Ball-mill particle size distribution from

When a raw coal is wet ball-milled for a sufficient time to produce a slurry with a particle diameter mode in the range of 4 pm there results two forms of mineral matter That fractured away from the coal and that which is still enveloped in the coal particles. Figure 3 illustrates a typical particle size distribution for the separated product coal as compared to the separated free mineral matter (90 weight percent ash) from one milling test. The separated mineral matter is clearly smaller in diameter than the coal which is probably due to its more brittle properties. Note that in Figures 3 and 4 an integration of the curves will yield 100% of the mineral matter (or ash) under consideration rather than the ash content of the coal as was the case in Figures 1 and 2. 

FIGURE 1.91 Effective diameter and polydispersity (PD) as a function of the concentration of A-300 in the aqueous suspension ball-milled for 5 h. (Adapted from Adv. Colloid Interface Sci., 91, Gun ko, V.M., Zarko, V.I., Leboda, R., and Chibowski, E., Aqueous suspensions of fumed oxides particle size distribution and zeta potential, 1-112, 2001e. Copyright 2001, with permission from Elsevier.)... 

Spray pyrolysis is a method that can be used to obtain a powder with particle size distribution that is narrow and controllable from micrometer to sub-micrometer order [62]. The size of the particles is reduced to 300 nm by a combinatimi of spray pyrolysis with dry ball milling [63]. To decrease the size of the particles down to 150 nm on average, a wet milling is needed, and performed owing to 45 ml zirconia vial, ethanol being used as a medium [64]. 

Figure 2.50 shows the microstructure of the powder after milling for 15 min with the addition of 5 wt.% Inco m-Ni and n-Ni. The distribution of m-Ni is not quite uniform (Fig. 2.50a) in contrast to that of n-Ni which shows a very uniform distribution of Ni particulate (bright specks) in the entire mass of the powder (Fig. 2.50b). The average ECD particle size of the powder milled with the m-Ni additive is slightly larger than that of the one milled with n-Ni, although both are below the 1 pm mark. The XRD pattern in Fig. 2.51a shows that the microstructure of both powders consists of hydride phases 3- and y-MgH2, Ni, and a small amount of retained Mg and MgO that is formed during XRD test from the retained Mg. Table 2.19 shows grain size of the phases in the ABCR MgH2 ball-milled with Inco m-...

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