摘要
超细尾砂已成为金属矿山充填处理的最大宗固体废料,流变模型是刻画超细尾砂料浆流动特性及确定管输参数的主要依据。基于超细颗粒絮凝结构形成机制,引入结构参数来描述超细尾砂料浆剪切响应过程。采用旋转黏度计对某矿山质量分数72%、74%、76%和水泥添加量240、260 kg/m^(3)的超细尾砂充填料浆进行24组不同剪切强度下的流变测试。结果表明:在恒定剪切速率下,料浆剪切应力随着剪切时间延长而逐渐减小,最后趋于稳定;任意剪切时间下,剪切应力与剪切速率(>20s^(-1))的关系近似满足Bingham模型,且Bingham回归参数具有明显的时变性。这些宏观规律的原因可归结于浆体结构参数的变化。基于此,构建了关于浆体剪切强度和剪切时间的双变量流变模型,模型中7个参数均具有物理含义。通过试验数据对模型进行了验证,拟合得到试验配比下的超细尾砂料浆流变参数,最大屈服应力和最大塑性黏度范围分别为120~220Pa和1.7~7.2Pa·s,可为启动压力计算提供参考;极限屈服应力和极限塑性黏度范围分别为20~120 Pa和0.5~3.2 Pa·s,可为浆体稳态流动阻力计算提供参考。另外,介绍了新流变模型的适用条件及应用方法,并与现有流变模型进行了对比讨论。
Ultrafine tailings have become the largest solid waste in metal mine filling treatment.The rheological model provides a theoretical foundation for capturing its flow characteristics and determining the pipeline transportation parameters.To describe the shear response process of ultrafine tailings slurry,firstly,the concept of the structural parameter in this paper was introduced based on the formation mechanism of ultrafine particle flocculation structure.Then,a rotary viscometer was used to conduct 24 groups of rheological tests on the ultrafine tailings slurry with mass fractions of 72%,74%and 76%and cement contents of 240 and 260 kg/m^(3) under different shear strengths.The results show that under constant shear strength,the shear stress of the slurry gradually decreases with the increase of shear time,and ultimately tends to be stable;under any shear time,the shear stress and shear rate(>20 s^(-1))approximately satisfy the Bingham model,and the Bingham regression parameters are obviously time-varying.The reason for these macroscopic laws can be attributed to the change of the slurry structural parameters.According to these evidences,a bivariate rheological model of the ultrafine tailings slurry with respect to shear strength and shear time was proposed,in which seven parameters have certain physical meanings.The proposed model was verified by the experimental data,and the rheological parameters of the ultrafine tailings slurry with the given mix are obtained by the best fitting.The maximum yield stress and maximum plastic viscosity range from 120 Pa to 220 Pa and from 1.7 Pa·s to 7.2 Pa·s,respectively,which can provide a reference for the calculation of the starting pressure;the range of the limit yield stress and plastic viscosity are from 20 Pa to 120 Pa and from 0.5 Pa·s to 3.2 Pa·s,respectively,which can give a reference for the calculation of the steady-state flow resistance of the slurry.Lastly,the applicable conditions and methods of the proposed rheological model are discussed,and also compared wi
作者
付自国
李化
邓建辉
乔登攀
王佳信
FU Zi-guo;LI Hua;DENG Jian-hui;QIAO Deng-pan;WANG Jia-xin(College of Water Resources and Hydropower,Sichuan University,Chengdu 610065,China;State Key Laboratory of Hydraulics and Mountain River Engineering,Sichuan University,Chengdu 610065,China;Key Laboratory of Deep Earth Science and Engineering,Ministry of China,Sichuan University,Chengdu 610065,China;Faculty of Land Resource Engineering,Kunming University of Science and Technology,Kunming 650093,China)
出处
《中国有色金属学报》
EI
CAS
CSCD
北大核心
2021年第6期1672-1685,共14页
The Chinese Journal of Nonferrous Metals
基金
国家自然科学基金资助项目(U19A2098,41772322)
国家重点研发计划资助项目(2016YFC0600702)。
关键词
充填料浆
超细尾砂
絮凝结构
触变性
流变参数
流变模型
filling slurry
ultrafine tailings
flocculation structure
thixotropy
rheological parameter
rheological model
