The results of an investigation of the physicochemical and sorption properties of pelleted lithium fluoride based sorbent obtained using ammonium carbonate as the porophore are presented. It is shown that the properties of granular lithium fluoride using ammonium carbonate are similar to those of a sorbent obtained on the basis of lithium fluoride and ammonium fluoride. The results of sorption separation of the mixture WF 6 -HF on granular sorbents are presented. The sorbent possesses selectivity to hydrogen fluoride and makes it possible to remove efficiently the volatile fluorides of refractory metals while strictly maintaining the quality of the sorbent and the conditions under which sorption and desorption are performed.Selective catching of hydrogen fluoride on lithium fluoride has been well studied and has found application for obtaining and purifying uranium hexafluoride. At the first step in the development of the technology, powdered lithium fluoride with an extended surface, which together with high sorption activity had drawbacks also, was used. For example, hydrogen fluoride extraction on LiF powder requires a horizontal apparatus as adsorbents, which makes it impossible to attain the required contact time between the adsorbate and the sorbent, so that the production capacity is limited. Vertical adsorbents filled with powdered materials are impossible to use because of the high gas-dynamic resistance of the layer. To improve the efficiency of sorption extraction of hydrogen fluoride, a technology was developed for making pelleted lithium fluoride based sorbents. It incorporates charge formation, granulation, and heat-treatment of the sorbents and uses ammonium fluoride as a porophore agent [1].Ammonium fluoride is a corrosive substance. Corrosion activity, accompanied by the formation of hydrogen fluoride and ammonia gases, is highest in the presence of decomposition during drying and calcination. At temperatures above 140°C, ammonium fluoride decomposes via the reaction NH 4 F ↔ NH 3 ↑ + HF↑. This reaction is reversible: on cooling recombination occurs with ammonium fluoride being formed. On an industrial scale, when outgoing gases containing NH 3 and HF come into contact with the cold walls of ventilation pipes and pipelines they recombine forming ammonium fluoride in the form of solid corrosive deposits. As the sorbents undergo calcination, the action of hydrogen fluoride vapors on the process equipment results in strong corrosion of the metal surfaces of the furnace chambers, drawing boats, and baking pans while the products of corrosion, in turn, contaminate the sorbent. The contaminated sorbent cannot be used to purify volatile fluorides, since the products of corrosion form chemical compounds with the latter.Thus, ammonium fluoride is best used as a porophore only on laboratory and research scales. A porophore that does not have these drawbacks must be used for prototype and commercial production.This article presents the results of investigations of the physico-mechanical and sorption propert...

Methods of obtaining granular sorbents for catching and purifying volatile inorganic fluorides are examined. The results of optimizing the technology of granular lithium fluoride and approaches to obtaining pelleted barium and calcium fluorides are presented. The granules obtained gave capacity to 0.6 g HF/g sorbent while maintaining the initial structure. The initial destruction was negligible, the number of destroyed granules was the same after three sorption-desorption cycles.Absorption processes are finding wide applications for obtaining and purifying volatile inorganic fluorides in the technologies of the nuclear-fuel cycle [1]. The best known sorbent is one that is based on powdered or granular sodium fluoride -a universal absorber of many volatile inorganic fluorides. Thus, positive experience has been gained in using powered and granular lithium fluoride for deep removal of hydrogen fluoride from uranium hexafluoride. Calcium, strontium, and barium fluoride possess high selectivity to technetium and boron fluorides. Barium fluoride has a substantial (to 5 molecules) theoretical capacity for hydrogen fluoride [2]. The main physicochemical and sorption properties of these fluorides have been well studied but the absence of technologies for obtaining in a granular form and regenerating after use is impeding their industrial applications. In this connection, the search for new methods of obtaining sorbents based on fluorides of alkali and alkali-earth methods, meeting modern technological and economic production requirements, is a pressing problem.This article presents the results of production of pelleted sorbents based on lithium, calcium, and barium fluorides and their compositions, suitable for sorbtion removal of hydrogen fluoride from volatile uranium fluorides and refractory metals [3,4].The production of pelleted sorbents is based on the formation of moistened powders with the formation of a "brittle gel," formed during the hydration of NaHF 2 or NH 4 F type salts. Correspondingly, the method of obtaining sorbents includes the following operations: preparation of a mix using ammonium fluoride as the binder and pore-generator, formation on a granulator, drying of sorbent pellets in a hot air stream at 100°C, development at 150-200°C and fixing of a porous structure (sintering) at 350-400°C.The drawbacks of using ammonium fluoride as the pore-generator were revealed in the course of practical tests. Thus, the decomposition of ammonium fluoride gives rise to intense corrosion of the construction materials used for the pro-

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