Study On Physical Chemical Seepage Law Of Low Seepage Sandstone Uranium Ore Rock

Survival and development is the basic issues related to people closely. Energyproblem is key to the development, and the energy problem is depended on energytechnology and natural resources. Currently, uranium resources are actively prospected andexploit to meet the country’s nuclear power construction. With the development ofconstruction of the nuclear power quickly, nuclear fuel uranium will generate huge demand,which result that the development of uranium resources will be further strengthened. Dueto leaching of uranium without underground construction, the low cost of production, smallsurface damage on the ecological environment, so situ leaching is a ideal mining method tothe low-permeability sandstone uranium ore mined. However, in the sandstone typeuranium resources has proven in China, the low-permeability of resources occupied morethan50%, and it’s low-grade uranium deposits, and small-scale. Therefore, it has importantsignificance for the in-situ leach uranium mining to carry out experimental study onlow-permeability sandstone-type uranium rock seepage law.The project take a uranium mine as the research object, to study that the factors, suchas the leaching solution, and the nature of the porous medium, flow environment (chemicalreactions, pressure) and so on, affect the mechanism of action of physical and chemicalseepage law of low permeability rock mine by collecting information on the region ofinterest, and dip mine geology, hydrology, geochemistry and processes. The paper carriedout the physical and chemical seepage experiment by using cylindrical ore leaching agent,analyzed the porosity changes (changes in permeability) and fluid rheology in the chemicalreaction process between Chemical liquid and ore, and study the impact of these changeseffects on the laws of fluid flow, and the impact of physical and chemical process betweenleaching solution, oxidant and the uranium sandstone medium seepage law effects on the laws of fluid flow, and established the dynamics simulation method of physical andchemistry–transport based on GMS to Simulate the reaction migration law of leachingsolution in the physical and chemical effects, which make us Learn the law of chemicalseepage between the sandstone type uranium ore and leachant in-depth.Through the experiment research and numerical simulation, we found that thefollow results,(1) the law of analog curve movements and capillary pressure curves isenslaved to the pore structure of the mainly, and when the throats of porous media isdistribution, the porosity is large. That is to say, the more the intercept between thelongitudinal axis and a straight line that it is parallel to the coordinates of the horizontalcoordinates and through analogy capillary pressure points along the curve is smaller, themore the pore structure of is better and the permeability coefficient of the ore rock isgreater. or else, on the contrary.(2) Experiments indicated that, there are3seepage stagesin the low permeability rock. The starting pressure gradient of this rock is about13, thepressure gradient of linear flow is about48. When the pressure gradient is less than13,there does not occur in liquid flow. When the pressure gradient is between in13and48,there exist a nonlinear relationship between the flow coefficient and the pressure gradient.When the pressure gradient is greater than48, there exist a linear relationship betweenthe seepage coefficient and the pressure gradient.(3) After the media of ore and leachingsolution react chemically, the medium ore of pore structure is altered, and some of thesmaller radius of pore is larger and connected, which result the seepage of fluid is largerin the unit area and per unit time, thereby enabling the overall permeability of sandstonemedium becomes large. Besides, as the gradient pressure increases, the media porestructure will make the further evolution and the overall coefficient of sandstonepermeability is changed (the changes of lithology on physical properties) under the orechemistry driven by external pressure effect. The surface tension of the fluid is the keyfactor affecting the fluid flows the smaller diameter of pore, which can increase theoverall permeability of the rock ore by reducing the surface tension of the fluid, andpromote the full oxidation-reduction reaction of solution and the rock, and reduce the problem of dead leaching occurs in the leaching of uranium.(4) In this situation that thespacing of pumping and injection wells is same, as the liquid proportion of pumping andinjection wells increases or that the liquid proportion of pumping and injection wells issame, as the spacing of pumping and injection wells increases, the seepage field offive-point type wells changed open from near-closed gradually, which caused a huge ofleaching solution is loss and increased the leaching dead area. Through simulationanalysis, the liquid ratio of pumping and injection is one and the spacing of wells is20mis suitable for the study area.