Operational results of a vertical roller mill modified with a high efficiency classifier

Major modifications have been made to a roller mill in British Columbia. It is possible to identify their effect on the mill system. A good production increase was attained. While this increase was at a coarser raw meal fineness, there was no adverse affect noted on the clinker quality or on the pyro system operation. The particle size distributions of the raw meal before and after the static classifier was replaced show a definite improvement in eliminating the coarse fraction in the raw meal. The data confirm that in addition to rotor speed control, common to all dynamic classifiers, the high efficiency classifier will also allow the slope of the particle size distribution to be varied. This is achieved by adjusting the guide vane settings. Particle size analyses confirm that a more uniform raw meal is being made