外加剂对膨胀充填材料性能的影响

The Influence of Additives on the Properties of Expansion Filling Materials

充填采矿法因其具有矿石回收率高、矿石损失贫化小以及能有效控制采场地压等优点而在国内外金属矿山得到广泛应用。但充填料浆泌水沉降、空区形状不规则等原因造成充填体不能充分接顶,这将严重影响井下安全生产和地表构筑物的稳定性。为解决此类问题,本工作通过向充填料浆中添加外加剂来制备可以主动接顶的膨胀充填材料,并探讨了外加剂用量对充填料浆的流动性、膨胀充填体的单轴抗压强度(UCS)、表观密度和孔隙率的影响。研究结果表明:在试验选取的掺量范围内,增稠剂、发泡剂会降低充填料浆的流动性和表观密度,当增稠剂掺量为0.6%(质量分数,下同)时,充填体UCS达到最大值1.16 MPa;稳泡剂通过改善气泡稳定性会轻微提高充填体强度,当稳泡剂掺量为0.5%~0.7%时,充填体UCS提高约2.7%;膨胀充填体基本在30 min内停止体积增长,当发泡剂掺量从1.5%增加到3%时,充填体28 d强度和孔隙率相应地降低了37.3%和提高了13.9%。

Backfill mining method is widely used in domestic and foreign metal mines due to its advantages such as high ore recovery rate,small ore loss dilution and effective control of mining site pressure.However,the goaf cannot be fully filled due to the bleeding and sedimentation of the filled filler slurry and the irregular shape of the empty area,which will seriously affect the safety of underground production and the stability of surface structures.In order to solve such problems,this work prepared the active top-up of the expansive filler by adding additives to the slurry,and explores the fluidity,UCS,apparent density and porosity of cemented paste backfill(CPB).The results show that within the range of the amount selected in the experiment,the thickener and foaming agent will reduce the fluidity and apparent density of the slurry.When the thickener content is 0.6%(mass fraction,the same below),the UCS content reaches a maximum 1.16 MPa.Foam stabilizer affects the strength of the filler by improving the stability of the bubble.When the content of foam stabilizer is 0.5%—0.7%,the UCS of CPB increases by about 2.7%.The volu-me expansion of the CPB basically stops within 30 min.With foam agent increasing from 1.5%to 3%,the strength(28 d)of CPB decreases by 37.3%and the porosity of CPB increases by 13.9%.