充填尾砂颗粒干扰沉降过程实验研究

尾砂浓密作为充填料浆制备的关键工序是目前研究的热点，并已经取得了包括尾砂仓浓密机理，絮凝剂选择方法在内的多种实践性研究成果。但该工序中所涉及的充填尾砂颗粒“干扰沉降”过程的机理研究却相对滞后，缺乏相应的经验或理论计算模型，已经成为制约不同级配尾砂高效浓缩、稳态造浆与精准过程控制的技术瓶颈。因此，探索尾砂颗粒“干扰沉降”过程的特征，在总结与综述国内外具有代表性的干扰沉降相关理论基础上，利用某矿山经分级处理后的分级尾砂与溢流细砂为原料，开展了多种配比尾砂浆的干扰沉降实验，并依据Kynch理论，对实验数据进行拟合处理，在此基础上分析论证了Richardson-Zaki均匀干扰沉降与Selim非均匀干扰沉降理论在研究充填尾砂颗粒沉降过程时的适用性。研究结果表明:基于Richardson-Zaki理论计算的尾砂颗粒均匀干扰沉降速率值与实验实测结果相吻合，两者的相关性可决系数达0.87，且残差值无明显规律，验证了其对尾砂颗粒均匀干扰沉降速率计算的适用性。基于Selim理论所得计算结果较均匀干扰沉降理论计算值更接近实验中尾砂浆非均匀干扰沉降的实测值，从而证明该理论能够反映尾砂颗粒非均匀干扰沉降中因不同粒径颗粒相互作用而降低了各自的沉降速率的特性，能够为尾砂浓密工程实践提供参考。同时，通过分析，为进一步阐明尾砂颗粒干扰沉降机理，将继续对尾砂级配对干扰沉降的影响及其定量化表征以及粗细颗粒相互作用的机理等问题进行深入研究。

Experimental study on the hindered settling process of backfill tailings

As a key procedure of preparation of backfill slurry,the tailings thickening has hence been treated as a research focus.Many practical results including the thickening mechanism of tailings tank and principles of selection of flocculants have already been obtained.However,the mechanism studies of the hindered settling of tailing particles have been lagged,resulting in lacking empirical or theoretical calculation models,which will restrict the high efficient thickening of tailings and the precise control of preparation of different tailings slurries.Therefore,to further study the insuffi-cient aspects of aforementioned researches and to gain the features of the hindered settling of backfill tailing par-ticles,by using the classified and fine tailings from a real mine,the hindered settling experiments with the different contents of tailings and concentrations have been carried out.Based on Kynch theory,the experimental results have been fitted to describe and demonstrate the applicability of Richardson-Zaki theory and Selim theory in calculating the hindered and polydisperse settling of tailing particles.The fitted results show that the R-square figure between the calculated settling rates based on Richardson-Zaki theory and the experimental results is over 0.87 and there is no obvious relations among the residual errors,which proves the applicability of Richardson-Zaki theory.Comparing to the values calculated through Richardson-Zaki theory,the results based on Selim theory are closer to the real ones of polydisperse settling,which means Selim theory can represent some features of polydisperse settling,namely the velocity decrease features caused by the interactions of tailing particles and can be utilized as a reference in tailings thickening.Furthermore,to clearly explain the mechanism of hindered settling process,the effects of PSD of tailings on hindered settling and its mathematical expression and the mechanism of interactions between coarse and fine tailings in this process will be studied in the future.