| Particulate materials are routinely handled in large quantities by industries such as, agriculture, electronic, ceramic, chemical, cosmetic, fertilizer, food, nutraceutical, pharmaceutical, power, and powder metallurgy. These industries encounter segregation due to the difference in physical and mechanical properties of particulates. The general goal of this research was to study percolation segregation in multi-size and multi-component particulate mixtures, especially measurement, sampling, and modeling.;A second generation primary segregation shear cell (PSSC-II), an industrial vibrator, a true cubical triaxial tester, and two samplers (triers) were used as primary test apparatuses for quantifying segregation and flowability; furthermore, to understand and propose strategies to mitigate segregation in particulates. Toward this end, percolation segregation in binary, ternary, and quaternary size mixtures for two particulate types: urea (spherical) and potash (angular) were studied. Three coarse size ranges 3,350-4,000 mum (mean size = 3,675 mum), 2,800-3,350 mum (3,075 mum), and 2,360-2,800 mum (2,580 mum) and three fines size ranges 2,000-2,360 mum (2,180 mum), 1,700-2,000 mum (1,850 mum), and 1,400-1,700 mum (1,550 mum) for angular-shaped and spherical-shaped were selected for tests. Since the fines size 1,550 mum of urea was not available in sufficient quantity; therefore, it was not included in tests. Percolation segregation in fertilizer bags was tested also at two vibration frequencies of 5 Hz and 7Hz. The segregation and flowability of binary mixtures of urea under three equilibrium relative humidities (40%, 50%, and 60%) were also tested. Furthermore, solid fertilizer sampling was performed to compare samples obtained from triers of opening widths 12.7 mm and 19.1 mm and to determine size segregation in blend fertilizers.;Based on experimental results, the normalized segregation rate (NSR) of binary mixtures was dependent on size ratio, mixing ratio, material, strain rate, and strain. Segregated fines mass of potash and urea particles was significantly different for the same size ratio (p<0.05). The (NSR) and segregation rate of fines for binary mixtures were higher for larger size ratios, as expected (2.4:1.0>2.0:1.0>1.7:1.0). Segregation rate was the highest and lowest for mixing ratios 33:67 and 67:33, respectively, when coarse mean size was 3,675 mum. The NSR decreased when the strain rate was decreased from 1.0 Hz>0.5 Hz>0.25 Hz for the binary size ratios 1.7:1.0, 2.0:1.0, and 2.4:1.0 (p<0.05). The NSR was dependent on multi-size mixtures (binary>ternary>quaternary). At strain rate of 0.5 Hz for the size ratio 2.0:1.7:1.0 in ternary mixture, the NSR for potash (0.83 kg/kg-h) was higher than the NSR for urea (0.21 kg/kg-h) (p<0.05). The NSR increased with the increase in strain from 2% to 10%. At strain of 6% and strain rate of 0.5 Hz, for the size ratio 2.0:1.7:1.0 in ternary mixture, the NSR for potash (0.83 kg/kg-h) was higher than the NSR for urea (0.21 kg/kg-h) in ternary mixtures (p<0.05).;For size ratios 2.0:1.0 and 1.7:1.0, only 2.8% and 7.0% of decrease in NSRs were recorded for increase in relative humidity by 10 points (from 40% to 50%), respectively, whereas 36.0% and 45.0% decrease in NSRs were recorded for increase in relative humidity by 20 points (from 40% to 60%), respectively (p<0.5). Additionally, flowability was quantified using a Cubical Triaxial Tester (CTT) for size ratios 2.0:1.0 and 1.7:1.0, angle of internal friction increased from 31.3° to 35.9° to 39.0° and 27.4° to 32.0° to 36.0° when relative humidity increased from 40% to 50% to 60%, respectively (p<0.05), whereas cohesion remained close to zero (p>0.05).;An innovative time-sequence procedure for sampling of bags was devised and implemented. The size guide numbers (SGNs) of 10-10-10 blend samples using 19.1 mm width trier were larger than those obtained using the 12.7 mm width trier, there were no substantial differences between the SGNs and uniformity index (UIs) of the two different width triers, i.e., except for 10-10-10 (sample from second quarter) from blend plant 1, all SGNs and UIs were within 7 and 2, respectively. Eleven out of the twelve samples from bagged fertilizers using 12.7 mm vs. 19.1 mm had the same outcomes, i.e., only one sample from blend plant 3, of 10-10-10 (sample from third quarter) using 12.7 mm vs. 19.1 mm had a conflicting outcome---the sample obtained using 19.1 mm width trier (SGN=259, UI=47) passed, whereas, the sample with 12.7 mm trier (SGN=256, UI=47) failed the AOAC chemical analysis test. (Abstract shortened by UMI.)... |
