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By: Ashley November 07, 2019 Last Updated :November 07, 2019

What Should I Do to Increase 20 Percent Capacity of Raymond Mill?

Raymond Mill whose powder amount directly affects the efficiency of the entire project is one of the most common industrial milling equipment at present. In the practical application of the Raymond mill, low yields are a common problem. How to improve the production efficiency of Raymond Mill and increase the amount of powder? We will advise you from three aspects:materials, machinery and maintenance.

What Should I do With the Materials?

Dry or Wet Materials

The water content of the material should be less than 6% (can be kneaded into a ball by hands without water seepage) in Raymond mill. Whether the material is too wet or too dry, it will directly affect the capacity of Raymond mill. Studies have shown that when the comprehensive moisture content of the material is higher than 1.5%, the output is reduced; when it is higher than 2.5%, it’s reduced by 15% to 30%; when it’s higher than 3.5%, the fine powder in the Raymond mill will adhere to the grinding body and the liner, which greatly reduces the grinding efficiency and even powder selection and dust removal system failures will be increasing or the Raymond mill will be forced to stop.

Therefore, the comprehensive moisture content of the material should be controlled within 1.5%. Materials with excessive humidity can be dried naturally or by a dryer. However, we shouldn’t dry the material as much as possible. If the material is too dry, its speed in the Raymond mill will be very fast, which will affect the quality of the final product and produce large dust pollution during grinding. In this case, we can properly spray water to the feed mouth to increase its humidity.

In this way, we need to find specifications for the moisture content of the materials of the Raymond mill, some of which will be presented in the following:

Material Standard Moisture Content
clinker <0.5%
gypsum <8%
mixed material <2%
clay <2%
coal <4%
iron powder <8%
limestone <1%

Sieve the Materials

Whether the feed size is too small or too large, it will affect the production of Raymond mill. When the mixed material with particle size less than 10 mm is more than 70%, the powdery materials will be too many, then they will be basically free from being squeezed and falls freely. Raymond mill loses the meaning of its extrusion grinding. When the mixture contains a bulk material with a particle diameter of over 150 mm, the roll gap is forcibly opened and the bed is destroyed. Therefore, we advise to screen the material with a vibrating screen firstly before the milling process to filter the fine powder and large pieces of material larger than 150 mm to avoid hem entering the Raymond mill.

Feed Size Content
<10 mm <70 mm
>150 mm 0

Cool the Materials

Once the high-temperature material is fed into the Raymond mill, the tendency of the nip between the pressure roller and the material will be increased and the granulation between the granules of the bed won’t be formed, resulting in the ramming. The actual situation shows that when the temperature of the clinker exceeds 80 °C, the output will decrease. Therefore, when grinding cement without mixed materials or with a small number of mixed materials, the temperature of the clinker should generally be controlled below 80 °C; and when grinding the slag cement or cement with lots of materials, it should be controlled below 100 °C. If the temperature of the material is too high, water can be sprayed into the cooler or on the clinker belt to allow it to cool.

What Should I do With the Machine?

Choose Reasonable Speed of Main Engine

Because the grinding force of Raymond mill comes from the centrifugal force of the grinding roller, the speed of the main engine directly affects the grinding force. The low-speed driving shaft may be one of the reasons for the low powder yield. For example: for processing 200 meshes barite powder, the output of Raymond mill is up to about 8-10 tph. At this time, the machine’s rotation speed is 103r/min, which is the best grinding speed. we should keep the rotation speed at this fixed number all the time or a reduction in production will be caused.

Raymond mill

choose reasonable speed according to requirements

Choose Reasonable Reducer

The large Raymond mill is equipped with a reducer system, which makes the mill produce more powerfully in the grinding process. How do we choose the best reducer? First of all, we should consider the reduction ratio, a comprehensive parameter. we should choose the ideal reduction ratio as much as possible: the optimal reduction ratio = the motor speed / the output shaft speed of the reducer.
Secondly, it is the maximum torque of the reducer. It is very important for the life of the reducer and the calculation of the torque. It should be noted that it cannot exceed the maximum load torque of the reducer.

how to choose reducer of Raymond mill

suggestions to choose reducer of Raymond mill

What Should I do When I Operate and Maintain the Machine?

Only by ensuring that the Raymond mill is operated and maintained properly, can its service life and working efficiency be improved.

Replace Wear Parts

1.The most easily damaged parts are the grinding roller and the grinding ring. The grinding roller should be replaced after using more than 500 hours. The rolling bearings in the roller sleeve must be cleaned, and the damaged parts should be replaced in time. The scrapping limit of the grinding roller and the grinding ring is that the remaining wall thickness shall not be less than 10 mm.

2.Raymond mill’s shovel knife is responsible for scooping up the material. When the blade is used for a period of time or the quality is not too strong, the material can not be shoveled and the phenomenon of no powder or less powder will be caused. A new blade needs to be replaced to ensure proper operation of the equipment.

wear parts

grinding rollers, grinding rings and shovel knifes

Adjust the Parts in Time

3.After the end of daily production, it is necessary to clean the inside of the grinding chamber and the air duct, and check the connection parts of each pipeline to see if it is damaged. Air leakage and air leakage will affect the circulation of air volume and reduce output;

4.The belts of the main engine and the fan should be inspected regularly. If they are loose, we should tighen them immediately. Otherwise, it not only causes reduced production, but also certain damage and malfunction to the machine.

5.If the sealing of the power locker is poor in the process of grinding, the phenomenon of powder suck-back will be formed, resulting in no powder or less powder, so remenber to check the seal of the locker and adjust the degree of sealing.


Every owner of Raymond Mill is concerned about the issue of its production. Due to various factors, the production of Raymond mills will decrease during use. However, we can improve it by using appropriate methods, such as controlling the humidity, composition and temperature of the material; selecting the most suitable speed of main engine and reducer; and timely repairing the machine, only in this wat can the machine exert greater capacity. If the above method still can’t solve the problem, we can also change to a higher quality Raymond mill and try Fote Raymond Mill.


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