Video: Recycling aluminum alloys

Not sure if it was already posted here, but I watched that video tonight. It shows a German plant where they recycle aluminum window frames and get only one type of alloy at the end. It was interesting to watch, but I noticed that they receive contaminated aluminum when I would have expected them to receive clean aluminum and then sorting their alloys. Also, I am not sure to understand how they can get dirty aluminum as raw material since scrap yards will downgrade any contaminated piece of aluminum. If they don't cut out the dirty part, it seems that that piece would go to the dirty / ferrous aluminum lane (a totally different process).

https://www.youtube.com/watch?v=chIFt2A9MRI

I've got a few thoughts on this. It might make sense.

Okay ... so aluminum is generally sorted according to one of three categories at the scrapyard. They are cast,sheet, and extruded.

The company in the video specializes in processing scrap extruded. It's a narrow field ... it's what they do ... and they're pretty good at it.

The main problem they had to overcome was that there are many different aluminum alloys used to make extruded products. They seem primarily interested in 6060 according to the video ?

What they have coming in could be a mix of 6060, 1100,3003, 6061,6062, and so on. Each specific alloy used in making extruded aluminum has it's own mechanical & design properties.

It's kinda like the same basic sorting we do at the yard but on steroids.

Maybe this link would help make sense of it ? Maybe the confusion revolves around the meaning of the word alloy as it's used in the video ? Something lost in translation from German to English ?

Gawd only knows what it would turn into when you translate it into Canadian. ;)

https://tri-stateal.com/resources/extrusion-guide/

One of the other issues you raised was contaminants. That's a fair point, but nothing in the scrap world is ever perfect. Contaminants in the load are expected. The main thing is that they are kept to below a certain allowable threshold. A few nuts and bolts here and there aren't a problem ? They catch that stuff early on in the shredding & sorting process ?