MO MCQ -1 | Mill (Grinding) | Materials - ScribdPebble mills are tumbling mills widely used for grinding in the manufacture of paints & pigments and cosmetic industries, where iron contamination in the product is highly objectionable. Pebbles used in pebble mill are made of a) Stainless steel b) Bronze c) Concrete d) Flint or porcelain 2. Crushing of mineral particles is.mills for crushing porcelain,BioSpec Products • Tissue Grinders. nitrogen temperatures are very easily fractured into powder using the crushing action of a motar and pestle. This special process is called cryogrinding. Another catagory of mechanical homogenizer that also operates, at least in part, by similiar hard surface to hard surface grinding forces are beadbeaters (aka, bead mills).