Date:12-13-2011 Hit:
Vertical mill is based on advanced home and abroad technology, combine with years of experience in the production of grinding machine. The vertical grinding machine is an ideal equipment that integrates crushing, drying, grinding and grading conveyor all together. Vertical mill is the ideal substitute of the traditional grinding mills like raymond mills, high pressure suspension grinding mills, ball mills, etc. It is the solution for fine grinding and classification of a wide variety of materials including, but not limited to calcium carbonate, dolomite, talc, bentonite, barites, petroleum, coke, calcium oxide and gypsum.
Vertical roller mill used in cement grinding plant
Vertical roller mill for use in cement manufacture with the continual increasing demand for portland cement and constant pressure for reduced energy consumption, producers are exploring a wide variety of cost-saving manufacturing options. One option is vertical roller mill technology for finish grinding.
Traditionally, plants used ball mills to grind clinker and gypsum into cement. The result: the majority (60%) of finish grinding in the world is still performed using the ubiquitous ball mill. Ball mills are cylindrical steel shells with steel liners. These rotating drums contain grinding media that tumble inside the cylinder. The grinding balls cascade and tumble onto the clinker and gypsum to produce cement. Almost all ball mills use a form of closed circuit grinding that returns material that is too coarse back to the ball mill inlet while material fine enough to meet product requirements is collected. The separator or classifier determines which particles will be returned and which particles are sufficiently fine. With an effort to increase production, ball mill physical size has increased almost to the physical limitation dictated by the gas velocities and accompanying pressures necessary for the process. Ball mills may not be the most efficient means of size reduction but their reputation for product consistency and their simplicity of operation have made them an historic plant favorite.
Cement plants are increasingly looking to vertical roller mill technology for their finish grinding needs. Vertical roller mills present a compact and efficient grinding method. Clinker and gypsum is ground on a rotating table that passes under large rollers. Material is forced off the table by centrifugal force, where it is then swept up into an airstream to a classifier immediately above. Just as with a ball mill, material that is too coarse is returned to the table for additional grinding while material that is fine enough is collected as product. The compact design of a vertical roller mill allows it to dry, grind, and classify, all within one piece of equipment and all in a relatively compact space. Vertical roller mill technology allows: (1) power consumption savings; (2) consistent product quality and (3) process simplification.