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电除尘粉煤灰对铅锌尾砂胶结充填体性能的影响
Effect of Fly Ash Collected by Electrofilter on Cementation Backfill Performance of Lead-Zinc Tailings
【摘要】 为研究电除尘粉煤灰(EFA)对铅锌尾砂胶结充填体性能的影响规律。通过坍落度测试和流变性计算,分析了料浆的流动性。同时,测定了充填体抗压强度的变化情况,并通过低场核磁共振技术(L-F NMR)分析了充填体孔隙的变化规律。结果表明,EFA和普通硅酸盐水泥(OPC)的最佳掺比为EFA∶OPC=4∶6。此时,料浆的坍落度为27.0 cm,且其屈服应力和塑性黏度分别降低了16.60 Pa和0.0258 Pa·s。在最佳的EFA掺比下,后期充填体强度显著增加,且在第28天养护龄期下的充填体抗压强度最高,为2.76 MPa。同时,L-F NMR测试结果表明,在最佳的EFA掺比下,后期充填体中的孔隙率显著降低,第28天时充填体总孔隙率为12.50%,充填体中的微孔、过渡孔、中孔和大孔的孔隙率分别为5.51%、4.48%、1.37%和1.14%。铅锌尾砂充填效果改善的原因是最佳的EFA掺比改善了料浆的颗粒级配,降低了料浆的屈服应力和塑性黏度,同时,改善了充填体的内部结构,降低了孔隙率,提高了充填体的密实性和抗压强度。
【Abstract】 In order to investigate the influence of Fly ash collected by electrofilter(EFA) on the cementation filling performance of lead-zinc tailings, the flowability of the slurry was analyzed by slump and rheological calculation. At the same time, the change of the compressive strength of the backfill was measured, and the change rule of the porosity of the backfill was analyzed by low-field nuclear magnetic resonance(L-F NMR). The results show that the optimum blending ratio of EFA and OPC is 4∶6.At this time, the slump of the slurry is 27.0 cm, and its yield stress and plastic viscosity are reduced by 16.60 Pa and 0.0258 Pa·s, respectively. Under the optimal EFA blending ratio, the strength of the later backfill increases significantly, and the compressive strength of the backfill is the highest at the curing age of 28 days, which is 2.76 MPa. Meanwhile, the L-F NMR test shows that the porosity of the later backfill is significantly reduced under the optimal EFA blending ratio. At 28 days, the total porosity of the backfill is 12.50%, and the porosity of the micropores, transition pores, mesopores and macropores in the backfill is 5.51%, 4.48%, 1.37% and 1.14%, respectively. The reason for the improvement of the filling effect of lead-zinc tailings is that the optimal EFA blending ratio improves the particle gradation of the slurry, reduces the yield stress and plastic viscosity of the slurry, and improves the internal structure of the backfill. Meanwhile, the porosity is reduced, and the density and compressive strength of the backfill are improved.
【Key words】 Fly ash collected by electrofilter; Compressive strength; Low-field nuclear magnetic resonance; Porosity;
- 【文献出处】 矿业研究与开发 ,Mining Research and Development , 编辑部邮箱 ,2024年06期
- 【分类号】TD853.34
- 【下载频次】48