News Date:2015-12-14 10:57:17
Traditionally, ball mill is used in cement industry for raw material, fuel and product grinding. Ball mill use an established technology and offer certain advantages. However, they have higher energy requirements. By using an appropriate kind of the more efficient vertical roller mills technologies – either as a replacement or in combination with ball mill – considerable energy savings can be achieved without compromising product quality. The following roller mill concepts are applicable to cement manufacturing:
Vertical roller mill: In these mills materials are crushed between a rotating grinding table and 2 to 6 grinding rollers positioned slightly less than 90 degrees from the table surface and pressed hydraulically against it. Main advantages of vertical roller mills are including:
1. Relatively low power consumption (less than 10 kWh/t – for medium raw material hardness and medium fineness);
2. Ability to combine grinding, drying (using waste heat from kiln system) and separation;
3. Ability to manage larger variations in mass flow rate (30 to 100% of mill capacity).
In China, market penetration of vertical roller mills within the building materials sector was expected to reach 50% during the eleventh five year development period, demanding an investment of around 1.08 billion RMB, and holding a potential to reduce energy consumption by 500 GWh.
Vertical roller mills are installed in new cement plant with dry systems, and also often replace ball mill during plant modernization, the raw material moisture content is less than 25%. As of 2010, vertical roller mills for raw material preparation had a penetration rate of 45% in Chinese market. During the twelfth five year period, the market penetration of the technology is expected to reach 80%.
