Study on Meso-mechanism of Deep Dewatering of Mine Filling Materials Based on CT Scanning
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摘要:
针对全尾砂浓密脱水困难、底流质量浓度低的问题，开展了基于压缩床层不同高度处料浆絮团细观结构深度浓密脱水研究。通过对全尾砂进行动态浓密实验获取压缩床层料浆样品，借助SEM及高精度CT扫描设备，对获取的絮团结构进行扫描及三维重构处理分析沿压缩床层方向孔隙结构变化规律。结果表明：沿着床层向下，五组料浆内部孔隙平均半径分别为9.58 μm、9.23 μm、8.76 μm、8.63 μm及8.31 μm。床层顶部料浆质量浓度为59.4%，絮团呈现松散无规则状，底部料浆质量浓度为62.1%，絮团呈现致密规则状。对比顶部和底部料浆，孔隙率下降3.7个百分点，连通孔隙比下降了35.53%，孔隙平均配位数减小了22.73%，孔隙连通性大大降低。本文从细观角度定量表征了微观孔隙结构特征，为矿山充填材料进一步脱水提供理论依据。
Abstract:Aiming at the problems of difficult thickening and dewatering of total tailings and low underflow mass concentration, the deep thickening and dewatering of slurry flocs based on the meso−structure of slurry flocs at different heights of the compressed bed was studied.Through the dynamic thickening experiment of the whole tailings, the slurry sample of the compressed bed layer was obtained. With the help of SEM and high−precision CT scanning equipment, the obtained floc structure was scanned and three−dimensionally reconstructed to analyze the pore structure variation along the direction of the compressed bed layer. The results show that the average pore radius of the five groups of slurry is 9.58 μm, 9.23 μm, 8.76 μm, 8.63 μm and 8.31 μm respectively. The mass concentration of slurry at the top of the bed is 59.4%, and the flocs are loose and irregular. The mass concentration of slurry at the bottom is 62.1%, and the flocs are dense and regular. Compared with the top and bottom slurry, the porosity decreased by 3.7 percentage points, the connected pore ratio decreased by 35.53%, the average coordination number of pores decreased by 22.73%, and the pore connectivity was greatly reduced. This thesis the microscopic pore structure characteristics are quantitatively characterized from the microscopic point of view, which provides a theoretical basis for further dehydration of mine filling materials.
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Key words:
- unclassified tailings /
- compressed bed /
- floc structure /
- CT scanning /
- porosity
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表 1 1800万分子量阴离子型絮凝剂基本特性表
Table 1. Basic characteristics of 18 million molecular weight anionic flocculants
聚丙烯酰胺 单位
分子量/万固相
质量分数/%粘度/(mPa·s) 溶解
速度/h阴离子型 1800 88~92 3~4 ≤1 
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表 2 压缩床层不同高度处样品质量浓度
Table 2. Mass concentration of samples at different heights of compressed bed
样品编号 L1 L2 L3 L4 L5 样品料浆取样高度/ cm 16~20 12~16 8~12 4~8 0~4 平均质量浓度/% 59.4 60.3 60.9 61.5 62.1
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表 3 孔隙连通性结果统计表
Table 3. Statistical table of pore connectivity results
样品 L1 L2 L3 L4 L5 总孔隙率/% 41.6 39.7 39.1 38.5 37.9 孤立孔隙数量/ 个 454 696 301 839 1829 连通孔隙比 fp 0.76 0.71 0.64 0.58 0.49
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表 4 孔隙网络模型结构参数统计
Table 4. Statistics of structural parameters of pore network model
样品 值 孔隙数量 孔隙半径/μm 喉道数量 喉道半径/μm 配位数 (a)L1 大 742 20.84 3510 15.43 48 平均 9.58 3.56 9.46 最小 2.73 0.27 1 (b)L2 最大 715 22.41 3150 13.04 46 平均 9.23 3.40 8.81 最小 3.09 0.27 1 (c)L3 最大 672 18.98 2627 10.73 33 平均 8.76 2.91 8.43 最小 2.68 0.27 1 (d)L4 最大 643 21.77 2708 11.73 31 平均 8.63 3.17 7.82 最小 3.09 0.30 1 (e)L5 最大 464 19.61 1697 10.82 32 平均 8.31 2.91 7.31 最小 2.86 0.27 1
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