2018 New Technology Latest Price Vertical Roller Mill - Buy . Roller mills are widely used in grinding non-flammable and non-explosive materials under 9.3(the Moh's hardness), such as grinding quartz, feldspar, calcite, talcum, barite, fluorite, iron ore, copper ore quartz, slag, cement clinker, zircon sand, fly ash and carborundum, coal, etc. Roller mill is mainly suitable for medium, low.