Experimental Study Of A Uranium Tailings In Hunan Uranium Activity And Fixed

Sequential chemical extraction method because of its simple operation, wideapplication range, can provide information on the advantages of rich, obtained thewidespread application of people. Chemical extraction step is simulated by a variety ofpossible, man-made and natural environmental conditions change, reasonable use of aseries of selective extraction agent, in accordance with the following principles, continuousdissolution of different adsorption of trace mineral phase.Chemical speciation analysis has become an active front subject in EnvironmentalScience, geochemistry, biochemistry and Life Sciences, and chemical speciation ofradionuclide will directly influence the leaching rate in the medium and the mobility in theenvironment and biological availability. This paper takes Hunan as an example of auranium tailings, using sequential chemical extraction technology, uranium tailings samplewill be collected in the uranium is divided into exchangeable (including water soluble),carbonate bound, organic matter bound, amorphous Fe Mn oxides/hydroxides bound,amorphous Fe Mn oxides/hydroxides bound step by step, residue, respectively, wereextracted, and quantitative analysis of uranium in each phase of the share. Then, throughlaboratory simulation, using chemical methods (mainly in the ammonium phosphate andcalcium chloride) were fixed in situ experiment on the activity of uranium tailings sample,in order to find out the effect of fixed active uranium in. The main research results are asfollows:(1) The sequential chemical extraction of6phases, exchangeable (including watersoluble), carbonate bound, organic matter bound, the3phase of uranium easily byweathering, oxidation, rain, surface runoff, release to the environment, the most active partof uranium, known as the activity of uranium; amorphous Fe Mn oxides/hydroxidesbound and amorphous Fe Mn oxides/hydroxides bound only in a strong reducing conditions, will be released this part of uranium, uranium activity is relatively weak, calledthe potential activity of uranium. Among them, active and potentially active uraniumpercentage of sequential chemical extraction for total uranium content (average):42.41%(range:37.41%~48.13%). In Hunan a uranium tailings on average about40%uraniumthreat and a potential threat to the environment, the environmental quality assessment andenvironmental pollution control are most concerned part.(2) The study on the speciation of uranium in uranium tailings technology bysequential chemical extraction, residue is the main existing form of uranium in uraniumtailings, generally occurs in the primary, secondary silicates and other stable minerals, canexist for a long time and is difficult to environment released in the environment, to be safeenvironment.(3) In the study, about40%of the uranium can directly or through a simpleweathering, oxidation, reduction, release into the environment, is an easy to release thepotential of radioactive pollution source. Therefore, the author in the laboratory conditions,dilute H2SO4dip tailings samples with different pH values. Then, in the fixed on theactivity of uranium after filtering the soaking liquid with different concentration ofammonium phosphate and calcium chloride solution. The results show that, whether it isthe same or different specimen, specimen was soaked; uranium concentration is decreasedwith the increase of the pH values. When the pH value is greater than or equal to4, thesoaking liquid uranium concentration is too low, even lower than the9types of soil inChina in the uranium content (1.30~3.99μ g/g), fixed little significance.