Effect of material properties on the grinding effect of vertical grinding machine
Vertical grinding machine is the main grinding equipment in the grinding industry at present, and it can be seen in the grinding process of various industries. In view of its widespread application, SBM mill manufacturers summarized the impact of material characteristics on the grinding effect of vertical grinding machine in order to improve the production efficiency of vertical grinding machine.
The characteristics of grinding materials mainly refer to the hardness, particle size, moisture content and grindability of materials.
The hardness of the feed is usually characterized by Mohr hardness (range 1-10). The hardness of calcite is generally between 2.8-3.0, which varies with the type and content of inclusions in the raw ore. Generally speaking, the material has high hardness, poor wearability and high wear, so the material hardness is directly related to the output of the product and the service life of the wear-resistant parts of the mill.
The granularity of materials can be reasonably controlled according to the fineness of finished products. Vertical grinding machine has a certain range of requirements for the size of raw materials, too large or too small size will destroy the gradation balance of the material layer, which is not conducive to the normal operation of the mill. If the feed size is too large, the primary grinding efficiency will be reduced, the number of material cycles will be increased, and the grinding power consumption of the mill will be increased virtually. At the same time, the vibration of the mill will be increased due to the lack of buffer of fine particles. When this problem occurs in operation, proper material reduction should be carried out to stabilize the pressure difference and material layer of the mill. If the feed size is too small, the powdery material will increase. Because of the poor adhesion of fine particles and the effect of internal air flow, the fluidization trend of the feed bed is obvious, which makes the vertical grinding machine unable to effectively engage a large number of particles, resulting in the instability of the feed layer and the vibration of the mill.
3.Water content of feed
The control of feed water content is very important for the stable operation of vertical grinding machine. Taking the production line of heavy calcium powder as an example, if the moisture content of raw material is too large, the new material will bind the fine powder on the feeding bed, resulting in the formation of cake on the grinding disc. Under the condition of continuous feeding, the grinding disc layer will be continuously thickened, resulting in the grinding roller can not effectively roll and grind the material, and the grinder will vibrate or vibrate due to excessive load. Stop.
The grindability of feed directly affects the mill output, power consumption and service life of roll liner. Material is easy to grind, crush and grind, and produce superfine powder. Conversely, materials with poor grindability need repeated grinding and greater grinding pressure to increase grinding power consumption, accelerate the wear of roll sleeve and liner, and reduce their service life. The grindability of raw materials is generally reflected by the Grindability Index (Bond Gong Index). The Bond Gong Index of calcite raw materials is usually 9-11 kW h/t. The smaller the value, the easier the material grinds.
In addition, the feed of the vertical grinding machine is stable and continuous, and the material should be gradually increased or decreased when adjusting. If the feed quantity fluctuates greatly, it will break the dynamic balance of the material in the mill, cause the fluctuation of the material layer, make the abrasive material grinding uneven force, and easily lead to the vibration or failure of the mill.