不同剪切模式下的全尾砂浆触变特性研究

Study on the thixotropic characteristics of the unclassified-tailing mortar in different shear modes

为了探究尾砂胶结充填料浆的触变特性,以某铁矿全尾砂为研究对象,测试充填料浆在恒定剪切模式、环形剪切模式和阶跃剪切模式下的流变参数变化规律。结果表明:恒定剪切模式下剪切应力与表观黏度都随着时间的增加逐渐下降直至趋于稳定,而随着剪切速率的升高,料浆的屈服应力逐渐升高且塑性黏度逐渐减小;循环剪切模式下无论剪切速率升高或是降低,剪切应力总体呈现下降趋势,而表观黏度变化规律则与剪切速率变化相反;阶跃剪切模式下随着剪切速率的突增,尾砂料浆会再次进入弹性变化阶段剪切应力与表观黏度皆有略微升高随后进入应力松弛阶段剪切应力及表观黏度逐渐降低。对尾砂料浆的触变性规律做出了一定的解释,对矿山现场管道输送提供一定的指导意义。

In order to explore the thixotropic characteristics of the cementing filling slurry with tailings,the rheological parameters of an unclassified-tailing are tested under the conditions of constant shear mode,annular shear mode and terraced shear mode.The results show that the shear stress and apparent viscosity in a constant shear mode decrease gradually with the increase of time until they tend to be stable,while the yield stress of slurry increases gradually with the increase of shear rate and the plastic viscosity decreases gradually.In cyclic shear mode,no matter the shear rate increases or decreases,the shear stress generally presents a downward trend,while the change of apparent viscosity is opposite to the change of shear rate.In the step shear mode,with the sudden increase of shear rate,the tailings slurry will enter the elastic change stage again,and the shear stress and apparent viscosity will increase slightly,and then enter the stress relaxation stage,the shear stress and apparent viscosity will gradually decrease.The thixotropic law of tailing slurry are explained,which is of certain guiding significance to the field pipeline transportation of mine.