Effect of Fly Ash Collected by Electrofilter on Cementation Backfill Performance of Lead-Zinc Tailings
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.
Fly ash collected by electrofilterCompressive strengthLow-field nuclear magnetic resonancePorosity
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