Magnesia value

Let us consider the calculation of sensitivity threshold in the case when the cracks are revealing by PT method. Constant distance H between crack s walls along the whole defect s depth is assumed for the simplicity. The calculation procedure depends on the dispersity of dry developer s powder [1]. Simple formula has to be used in the case when developer s effective radius of pores IC, which depends mainly on average particle s size, is smaller than crack s width H. One can use formula (1) when Re is small enough being less than the value corresponding maximum sensitivity (0,25 - 1 pm). For example. Re = 0,25 pm in the case when fine-dispersed magnesia oxide powder is used as the developer. In this case minimum crack s width H that can be detected at prescribed depth lo is calculated as... 

Snyder [28] has shown that there is a correlation between the e° values for a certain polar adsorbent (silica gel, florisil, and magnesia) and alumina. For example. 

The value of 3.5 x 10 / for the solubility product of CaS0o l/2 H20(s) was derived from 1imestone/magnesia scrubber inlet liquor analyses obtained at the Environmental Protection Agency (EPA) Shawnee test facility (9), and may include kinetic, as well as thermodynamic, interaction between slurry solids and liquor. 

In magnesia-stabilised / "-alumina, the formula is Na, (Mg2 Al5 (08 and X is essentially fixed at 0.175. An alternative way of representing it is in terms of a derivation from the stoichiometry NaAlnOi, with the formula Nai+2Mg2Aln jOi7. Various values of 2 are quoted in the literature, between 0.5 and 0.8. The value 0.747 which is in this range coincides with that obtained using the alternative, spinel-like formula given above, with x = 0.175. 

The Active Magnesia Process (24) can be viewed as the gas phase equivalent of the Wellman-Lord (to be discussed below) in that it serves primarily to concentrate the SO2 values in the combustion effluent to a suitable concentration for feed to an oxidative process yielding sulphuric acid. The absorption temperature, however, is quite low compared with typical combustion effluent temperatures. 

The thermodynamic data shown in Figure 21 indicate, post factum, how magnesia and alumina fit the requirements for the UltraCat process. The figure shows values for standard AG for reduction of the sulfate with hydrogen at 980°F to make SO2 for... 

In contrast with the dipersion results, the low values obtained for the ammoniacal preparations show an important precursor effect and a small one on the nature of the support. However, the selectivity values for the formation of the three hydrogenated products reported in Table 2, demonstrate that selectivity depends on the nature of the support. Magnesia support presents the highest selectivity (90 /0 to the carvotanacetone formation. Particle size effects in selectivity were not detected, since, the small changes observed... 

An example of dispersion of sound in an air-magnesia mixture with solid-to-air mass ratio, mp, of 0.3 for pp/p (=f) of 100 and 1,000 is illustrated in Fig. 6.10 [Soo, I960]. The figure gives the dispersion of sound for various values of N when the heat transfer is neglected. Under the same experimental condition, the relationship between pag/co and Na, is shown in Fig. 6.11 [Soo, I960]. It is noted that the preceding model is valid only... 

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