A mill for grinding particles to submicron size. The mill has a rectangular prism-shaped housing for two internal barrels. Each internal barrel has a shaft and a plurality of overlapping circular discs attached to the shaft for grinding materials to submicron size. Each barrel also has blocked corners providing a cross-sectional shape of half of an octagonal prism disposed toward opposing ends of the housing. The housing also includes comprises curved acceleration ramps disposed between the barrels proximal to the overlapping circular discs on opposing sides of the housing. An inlet is provided for feeding material to be ground by the mill to an overlapped portion of the overlapping circular discs. An outlet is disposed at an end of the mill opposite the inlet for removing ground material from the mill. The overlapping circular discs are rotated in the mill at a shaft speed ranging from about 200 to about 1200 RPM.
