Abstract：This paper discusses the effect of small grain agglomeration on the particle size distribution (PSD) of 5A submicron zeolite and the appropriate measuring methods. Water and sodium hexametaphosphate were chosen as a disperse medium and a dispersant, respectively. The influences of zeolite concentration, dispersant dosage and time of ultrasonic treatment on the dispersion state were studied by a potential/particle size analyzer with ultrasonic treatment. Results show that when zeolite concentration is more than 5 g/L, the PSD appears to be a unimodal distribution (false appearance), leading to a large measured size due to severe agglomeration. A small amount of sodium hexametaphosphate (0.005-0.195 g/L) additive can alleviate the agglomeration by dispersing most large agglomerated particles (more than 2.8 μm) into relatively small agglomerates (about 1.3 μm) and some agglomerates into single crystals so that the small particles can be measured. Ultrasonic treatment reduces the PSD intensity of large agglomerates (0.85-2.80 μm) and increase the PSD intensity of small agglomerates (0.30-0.85 μm). However the time of ultrasonic treatment should not be too long, otherwise the agglomeration becomes severe. When the sample content is 5g/L and dispersant concentration is 0.195 g/L, after 4 min ultrasonic treatment, the PSD is determined to be 0.25-0.80 μm, of which the peak value is 0.473 μm and the median diameter d50 is 0.784 μm, that is consistent with SEM results.
Shi Lu,Cui Qun,Wang Haiyan. Effect of Agglomeration on the Analysis of Particle Size Distribution of 5A Submicron Zeolite[J]. 化学反应工程与工艺, 2013, 29(1): 59-64.
