Ultrafine Mill

Ultrafine Mill

Ultrafine mill machine is one of the important equipment for deep processing of nonmetallic ore. It is suitable for barite hardness of barite, calcite, potassium feldspar, talc, marble, limestone, ceramics and glass, not more than 7, humidity below 6% Of non-flammable and explosive mining, chemical, building materials, metallurgical and other industries more than 280 kinds of materials, milling processing, finished product size in the range of 100-325 mesh arbitrary adjustment. Because the stability of production has been widely applied.

Ultrafine mill is a horizontal rotary cylinder. The cylinder is divided into three to four positions by a partition plate, and a suitable grinding body is filled in each bin. When the ultrafine mill rotation, the grinding of the grinding body due to the role of centrifugal force attached to the inside of the inner wall with a rotation, was brought to a certain height, due to the role of gravity from the inner wall of the drop, the mill material crushed. In addition, the ultrafine mill in the grinding body when there are rolling and sliding phenomenon, the material plays a rubbing grinding effect. The effect of grinding and grinding of the material can be seen, when the grinding of the grinding body size larger, less loading, and the cylinder speed is faster, the resulting centrifugal force, grinding body was brought high, The distance increases, and thus the ability to crush the material strong. As if people holding a heavier hammer in the hands, held higher, the power to fight on the big reason similar. In this case, the sliding phenomenon of the polishing body is small, so that the grinding of the material is reduced. If the mill is loaded with a large number of feet and smaller, distributed in the simplified section close to the center of the grinding body, in the ultrafine mill rotation, followed by the slow rise of rotation, resulting in centrifugal force is small, can not be To bring the appropriate height of the drop, rolling and sliding phenomenon increased, the role of the material to enhance the grinding. Therefore, the grinding material in the grinding of the larger size of the hard, the need for greater impact, should be in the mill to increase the diameter of the ball, so that the average diameter of grinding off, if the grinding particle size is small, fragile material , Can be loaded with a smaller average diameter and more grinding body. It can be seen that the loading capacity of the grinding body, the size of the fit, directly affect the performance of ultrafine mill work.

Ultrafine mill process characteristics

  • 1, The choice of large rotor-type ultrafine mill of the analyzer, strictly control the large particles into the product. The selected coarse particles are returned to the pulverized area by itself. So that ultrafine mill system can be directly from the block material to produce 800 mesh fine powder.
  • 2, To improve the existing large cyclone dust collector, improve the ability to capture the product.
  • 3, To cancel the original small cyclone dust collector, with a bag filter instead, to improve the ability to capture the fine powder to reduce the pollution of the surrounding environment while reducing the internal heat of the mill gathering.
  • 4. Improve the grinding part of ultrafine mill, improve the grinding capacity of fine powder, reduce vibration.

The principle and structure of ultrafine mill

Cement production needs to be a certain ratio of raw materials into raw materials, into the kiln forging mature materials, but also ground into cement. ultrafine mill is an indispensable fine grinding machine for cement production, which is the main machinery and equipment of cement plant.

Ultrafine mill mainframe, fan, pipe, dust and other parts, raw materials through the feed inlet into the grinding room inside, grinding between the grinding roller and grinding ring, shovel shovel material sent to the grinding mill between the grinding ring, Grinding to a certain extent, the role of the wind through the material sent to the analyzer, through the analyzer screening effect, to achieve the finished fineness of the material through the pipeline into the finished product unloader, can not reach the fineness of the finished product back to the grinding Room until the desired fineness is achieved.

Ultrafine mill has a rotating cylinder, containing steel balls and steel section (steel column), collectively referred to as grinding body. When the cylinder rotation, the grinding body due to the role of centrifugal force attached to the inner wall of the mill cylinder and the cylinder with a rotation, and was brought to a certain height, by the gravity of the free fall, part of the lighter grinding body along the slide, The use of grinding the impact of grinding and grinding, the material grinding.

Material from the disc feeder by chute into the hopper, the feed screw, hollow shaft into the cylinder. The feed device is fixed on the machine, the screw is fixed on the hollow shaft, and the feed device and the screw are sealed with felt. Hollow shaft and mill end cap as a whole, bolted to the cylinder flange. The cylinder is separated into two tanks by the partition plate, and the material is crushed by the impact of the material. The broken material is allowed to enter the warehouse by the socket hole of the bin plate, and the steel section is fully ground. The cylinder body has a lining plate to protect the cylinder from wear. To achieve a certain degree of fineness of the material through the material to the material output to the material side of the hollow shaft, was installed in the hollow shaft of the material out of the spiral cylinder to the discharge of the cylinder sieve, the slip tube discharge. The whole simplified by the main bearing support.

Ultrafine mill's upgrade

  • (1) to improve the analyzer, increase the number of leaves, improve speed, and some also use double leaves, product fineness increased to 600 head;
  • (2) increase the dust collection system, reduce dust pollution;
  • (3) using the secondary classification system, from the 325 mesh finished powder sorting out 800-1250 purpose ultrafine powder. Although some progress has been made, there are still some defects such as the smaller secondary yield, low efficiency, and the difficulty of processing the subordinate materials, so the comprehensive economic benefits are still not 20A.

Ultrafine mill continue to upgrade to improve the classification machine can achieve a good classification function, in addition to its own structural parameters, but also depends on the match with the wind delivery system. From the separation particle size formula of the impeller classifier, it can be seen that the size of the separated particle size is inversely proportional to the impeller speed and is proportional to the square root of the air flow through the impeller. The traditional ultrafine mill of the blower and fan-shaped analyzer to match, the rated air volume is very large and low wind pressure to meet the classification of 80 to 325 mesh range. For the target range of 100 to 1250, we have made a great change in the classification range, so the air volume of the blower must be drastically reduced in order to achieve superfine classification. And its wind pressure should be greatly increased in order to overcome the introduction of high-speed large impeller classifier after the increase in resistance (according to our test, the 4R, 5R ultra-fine grading machine in the classification of 1250 head when the wind pressure can reach 1800 ~ 2200 Pa). From the separation of the particle size formula can be obtained to obtain a smaller grading particle size must increase the impeller speed and reduce the air volume, but also must be through the impeller air flow in the laminar flow state. The smaller the air volume and the flow rate is not easy to bring the large particles within the grinding chamber into the classification zone, can reduce the pressure on the periphery of the grading wheel, more importantly, it is easy to form the laminar flow through the impeller air flow, And the improvement of precision. A large number of experiments have shown that in order to obtain a smaller graded particle size, the effect of reducing the flow rate is often better than the effect of increasing the impeller speed. Of course, too small flow will reduce the output, it must be repeated testing, a reasonable choice to find the best process parameters (impeller speed and air volume matching).