Experimental Research On Aeration Assisted Bioleaching

Solution mining technology, especially the bioleaching technology, is a better way to recover the useful components from low-grade minerals, which has improved the availability of underground mineral resources conservation. However, while it was applied to treat with low-grade primary sulfide ore, this technique has some disadvantages of low leaching velocity and low leaching rate and can not be resolved fundamentally.This thesis is supported by the "973" National Key Fundamental Research and Development Program of China "The Multifactor Strong Relating in Leaching System "(2004CB619205), the National Science Fund for Distinguished Young Scholars of China "The Study on Dynamics of Multilevel Seepage and Mass Transfer in Multiphase Granular Medium"(503254l5), the National Natural Science Fund of China "the study on solution seepage mechanism in heap leaching granular medium under the function of stress wave "(50574099), and so on. Combining with partial research work of these programs, this thesis aims at increasing the leaching rate of low grade sulfide minerals. Through theoretical analysis, indoor experiments, numerical simulation methods and so on, the work focuses on aeration intensified heap bioleaching, and the main contents are as follows:(1) The mechanism of sulfide bioleaching was expounded by the viewpoints of leaching chemistry and mineralogy. The microorganisms available for leaching and their growth characteristics were introduced. Several doctrines about bioleaching mechanism, famous at home and abroad, were summarized. Theories of gas-liquid seepage were summarized and analyzed.(2) A series of experiments of aeration assisted bioleaching were carried out, and the combined influence of air rate, pore structure, bubble size, etc. on leaching rate, bacteria concentration, TFe concentration, etc. was investigated. The ordering relation of the factors and the internal relations between the factors and the variables were proved up, and the regression equation shown the relation of porosity, aeration velocity, gas-jet size and Cu²⁺ concentration was obtained.(3) A new concept of medium-high temperature heap leaching was inducted. The temperature field of heap model was analyzed. The functions of aeration in medium-high temperature heap leaching and some new techniques and measures needed by the medium-high temperature heap leaching technology were studied and the basic technological flow and operate procedures were described systematically.(4) The process of aeration assisted heap leaching was numerically simulated by the COMSOL Multiphysics software. The specialities of seepage field and dissolved O² distribution in classical heap leaching process and aeration assisted heap leaching process were comparatively analyzed, and the experimental results were proved.