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 The difference between ball mill and bar mill

Date:2019-05-27 17:33     writer:admin     Views:

  The grinding equipment widely used in concentrator is ball mill and bar mill.

  They are similar in shape and grinding principle, but different in structure, performance and application.

  This paper analyzes their similarities and differences from seven aspects, and tell you how to choose the ball mill and rod mill!

  From the crushing mechanism analysis, ball mill and rod mill when the cylinder rotate in a cylinder body of grinding media ball (or rod) under the effect of friction force and centrifugal force, as the cylinder rotary and was promoted to a certain height, and then according to certain linear velocity falls, then within the tube on material impact, grinding and extrusion, make its pieces.

  The working principle is similar, but ball mill and rod mill differ greatly in details, as shown below:

  1, shape and structure analysis of the two cylinder shape proportion is different, rod mill cylinder length to diameter ratio is generally 1.5-2.0, and the end cover of the lining plate inner surface is a vertical plane.

  The ratio of cylinder length to diameter of a ball mill is small, and in most cases the ratio is only slightly greater than 1.

  In addition, the rotating speed of barrel of rod mill is lower than that of ball mill of the same specification, so that the medium in it is in the state of flowing down.

  In the ball mill, the commonly used grid type ball mill and overflow type ball mill (named from different drainage structure), and bar mill does not grid plate drainage, only overflow type and open mouth type, the diameter of the hollow shaft at the end of the drainage is larger than the general specifications of the ball mill.

  The difference between grid and overflow type ball mill can be click "two mainstream ball mill: grid and overflow type, 7 big differences tell you choose who is better!

  Look at it.

  3. Analysis of grinding medium: steel rod with a diameter of 50-100mm is commonly used as grinding medium in bar mill, while steel ball is used as grinding medium in ball mill. The difference of grinding body is the main difference between them.

  There is point contact between steel balls of ball mill and line contact between steel rods of bar mill, so their working characteristics are obviously different.

  Dielectric filling rate analysis dielectric filling rate is the percentage of the grinding medium in the volume of the mill.

  For different grinding methods, grinding machine structure, operating conditions and medium shape, the medium filling rate has an appropriate range, too high or too low will affect the grinding effect.

  Usually, the filling rate of ball mill is 40%-50%, stick mill 35%-45%. In addition, the filling rate of self-mill is 25%-40%, and that of gravel mill is about 43%.

  5. Performance analysis the process characteristics of bar mill are rough products, but uniform particle size, less coarse particles and slime, less crushing, and the particle size characteristics of bar mill products are related to the situation of bar mill ore.

  The performance of the ball mill is characterized by high production capacity, strong adaptability to materials, high degree of fineness of materials, fine particle size, easy fine grinding, remarkable energy saving, but its over-crushing phenomenon is serious.

  6, stability analysis in the operation of the ball mill without inertia impact, to ensure that the equipment can be normal, efficient operation, reduce the equipment downtime, improve the production efficiency.

  7, use analysis when the tungsten and tin ore and other rare metal ore re separation or magnetic separation, often use bar mill to prevent the generation of over crushing;

  In the second stage grinding process, rod mill is generally used as the first stage grinding equipment, with larger production capacity and higher efficiency.

  In the treatment of soft or not too hard ore, can use bar mill instead of short head cone crusher for fine crushing, not only configuration is simple, the cost is lower, and can make the dust removal workshop simplified.

  The ball mill is not suitable for the reprocessing line of metal dressing because of its fine grinding materials.


  Understand the difference between ball mill and rod mill, and lay a foundation for the selection of equipment.

  Generally speaking, the user can choose according to its raw material, finished product granularity and effect, production mode and so on.

  1. Processing selection according to raw materials

  In the operation, if the user needs to process the raw materials for tungsten and tin ore, bar mill is a better choice, and if the user needs to grind the materials for aluminum ash, lime, slag, molybdenum ore, etc., ball mill processing capacity is stronger.

  2. According to the particle size of finished products

  In the coarse grinding, when the product size is 1-3mm, the processing capacity of the rod mill is greater than that of the ball mill with the same specification. When the product size is less than 0.5mm for the fine grinding, the grinding effect of the ball mill is greater than that of the bar mill with the same specification.

  That is, ball mill products tend to be more fine, bar mill products are more rough, but more uniform.

  3. Choose according to the mode of production

  In the heavy separation or magnetic separation of rare metal ore, in order to prevent the harm caused by excessive powder in the operation, the grinding of materials often adopts bar mill for production and processing, and most of the production and processing of cement plant choose ball mill.

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