Why? Aluminum production needs a lot of electricity but if you recycle back, costs goes down, total aluminum energy cost of Apple is likely much lower than all those servers running throughout the year.
Recycling rates are generally pretty low. I think the highesst rates have been ~80% for lead (batteries). For aluminium in the US, it's closer to 40% IIRC.
USGS has online reports.
http://minerals.usgs.gov/minerals/pubs/commodity/recycle/rec... 40% ~2001
For 2015, it looks as of 30% of supply came via recycling: http://minerals.usgs.gov/minerals/pubs/commodity/aluminum/
http://minerals.usgs.gov/minerals/pubs/commodity/aluminum/mc...