Raw mill is also called cement raw mill, similar to cement ball
mill, it is an important cement milling equipment used in the
cement production process. Raw mill is mainly used for grinding
cement raw meal in the cement factory production process. It is
also suitable for metallurgical, chemical, electric power and other
industrial mining enterprises to grind various ores and other
grindable materials.
Cement raw meal is a mixture of various raw materials before cement
calcination. It is a mixture of lime raw material (mainly composed
of calcium carbonate), clay raw material (aluminosilicate
containing alkali and alkali soil) and a small amount of
calibration raw material in a certain proportion and ground to a
certain fineness. In order to meet the success of the subsequent
calcination process, the grinding of the raw meal must be uniform
in fineness and ensure the chemical composition of the mixture is
stable.
Raw mill in cement plant is very suitable for cement raw meal
grinding because of its strong adaptability to raw materials and
adjustable grinding fineness. It is the most commonly used grinding
machine in the grinding stage of raw materials in the cement plant.
Working Principle Of Raw Material Mill
The cement raw mill is generally cylindrical in the horizontal
direction, and gears are driven at both ends. After the motor is
turned on, the cylinder is rotated. Raw materials are evenly fed
into the first inner silo from the feed port at one end. The inner
wall of the silo is provided with a step liner or a corrugated
liner, and steel balls of different specifications are installed
inside as the grinding media.
When the raw material grinding process starts, with the rotation of
the cylinder body, the steel balls and materials are brought to a
certain height and then fall down, so that the reciprocating cycle
can produce impact and grind on the materials. Material is ground
at the primary stage in the first inner silo to achieve rough
grinding size. After that, the material passes through the
single-layer partition board to enter the second inner silo for
further grinding.
The structure of raw mill
The inner wall of the second inner silo is a flat liner plate. The
number of steel balls is more and the size is smaller than that of
the first inner silo. The grinding of materials is more sufficient.
In the raw mill grinding process, the grinding material is
discharged from the grinder through the discharge hole, and the
fineness of the qualified material is sorted by the sorting
equipment, while the fineness of the unqualified material is sent
back to the cement raw mill by the sorting machine. And unqualified
material will be ground until the fineness meets the requirements.
Technical Detail of Raw Mill
| Specification(m) | Capacity(t/h) | Rotate Speed(r/min) | Grinding Media Load(t) | Effective Volume(m3) | Motor Power(kW) | Weight(t) |
|---|
| φ2.4×7.5 | 21-23 | 20.4 | 37.5 | 29.5 | 475 | 76 |
| φ2.4×10 | 30 | 20.4 | 50 | 39 | 570 | 94 |
| φ2.6×8 | 20-24 | 19.57 | 52 | 38.1 | 630 | 97 |
| φ2.6×9(closed-circuit) | 42 | 19.57 | 58 | 42.7 | 710 | 125 |
| φ3.0×9 | 28-32 | 18.3 | 78 | 57.4 | 1000 | 150 |
| φ3.4×7.5 | 60 | 16.9 | 80 | 58 | 1000 | 167 |
| φ3.8×7.5 | 90 | 17 | 95 | 91.8 | 1600 | 218(excluding motor) |
| φ4.0×9 | 120-140 | 16 | 140 | 106 | 1800 | 269 |
| φ4.6×10+3.5 | 190 | 15 | 190 | 177 | 3550 | 352(excluding driving parts) |
| φ4.6×10.5+3.5 | 210 | 15 | 200 | 185 | 3550 | 358(excluding driving parts) |
