Abstracts Experimental geoecology Galstyan A.V., Gevorkyan R.G., Sarkisyan S.E. formed by the junction of a common vertices of SiO4 and Sulfuric gases neutralization of non-ferrous AlO4 tetrahedra, where are interconnected cavities metallurgy by natural zeolites of Armenia occupied by large ions and water molecules. The term “molecular sieve” is applied, as dehydrated zeolite Yerevan State University (YSU), Armenia crystals, due to the system of channels and cavities Abstract. Neutralization of sulfuric gases of non-ferrous penetrating crystals, have well developed internal surface, metallurgy is a difficult task due to the large volume, high accessible to the adsorbed molecules [Alietti A., 1972]. temperature, low concentration of sulfur dioxide in the flue gas In Armenia there are known major deposits of zeolite emissions into the atmosphere. The utilization of sulfur dioxide rocks: Noyemberian, Alaverdi, Shirak, Ijevan, Tavush should be organized with the use of solid adsorbents, one of which region, Vayk, Kapan. Of these, the most studied is is a natural zeolite. According to its adsorption properties Armenian zeolites are an indispensable raw material for extraction Noyemberyan’s, containing its composition 65–80% of of flue gas desulfurization in non-ferrous metallurgy. clinoptilolite. Key words: zeolite, adsorbent, metallurgy, sulfuric gases, The adsorption properties of natural zeolites by SO2 temperature, utilization. are caused by: clinoptilolite content in the rock, the silicium oxide, the temperature of adsorption and the type Citation: Galstyan A.V., R.G. Gevorkyan, S.E. Sarkisyan (2013) of zeolite modification. At the same time the adsorption Sulfuric gases neutralization of non-ferrous metallurgy by natural capacity for SO2 is directly dependent on the clinoptilolite zeolites of Armenia. Vestnik content in the breed [Tsitsishvili G.V., Andronikashvili In Armenia, non-ferrous metals occupy an important T.G., KirovG.N., Filizova L.D., 1985] place in the industrial production and have a huge tendency of growth (compared to 1990 increased from 8 to Table 1. Adsorption capacity for SO2 due to the 31% [2nd National Messages, 2010]). At the same time, clinoptilolite content this industry is one of the major pollutants of air basin by sulfur dioxide. The neutralization of sulfur dioxide in non- ferrous metallurgy is a difficult task, due to the large volume, high temperature and low concentration of sulfur 75 6,3 dioxide in the flue gas emissions into the atmosphere. The 65 4.1 utilization of sulphurous anhydride in the latest would 50 2.6 solve several problems at once: to protect the environment 75 6.2 and help to avoid irretrievable loss of valuable raw 80 6.0 materials, that can be used in the future for the production 40 2.4 of sulfuric acid and other useful sulfur compounds. Currently, there are two directions in the utilization of The very important factor to arrange SO2 recovery is sulfur dioxide: wet process related to SO2 absorption by various solutions and processes of dry or adsorption in the formation of kremen content as lawflint zeolites are purification, based on availability of cheap sorbents that characterized by a high adsorption capacity and low acid resistance, while the High-silicons – have a low have significant SO2 [Anurov S.A., Torocheshnikov N.S., Smola V.I., 1999] activity. adsorbability to SO2 and high acid resistance. The utilization of sulphurous anhydride should be Thus lawflint zeolits can be used for the extraction of organized with the use of natural sorbents, one of which the SO2 from pre-dehydrated systems, high-silikons – for are zeolites. At present there are more than 40 types of catching SO2 from wet environments, since the action to zeolite minerals, of which only six are of industrial them of acids even slightly improves their absorption importance (clinoptilolite, mordenite, erionite, chabazite, capacity [Tamboli J.K., Sand L.B., 1970]. Acid stability is ferberit, philipsite), and among these, the most significant a very important factor in the organization of SO2 role is of clinoptilolite [Chelishchev N.F., Berenshtejn recycling, as in the regeneration process, due to high B.G., Volodin V.F., 1987]. Zeolites are water acidity the SO2 zeolitic structures collapse and, therefore, aluminosilicates, with infinite openwork frame structure, can not be used for multicycle processes. Table 2. Comparative chemical composition of major oxides (SiO2, Al2O3) containing clinoptilolite tuff from various fields in the world SiO2 68.87 68.75 68.23 69.31 66.80 66.82 65.27 61.30 65.90 Аl2О3 12.20 11.92 12.48 12.09 10.58 12.24 14.84 13.00 12.90 SiO2 /Al2O3 9.6 9.8 9.3 9.8 10.7 9.3 7.5 8.0 8.7 112 Institute of Experimental Mineralogy Experimental geoecology … Table 2 shows the content of the basic oxides (SiO2, - high content of silicium oxide in the mineral, on Al2O3) in klinoptilolic tuffs of different regions, from which the use of zeolite multicycle is directly dependent which it follows that the Armenian zeolites are the richest on; with silicon and this is why they are high resistance of - zeolite rocks of Noemberian deposits of Armenia is acids. readily available in the extraction since come to the The sorption of SO2 on clinoptilolite at low SO2 surface, and the prospective reserves are of 400–500 concentrations and with temperature up to 2000C remains million tons. high. This allows you to recommend the clinoptilolite as Therefore, the Armenian zeolites are an indispensable an efficient absorber of SO2 at low concentrations of SO2 raw material for the organization of recycling waste and of high temperatures, which is important for the sulfuric gases of ferrous metallurgy. production [Liang P.M., 1989]. The adsorption capacity References: for SO2 largely depends on the ion exchange shape of the modified zeolite, thus the exchange of Na+ to Ca2+ and Mg2+ ions in the zeolite structure significantly increases 1. Alietti A. (1972). Polymorphism and crystal-chemistry the adsorption capacity. Obviously in exchange of ions of heulandites and clinoptilolites. American two sodium cations are replaced by a cation of calcium, Mineralogist, v.57, pp.1448-1462. and the input window expands, and this facilitates the 2. Anurov S.A., N.S. Torocheshnikov, V.I. Smola (1999). The purification of non-ferrous metals from SO2 by penetration of SO2 molecules in the cavity of the zeolite structure [Barrer R.M., 1956] clinoptilolite. Moscow Chemical Engineering Institute Widespread use of zeolites in the industrial scale is by Mendeleev D. I., pp.184-187. 3. Barrer R.M. (1956). J. Chem. soc., pp.2892-2903. due to the possibility of complete and SO2 desorption at 0 4. Chelishchev N.F., B.G. Berenshtejn, V.F. Volodin 350–400 C. Desorption of SO2 and appropriate regeneration of the “spent” zeolite is one of the important (1987). Zeolites a new type of mineral raw materials. steps that basically defined the technical and economic M.: Science, 176 p. value of the adsorption process. 5. Liang P.M. (1989). Environmental protection, waste In order to obtain by desorption concentrated gas management, waste water treatment and emissions, various variants of zeolites' regeneration were industrial sanitation and hygiene in the medical and microbiological industry, M. 26 p. investigated: nd 1) the use of hot air as heat carrier and stripping gas 6. Tamboli J.K., L.B. Sand (1970). Proc. of the 2 Int. leads to the dilution of desorbed gas; Clean Air Congress, pp.861-865. 2) uniformly intense heating of the sorbent layer (5, 7. The collection of works of the Second National Messages on Climate Change (2010), Yerevan, p.26. 10, 20 deg/min) with simultaneous stripping, SO2 evolvment forms gas with a maximum concentration of (in Armenian). about 24%; 8. Tsitsishvili G.V., T.G. Andronikashvili, G.N. Kirov, 3) the desorption by gas, circulating in a special closed L.D. Filizova (1985). Natural Zeolites. M.: Science 0 141 p. circuit with 300–35 C allowes to extract SO2 with the concentration of about 30%; 4) purging of the spent layer by the superheated steam 0 Gevorkyan R.G., Harutyunyan R.S., Sarg- (220–260 C) the SO2 may be allocated in a concentrated form after the condensation: syan H.O., Sargsyan O.H., Badalyan G.G., Three last ways of the regeneration of natural zeolites Gevorkyan M.R. Extraction of radionuclides can allow to utililize SO2 by next using it in the sulfuric and heavy metals from industrial water using acid production, or in the production of liquid sulfur natural and modified zeolites of Armenia dioxide [Tsitsishvili G.V., Andronikashvili T.G., Kirov G.N., Filizova L.D., 1985]. Yerevan State University (YSU), Armenia When using zeolites in many cycles its activity Abstract. In Armenia are known many wide-spread deposits of decreases only for the first 5–10 cycles and only for 10– zeolite type rocks of volcanoes-sedimentary origin. The main 12%, but in subsequent cycles this capability remains zeolitomaker and bentonitomaker minerals are clinoptilolite unchanged. The main conditions for the use of zeolites for (heulandite), mordenite, stilbite, phillipsite, chabazite and bentonite-montmorrilonite. Adsorption properties of zeolites are the neutralization of non-ferrous metallurgy's waste gases studied but the highest selectivity for the radionuclides and heavy are: metals showed the clinoptilolite. - the ability to light thermo-chemical modification of Key words: zeolite, radionuclide, metals, clinoptilolite, sorbent. the zeolite, which is very important for the selective adsorption; Citation: Gevorkyan R.G., R.S. Harutyunyan, H.O. Sargsyan, O.H. - the adsorptive properties of zeolites depend little on Sargsyan, G.G. Badalyan, M.R. Gevorkyan (2013), Extraction of up to 2000C flue gas temperature and therefore a wide radionuclides and heavy metals from industrial water using natural temperature range without changing the adsorption and modified zeolites of Armenia.