Pore model reconstruction of copper sulfide ore agglomerate and simulation of solution seepage
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摘要: 以次生硫化銅礦粉為原料，添加黏結劑、氯化鈉制備礦粒，并借助CT掃描技術、圖像處理及三維重構方法，開展了單個礦粒浸出試驗，探究了溶浸前后礦粒內部的孔隙變化；運用COMSOL Multiphysics模擬仿真軟件，構建了溶液在孔隙通道中流動的仿真模型。結果表明：經過一周時間的溶浸，礦粒內部孔隙的數目、平均體積、平均表面積及孔隙平均等效直徑分別增長了99%、151%、223%和90%，孔隙率增長了4倍，孔隙連通度增長了近2倍。在孔隙通道較狹窄的區域和底部區域，溶液的流速、壓力急劇增加，對礦粒結構的穩定性產生較大影響。Abstract: Bioleaching technology, a method used in mining, utilizes organisms or microorganisms to dissolve and leach useful components from ore. This technology is applied widely in many countries in mining and production of various metals. Although considerable economic benefits have been obtained with the help of bioleaching technology, this technology faces many challenges. For example, as the leaching process progresses, the permeability of the ore heap is worsened from the presence of fine particles and muddy ore. As such, improving heap permeability is a key focus in the field of leaching mining technology. Agglomeration technology, an effective method for improving the permeability of ore heaps, involves crushing the ore and agglomerating it with binders before leaching, which alters the structure of the ore, especially ore powder. The resulting granular structure provides space for the flow of the solution and greatly improves the permeability of the leaching system. The pore structure is constantly changing as the leaching process progresses, which affects the seepage of the solution and even the effect of leaching the ore. In this study, leaching tests were conducted using single-ore granulation of secondary copper sulfide ore powder, binders, and NaCl. Changes in the pore structure during leaching were investigated using X-ray computerized tomography, digital image processing, and three-dimensional reconstruction methods. In addition, COMSOL Multiphysics simulation software was used to construct a simulation model of the flow of the solution in the pore channels. The results reveal that the number, average volume, average surface area, and average equivalent diameter of pores inside the granulated ore increase respectively by 99%, 151%, 223%, and 90%. In addition, the porosity increases fourfold and the pore connectivity nearly triples. The flow velocity and pressure of the solution was found to increase sharply as the solution flows through the narrow and bottom areas of the pore channels, which has a great impact on the stability of the ore granulation structure.
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Key words:
- copper sulfide ore /
- agglomeration technology /
- CT technology /
- pore evolution /
- numerical simulation
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圖 2 試驗礦粒。（a）溶浸時；（b）晾干后
Figure 2. Photographs of mineral agglomerate used in the test: (a) during leaching; (b) after drying
圖 3 掃描原圖。（a）浸出前；（b）浸出后
Figure 3. Original CT scan images of mineral agglomerate: (a) before leaching; (b) after leaching
圖 7 邊界條件。（a）導入網格數據；（b）入口；（c）出口
Figure 7. Boundary conditions: (a) imported grid data; (b) entrance; (c) export
圖 8 速度流線圖。（a）流線間隔為0.1 μm；（b）流線間隔為0.01 μm
Figure 8. Streamline distribution of the solution: (a) streamline interval of 0.1 μm; (b) streamline interval of 0.01 μm
圖 9 速度切面圖。（a） X方向；（b） Y方向；（c） Z方向
Figure 9. Velocity sections in different directions: (a) X direction; (b) Y direction; (c) Z direction
圖 10 壓力分布圖。（a）壓力分布圖；（b）壓力等值線圖
Figure 10. Pressure profile: (a) pressure distribution; (b) pressure contour map
表 1 礦樣主要元素質量分數
Table 1. Mass fractions of major elements in mineral samples
% Elements Cu Fe S CaO MgO Al2O3 SiO2 Mass fraction 0.70 1.67 1.10 0.30 0.04 5.19 91.00 
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表 2 銅物相分析結果（質量分數）
Table 2. Cu phase analysis results of mineral samples
Phase Mass fraction/% Copper oxide 0.04 Primary copper sulfide 0.05 Secondary copper sulfide 0.60 Combined copper 0.01 Total 0.70
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表 3 礦粒孔隙參數變化
Table 3. Variation of pore parameters
Parameter Pore number Mean pore volume/(108 μm3) Average pore surface area/(106 μm2) Average equivalent pore diameter/μm Before leaching 288 1.71 1.16 304 After leaching 575 4.29 3.75 579 Growth rate/% 99 151 223 90
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表 4 礦粒孔隙率及孔隙連通度變化
Table 4. Evolution of porosity and pore connectivity
Parameter Porosity/% Growth rate/% Porosity connectivity/% Growth rate/% Before leaching 3.20 400 29.96 195 After leaching 16.00 88.26
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中文字幕在线观看表 5 構建模型的關鍵參數
Table 5. Key parameters used in the model
Parameters Symbol Value Density/(kg·m?3) ρ 1100 Temperature/K T 298.13 Dynamic viscosity/Pa·s μ 0.9 Initial pressure/Pa P0 0.715
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