| A large number of Brannerites were found in the deep of Zoujiashan uraniumore-deposit with the increasing of mining depth and researching degree. Brannerite belongsto refractory uranium ore and leads to the waste of uranium resources, the pollution of theenvironment and seriously affect the quality of the product of uranium. Therefore togenesis the phase behavior of uranium in uranium ore which rich in Brannerite hasimportant economic, environmental, and ore deposit genesis significance.The paper is about immersion tests of the representative sample of bonanza inZoujiashan uranium ore-deposit. Leaching agent respectively were distilled water, sulfuricacid solution, acid and oxidants. Uranium content in leaching liquid were measured in theprocess of experiment. Then the Chemical and mineral composition, the macroelementand the microelement which in original ore samples and residue samples were measured byusing Electronic probe and ICP-MS. The conclusion is as follows：(1)The main uranium forms are Pitchblende, Brannerit and Coffinite in Zoujiashanuranium ore-deposit.The other is the Isomorphism that contains Enalite and Thorite, and soon.(2)The leaching rate of uranium was increased with the increaseing of the sulfuricacid concentration and amount of oxidant in the parallel experiments.The largest leachingrate is98.26%under the conditions of30g/L of sulfuric acid and10ml hydrogen peroxide.(3)The results of sequentially extracting experiment are as follows:The leaching rateof uranium is0.51%in distilled water. The four cumulative leaching rates respectivelywere24.64%,55.37%,90.76%and93.94%which were respectively immersed in40g/L ofsulfuric acid. The cumulative leaching rate increase to97.11%by using20ml hydrogenperoxide.(4)The dissolved uranium accounts for0.51%in the stage of usinging distilled water,and this part of uranium form mainly is active hexavalent uranium such as Pitchblende.Thedissolved uranium accounts for93.43%in the stage of usinging sulfuric acid. and this partof uranium form mainly is complicated compound which is comprised of active hexavalenturanium, such as Pitchblende, Uranatemnite, Coffinite, Zippeite. Carbon fiber uraniumdeposits and so on. Then there may be a few of tetravalent uranium compounds weredissolved because of oxidized.The dissolved uranium accounts for only3.18%in the stage of usinging sulfuric acid and oxidant.It is a few of complicated compound comprised byinsoluble tetravalent uranium, such as Brannerite, Silicate uranium minerals, and so on.Theisomorphism that contains Enalite and Thorite and most of Brannerites are still difficult todissolve although under the condition of powerful oxidizing.(5) Brannerite belongs to refractory uranium ore. However, there is still a small partof Brannerite was dissolved under the condition of powerful acids and oxidants. This isrelated to the fine particle size (200mesh) and the reaction time is long enough.(6) The average∑REE of Uranium mineralization in Zoujiashan uranium ore depositis3231.55×10-6and HREE is2933.39×10-6, so it belongs to the precious REE type withHREE enrichment REE.The leaching rate of HREE is more evidenter than LREE’S and thelargest leaching rate is Gd and the lowest one is La.Other macroelements andmicroelements have been leached. in different degrees except for Ca, Cr, Sr, Ta, Cr, Ni, Thand so on. |
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