Particle Size Distribution of Quartz and Other Respirable Dust Particles Collected at Metal Mines, Nonmetal Mines, and Processing Plants

摘要

The primary objective of the Bureau of Mines research was to measure the size distribution of respirable quartz collected at metal mines, nonmetal mines, and processing plants to select the best reference standard for use in quantifying quartz in mine and plant dust samples. The secondary objective was to size all the nonquartz particles collected at the same sites. Particle size measurements were made on 29 samples using a scanning electron microscope in the backscatter mode of operation, interfaced with an image analysis system. The accumulated particle size measurements indicate that NBS 1878, minus 5-micrometers Min-U-Sil, and minus 5 micrometers Supersil would be preferred over Silver Bond B as reference standards for most quantitative determinations by X-ray diffraction and infrared spectrometry. The respirable dust samples collected at sand plants, however, would be better served by a new reference standard having a quartz particle size distribution of approximately 2.2 micrometers, as none of the four existing reference standards matched closely with them.