Transactions of Nonferrous Metals Society of China The Chinese Journal of Nonferrous Metals

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中国有色金属学报

ZHONGGUO YOUSEJINSHU XUEBAO

第30卷    第9期    总第258期    2020年9月

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文章编号:1004-0609(2020)-09-2190-11
不同化学条件下孔隙比对尾矿砂渗透性影响试验
诸利一1, 2,杨 鹏2, 3,吕文生1, 2,程晓亮4,王 昆5

(1. 北京科技大学 金属矿山高效开采与安全教育部重点实验室,北京 100083;
2. 北京科技大学 土木与资源工程学院,北京 100083;
3. 北京联合大学 北京市信息服务工程重点实验室,北京 100101;
4. 中国电建集团北京勘测设计研究院有限公司,北京 100020;
5. 山东科技大学 矿业与安全工程学院,青岛 266590
)

摘 要: 为探究在不同酸碱性流体环境作用下孔隙比、浸泡时间对尾矿砂渗透性的影响规律,选取7组不同孔隙比试样,设计变水头渗透室内试验;通过控制变量法,研究8种浸泡时间下尾矿砂渗透性变化规律,并利用扫描电镜和X射线能谱仪分析不同化学条件下孔隙比对尾矿砂渗透性影响机理。结果表明:在化学条件下尾矿砂的孔隙比与渗透系数存在“似指数”变化关系。当控制试样孔隙比为0.65时,在强酸溶液中(pH=3),尾砂的渗透系数随浸泡时间延长而增加,表现为二次抛物线关系,浸泡1600 s较浸泡200 s增加了56.92%;在强碱环境下(pH=11),尾砂的渗透系数随浸泡时间呈Logistic函数下降,浸泡1600 s较浸泡200 s下降了73.66%。基于太沙基、柯森、刘杰等渗透理论拟合得到酸性、碱性、中性三种条件下的修正关系模型。根据试验结果分析和扫描电镜观察发现,酸性条件下小颗粒尾砂被侵蚀,大颗粒尾砂棱角凸显,结合水膜变薄,孔隙增大,渗透系数变大;碱性条件下,尾砂颗粒表面与尾砂颗粒间有沉淀胶体覆盖或填充,结合水膜变厚,孔隙减小,渗透系数随之减小。

 

关键字: 尾矿砂;化学环境;渗透系数;孔隙比;微观结构

Experimental on influence of pore ratio on tailings sand permeability under different chemical conditions
ZHU Li-yi1, 2, YANG Peng2, 3, Lü Wen-sheng1, 2, CHENG Xiao-liang4, WANG Kun5

1. Key Laboratory of High-Efficient Mining and Safe of Metal, Ministry of Education, University of Science and Technology Beijing, Beijing 100083, China;
2. School of Civil and Resource Engineering, University of Science and Technology Beijing, Beijing 100083, China;
3. Beijing Key Laboratory of Information Service Engineering, Beijing Union University, Beijing 100101, China;
4. Power China Beijing Engineering Corporation Limited, Beijing 100020, China;
5. School of Mining and Safety Engineering, Shandong University of Science and Technology, Qingdao 266590, China

Abstract:In order to explore the feature rule of pore ratio and soaking time on the permeability of tailings sand under the action of different acid and alkaline fluid environments, seven groups of samples with different pore ratio were prepared. A laboratory experiment of variable head permeability was designed to analyze the permeability of tailings sand. The permeability variation of tailings under eight soaking times was studied by the method of controlling variables. The scanning electron microscope and X-ray energy spectrometer was used to investigate the mechanism between pore ratio and permeability of tailings under different chemical conditions. The results show that a similarity index relationship between pore ratio and permeability coefficient of tailings under different chemical conditions. When the void ratio of the sample is 0.65, in strong acid solution (pH=3), the permeability coefficient of tailings increases with the increase of soaking time, showing a quadratic parabolic relationship. The permeability coefficient of the tailings soaked for 1600 s increases by 56.92% compared with that soaked for 200 s. In the strong alkali environment (pH=11), the permeability coefficient of tailings decreases with the soaking time as a logistic function, and the permeability of tailings decreases by 73.66% in 1600 s compared with that in 200 s. Based on the penetration theory of TERZAGHI, KOSEN and LIU JIE, the modified relationship model is obtained under acidic, alkaline and neutral conditions. According to the analysis of test results and the images observed from scanning electron microscopy, it is found that under acidic conditions the small tailings are eroded and large tailings have prominent edges and corners. Meanwhile, the bound water film thinner, the pore size increases, and the permeability coefficient increases. However, under alkaline conditions, the surface of tailings particles and tailings particles are covered or filled with precipitated colloids. Furthermore, the bound water film becomes thicker, the porosity decreases, and the permeability coefficient decreases accordingly.

 

Key words: tailings sand; chemical environment; permeability coefficient; pore ratio; microstructure

ISSN 1004-0609
CN 43-1238/TG
CODEN: ZYJXFK

ISSN 1003-6326
CN 43-1239/TG
CODEN: TNMCEW

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