Vertical grinding mill

The vertical mill (also known as a vertical mill or roller mill) is a core piece of equipment in modern industrial grinding. It represents a highly efficient grinding technology approach distinct from the ball mill.

Working Principle:

The vertical mill utilizes the "burden grinding" principle. Its core working components are a horizontally rotating grinding disc and a set of grinding rollers (usually 2-4) vertically pressed against it. Material falls from the inlet into the center of the grinding disc and is flung toward the edge of the disc by centrifugal force. As it passes through the gap between the grinding rollers, it is crushed by the rollers. The crushed material is lifted by a hot air stream blown from nozzles surrounding the grinding disc and enters the classifier at the top of the mill. Fine powder is discharged with the airflow and collected as the product, while coarse powder falls back to the grinding disc for re-grinding.

Main Applications:

Cement Industry: Grinding of raw meal, pulverized coal, slag, and cement clinker.

Metallurgical Mining: Large-scale grinding of metallic and non-metallic ores.

Power Industry: Grinding of desulfurized limestone for power plants.

Chemical and Other Industries: Grinding and drying of various materials.

Core Advantages of Vertical Grinding Mills

Compared to traditional ball mills (whether dry or wet), vertical grinding mills offer significant advantages in several areas:

1. High grinding efficiency and low energy consumption (the most prominent advantage)

Bed grinding principle: Materials are collectively crushed in a "bed" of material, rather than the single-point random impact and grinding of steel balls against the material as in a ball mill. This principle offers far greater energy efficiency than a ball mill.

Data Support: Compared to traditional ball mills, vertical grinding mills typically reduce power consumption by 20% to 50%, a significant advantage in today's high energy costs.

2. Integrated Crushing, Grinding, Drying, and Powder Selection

This is a highly integrated system. Hot air can enter the mill from the bottom, simultaneously drying materials with high moisture content while grinding (typically handling materials with moisture contents up to 15%-20%).

The built-in dynamic classifier instantly separates qualified fine powder, preventing over-grinding and allowing for quick and easy adjustment of product fineness. This significantly simplifies the process flow and reduces footprint.

3. Low Metal Wear and Noise

Low Wear: The grinding rollers and grinding discs do not directly contact each other; instead, they are separated by a material layer, minimizing direct friction between the metals. Metal consumption per unit of product is typically more than half that of a ball mill.

Low Noise: Due to the compaction principle, the primary noise comes from the drive motor and fan. The overall noise level (approximately 80-85 decibels) is significantly lower than that of a ball mill with colliding steel balls (which can reach over 100-110 decibels), resulting in a better working environment.

4. Stable Product Quality and Easy Adjustment

The built-in high-efficiency classifier ensures a narrow and uniform particle size distribution, improving final product quality.

Simply adjusting the classifier speed allows for quick and precise adjustment of product fineness, providing exceptional operational flexibility.

5. Simple system and small footprint.

The vertical structure occupies a significantly smaller footprint than ball mill systems of similar production capacity. Furthermore, it eliminates the need for bulky auxiliary equipment such as grinding ball lifting and conveying, resulting in lower construction and installation costs.

6. No-load start and stable operation.

The grinding rollers can be lifted hydraulically, enabling no-load start-up, significantly reducing starting current and impacting the power grid. During operation, the hydraulic system provides stable grinding pressure, resulting in relatively low vibration.

Vertical grinding mills are the absolute mainstay of modern large-scale, high-efficiency, low-energy grinding operations. They have essentially replaced ball mills as the preferred choice in newly built cement, slag, coal and other production lines.