Preparation of natural pyrite nanoparticles by high energy planetary .
WEBFeb 1, 2015 · Ballmass to powdermass ratio of 10:1 was selected to prepare the nanopowders. The milling was done in a high energy planetary ball mill (Model PM 2400, ) at a rotation speed of 320 rpm. Powder samples were withdrawn at time interval of 2 h for different analyses. This kind of milling is known as interrupted milling.