Experimental Study On Release Of Uranium In Different Partical Size Uranium Tailings Under Water Medium

The particle size has very important influence to releasing of uranium in uranium tailings. Particle size have a great relationship uranium extraction rate in the acid extraction of uranium process, which is directly related to the residual amount of uranium in tailings; water is one of the most important driving force release of uranium, and the particle size is a key factor in the contact area of the tailings and water effects. As abundant rainfall and groundwater complicated geographical movement conditions in southern China, study on influence of particle size to the release of uranium is necessary.Two different experiments were used : to simulating natural environment, particle affect the of tailings immersed in aquifers by static immersion test; leaching to simulate the natural environment, the particle size effect the process of uranium leaching in tailings buried shallow by dynamic leaching experiments. And the dynamic characteristics of the process of uranium release is probed under tow experimental condition above. Through experiment there are some following conclusion:1. Analyzed the effects of particle size on the release process of uranium tailings.To simulate in the reservoir area environment through static immersion and dynamic leaching experiments, studied on different particle size of uranium tailings sample affects the process of uranium releasing in the different tailings-water coexistence system.The results showed that:(1) In static soaking condition, the release process of uranium in different particle sizes uranium tailings is similar;under dynamic leaching condition, smaller the tailings particle size is,faster the release process of uranium tailings.(2)Smaller the particle size is, the greater the uranium leaching rate. But the smaller tailings is more prone to compaction, affecting the release of uranium, under the static soaking conditions. Smaller the Tailings’ particle size, the smaller the gap between the various stages of the uranium concentration of saturated solution of uranium concentration stage, the more stable the uranium’s entire release process, the less uranium concentrations fluctuate, more conducive to long-term storage.2. Analyzed leaching mechanism and dynamic sanalysis the process of uranium released from the tailings. Pointed there are differences in dynamic mechanism of uranium released that in different tailings-water coexistence system by simulated of the uranium concentration phenomenon the experiment with the finite element method regression analysis of experimental data.The simulation results showed that:(1) Uranyl-ion attached on the surface of the tailings is the major source of rapid dissoluting uranium.(2)the release of uranium tailings is in line with the unreacted shrinking core model features under the static soaking conditions; Surface elution is the main form of uranium tailings discharge in dynamic leaching conditions.