Why cement vertical raw mill flactuate it is grinding pressure

The flactuation of cement vertical raw mill's grinding pressure

The flactuation of cement vertical raw mill's grinding pressure is caused by many factors. First, the material itself has a certain moisture content, which will cause the material to swell and shrink when it encounters water. Second, when the material is ground, the particles are not uniform in size, and some are finer than others. This will also cause the grinding pressure to flactuate. Third, the speed at which the material is ground can also affect the grinding pressure. If the material is ground too quickly, it will create more friction and heat up the particles, causing them to expand and resulting in a higher grinding pressure. Fourth, if there is an uneven distribution of particles in the mill, this will also lead to a flactuation in grinding pressure. Finally, external factors such as temperature and humidity can also impact the grinding pressure.

The reasons of the flactuation

The main reasons for the fluctuations in the grinding pressure of a cement vertical raw mill are:

1. Incorrect Settings: The settings of the mill (e.g. rollers, table, damper) should be checked and adjusted regularly to avoid this problem.

2. Wear of Mill Components: Over time, wear of the mill components can lead to fluctuations in the grinding pressure. This can be minimized by regular maintenance and replacement of worn parts.

3. Material variations: The properties of the raw materials used can also lead to fluctuations in the grinding pressure. This can be minimized by using consistent and high-quality materials.

How to adjust the grinding pressure

Cement vertical raw mills are able to reach production capacities of over 500 t/h. Mill OPC grinding pressure as per international standards is around 250 bars. The actual values can however flactuate based on a number of parameters such as:

- feed moisture content

- feed size (HGG)

- fresh feed composition

- clinker activity

- recirculation load inside the mill

All these parameters are interlinked and their effect on each other is not always linear. As such, it can be tricky to optimize the mill settings and avoid pressure flactuations. Here are a few tips on how to adjust the grinding pressure:

1. Start by ensuring that the HGG feed size is correct and constant. Incorrect or variable feed sizes will result in pressure flactuations.

2. Make sure that the fresh feed composition is consistent. Changes in the fresh feed composition can affect the clinker activity and, as a result, the mill pressure.

3. Try to keep the recirculation load inside the mill at a minimum. Too much recirculation will lead to increased grindability demand and unstable pressures.

4. Adjust the dam ring height if needed. The right dam ring height is crucial for maintaining stable pressures and efficient grinding in cement vertical raw mills.

What causes cement vertical raw mill flactuate it's grinding pressure?

The main reason for the fluctuations in the grinding pressure of the cement vertical raw mill is due to the inconsistency of the feeding material. If the feeding material is too dry, the grinding pressure will be too high; if the feeding material is too wet, the grinding pressure will be too low. In addition, other factors such as wind speed, air humidity, and temperature can also affect the grinding pressure.

How to prevent cement vertical raw mill flactuate it's grinding pressure?

As we all know, cement vertical raw mill is an important grinding equipment in the cement production process. Its grinding pressure is related to the efficiency of the whole production line. So how to prevent the cement vertical raw mill from flactuating its grinding pressure?

First of all, we need to find out the reason why the cement vertical raw mill flactuates its grinding pressure. There are many reasons that may cause this problem, such as material properties, feed size, etc. Once we find out the reason, we can take corresponding measures to prevent it.

For example, if the material properties are the reason, we can adjust the feed size and material composition; if the feed size is too large, we can reduce it; if the material composition is not suitable, we can adjust it accordingly.

In short, there are many ways to prevent cement vertical raw mill from flactuating its grinding pressure. We just need to find out the root cause and then take corresponding measures.

Fluctuaion of grinding pressure

The main reason why the grinding pressure of cement vertical raw mill fluctuates is that the material bed is unstable. When the material bed is unstable, the grinding pressure will increase or decrease accordingly. There are many factors that can cause the material bed to be unstable, such as:

1) The feeding rate is too high or too low. If the feeding rate is too high, the material bed will be "fluidized", meaning that the material particles will be suspended in air and will not be able to effectively grind. On the other hand, if the feeding rate is too low, the material bed will be too dense and will also not be able to grind effectively.

2) The particle size distribution of the feedstock is not uniform. If there are more fines (smaller particles) in the feedstock, it will be difficult to maintain a stable material bed and the grinding pressure will fluctuate.

3) The moisture content of the feedstock is not uniform. If there is more moisture in some areas of the feedstock, it will again be difficult to maintain a stable material bed and the grinding pressure will fluctuate.

Reasons for the fluctuation of grinding pressure

Grinding pressure is applied to the grinding wheel by a hydraulic system and regulated by the operator. The pressure fluctuates depending on the amount of material being ground, the speed of the wheel, and other factors. If the pressure is too high, it can cause the wheel to break or wear down prematurely. If the pressure is too low, it can cause the material to not be ground evenly.

How to control the grinding pressure

In order to control the grinding pressure of a cement vertical raw mill, operators must continuously monitor and adjust the settings of the mill. The most important parameters that need to be monitored are the Mill Motor Power and the Damper Position. The ideal setting for the Mill Motor Power is when it is at its lowest power consumption point. This can be achieved by adjusting the speed of the fan, if necessary. The Damper Position should be set so that there is minimal airflow through the mill. This will allow for proper grinding and prevent excessive wear on the equipment.

Conclusion

The cement vertical raw mill is subject to a number of forces that can cause it to flactuate its grinding pressure. These include the weight of the grinding media, the rotation of the mill itself, and the centrifugal force created by the rotation. Additionally, there may be other factors at play that can cause fluctuations in the grinding pressure, such as changes in temperature or humidity. Whatever the cause, it is important to keep an eye on the grinding pressure and make adjustments as necessary to ensure that it remains within acceptable limits.