含硫酸盐废水对磷石膏胶结充填体材料性能的影响  

Effect of Sulfate-Containing Wastewater on the Properties of Phosphogypsum-Based Cemented Paste Backfill

作　　者：石英[1] 聂锐洋 周诗彤 陆思成 卿子萱 SHI Ying;NIE Ruiyang;ZHOU Shitong;LU Sicheng;QING Zixuan(School of Resources and Safety Engineering,Central South University,Changsha 410083,Hunan,China)

机构地区：[1]中南大学资源与安全工程学院,湖南长沙410083

出　　处：《黄金科学技术》2024年第3期416-424,共9页Gold Science and Technology

基　　金：国家自然科学基金面上项目“骨料磷石膏对胶结充填体材料性能影响及改性研究”(编号:42177160)资助。

摘　　要：鉴于矿山废水处理工艺具有一定的局限性,且磷石膏充填工艺需要消耗大量的水资源,将矿山含硫酸盐废水作为磷石膏充填用水并探讨其可行性。结果表明:废水中的硫酸盐能够促进磷石膏充填体的早期水化反应,进而提升充填体早期强度。当SO_(4)^(2-)浓度从0增加至30 000 mg/L时,充填体7 d强度由0.46 MPa升高至0.63 MPa,提高了37%;14 d强度由0.64 MPa升高至1.03 MPa,提高了61%。这主要跟水化产物钙矾石(AFt)和水化硅酸钙(C-S-H)的形成有关;但随着养护时间的增长,充填体28,60,90 d强度均在硫酸盐浓度为15 000 mg/L时达到最高。过量的SO_(4)^(2-)会干扰水化硬化过程,充填体后期强度因受到钙矾石的膨胀特性以及Na2SO4重结晶等影响而出现下降。研究结果可为矿山废水治理和磷石膏充填工艺优化提供新思路。Based on the limitation of mine wastewater treatment process and the large demand for water resources in phosphogypsum backfill process,the feasibility of using sulfate-containing mine wastewater as phosphogypsum backfill water was discussed.Results show that the sulfate present in the wastewater promoted the early hydration of the phosphogypsum-based cemented paste backfill,consequently enhancing its early strength.Specifically,as the sulfate concentration increased from 0 to 30000 mg/L,the 7-day strength of the backfill samples increased from 0.46 MPa to 0.63 MPa,representing a 37%increase.The 14-day strength also exhibited a significant increase from 0.64 MPa to 1.03 MPa,indicating a 61%increase.This can mainly be attributed to the formation of hydration products such as ettringite and C-S-H.However,with the increase of the curing time,the 28-day,60-day,and 90-day strength of the backfill samples reach the highest values at a sulfate concentration of 15000 mg/L.Excess sulfate ions can interfere with the hydration and hardening processes,and the long-term strength of the backfill is affected by the expansion caused by AFt and the recrystallization of Na2SO4 and other influences,resulting in a decrease in the strength of backfill samples.The results can provide a new insight into mine wastewater treatment and phosphogypsum-based cemented paste backfill technology.

关 键 词：环境影响 硫酸盐废水 磷石膏 水化反应 胶结充填 抗压强度 

分 类 号：TD803[矿业工程—矿山开采]