Method for recycling aluminum alloys using contaminant concentration estimates for quality control

A method of recycling aluminum alloy wheels, the method comprising:

• providing a feed of aluminum alloy wheels of a particular alloy;
• fragmenting the aluminum alloy wheels into a plurality of fragments;
• cleaning the plurality of fragments to at least partly remove at least one contaminant element;
• for each fragment of a representative sample of fragments of the plurality of fragments, determining, for each contaminant element of the at least one contaminant element, a contaminant concentration estimate for that fragment;
• operating a data processor to either approve or reject the plurality of fragments, based on an aggregate contaminant concentration calculation for the plurality of fragments, the aggregate contaminant concentration calculation being based on, for each contaminant element of the at least one contaminant element, and for each fragment of the representative sample of fragments, the contaminant concentration estimate for that contaminant element in that fragment;
• when the plurality of fragments is approved, providing the plurality of fragments to a downstream recycling process to produce a target aluminum alloy;
• and
• when the plurality of fragments is rejected, not providing the plurality of fragments to the downstream recycling process to produce the target aluminum alloy without further cleaning to further remove any contaminant in the at least one contaminant element.