ABSTRACT
Solvent extraction of uranium from acidic and alkaline post-leaching liquors that were obtained by leaching of Polish ores is reported in this paper. The stripping of uranium from organic to aqueous phase was also studied. The synergistic mixture of 2-diethylhexylphosphoric acid (D2EHPA) and tri-n-butylphosphate (0.2 M:0.2 M) was found as a good extracting agent for uranium. Recovery of uranium was reached even 98 %. The effect of such parameters like uranium concentration and concentration of reagents used in the experiments was evaluated in advance by using a model uranium solutions.
ABSTRACT
The recovery of uranium and other valuable metals from Polish Peribaltic sandstones were examined. The solid-liquid extraction is the first stage of the technology of uranium production and it is crucial for the next stages of processing. In the laboratory experiments uranium was leached with efficiencies 71-100 % by acidic lixiviants. Satisfactory results were obtained for the alkaline leaching process. Almost 100 % of uranium was leached with alkaline carbonate solution. In post leaching solutions only uranium and small amounts of vanadium were present.
ABSTRACT
The optimization of experimental conditions for radiolytic removal of organic pollutants from water and waste with the use of ionizing radiation via controlling the concentration of target compound(s) requires also monitoring the toxicity changes during the process. Commonly used herbicides 2,4-D and dicamba were shown to increase toxicity measured with the Microtox test at low irradiation doses resulting from formation of more toxic transient products, which can be decomposed at larger doses. The changes of toxicity were examined with respect to dose magnitude and the presence of commonly occurring scavengers of radiation.
Subject(s)
Environmental Monitoring , Herbicides/radiation effects , 2,4-Dichlorophenoxyacetic Acid/chemistry , 2,4-Dichlorophenoxyacetic Acid/radiation effects , Ammonia/metabolism , Animals , Bacteria , Chromatography, High Pressure Liquid , Dicamba/chemistry , Dicamba/radiation effects , Dose-Response Relationship, Radiation , Herbicides/chemistry , Herbicides/toxicity , Luminescent Measurements , Ozone/chemistry , Radiation, Ionizing , Toxicity Tests , Water PurificationABSTRACT
The aim of this work was to make a comparison of indoor radon concentrations in dwellings and in soil air in the area of two geological formations in the Suwalki region (Poland). The mean arithmetic airborne concentration was found to be the highest (301 Bq m (-3)) in the basements of buildings in the gravel and sand areas, whereas in the boulder clay areas it reached 587 Bq m (-3). Out of 54 measurements of radon concentrations performed at the ground floor, in eight cases concentrations were found to exceed 200 Bq m (-3) - permissible radon level in new-built houses in Poland and in three cases these values were even higher than 400 Bq m (-3). The highest radon levels were noted in houses with earthen basement floors and with direct entrance from the basement to rooms or kitchens. The mean arithmetic radon concentration in the soil air in the sandy and gravel formations was 39.7 kBq m (-3) and in clay formation it was 26.5 kBq m (-3). Higher radon levels were also found in the water obtained from household wells reaching 8367 Bq m (-3) as compared with tap water (2690 Bqm (-3)). The mean indoor concentration for the whole area under study was found to be 169.4 Bq m (-3), which is higher than the mean value for Poland (49.1 Bq m (-3)) by a factor of 3.5.
