High-pressure roller mills are widely used in major mines and related material crushing industries. They have the characteristics of large production capacity, fine output granularity, low unit energy consumption and low steel consumption. After years of research, it is found that the particle size of the high-pressure roller mill is not only related to the nature of the original ore, but also related to the operation and other factors.
First, roll surface pressure
It was found through experiments that by increasing the pressure on the roll surface of the high-pressure roller mill, the output particle size of the middle and side materials became finer, the particle size distribution of the middle material was more concentrated, and the particle size distribution of the side material was more uniform. The crushing effect of high-pressure roller mills on materials mainly depends on the pressure on the materials near the small distance between the two rollers. Usually, the specific pressure (the ratio of the total pressure provided by the hydraulic system to the diameter and width of the rollers) is used as a measure of the working pressure. Job parameters.
With the increase of the pressure on the roll surface, the uniformity coefficient of the middle material increases, the particle size distribution is more concentrated, the crushing ratio increases, the output particle size becomes finer, and the fine-grained part of the middle material after the crushing accounts for the majority; As the pressure increases, the uniformity coefficient of the edge material decreases, the particle size distribution becomes wider, the crushing ratio increases, and the discharge particle size becomes finer. The high-pressure roller mill edge material is closer to the conventional crushed product.
The fine-grained part of the crushed media is the majority. This is because the “size effect” of the mineral particles (the mechanical strength of the ore particles increases significantly with the decrease of the ore size) during the pulverization process. The fine-grained materials are more difficult to pulverize than the coarse-grained materials under the pressure of the roll surface, so that the fine-grained materials account for the majority.
The high-pressure roller mill side material is closer to the conventional crushed product, which is caused by the “edge effect” of the pressure roller during the crushing process. The lower roller surface pressure on the baffles at both ends of the pressure roller and the edge of the pressure roller makes the material easily slide relative to the edge of the pressure roller, reducing the crushing effect of the material layer, so that the crushing method of the material by the edge of the roller is closer to the conventional crushing method .
Second, the speed of the roller surface
Under the same roll surface pressure, when the roll surface speed is increased to a certain amount, the uniformity coefficient of the intermediate material increases, the particle size distribution is more concentrated, the crushing ratio increases, and the product particle size becomes finer, but it affects the uniformity coefficient of the side material and The change of the crushing ratio is not obvious; but when the speed of the roller surface is continuously increased, the change of the crushing ratio of the intermediate material is no longer obvious.
The appropriate speed is related to the surface characteristics of the roll, the hardness of the material, and the size of the ore feed. The speed of the roll surface directly affects the crushing capacity and the degree of wear on the roll surface, and it will affect the particle size characteristics of the product. Increasing the speed of the roller surface has little effect on the particle size characteristics of the discharge, and the unit energy consumption of the high-pressure roller mill has not changed significantly, but its processing capacity has been greatly enhanced. However, higher roller surface speed will wear the roller surface and bearings, which will affect the service life of the equipment.
Third, the material moisture content
The raw ore produced on site often has a certain water content. With the change of the water content of the ore, the strength and viscosity of the ore change, which will affect the material characteristics of the crushing process. When the roller surface pressure and roller surface speed are constant, the ore moisture content increases, the uniformity coefficient of the middle material increases, and the particle size distribution is more concentrated; the crushing ratio of the side material increases, but the increase is not obvious, and the particle size distribution becomes wider.
It can be seen that the increase of the moisture content of the raw material has little effect on the particle size of the discharge. At the same time, the moisture content of the material at the production site of the high-pressure roller mill is generally between 3% and 5%, so in normal production, it will not affect The discharge has a greater impact.
In summary, in fact, most of the factors affecting the output particle size of the high-pressure roller mill are in the operation mode. When the appropriate roller surface pressure and roller surface speed are selected, the output particle size of the high-pressure roller mill can reach production. Demand, which requires the production personnel to have a considerable degree of familiarity with the raw ore materials and mechanical equipment, so for the actual operators, their professionalism is the key factor affecting the particle size of the high-pressure roller mill.