Study On In-situ Leaching Of Uranium With Polymer Fluid Control Agent

The types of sandstone uranium deposits in our country are complex. Seam heterogeneity is serious and the channels in the seam distribute unevenly. Especially in the mid and late in-situ leaching of uranium, a large number of leaching agent flows to the high permeability seam, which causes that the leaching agent flows unevenly and over time this trend has accelerated. As a result, the concentration of leaching agent is becoming low, and also the contact time of leaching agent and seam is getting shorter and the leaching rate of low permeability seam is getting lower.In order to improve the leaching range of the leaching agent and leaching effect, and to eliminate or reduce the disadvantage of restoration of groundwater, a series of technical measures are taken to adjust the permeability of seam and the leaching range. The technical measures are called fluid control. The fluid control agent are injected in the seam via the injection well, which forms blockage after gelling under the geological conditions. The blockage reduce the permeability of high permeable and force the leaching agent into low permeability layer, therefore the low permeability layer’s leaching effect are improving.This paper choose HPAM(partially hydrolyzed polyacrylamide, concentration 1～1.5 g/L) which are cost less and widely used and aluminum crosslinking agent(concentration 0.3～1%) as row material for synthesis of fluid control agent and its formula, and studies selection of cross -linking agent and the influence factors of gel systematically and comprehensively.According to the analysis of the fluid control agent gelling factors which are different ratio and concentration of cross-linking agent, relative molecular mass and concentration of polymer and simulation of groundwater salinity. In order to ensure them crosslinked efficiently, the optimum synthesis conditions are defined. And also carry on the flow test in porous media, etc.Influence factor experiments indicate that the viscosity of polymer rises with the rise of concentration of HPAM, the viscosity of crosslinking system rises with the rise of concentration of crosslinking agent, and the temperature also rises with the reduces of viscosity of HPAM and crosslinking system, etc.Flow tests show that fluid control agent can flow priority to the channels of high permeability seam. By comparing before and after adding fluid control agent unit of water seepage flow draw fluid control agent has change simulation seam permeability and make the fluid to the role of low permeability, so as to achieve the purpose of rising the leaching rate.