硫化钠调控膏体充填料浆凝结硬化性能研究

Study of Sodium Sulfide to Regulate the Coagulation and Hardening Properties of Paste-filled Slurry

为解决某矿膏体充填料浆凝结硬化缓慢而引发的充填体质量差、采充周期长、矿石生产效率低等问题,研究采用硫化钠作为改性剂调控膏体充填料浆凝结硬化性能。研究结果表明:硫化钠通过钝化尾砂-水泥-矿渣基复合胶凝体系中的锌离子和加速碱矿渣水化反应进程,发挥出显著的促凝效果,随着硫化钠添加量的增加,膏体充填料浆凝结时间呈线性降低趋势,塌落度和流动度呈负相关,稠度呈正相关,充填体7 d、14 d、28 d抗压强度呈先上升后降低的趋势,且硫化钠添加量1.5%是充填体抗压强度变化的拐点。当灰砂比为1∶8,硫化钠添加量为1.5%时,膏体充填料浆塌落度为28.0 cm,稠度为11.4 cm,流动度为73 cm,充填体7 d、14 d、28 d抗压强度分别为2.08,3.11,3.99 MPa,可满足矿山充填开采的要求。

In order to solve the problems of poor quality of filling body,long mining and filling cycle,and low ore production efficiency caused by slow solidification and hardening of paste-filled slurry in a mine,using sodium sulfide as a modifier to regulate the solidification and hardening performance of paste-filled slurry was studied.The results are concluded as follows.Sodium sulfide plays a significant role in promoting coagulation by passivating zinc ions in tailings-cement-slag-based composite cementitious system and accelerating the hydration reaction process of alkali slag.With the increase of sodium sulfide addition,the coagulation time of paste filling slurry decreases linearly,the slump and fluidity are negatively correlated,the consistency is positively correlated,and the compressive strengths of filling body at 7,14 and 28 days increase first and then decrease.And sodium sulfide addition of 1.5%is the inflection point of the change of the compressive strength of the filling body.When the cement-sand ratio is 1∶8 and the sodium sulfide addition is 1.5%,the slump of the paste-filled slurry is 28.0 cm,the consistency is 11.4 cm,the fluidity is 73 cm,and the compressive strengths of the filling body at 7 d,14 d and 28 d are 2.08,3.11 and 3.99 MPa respectively,which can meet the requirements of filling and mining in mines.