluminum can look identical. However, there are a few indicators: 1) Look for certification or labels on the coil indicating it's made from recycled material. 2) Check with the supplier for documentation or a certificate of analysis that confirms the material's origin. 3) Analyze the coil's composition; recycled aluminum may have slight variations in purity or alloy composition. 4) Use spectrographic analysis to determine the exact composition of the aluminum, which can sometimes reveal if it's recycled. Ultimately, transparency from the supplier is key to confirming the source of the aluminum.