Crystal size weight average

The indirect method described here returns the weight-average crystal size [121], irrespective of the model shape chosen. On the other hand, the direct Fourier inversion according to Warren-Averbach returns the number average of the crystal size distribution. 

The first three columns of Table 10.5 show sieve data for a 100-cc slurry sample containing 21.0 g of solids taken from a 20,000-gal (75-m3) mixed suspension-mixed product removal crystallizer (MSMPR) producing cubic ammonium sulfate crystals. Solids density is 1.77 g/cm3, and the density of the clear liquor leaving the crystallizer is 1.18 g/cm3. The hot feed flows to the crystallizer at 374,000 lb/h (47 kg/s). Calculate the residence time r, the crystal size distribution function n, the growth rate G, the nucleation density n°, the nucleation birth rate B°, and the area-weighted average crystal size L3 2 for the product crystals. 

Calculate the crystal size distribution function n. The crystal size distribution for the ith sieve tray is n, = 1012M3AVTj/(L3ALj), where AIT, is the weight fraction retained on the ith screen, /., is the average screen size of material retained on the ith screen (see Example 10.7, step 2), and A/., is the difference in particle sizes on the ith screen (see Example 10.7, step 3). For instance, for the Tyler mesh 100 screen, nio = 1012(0.119)(0.040)/(1613 x 28) = 40.7 crystals per cubic centimeter per micron. Table 10.5 shows the results for each sieve screen. 

Effective crystal radius, cm Number average particle size, cm Weight average particle size, cm Intracrystalline diffusivity, cm /sec... 

These relationships are illustrated in Fig. 6 in which the variation of coating weight, crystal size, the relative surface coverage, and the rate of substrate dissolution were measured as a function of time for the phosphatation of steel in a laboratory trication phosphatation bath. The partial free metal surface ( -9) decreases as the average crystal size (di) and coating mass increase. The dissolution rate of the metal rjiss (here defined as a negative value) drops toward zero at the end of the reaction. 

The weight-average crystallite size D, and the maximum distortion parameter g are obtained by line broadening analysis. The results are summarized in Table 4.2. In PTeOX obtained at 105 °C, g decreases by annealing at 170 °C for 2 hours. In PTOX no special change is observed excq>t when annealed at 180 °C for 30 min. In this case, the folded chain crystal is formed inbetween the extended chain crystals, or main crystals, to give larger g values. 

Fractionation of the cellulose from the alga Valonia afforded a component of weight-average DP 4.4 x 10 , which is thought to determine the size of the template required for the synthesis of the polysaccharide. The synthesis of cellulose II growing at right-angles to the axis of the microfibril. An alkali-resistant chain structure. Cellulose I crystallizes after it is detached from the site of synthesis. 

Calculate the average crystal sk.e. The number-weighted average crystal size Lj o = M IMq. 

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