How to Improve Grinding Efficiency of Vertical Roller Mill

The vertical roller mill is used to grind the material by using the principle of material bed pulverization. It gathers materials for grinding, conveying, powder selection, drying and separation of metal blocks and medium ore. Under normal conditions, the roller mill can run smoothly, increase production, reduce energy consumption, increase operating rate, and continuously improve economic efficiency are central issues in the management and operation of vertical roller mills.

Air Volume Control

The differential pressure of the vertical roller mill is generally controlled at 5000~7000Pa to ensure the proper air volume. The change of the pressure difference within the mill is mainly affected by the feed amount when other conditions are constant. Therefore, the feed amount should be stabilized.

Vibration of Verticle Roller Mill 

When vertical roller mill is in normal operation, its vibration is weak. When the mill is vibrating strongly, it should be stopped and checked to ensure the equipment is working properly. There may be some reasons for the excessive vibration, and the cause should be analyzed:

1. The upper layer of grinding disc is too thin or too thick;
2.  metal foreign matter enters the vertical roller mill;
3.  feeding a large amount of large pieces of hard materials;
4.  The air volume is too small, and the finished product is not delivered in time;
5.  The separator speed is too high and the cyclic load is too large;
6.  The roller bearing is damaged;
7.  The proportion of hard materials in the raw materials is too large, and the amount of fine powder is too small;

When the mill is overloaded, the vibration is increased. At this time, the current increase of the main motor should be observed. After the alarm, it should be processed in time.

Feeding Amount Control of Verticle Roller Mill

Mainteining material laye thicknessr is the main content of the operation control. The stability of the material layer is a prerequisite for safe operation of the verticle roller mill. The amount of feed in the mill can be tested by 3 methods:

1. Grinding roller limit device clearance;
2. The power of the mill (ie the main motor current);
3. Metering of belt scales;

If the layer is too thick, the following phenomena will occur:

1. The mill pressure difference increases;
2. Grinding machine vibration increases;
3. Mill current increases;
4. The amount of slag in the mill increases;

If the material layer is too thin, the following phenomena will occur:

1. Grinding machine vibration increases;
2. The mill pressure difference becomes smaller ;
3. The main motor current increases;

Mill Air volume control

During the operation, when air volume changes greatly, it must be adjusted in time. If air volume is too small, the following will occur:

1. The finished product cannot be output in time, the amount of circulation in the mill is increased, the mill is overloaded, and the fineness of the product is exceeded;
2. The wind speed of the wind ring is low, and the amount of slag thrown by the mill increases ;

When air volume is too large, the following will occur:

1. Product fineness becomes thicker;
2. Vertical grinding pressure difference increases;
3. The energy consumption of the main fan increases;

 Product Fineness Control

If raw material fineness is too coarse, it will affect the firing of the clinker. If the fineness exceeds the fine rules, the mill output will decrease and the power cent result of the raw material fineness per hour according to the laboratory. The speed of the separator is such that the fineness is controlled within the range of R 0.08≤14~16%.