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An article to understand the Raymond mill

Source: clirik   By Administrator   Posted: 2022-10-12   

Raymond mill, also known as hanging roller mill or pendulum mill, is widely used in metallurgy, building materials, chemical industry, mining and other fields. It can be used for grinding non-flammable and explosive minerals with Mohs hardness not higher than 7 and humidity not exceeding 6%. The fineness of finished products is generally between 25 meshes and 325 meshes.

Raymond mill

The complete Raymond mill production line generally includes main engine, analyzer, piping device, blower, finished product cyclone, jaw crusher, bucket elevator, electromagnetic vibrating feeder, electric control motor, etc. Among them, the main engine of Raymond mill is composed of a frame, an air inlet volute, a blade, a grinding roller, a grinding ring, a cover, and a motor.


Raymond mill production line


raymond roller mill


The advantages and application fields of Raymond mill

Raymond mill has the advantages of stable performance, simple process, convenient operation, relatively small footprint, strong systematicness, and strong completeness. It can form an independent production system for raw material rough processing, transportation, milling and packaging. Widely used in calcite, marble, chalk, limestone, talc, wollastonite, gypsum, hard kaolinite, clay, feldspar, barite, bentonite, graphite, tremolite, illite, sericite and other non-metallic materials Mineral powder processing.


The basic working principle of raymond mill

After the material is crushed (jaw crushing, impact crushing, etc.) to the required particle size, the material is sent to the storage hopper by the elevator, and then sent to the main grinding chamber of the Raymond mill uniformly and continuously by the vibrating feeder. Due to the centrifugal force during rotation, the grinding roller swings outward and is pressed against the grinding ring. The shovel scoops up the material and sends it between the grinding roller and the grinding ring. Due to the rolling of the grinding roller, the purpose of crushing is achieved. The fine powder after the material is ground is brought into the analyzer for sorting with the circulating air of the blower, and the material with excessive fineness falls back for regrinding.


Important parameters of Raymond mill

Raymond mills are divided into 3R (3 rollers), 4R (4 rollers) and 5R (5 rollers) according to the number of grinding rollers. The main technical parameters are the inner diameter of the grinding ring, the number of grinding rollers, the size of the grinding rollers, the speed of the main shaft, the maximum feeding particle size, the product particle size, the production capacity, the diameter of the impeller of the classifier, the air volume of the fan, the power of the main engine, the weight and shape of the equipment, etc.

Model Rollers Roller size
Grinding ring
inner diameter
and height(mm)
Max feed
size (mm)
rate (KW)
3R2615 3 260×150 780×150 20 1.6-0.045 0.8-2.5 18.5 4.2 5650×3305×5950
3R2715 3 270×150 830×150 20 0.9-2.8 22 4.8 5600×3400×5900
4R3216 4 320×160 970×160 25 1.8-4.5 37 15 7900×8000×9700
5R4121 5 410×210 1280×210 30 2.5-9.5 75 25.7 9900×5800×10580
Note: For the weight of the above machines, 3R2615 and 3R2715 refer to the weight of the main unit, while 4R and 5R refer to the weight of the whole machine.



Solutions to Raymond Mill Production Decline


1 Check the powder lock

If the powder lock of the Raymond mill is not tightly sealed, the phenomenon of powder sucking will occur, resulting in the phenomenon of no powder or less powder. It is very important to regularly check the tightness of the powder lock to ensure the stable powder output.


2 Check the analyzer

The function of the Raymond mill analyzer (powder separator) is to analyze the size of the finished powder, whether it meets the finished product standard, and decide whether the powder needs to be sanded again. If the blades of the analyzer are severely worn, it will affect the effect of classification. If the powder is too coarse or too fine, new blades can be replaced.


3 Check the fan

The air volume of the Raymond mill has a direct impact on the powder output. If the air volume is too large, the powder output is too coarse, while the air volume is too small and the powder output is too fine. It is necessary to adjust the air volume of the fan according to different materials to correct the powder particle size.


4 Check the blade

The blade of Raymond Mill is responsible for scooping up the material. When the blade is worn out, the shovel will be affected, which will indirectly affect the powder output. Timely replacement of the blade can ensure the powder output efficiency and the normal operation of the equipment.


Raymond Mill Equipment Upgrade and Development


1. Raymond mill upgrade

More than 100 years have passed since the invention of Raymond mill, and major improvements in structure and internal classification occurred around 2000, such as increasing the quality of the grinding roller, increasing the pressure of the grinding roller, increasing the swing speed of the grinding roller, and improving the classification fineness of the sorting machine. and precision, while improving the hardness and strength of grinding rollers and grinding rings. These improvements significantly increase the production capacity of traditional Raymond mills and reduce energy consumption and wear per unit of product. In addition, by increasing the number of classifier blades, increasing the speed of the classification impeller, or configuring a turbo air classifier for secondary classification, the product fineness can be improved, and finer powders such as 600 mesh (20 μm) and 800 mesh (15 μm) can also be produced.


2. Raymond mill secondary upgrade

From an ideal state, grinding equipment with large processing capacity, high sorting efficiency, low energy consumption, energy saving and environmental protection will be more favored. As far as Raymond mills are concerned, material grinding accuracy has always been a technical difficulty in equipment improvement and one of the main bottlenecks in its development.