浸矿过程中离子吸附型稀土矿力学特性实验研究

Experimental Research on Mechanical Properties of Ion-adsorption Rare Earth in Leaching Process

为研究离子吸附型稀土矿在整个浸矿过程中矿样力学特性的演变规律,利用不固结不排水三轴实验,并结合核磁共振测试技术,得到了不同浸矿时间下稀土试样的应力-应变曲线和试样核磁共振反演图像,建立了稀土试样的应力-应变本构模型。结果表明,伴随着离子置换反应自上而下的过程,稀土试样内部也存在固体微细颗粒自上而下运移过程,该过程会弱化矿体强度。相同围压条件下,在有效浸矿时间内,浸矿试样的偏应力随着浸矿时间的增加而逐渐减小,但在有效浸矿时间过后,其偏应力随着浸矿时间的增加而有所增大,但不会超过其初始偏应力值。在三轴压缩过程中,对试样施加的围压增大的同时,其相应的偏应力也有所增大。实验结果与邓肯-张模型计算出的数据基本一致,拟合精度良好,可采用邓肯-张模型描述和预测不同浸矿时间的稀土矿样的应力-应变的曲线走势。

In order to study the evolution of the mechanical properties of ion type rare earth ore in the whole leaching process,the stress-strain curve of samples under different leaching time was obtained by unconsolidated undrained triaxial test and combining with the nuclear magnetic resonance testing technology,the inversion images of samples was also obtained.The results show that with the ion displacement reaction from top to bottom,there are also solid fine particles involving in migrating process in the rare earth sample from up to down,which will weaken the strength of the ore-body.Under the same confining pressure condition,the deviatoric stress of the leaching samples decreases with the increase of the leaching time during the effective immersion time.After the effective leaching time,the deviatoric stress of the samples gradually increases with the increase of the leaching time,but does not exceed the initial deviatoric stress value of the samples.During the triaxial compression process,the confining stress applied to the sample increases,and the corresponding deviatoric stress of the sample also increases.The results are basically consistent with the data calculated by the Duncan-Chang model,and the fitting accuracy is good.The model can be used to describe and predict the stress-strain curve of rare earth ore samples with different leaching time.