Abstract

Along with slurry concentration and particle density, particle size distribution (PSD) of tailings also exerts a significant influence on the yield stress of cemented paste, a non-Newtonian fluid. In this work, a paste stability coefficient (PSC) was proposed to characterize paste gradation and better reveal its connection to yield stress. This coefficient was proved beneficial to the construction of a unified rheological model, applicable to different materials in different mines, so as to promote the application of rheology in the pipeline transportation of paste. From the results, yield stress showed an exponential growth with increasing PSC, which reflected the proportion of solid particle concentration to the packing density of granular media in a unit volume of slurry, and could represent the properties of both slurry and granular media. It was found that slurry of low PSC contained extensive pores, generally around 20 μm, encouraging free flow of water, constituting a relatively low yield stress. In contrast, slurry of high PSC had a compact and quite stable honeycomb structure, with pore sizes generally < 5 μm, causing the paste to overcome a higher yield stress to flow.

中文翻译：

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颗粒级配特性对水泥浆回填屈服应力的影响

摘要

除浆液浓度和颗粒密度外，尾矿的粒度分布（PSD）也对非牛顿流体胶结浆的屈服应力产生重大影响。在这项工作中，提出了一种糊剂稳定性系数（PSC）来表征糊剂级配并更好地揭示其与屈服应力的关系。实践证明，该系数有利于建立统一的流变模型，适用于不同矿山中的不同物料，从而促进流变学在糊料管道输送中的应用。结果表明，屈服应力随PSC的增加呈指数增长，反映了单位体积浆料中固体颗粒浓度与颗粒介质堆积密度的比例，可以代表浆料和颗粒介质的特性。已经发现，低PSC的浆液包含大孔，通常为约20μm，这促进了水的自由流动，构成了相对较低的屈服应力。相反，高PSC的浆料具有致密且相当稳定的蜂窝状结构，孔径通常<5μm，从而使浆料克服了较高的屈服应力而流动。