Vertical roller mill (VRM) is a type of grinding equipment that uses vertical rollers to grind raw materials, coal, and cement. It is an energy-efficient alternative to conventional ball mills.
How does a vertical roller mill work?
~ Feeding: The material to be ground is fed into the grinding table area of the VRM by a feeding system, which can include a screw feeder or chute.
~ Grinding: The grinding table is a horizontal rotating disk with a grinding surface. Above the table, there are one or more rollers that apply pressure to the material as the table rotates. A hydraulic system controls the pressure and position of the rollers.
~ Crushing: The material is crushed and pulverized by the pressure applied by the rollers on the grinding table. The grinding action is a combination of compression, shear, and impact forces.
~ Classification: The ground material is carried by the airflow to the classifier, which separates the particles according to their size. Fine particles that meet the required specifications are carried away by the airflow, while coarser particles are returned to the grinding table for further grinding.
~ Drying: In some VRMs, the airflow is also used to dry the material, which is particularly important for moisture-rich raw materials such as raw meal or coal.
~ Exhaust: Fine particles that pass through the classifier are carried out of the mill and collected in a bag filter or dynamic separator, and then stored or further processed.
~ Circulation: A portion of the airflow is recirculated back to the mill after passing through the classifier to maintain an optimal balance between airflow and material conveying.
Application areas of vertical roller mills
~ Cement industry for raw meal and cement grinding.
~ Power industry for coal grinding.
~ Metallurgical industry for grinding ores such as iron and copper.
~ Chemical industry for grinding non-metallic minerals such as limestone and gypsum.
Features of vertical roller mills
~ High efficiency: VRMs offer higher grinding efficiency compared to conventional mills.
~ Energy saving: The design of VRMs significantly reduces energy consumption.
~ Low maintenance: VRMs have a simple structure, simpler maintenance and lower costs.
~ Versatility: VRMs can handle a wide range of feed materials with different hardness and moisture content.
~ Environmentally friendly: The VRM's closed design helps reduce dust emissions and noise pollution.
~ Automation: The VRM is equipped with advanced automation systems for easy operation and consistent production quality.
The working principle of the VRM vertical roller mill is at the core of its high-performance grinding capabilities. With precise control and optimized design, the VRM meets the high standards of modern industry for efficiency and environmental requirements.
