Separation of Volatile Elements and Oxides: Thermochromatography and the Use of Chemical Filters

摘要

The possibilities of gas-chemical separation of elements of the periodic system by alternation of gas phase composition (hydrogen,oxygen), temperature (thermochromatography, a moving temperature gradient) and composition of stationary phase (quartz, stainless steel, gold, calcium oxide) are considered. Thermochromatographic separation of numerous elements in hydrogen or oxygen stream is performed in a carrier-free state and in the presence of a carrier up to milligram quantities. Adsorption heat on different surfaces is calculated. Absorption of volatile in oxygen stream elements by a CaO filter (1100 exp 0 C) is examined. Complete absorption of F, As, Sb, Bi, Te, Po, In, Mo, Tc, Ru; partial absorption of Re, Rh, Ir, Pt; practically no absorption of Br, I, At, Se, Pb, Tl, Zn, Cd, Hg, Os are observed. Complete separation of At and halogens by thermochromatography on CaO is achieved. The use of these methods in different fields of radiochemistry is discussed. The investigation has been performed at the Laboratory of Nuclear Reactions, JINR. (ERA citation 09:033810)