The distribution of particle sizes smaller than 75um is determined by which process?

The correct process for determining the distribution of particle sizes smaller than 75 micrometers (μm) is sedimentation. This technique involves allowing the particles to settle in a liquid, where the rate at which they settle can be influenced by their size, shape, and density. According to Stokes’ law, smaller particles will settle more slowly compared to larger ones. By measuring the time it takes for particles to settle, one can ascertain their size distribution, particularly for those fine particles that are under 75 μm.

Sedimentation is particularly suitable for analyzing fine aggregates because it effectively separates particles based on size in a controlled environment, allowing for a more accurate assessment of the distribution of very small particles. While sieving is effective for larger particle sizes, its capability diminishes as particle size decreases below about 75 μm, making it unsuitable for this specific purpose. Compaction and floating are principles that relate to physical properties of materials but do not serve to analyze particle size distribution in the same way that sedimentation does.