LM Vertical Mill In Cement Grinding Process
Cement grinding is the final process of cement manufacturing and consumes the most electricity.
Its main function is to grind cement clinker (and retarder, performance adjustment materials, etc.) to the appropriate particle size (in terms of fineness, specific surface area, etc.), form a certain particle grade, increase its hydration area, accelerate hydration rate, to meet the requirements of cement cement condensation, hardening.
The clinker is the main component of cement particles, which is composed of C 3 S, C 2 S, C 3 A and C 4 Af minerals.
Gypsum is the main raw material next to clinker, gypsum can adjust the setting time of cement, ensure that cement is set at the appropriate time, ensure reasonable construction, improve the hydration products of cement, adjust the performance of cement.
With cement hydraulic rigidity, commonly used mixing material, Slag can improve the performance of cement.
By adjusting the content of slag, the grade of cement can be adjusted, the performance of cement can be improved, and the output can be increased or decreased
Fly ash is also an active mixing material, which is composed of crystals, vitreous and a small amount of unburned carbon.
The activity of fly ash mainly comes from ferric vitreous, and the higher the content, the better the activity, and the crystals do not have activity.
Lime is a poor mixed material, adding too much will greatly reduce the strength of cement, a certain amount of adding will increase the productivity, and after adding CaO in limestone and water reaction will increase the concentration of OH – particles, increase the hydration rate of C 3 S in cement clinker, improve the early strength.
According to the process flow, the mud mill can be divided into: 1, open grinding system, 2, closed grinding system.
Open circuit grinding process: the material through the mill after the product. It has the advantages of simple process, less equipment, less investment, but easy to produce over grinding phenomenon.
Closed-circuit grinding process: after the material is ground, the product is selected through the classifying machine system, and the coarse powder is returned to the mill for regrinding. It can reduce over grinding phenomenon, increase output, reduce power consumption and product fineness is easy to control, but the system equipment investment is large. The operation and maintenance is more complex.
In the process of Cement production, many customers has chosen Shanghai Zenith LM Vertical Roller Mill, it is a simple and multifunctional mill with stable and powerful performance and compact layout.
1. Lower Investment
LM vertical mill integrates the advantages of grinding, conveying, Classifying and drying materials. Due to the multifunction of crushing, drying, grinding, classifying conveying in one, the LM Vertical Mill system is simpler with compacter layout, covers an area of about 50%-60% of the ball mill Line, and it can be arranged in the open air, so it can greatly reduce the overall investment cost.
2. Low operating cost
(1) High efficiency: the roller directly rolls and grinds the material on the grinding disc, which has low energy consumption and saves 30% ~ 40% energy consumption compared with the ball grinding system.
(2) Less wear: the roller is not in direct contact with the grinding disc, and the roller and the lining plate are made of good quality materials such as high chrome steel. So the service life is longer and the wear is less.
3. High drying efficiency. Hot air from the outside into the mill, in the mill directly, many times full contact with the powder material, drying ability is strong, can save a dryer for the mill system, energy saving, by adjusting the temperature of hot air, can meet the requirements of materials with different humidity.
4. Easy to operate and maintain
(1) Equipped with automatic control system, can realize remote control, easy operation.
(2) Equipped with a limit device to prevent direct contact between the roller sleeve and the grinding plate liner, to avoid destructive impact and violent vibration.
(3) By overhauling the cylinder, turning over the arm, replacing the roller sleeve and liner, it is convenient and fast to reduce the loss of shutdown.