Comparison of ASTM round-robin data on particle size using three different methods

Abstract

crease the reaction rate and also increase the possibility of further hydrogenation of the hydroxylamine.

Comparison of particle size of cracking catalyst determined by laser light scattering and dry sieve methods

“…As mentioned earlier, the Microtrac Model 7795-11 was unable to measure particles greater than 176 /*m. The nonsphericity of the large particles was a major factor in the variation in particle size measured by these methods. These results were consistent with a published ASTM study (Flank, 1987).…”

“…Today most laboratories have abandoned dry sieving in favor of faster and less labor intensive techniques such as laser light scattering. This study, in agreement with other researchers (Flank, 1987;Frock et al, 1984; Novak and Thompson, 1986), has shown that the particle size determined by laser light scattering is greater than sieve values for cracking catalysts. Therefore, although refiners Figure 9.…”

Rapid particle sizing by photosedimentometry

“…The HIAC Model PC-320 instrument is a single particle counter using the principle of light blockage (Allen 1981 p 585). Work done by the Particle Size Task Group of the ASTM Committee D-32 (Flank 1987) indicates the level of agreement that can be expected when comparing PSDS determined using different sizing methods. For example, it was reported that an electroconductive sensing method gave a volume median diameter (d5O) of 55.5 pm for a sample of a silica cracking catalyst for which the d50 results using laser.light diffraction and dry sieving were 65.7 pm and 66.3 pm respectively.…”