SCM Ultrafine Grinding Mill

Product Features: Ultrafine powder, wide applications, excellent environmental effect
Input Size: 0-20mm
Capacity: 0.5-25TPH
Material: Limestone, calcite, dolomite, petroleum coal, gypsum, barite, marble, talc, coal powder, etc.

Working Principle

After hammer crushers break large bulky materials to smaller ones, elevator works to send materials to material bin. Next, materials are sent to the grinding mill evenly and they would fall onto the dispersing plate firstly. When the grinding mill runs, dozens of grinding rollers start to rotate and roll. Under the action of centrifugal force, materials on the dispersing plate are then thrown to the rim and drop to the grinding chamber. In the circuit, materials would be squeezed and ground. After being ground several times, materials are blown into the powder selector by airflow. Under the action of the impeller of powder selector, materials which fail to meet fineness would be sent back to grinding chamber to get another grinding while qualified powders would be collected by cyclone powder collector and discharged from the bottom as finished products. Some remaining powders would be collected by impulse dust remover and they may stick to the surface of filler-bag. So, next, high-pressure airflow controlled by the impulse valve blows the filler-bag to make it swell and shake violently. This sudden shake can help kick off materials on the filler-bag and collect them as finished products. After filtering, the airflow would be discharged to the air. This system adopts an open circuit and runs under negative pressure.

Application Of Ultrafine Mill

Ultrafine mill is a relatively high yield, product quality is also better grinding machinery and equipment, in the application than other grinding equipment to a wide range, more in line with people's production requirements. The ultrafine mill is one of the types.

This mill is mainly used in the cement plant finished some of the grinding, and it also applies to metallurgical, chemical, power and other industrial and mining enterprises of the grinding process. Can be used for open grinding, but also for the composition of the circulation with the powder ring grinding. Mill has a strong adaptability to the material, can continue to produce, broken than large, easy to speed grinding products, such as the fineness of the characteristics. It can be dry production or wet production, can also be grinding and drying at the same time operations.

In the production and processing, the performance of its equipment, product performance structure than the other grinding equipment is better, more applicable to the production and processing, the current application of ultrafine mill has been more than ordinary ordinary ultra-fine grinding application range, in the Some of the production and processing of the process showed a lot of performance and structural advantages, for example, the process is relatively simple, less investment, but the price is relatively high and quick; in the internal structure of the mill liner, activation ring, Plate, export grate plate and other grinding results, slag powder grinding power consumption is less than 55Wh, cement powder grinding power consumption is less than 30kWh; and in the overall structural performance, which meets the clinker, slag grinding characteristics and finished product quality Some requirements, resulting in its grinding area is greater than 430 square meters / kg.

The process of ultrafine milling machine

The material is fed from the feed hopper in the upper part of the extruder mill. Under the rotation of the two rollers, the centrifugal ultrafine mill is extruded first in the roll gap and then the column is formed along with other materials. Where the material is pressed and subject to increasing pressure until the minimum gap between the two rolls, the pressure reaches the maximum, the pressure of the material layer, that is, the material column, from the beginning to enter the α angle, with the Laying layer down to move, increasing density, the formation of cake.

Any of the particles in the layer are subjected to extrusion from adjacent particles in all directions. Particles in the great pressure when the strain occurs, resulting in crushing and micro-crack effect, the so-called grain crushing effect. This process is granule crushing process.In theory, the crushing of the formation of granulation layer crushing conditions are three main points:

First, must be forced to feed, the material can not be free to fall between the two pressure roller;

Second, the feed size should be less than the gap between the two rollers;

Thirdly, the pressure applied between the material particles is above 50 MPa. In fact, the second point is not absolute except for the first and third points, and the feed size can be slightly relaxed, as long as the two press rolls Smooth bite the material particles can be.

In addition, BHBergstom's study shows that when the particles are crushed, a large amount of noise and debris spatter will occur if the strain is released rapidly. This part of the energy and kinetic energy loss is about 45% of the total input energy. To reduce these losses, the design of extrusion grinding using two measures:

1. To avoid the sudden pressure of the material and the rapid release of the strain energy, in the material before crushing a gradual compaction of the transition zone, from the roll began to squeeze the material layer until the cake from the gap between the two rollers, the pressure angle α About 50 to 6 degrees;

2. All aspects of restrictions on the splash of material fragments, the use of the top of the forced feeding and side baffle seal to form a dense column, the debris of the kinetic energy too late to splash it, was immediately absorbed by the material layer, part of the recycling into The material is subjected to crushing. The whole crushing process is divided into three stages - compacting, crushing and kneading, in the area (point load) material particles squeeze each other compact, the gap between the particles dropped, the volume shrinks, keep intimate contact between particles, then The pressure (stress) is not large, the material layer displacement (strain) is very large in the 2 area (line load) pressure gradually increased, the pressure between the particles to each other to reach its damage stress value, the particles have been crushed, The slope of the curve increases.

At the same time due to the continuous occurrence of comminution, has been shattered debris, debris and powder need to re-arrange the position to maintain the state of mutual crabs, so the pressure increases, the material layer volume continues to shrink in the 3 area (radial Extrusion) crushing operations are continuously deepened in uniaxial crushing, the material is further pulverized, or microcracks are generated inside the particles. This is the main area of ​​the crushing operation, the highest pressure, the curve is also the steepest, the crushing efficiency is also the highest for a certain material, stress and strain curve has an ideal representative of the ideal design conditions - called the critical pressure. The process parameters of the extruder mill should take into account the above-mentioned material pulverization process to achieve stable operation and the best crushing effect.The process parameters mainly include the ratio of the diameter D of the press roller to its width w, the choice of working pressure, Roller peripheral speed, spacing and material throughput.


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