引发全尾砂料浆触变特征的临界粒径研究

Study on critical particle size of thixotropic characteristics of full tailings slurry

细粒径尾砂颗粒絮凝−分解是充填料浆产生触变性的根本原因,然而目前对引发充填料浆触变性的临界粒径研究极少。通过对不同粒径尾砂制备的充填料浆开展触变试验与微观结构的演化测试,结合Patwardhan提出的非牛顿流体理论分析尾砂颗粒间相互作用力,推导引发全尾砂料浆触变性能临界粒径的理论值,最终建立了充填料浆触变性模型。结果表明:充填料浆触变性能与剪切速率、质量分数、尾砂细颗粒含量呈正相关,通过理论推导得出引发充填料浆触变性能的临界值为45μm。由此可以认为,当充填料浆中含有粒径<45μm颗粒,且质量分数≥6%时,充填浆料则具有触变效应;反之,充填浆料则不具备触变性。基于实验结果采用Hattori−Lzumi理论构建触变性模型,并结合流变测试结果拟合得到了充填料浆触变性系数。

The flocculation-decomposition of fine-size tailings particles is the fundamental reason for the thixotropy of filling slurry.However,there is little research on the critical particle size of filling slurry that causes the thixotropy.Through thixotropic tests and microstructure evolution tests on filling slurry prepared from tailings with different particle sizes,combined with non-Newtonian fluid theory proposed by Patwardhan,the interaction force of tailings particles was analyzed,and the theoretical value of critical particle size leading to thixotropic performance of full tailings slurry was derived.Finally,the thixotropic model of filling slurry was established.The results show that thixotropy of filling slurry is positively correlated with shear rate,mass fraction and fine particle content of tailings,and the critical value of thixotropy of filling slurry with particle size of 45μm is obtained by theoretical derivation.When the filling slurry contains particles with particle size<45μm and mass fraction≥6%,the filling slurry has obvious thixotropic effect.On the contrary,the filling slurry has no thixotropy.Based on the experimental results,the Hattori-Lzumi theory is used to construct a thixotropic model,and combined with the rheological test results,the thixotropic coefficient of the filling slurry is obtained.