Is it

There are other more efficient ways available..

Love123, it is iron FILINGS one L and depending on how old you are, I am surprised you don't know !

There is another process that is simpler and exploits a physical property that Iron has that sand doesn't.

The earth has 2 ----poles. You can figure it out.

Microscope and a set of tweezers and a lot of time.

Iron has got magnetic properties. So instead use magnetism as method to separate iron fillings from sand.