Rating of vertical roller mills on the basis of grindability tests

The performance data of vertical roller mills are governed not only by the individual material properties but also by the degree of command of the scale-up method. The material properties described as grindability and abrasivity create the basis for the rating of industrial grinding plants. Reliable determination of these properties is therefore of major importance. Extensive experience has proved that these material properties can be determined most effectively with the help of a semi-industrial grinding plant in which the conditions of the future industrial plant can be simulated as precisely as possible. The good correlation of operating and test results confirmed the reliability of this test method. The laws governing a safe scale-up are theoretical, a whole range of operating results confirms them in practice. With a consistent application of the described experience and findings, vertical roller mills can be safely rated and operated also for high drive powers (> 6000 kW) and high throughput rates (> 600 t/h).