APPLICATIONS OF THE HELLENIC NATURAL ZEOLITE (HENAZE) AND SPECIFICATIONS OF ZEOLITIC TUFFS

The Hellenic Natural Zeolite (HENAZE) is free of fibres and contains 89 wt% clinoptilolite, 3 wt% mica + clay minerals, 3 wt% quartz, 2 wt% cristobalie ± tridymite and 3 wt% feldspars. HENAZE do not meet the requirements of the EU Regulation No 651/2013, and thus cannot be used as feed additive for all animal species and consequently as nutrition supplement, since it contains 3 wt% quartz. HENAZE is suitable for use as soil conditioner, since the concentration of trace elements are lower than the maximum allowable concentrations in agricultural soils (EU Directive 278/1986). HENAZE as soil conditioner: a) improved the pH of acid soils by 47-55%, b) reduced the leaching of metals by 33-71% from contaminated soils, c) reduced the Hg concentration by 47-78% in shoots and roots of plants, d) increased the production of agricultural products by 17-95%, e) decreased the plantlosses in new vineyard by 12% and f) improved the quality of tomato by 4-46%. The HENAZE neutralized sewage sludge (producing zeo-sewage-sludge), industrialsludge (producing zeo-sludge), battery solid waste and mine solid wastes (minetailings). The zeo-sewage sludge and zeo-sludge are odorless, cohesive and suitable for safe deposition. The treatment of sewage-sludge and industrial-sludge with the HENAZE, reduced the leaching of metals by 91-100% and of NO3 - by 81-82%. Depending on the trace element contents, the zeo-sewage-sludge can be used as soil conditioner. HENAZE sorbed-removed 37-92% of metals, radionuclides and cyanobacteria from their solutions and waters. The treatment of wastewaters (urban, dyeing-industry, industrial area and tanning-work) with HENAZE, improved the quality characteristics by 48-99%. The HENAZE reduced the NO3 - load by 54-94% in groundwater, nitrate-solutions, industrial and urban wastewaters. Considering, the European, Global and Greek legislation, the mineralogical, chemical, morphological and radiological characteristics, as well as the leachability and bioavailability of chemical elements, the specifications for the different applications-uses of the zeolitic tuffs are defined

Mineralogy and crystallochemical characteristics of HEU-type minerals from zeolitic tuff deposits of Serbia

The results of perennial research of several Serbian zeolitic tuffs enriched with HEU-type minerals are presented in this paper. There are several recognized zeolitic tuff deposits containing HEU-type minerals: Zlatokop, Igros, Beocin, Toponica, Slanci, but their comparative mineralogical and crystallochemical features have not been studied in detail so far. These zeolitic tuff deposits are spatially and genetically connected to volcanic and pyroclastic rocks of marine and lake environments of Senonian and Eocene, and Neogene age, respectively. As a result of devitrification and diagenesis process of volcanic glass within zeolitic tuffs hypocrystalline porphiry and vitroclastic textures occur. The studied zeolitic tuffs are mainly composed of heulandite occuring in a form of needle- to plate-like crystals of 0,1 do 100 ?m in length, associated with other silicates. Depending on the type and content of exchangeable cations as well as the thermal stability of these raw materials, 24 clinoptilolite-Ca and heulandite-Ca can be distinguished. The values of cation exchange capacity and surface area capacity range from 96 to 166 meq/100 g, and from 8,0 to 10,5 meq/100 g, respectively. HEU-type minerals can be distinguished either by a Si/Al ratio or arrangement of extra framework cations within the crystal structure of these minerals.

Regional zeolitic tuffs as effective additions to cements

Chemical and phase composition of the zeolitic tuff were studied by X-ray fluorescence and X-ray analysis. It was also investigated the thermal stability of the zeolitic tuff. It was considered the ionic exchange on the zeolitic tuff. It was measured conductivity and pH of the cement paste in the presence of zeolitic tuff for the understanding the role of the zeolitic tuff in the hydration process of cement. The influence of zeolitic tuff on the compressive strength was determined.