Re: Can the Iron(Fe) in human blood be magnatized?

The short answer to your question is "Yes, sort of".  Here's the story:

Iron particles can always be magnetized, of course.  In human blood (and that 
of other animals), the iron is not carried around in tiny particles in the 
bloodstream as some might think.  Instead, through a long series of 
chemical reactions, when you eat, or otherwise injest iron, the iron is 
converted to become part of a large molecule.  For example, hemoglobin is a 
large organic molecule with lots of carbon and hydrogen and oxygen atoms 
surrounding a single iron atom.

So now we're trying to magnetize a bunch of hemoglobin molecules carried in 
the red blood cells;  hemoglobin containing iron is what gives them their 
color.  Let's call this an ensemble, and let's put this ensemble inside a 
strong static magnetic field, like a strong permanent magnet.  Each iron 
atom has what's called a magnetic moment, think of it like an electric 
dipole, and the two ends are called North and South.  Inside of the strong 
externally applied magnetic field all of the moments line up very roughly 
parallel, just like iron filings.  So *within* the externally applied field 
you could say that the hemoglobin molecules are magnatized.  However, the iron 
in the bloodstream is not in its same magnetic form as a bar of iron would be.  
The bar has the magnetic property of 'ferromagnetism' (which just means 
that it's strongly attracted/repelled by an external field).  However, the 
hemoglobin molecule has the magnetic property 'paramagnetism' meaning that 
the molecules are attracted by a magnetic field only while in the magnetic 
field.  Another way to say it, is that hemoglobin (and thus iron) is 
magnetized only while inside an external field;  as soon as the blood 
leaves the external field it immediately forgets all about what's happened 
and has no residual magnetism.  Hence the initial answer "sort of".  
Actually, what's going on is a lot more complicated than the summary I've 
given, but let's stop while we're ahead.

I hope this helps!