| The gas phase is an important part of bioleaching system of copper sulfide ore,and forced aeration is an important means to increase oxygen content in heap leach pile.This paper takes the bioleaching system of copper sulfide ore under forced aeration as the research object,focuses on the bioleaching rules and solution seepage behavior under aeration,and aims to optimize the effect of forced aeration and improve the leaching efficiency.The main research work includes:(1)The column bioleaching experiment of copper sulfide ore under different aeration intensities was implemented,and the variation rules of the parameters such as bacterial concentration,pH,ion concentration and copper leaching rate during the leaching process were analyzed,and the characteristics of the influence of aeration intensity on the change of leaching parameters were obtained.The results show that the copper leaching recovery increases first and then decreases with the increase of aeration intensity.The composition and difference characteristics of microbial community in different leaching stages were studied by using 16S rDNA amplicon sequencing technology.The effects of aeration intensity on the microbial community structure evolution of leaching systems were revealed.(2)Based on high-precision Micro-CT scanning and image processing technology,the porosity change rule of leaching system under different aeration intensity was analyzed.The influence of aeration intensity on the annular,radial and axial porosity uniformity of the leaching column was revealed.The pore network model method was innovatively introduced to analyzing the evolution law of pore throat parameters of connected pores during leaching process.The quantitative analysis of the meso-structure parameters and connectivity characteristics of the connected pore clusters in the leaching system was realized.The influence of aeration intensity on the evolution of pore structure parameters in the leaching process was revealed,and the variation law of pore tortuosity in the leaching process under different aeration intensity was obtained.(3)The meso-physical model of heap leaching system was constructed based on refractive index matching,and particle imaging velocimetry and laser-induced fluorescence were used to test the meso-seepage field of solution in heap leaching system.The distribution characteristics of solution seepage velocity field in intergranular pores of ore under saturation and forced aeration conditions were studied,and the evolution characteristics of the mesoscopic flow velocity distribution in the heap leaching system with the liquid injection intensity and aeration intensity were revealed,and the effects of liquid injection intensity and aeration intensity on the maximum flow velocity,average flow velocity and standard deviation of the flow velocity were analyzed.(4)The mechanism of gas transfer in ore heap under natural conditions was analyzed,the critical starting pressure of forced aeration process was studied,and the effect of aeration pressure on gas phase morphology in solutions of interparticle pore was discussed.The transformation process among bubbly flow,slug flow and channel flow was studied,and the force situation of single bubble in inter-particle pore solution was analyzed.The gas-liquid flow equation of heap leach piles under forced aeration condition was established.The influence mechanism of forced aeration on flowing solution,immobile solution,ore pile shrinkage and pore clogging in leaching system was studied respectively.(5)The numerical simulation of air flow in forced aeration process of heap leaching system was carried out,and the effects of aeration time,aeration intensity and aeration pipe spacing on gas seepage behavior in ore heap were studied.The technical ideas of optimizing gas distribution in ore heap and strengthening gas-liquid mass transfer are put forward from the aspects of process optimization,adding admixture and applying physical field. |
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