| The thermal phase is an important part of the bioleaching system of sandstone-type uranium ore,which has an important impact on the leaching rate and pore structure evolution.This paper takes the bioleaching system of sandstone-type uranium ore under various temperature as research object,focuses on rules of leaching and pore structure evolution under various temperature,and aims to improve the leaching efficiency and reveal the evolution rule of pore structure.The main research work includes:(1)The static leaching,shaking flask bioleaching,and bioleaching of sandstone-type uranium ore were carried out.The variation rules of bacterial concentration,uranium leaching rate and etc were analyzed,and the influence characteristics of temperature on the variation of leaching parameters was obtained;Based on 16S rDNA sequencing analysis,the composition and difference characteristics of bacterial community at different stages of bioleaching were studied,and the influence of temperature on the succession of bacterial community structure was revealed.(2)The porosity and permeability of sandstone-type uranium ore without bioleaching were measured,and the influence characteristics of temperature on the porosity and permeability of sandstone-type uranium ore were obtained.Micro-CT scanning and image processing technology were used to study the evolution rule of pore structure of the bioleaching system.The influence characteristics of temperature on the evolution of pore structure was revealed,and variation rules of pore length,width and shape during bioleaching were obtained.(3)Combined with the Micro-CT scanning results of sandstone-type uranium ore at different stages,the influence of temperature on the corrosion precipitation during sandstone-type uranium ore bioleaching was studied by using XRD analysis,FTIR analysis and etc.The influence characteristics of temperature on the formation of precipitation by the reaction of alkaline gangue minerals with acid,and the formation of precipitation by ionic hydrolysis were revealed.The influence characteristics of precipitation on the evolution of pore structure were analyzed.(4)The meso-physical model of the leaching system was constructed,and the particle image velocimetry was introduced to test the meso-seepage field of leaching solution in the sandstone-type uranium ore bioleaching system.The distribution characteristics of solution seepage velocity field between ore particles were obtained,the influence of liquid injection intensity and temperature on solution seepage between ore particles was analyzed,and the evolution characteristics of solution microscopic velocity distribution of bioleaching system with liquid injection intensity and temperature were revealed.(5)The influence mechanism of physical,chemical and biological actions on the evolution of pore structure and permeability of sandstone-type uranium ore under various temperature was discussed,the seepage behavior characteristics of the sandstone-type uranium ore bioleaching system under various temperature were analyzed,the solution seepage-temperature-leaching reaction coupling model was constructed,and the evolution rule of pore structure and solution seepage performance during sandstone-type uranium ore bioleaching was revealed.(6)The numerical simulation of the effect of various temperature on the bioleaching system was carried out,and the influence of temperature on the solution seepage behavior and atc of the bioleaching system was analyzed;The technical methods and optimization measures suitable for the enhancement of bioleaching process were proposed from the aspects of process optimization,forced aeration,additive addition and etc. |
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