What is the best type of ball milling media?

I'm trying to decide what kind of grinding media to use for crushing powders in my ball mill. Is it better to have different sizes? Also, is it true cylinders work better that spheres? My two main choices are either brass balls or alumina cylinders, which one should I pick?

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Prfesser7 years ago
As to shape, spheres have been shown to give a wider distribution of particle size than do cylinders.  That can be good or bad, depending on the application of the finished material.

Re brass vs. alumina, it depends on what is being milled.  Individual chemicals that are non-reactive by themselves are often milled with alumina.  Mixtures that are spark-sensitive... one must ask whether the ignition of a half-kilogram of that mixture, all at once, would present a serious problem... Some types of ceramic media can generate sparks.
Ke-Bob (author)  Prfesser7 years ago
If the mill is to be used for potentially explosive chemicals (such as BP) what would you recommend?
if you are concerned about sparking I would suggest hardened lead balls,

check out united nuclear http://unitednuclear.com/index.php?main_page=product_info&cPath=25_35&products_id=366


looks like 2.5 pounds (100 balls) for 25 bucks