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Purified natural clinoptilolite as well as clinoptilolite converted into hydrogen and sodium form have been contacted with 0.1 mol/L silver nitrate solution at a ratio solid to liquid equal to 1 to 20, in order to load silver ions (Ag+) on the zeolite support. It has been found that sodium modified clinoptilolite exchanged in highest degree Ag+ ions, followed by natural zeolite. Preliminary transformation of natural clinoptilolite into hydrogen form leads to decreasing of zeolite ability to bind Ag+ ions. The kine...

The ore extraction from Krumovo deposit, located at the northern periphery of the Manastir heights in Southeast Bulgaria started in 1906 and continued till 1986. The ore comprised Fe3O4 with admixtures of sulfides such as pyrite, pyrrhotite, marcasite and chalcopyrite. Open pits and underground workings were used. The excavations severely degraded the habitats, vegetation and waters on an area of about 3 km2. By 1986 waste rock (comprising hydrothermally altered basic magmatic rocks, such as gabbro or diorites, ma...