Search

This paper reviews systematic studies aimed at developing the physicochemical foundations of adsorption purification of volatile compounds of Group II–VI elements (halides, inorganic hydrides, metalorganic compounds, and process gases) attractive for electronic and optical applications. The efficiency of fine purification via adsorption is analyzed in comparison with distillation, extraction, and crystallization, and the role of the adsorption step in integrated processes for the preparation of high-purity substances is discussed. Future directions in developing adsorption techniques for fine purification of substances are outlined.

Data on the structure of molecules in the gas phase are among the basic molecular characteristics that are used in various fields of investigation. It is not difficult to visualize how important is the question of reliability of numerical data on molecular structure; we need only enumerate the basic areas of the national economy using these data (along with other molecular constants) in practical calculations

Experimental data on the adsorption of Ar, Kr, Xe, CH4, and CF3Cl on zeolite NaX and of CH4 on PAU-10 carbon demonstrate that the linear temperature range dependences of the equilibrium matched standard values of lnpi,st and ln\(\bar c_{i,st} \), which are used in the calculation of adsorption equilibria in a subcritical temperature range, remain unchanged up to temperaturesT*≅Tcr+(100÷150).

1. It is proposed to extend the method of constructing characteristic adsorption curves and of describing them using the TMVF equation to the region of supercritical temperatures for pure adsorbates. 2. In constructing characteristic curves it is necessary to use standard states of the components in the two phases that are in equilibrium with each other. Using the adsorption of Xe, Kr, and CF3Cl on NaX as examples, the methods of finding the corresponding standard states are considered.

It is shown that hydraulic characteristics in a fluidized bed oscillate in a spectrum that is discrete due to the reciprocal effect of the fluidization regime on gas-blower operation.

The mechanism of elastic pressure waves in concentrated dispersed systems is discussed. It is shown that the continuously relaxing medium model is valid for describing acoustic effects in a fluidized vibrating layer.

An expression for the Joule-Thompson coefficient of a polydisperse medium subject to throttling is derived in the relaxation approximation of thermodynamics of irreversible processes, with both temperature and velocity relaxation in the phases taken into account.

The porosity of a fixed and a fluidized bed near a wall are determined experimentally by means of x-radioscopy and the results are presented.

In this paper we examine the problem of extracting Mo99 from irradiated samples of U3O8 and UO2, fired in vacuum and in a stream of argon from 400 to 1200 °. The relation of the per cent of Mo99 extracted to temperature and time of firing was demonstrated.

An approximate formula is derived for the heating time of particles in a fluidized polydispersion bed.