Liquid-phase formation

A similar scenario is not observed for the DTA peak at 816°C, which remains endothermic with about the same intensity for particle sizes 90-125 pm and smaller. This endotherm is a result of liquid phase formation amongst CaO, silica, and liquid phase. Hence, intimacy of particle contact is not so much an issue for this transformation. 

The first three of these are solely VLE-based approaches, involving a series of simple distillation column operations and recycles. The final approach relies on distillation (VLE), but also exploits another physical phenomenon, hquid-liquid phase formation (phase splitting), to assist in entrainer recovery. This approach is the most powerful and versatile. Examples of industrial uses of azeotropic distillation grouped by method are given in Table 13-20. 

Solid-acid catalysts can also be used to prepare a three-heteroatom five-membered ring system, but relatively mild reaction conditions are required. A recent example is the liquid-phase formation of 4-aminotriazole (29) by reaction of hydrazine and formic acid in the presence of a strong-acid resin [54]. 

The solids of interest in SCF processes usually have relatively low vapor pressures which results in an LCEP which is located close to the critical point of the SCF. The region between the critical point of the SCF and the UCEP generally defines the temperature range where unconstrained solid-vapor equilibria exist, i.e. liquid phase formation is absent. However, operating at temperatures below the UCEP does not always ensure unconstrained solid-SCF equilibria because the SLV line can exhibit a temperature minimum. At low pressures the SLV line begins with a negative slope, passes through a temperature minimum and then continues with a positive slope to the UCEP. Octa-cosane exhibits this type of behavior under the influence of CO2 [8]. 

The Si-B-C system was mainly investigated with view to the understanding of the sintering mechanisms of SiC with boron in combination with carbon and the sintering of boron carbide with silicon [4]. The silicon solubility of about 2.5 at.% in B4C at 2323 K and the comparatively low temperatures of liquid phase formation in the ternary system enhance the sintering of boron carbide. 

Fig. 2.29 Temperatures ranges of liquid phase formation in the system of sulphates sodium, potassium and calcium. (After [23])...

Figure 27. Isothermal section of the B o-Mo system at I000°C with indicated field of liquid phase formation [128].

Figure 7.2. Temperature regimes for liquid-phase formation in a severe reactor accident and possible consequences for reactor core damage...

Liquid phase formation, followed by reactions in two phases... 

The homogeneity on the atomic scale tremendously decreases the diffusion path compared to the oxides and carbonates mixture in the convenhonal ceramic synthesis. As a result, most of the mulhcomponent oxide materials form directly after the pyrolysis of the polymer or decomposihon of carbonates, which often occur significantly below liquid phase formation in the oxide system. In some cases the required metal stoichiometry can be achieved on the scale of few angstroms in the metal complexes bound to the polymer chain, and the decomposition of the metal complexes or an intermediate product becomes the only limiting step for the formation of required compounds. 

Mineralizat ion properties 0.201 Calcium ferrite generation The start generating temperature of liquid phase The complete generating temperature of liquid phase The flowing temperature of liquid phase The average velocity of liquid phase formation The volume of liquid phase 0.143 0.166 0.177 0.172 0.155 0.187... 

Alumina + Zircon + 8%Ce02 (AZC) 1500°C-4h Only mullite and zirconia Sintered well but had liquid phase formation... 

K Shinozaki, et al. Liquid phase formation and its migration in aluminum nilride ceramics. Ceramic... 

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