The finish cement grinding process is roughly divided into an open circuit grinding system and a closed circuit grinding system. The grinding mill used is a Raymond mill or ball mill. In the open circuit mill, the mill shell has a length of about 4 to 5 times of its diameter to obtain a prescribed fineness, and the shell outer wall is sprayed with water to prevent the temperature of the product in the mill from rising. It is also possible to spray water into the mill interior but the closest attention has to be paid so as not to deteriorate the product quality.
In the closed circuit mill, the mill has a length of 3 times or below of its diameter so as to accelerate the passage of the product. The separator works as a cooler for the product in addition to its function as classifier for the product.
As cement manufacturing is highly capital intensive, the lifetime of cement plants is usually 30 to 50 years. However, new equipment is not only found in places where capacities have been built up due to high market growth; typically the technical equipment of existing cement plants is modernized continuously, meaning that often after 20 or 30 years most of the original equipment has been replaced and is always adapted to modern technology. But a significant decrease in specific powder consumptions is only achieved through huge retrofits like chaging from cement grinding with ball mills to high efficient vertical roller mill or high pressure mill.
Grinding occurs at the beginning and the end of the cement making process. Approximately 1.5 tonnes of raw materials are required to produce 1 tonne of finished cement. We developed complete range of portable cement grinding unit for sale, such as ball mill, vertical roller mill, high pressure mill, ultrafine mill etc. It is covenient and mobile to move on the working site, greatly saving raw material tranport cost.