difference between the vertical mill and the ball mill
Date：2019-07-03 17:47 Source：未知Views:
As an energy-efficient grinding equipment, vertical mill is gradually applied to slag grinding, cement clinker grinding, power plant desulfurization, phosphate rock grinding, manganese ore grinding and many other industries due to its excellent performance. The preferred milling equipment for environmental protection. Today, as environmental protection requirements become more stringent, vertical mill has become the first choice for international raw material grinding and pulverized coal grinding.
1, structure and installation aspects
The vertical grinding structure is simple, vertical vertical installation, small footprint, simple construction, convenient installation and short time-consuming; the ball mill structure is more complicated, horizontal horizontal installation, difficult installation technology, high ground requirement, long cycle, The area is large. Both can be arranged in the open air, but in general, the vertical grinding building area is 70% of the ball mill, the building space is 50%-60% of the ball mill, and the investment cost is low.
2, the way of crushing
The vertical grinding mainly adopts the grinding and crushing method, and the impact force is second, which is suitable for fine grinding and ultra-fine grinding, the grinding medium consumption is small, and the inner life of the inner lining is long. The ball mill mainly adopts the impact crushing method, followed by the grinding, which is suitable for rough grinding and fine grinding, the wear and tear consumption is large, and the inner life of the inner liner is short.
3, process aspects
The vertical mill integrates crushing, drying, grinding and grading and conveying. Compared with the ball mill, the vertical grinding process is simple, and the capital investment is small, which can save one dryer for the mill system. Another vertical mill has a separator, which uses hot flue gas to transport materials. It does not need a powder separator and a hoist. The dust-containing gas is directly collected into the powder collector. Therefore, the vertical mill system has simple process, low failure rate and high operation rate. The layout is compact. In general, the finished product of the same fineness adopts the vertical grinding process. After two stages of grinding, the fineness of the product can meet the requirements. The traditional ball mill process requires three stages of grinding.
4, energy consumption
The vertical grinding has fewer moving parts, is low-energy type, and has low vibration; all the components of the ball mill are basically in motion, which is high-energy type and has large vibration. In addition, the vertical mill uses a grinding roller to directly crush the ground material on the grinding disc, and saves energy by 30% to 40% compared with the ball mill system. In general, the power consumption of the vertical mill can be reduced by 30% to 50% compared to the energy consumption of the ball mill in the case of the same material grinding property and the same product particle size.
5, drying ability
The vertical mill combines grinding, grading and drying (when the material moisture is large), and collects it in one body. It uses hot air to transport materials, and when grinding materials with relatively large moisture (such as coal, slag, etc.) Control the inlet air temperature to make the product reach the final moisture. The vertical mill can dry the material with 12%-15% moisture, and the drying ability is strong. Even if the ball mill is dried, only the material with moisture content of 3%-4% can be dried. . Therefore, vertical mills are used for the production of materials with large moisture content, which not only saves economic costs, but also saves time costs.
6, the way of discharging
The vertical mill discharge material is forced to avoid over-grinding. After the material is crushed by the grinding roller on the grinding disc, it is taken away by the high-speed airflow of the wind ring at the edge of the grinding disc, and the qualified fine powder is collected by the dust collecting device together with the air flow through the powder selecting machine. The ball mill discharge material is self-discharge type, which is prone to over-grinding, especially the overflow ball mill. Its material is automatically overflowed. When the material level is higher than the discharge port, it automatically discharges, consumes energy and is easy to over-grind.
7, product quality
1) Compared with the ball mill, the vertical mill has a high degree of homogenization and a higher purity. This is because the time taken for the finished powder to be classified during the vertical grinding is short, and the over-grinding is avoided.
2) Due to the unique working principle, during the operation of the vertical mill, no metal is in direct contact with each other, the metal wear is small, and the pollution of the finished material is small.
3) Vertical mill grinding adjusts the speed, wind speed and roller pressure of the separator. It is convenient to adjust the fineness of the product. The self-contained powder sorting device can remove the fine powder in time, reduce the phenomenon of over-grinding, and the product particle composition is stable. . The ball mill is easy to over-grind, the limestone unit wear is generally 4-6 g/ton, and the ball mill is up to 500 g/ton.
4) When grinding white minerals by vertical grinding, the effect on whiteness is much smaller than that of ball mills.
8, environmental impact
1) Vertical grinding is at work, the sound is soft, generally around 80 decibels. The grinding roller is not in direct contact with the grinding disc (installed with a device to prevent direct contact, avoiding damaging shocks and severe vibrations), and the noise is about 20-25 decibels lower than that of the ball mill.
2) The vertical mill adopts integral sealing, the system operates under negative pressure, the dust is less, the environment is clean, the ball mill is open, and there is dust problem.
9, development and application aspects
The vertical grinding process manufacturing technology started late, and the industrial production application was in the promotion stage; the ball mill's process manufacturing technology is relatively mature, and industrial production has been widely used. But in the future, with the more mature vertical mill technology, efficient and environmentally friendly equipment, its application range will be more extensive.
10, price and capacity aspects
The popularity of ball mills is not without reason. In large-scale grinding production equipment, ball mills are relatively inexpensive, with a small one-time investment, high productivity, wide application range and simple operation. Vertical mill does not have an advantage in terms of price, but its hydraulic system is designed to be convenient and quick to operate.