Mahlkörper

Mahlkörper is the German term for grinding media used inside milling equipment to reduce the size of solid materials. They are charged into mills such as ball mills, pebble mills, or attritors and transfer kinetic energy to the material through impact, attrition, and abrasion. The choice of Mahlkörper depends on the material to be milled, the mill design, and the desired product fineness.

Common Mahlkörper materials include steel balls and cylinders, ceramic beads (such as alumina and zirconia), and silica glass. Other options include tungsten carbide, silicon nitride, and various polymer or composite media for specialized applications. Densities and hardness vary widely, with steel media typically around 7.8 g/cm3 and denser options like tungsten carbide providing higher energy transfer but greater wear. The size range spans from sub-millimeter beads to several centimeters in diameter; industrial mills often use a media filling ratio of about 30–40 percent of the mill volume, depending on process requirements.

The performance of Mahlkörper is governed by hardness, toughness, abrasion resistance, and chemical compatibility with the milled material. Higher density and harder media can increase grinding efficiency and shorten milling times but may introduce more wear and potential contamination of the product. Media selection also influences the milling mechanism (predominantly impact or shear) and heat generation. Worn or broken Mahlkörper are removed and replaced to maintain product purity and process efficiency. The term is widely used in mining, cement manufacture, pigment dispersion, and laboratory milling contexts.