Particulate Analysis Instrumentation for the Cement Industry

At present, even though most cement plants are computer controlled, they depend on manual particle analysis and feed settings. Automatic process control through the use of continuous particle size analysis can provide the maximum obtainable throughput at optimum particle size. A new particle size measurement technology using a helium-neon laser and a unique optical filtering system has been reported previously. Fourier diffraction patterns of particles in the 2176 micron range are utilized to produce a 13 channel histogram of the complete particle size distribution. The histogram data are used to compute many parameters of the size distribution, such as, equivalent surface area, median, mean, and percent passing a number of micron sizes. A family of particle size instrumentation has been developed using this technology for both off-line quality control and on-line process control. The design of this equipment and its operation is described. In addition, experimental data are presented comparing the fineness measurements of Portland cement obtained by air permeability apparatus and those of the MICROTRACTM equipment.