| The disposal of Biological heap leaching to low-grade copper sulfide ore was a reliable processing technology around the world.The principle of bio-heap leaching was to convert the solid metal mineral into liquid metal salt solution by making use of the leaching agent containing effective bacteria.The physical properties of the mineral grain,such as particle size,micro cracks,porosity are the key factors influencing the penetrating quality of leaching agents.Zijinshan copper biological heap leaching factory was the most representative of low grade sulfide copper heap leaching plant in China.Based on the Zijinshan copper mine as the research object,this paper explore the effect of micro cracks,porosity and other physical properties in mineral grain on the penetrating quality in the process of heap leaching.In this paper,the principle of particle crack propagation in heap leaching of copper sulfide ore was studied by means of physical fracture test,leaching test,mathematical modeling,ANSYS finite element crack growth simulation and mechanism analysis.Comparing with the jaw crusher and the crushing under the high pressure roller mill and the effect of crack and studying the copper ore crushing material properties and agitation leaching characteristics of products,this paper further studies trend of particles crack in the conventional crushing with high pressure roller to establish the seepage model of crack and no crack is ed with the help of scanning electron microscope(SEM),bulk microscope(SM),incident light microscope(RM),EDS energy dispersive spectrometer etc.The specific research contents are as follows:Carry out the study of Zijinshan copper mine quality at the present stage.The results show that the grade of copper in the raw ore was only 0.21%,and the main metal mineral of the ore was copper sulfide,among which the digenite,covellite,enargite are important elements.Besides,main gangue mineral was quartz containing a small amount of alunite and dickite.Adopt the conventional jaw crusher and the crushing under the high pressure roller mill to smash copper ore respectively and make a comparison with the characteristics of particle size distribution,specific surface area,micro cracks and porosity of the pulverized products.The results show that the characteristics of material product in high pressure roller Grinding are superior to jaw crusher products.Make a comparison between the two different crushing manner.The results show that the products of the three different sizes are agitated and leached in the range of 0.9 mm～3 mm,3 mm～6 mm and 6 mm～9 mm respectively.Leaching rate of 3.1,6.4 and 2.5 percentage points,small column leaching results show that the high-pressure roller mill products than the conventional jaw crusher agitation leaching rate of 10.2,15.1 and 9.3 percentage points.Use the simulation software to establish mineral particle model which simulated the diffusion rate and diffusion depth of the leaching agent in the solid particles without crack,crack and multi-crack.And the unidirectional diffusion and bidirectional diffusion hypothesis were put forward.Finally we obtain under the condition of multiple crack,it is beneficial to leaching agent leaching of ore bacteria and minerals in the contact area and the diffusion depth.The multi-crack particles can significantly improve the leaching rate of copper ore in agitation leaching and small-scale column leaching experiments.The results of this study reveal the role and influence of the crack in the leaching of low-grade copper sulfide ore,which can provide some theoretical guidance for the application of copper in heap leaching field. |
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