Foerschler S.L.

Vertical Roller Mills by GEBR. PFEIFFER AG

For several years we've been representing this company in Spain, especially on the industrial ceramic sector.

The vertical roller mills by PFEIFFER in Kaiserslautern are mainly used in the cement industry to grind raw materials like limestone, marl and shales, obtaining outputs up to 600 t/h. They are also used to grind coal for the burners of the rotary kilns. In the last years, these mills are even being used for the grinding of very hard products like clinker and slags to obtain slag cement.

In the ceramic industry you don’t need such big outputs to produce roof, wall and floor tiles and hollow bricks.

In recent years there has been a transition in this industry from wet to dry process. With the vertical roller mill it is possible to dry the raw materials during the grinding process with the surplus heat from the kiln or additionally with the heat from auxiliary hot-gas generators. The raw materials can be ground to a very high fineness to obtain an extremely fine mass which can be extruded perfectly.

The main features of this type of mills are a rotary table on which three big wheels rotate fixed on a steel frame including heavy shock absorbers. The clays are ground by pressure and shear during the rotation. The resulting powder is sucked in by a dynamic classifier where the lamellae of a rotating wheel separate the product from the oversize, sending the latter back to be milled again. The finished product is retained in a bag filter.

With this kind of mill it is possible to obtain high specific outputs with a minimal wear, due to a layer of material between the rollers and the table and due to a peripheral speed below 3 m/s, in contrast to pendular roller mills. This modern machinery can be controlled very easily, regarding the temperature, pressure, flow and consumption conditions. The handling and maintenance are very simple to manage. Due to its construction characteristics and its housing the mill does not produce significant vibrations or too much noise.