尾砂颗粒级配对水泥-钢渣基复合充填料浆流变特性及力学强度的影响

Effect of Tailings Particle Size on Rheological Properties and Mechanical Strength of Cement-Steel Slag-Based Composite Filling Slurry

针对胶东半岛某金矿尾砂充填料浆流动性差、充填体质量低等问题,以该矿全尾砂为研究对象,以当地钢渣、脱硫石膏等工业固体废弃物制备新型胶凝材料,通过正交试验,探究尾砂粉磨时间、灰砂比、料浆质量浓度对充填料浆流变特性及力学强度的影响。研究结果表明,随着灰砂比和料浆质量浓度的增大,料浆黏度和屈服应力增大。尾砂粉磨时间从15 min增加至75 min的过程中,料浆屈服应力从31.17 Pa增加至54.51 Pa,增幅为74.88%,尾砂颗粒越细,较多的细颗粒会堆积在有效流动的料浆中,阻碍料浆正常流动,颗粒剪切接触越充分,屈服应力越大。随着尾砂粉磨时间的延长,细颗粒尾砂填充至胶凝体系大孔洞中,提高了充填体致密度,充填体抗压强度表现为上升趋势,但当尾砂粉磨时间超过45 min时,起骨架支撑作用的粗颗粒尾砂含量相对减少,颗粒间结构较松散,充填体后期强度增加越不明显。抗压强度极差分析结果显示,对充填体抗压强度影响的敏感性大小排序依次为:料浆质量浓度、灰砂比、尾砂粉磨时间。

Aiming at the problems of poor fluidity of tailings filling slurry and low quality of filling body in a gold mine in Jiaodong Peninsula,taking the full tailings of the mine as the research object,a new type of cementitious material was prepared from local steel slag,desulfurization gypsum and other industrial solid wastes.Through orthogonal tests,the effects of tailings grinding time,cement-sand ratio and slurry mass concentration on the rheological properties and mechanical strength of filling slurry were explored.The results show that the viscosity and yield stress of slurry increase with the increase of cement-sand ratio and slurry mass concentration.When the tailings grinding time is increased from 15 min to 75 min,the yield stress of the slurry increases from 31.17 Pa to 54.51 Pa,with an increase of 74.88%.The finer the tailings particles are,the more fine particles will accumulate in the effectively flowing slurry,preventing the normal flow of the slurry.The fuller the particle shear contact,the greater the yield stress.With the extension of tailings grinding time,fine tailings is filled into the large holes of the cementation system,which improves the density of the filling body,and the compressive strength of the filling body shows an upward trend.However,when the tailings grinding time exceeds 45 min,the content of coarse tailings that plays the role of skeleton support is relatively reduced,the structure between particles is relatively loose,and the strength increase of the filling body is less obvious in the later stage.According to the range analysis results of compressive strength,the sensitivity order of the impact on the compressive strength of the filling body is:slurry mass concentration>cement-sand ratio>tailings grinding time.