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
石英 1聂锐洋 1周诗彤 1陆思成 1卿子萱1
作者信息
- 1. 中南大学资源与安全工程学院,湖南 长沙 410083
- 折叠
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SO2-4 浓度从0增加至30000 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15000 mg/L时达到最高.过量的SO2-4 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.
Abstract
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Key words
environmental impact/sulfate-containing wastewater/phosphogypsum/hydration reaction/cemen-ted backfill/compressive strength引用本文复制引用
基金项目
国家自然科学基金面上项目(42177160)
出版年
2024
NETL
NSTL
万方数据