Research On The Evolution Of Micro Pore Structure In The Chemical Replacement Of Ion-Absorbed-Type Rare Earth

The in-situ leaching method is popularized and applied in ionic rare earth mines in the south because of its outstanding advantages in reducing the cost of mining and protecting the surface environment.However,many problems such as low mining recovery rate and slope slip of liquid injection occur during the promotion process.These outstanding problems are closely related to the seepage of the leach solution in the matrix,and the evolution of the pore structure of the rare earth ore body during the leach process becomes a leach.The key to good migration of ore fluids.However,consulting relevant research at literatures atdomestic and foreign relatedfound that many studies attributed the pore structure change in solution seepage process to physical and mechanical factors such as effective stress reduction of matrix skeleton and migration of parent matrix particles,but ignored the strong chemical exchange caused by ions.Secondary pore structure."This article is based on this issue,based on the in situ leaching process,and intends to study the mechanism of action and dynamic evolution of ion exchange on the pore structure of rare earth ore bodies through experiments.This paper mainly uses NMR test equipment to scan and detect the leaching process of the sample,so as to obtain the evolution rule of the porosity and pore radius of the sample continuously with the leaching.Through the leaching process,rare earth sample electron microscope scanning and energy spectrum test contrast Analysis,combined with NMR test results to ascertain the characteristics of rare earth ore fine particle migration during leaching and observe the migration of tiny particles inside the sample,this article mainly completes the following work:?1?According to the basic physical properties of the original rare earth remolded test sample,and then complete the leaching test,in the leaching process,the residual rare earth content?REO?in the test sample obtained effective leaching time.?2?The effective leaching time was divided into equal intervals?0.5h?.In the effective leaching time,the osmotic pressure of the immersion was kept constant.The porosity and pore size distribution of the samples at different time points were measured by NMR tester.The evolution of the porosity and pore size distribution of the samples during the chemical displacement process.?3?For the leaching process of?NH₄?₂SO₄ solution,the inversion results of the NMR measurements were obtained for different leaching time and compared with the inversion images of the leaching ore,and the chemical displacement effect on the rare earth was obtained.The influence of the microstructure of the sample is analyzed and its influence mechanism is analyzed.?4?The rare earth samples of different leaching time periods were taken to complete electron microscopy scanning and energy spectrum testing.The test results at equal intervals were compared and analyzed to obtain the material composition of the smallest unit in the particle transport process,further revealing the seepage process of the leaching ore.The characteristics of the ore-like microparticle transport and the migration mechanism were explained.