稀土废渣地质聚合物制备及其力学性能  

Preparation and mechanical properties of rare earth residue geopolymers

作　　者：黄龙 张骞[1,2,3] 胡佳乐 蓝桥发[1,2] 来鹏飞 刘帅峰 张小林[1,2] HUANG Long;ZHANG Qian;HU Jiale;LAN Qiaofa;LAI Pengfei;LIU Shuaifeng;ZHANG Xiaolin(Jiangxi Provincial Key Laboratory of Green and Low Carbon Metallurgy for Strategic Nonferrous Metals,Ganzhou 341000,China;School of Metallurgical Engineering,Jiangxi University of Science and Technology,Ganzhou 341000,China;Fuye Group Co.,Ltd.,Hangzhou 310000,China)

机构地区：[1]战略有色金属绿色低碳冶金江西省重点实验室,赣州341000 [2]江西理工大学材料冶金化学学部,赣州341000 [3]富冶集团有限公司,杭州310000

出　　处：《江西冶金》2025年第2期168-176,共9页Jiangxi Metallurgy

基　　金：国家重点研发计划项目(2021YFB3500902);国家“十四五”重点研发计划“战略性矿产资源开发利用”重点专项项目(2022YFC2905201)。

摘　　要：在稀土提取分离过程中会产生部分低放射性稀土废渣,对周边环境安全构成严重威胁,需要对其进行安全化处理。通常采用固化填埋处理稀土废渣,将其转制成抗压强度高的地质聚合物,可进一步提升填埋体的稳定性和安全性。本研究以稀土低放射性废渣和粉煤灰为原材料,在复合碱激发剂的作用下制备地质聚合物,考察稀土废渣掺量、液固比、固化温度、SiO_(2)/Al_(2)O_(3)摩尔比、Na_(2)O/Al_(2)O_(3)摩尔比对地质聚合物抗压强度的影响,通过正交实验得出了各影响因素的优先次序,优化了地质聚合物基固化物的工艺条件,并采用毒性浸出实验检测地质聚合物基固化物的安全性。结果表明,当固化温度为75℃、液固比(mL/g)为0.33、SiO_(2)/Al_(2)O_(3)摩尔比为4.0、Na_(2)O/Al_(2)O_(3)摩尔比为0.9、稀土废渣掺量为5%(质量分数)时,稀土废渣地质聚合物的抗压强度最高,达到30.47 MPa;在7 d毒性浸出液中Th、U累积浸出浓度均低于0.1μg/L,低于工业外排废水的放射性元素含量标准。Low-radioactive rare earth residues are generally produced in the rare earth extraction and separation process,which poses a serious threat to the surrounding environment and needs to be safely disposed.The common method of handling rare earth residue is solidification and landfilling,which can be transformed into geopolymers with high compressive strength,further improving the stability and safety of the landfilled body.This study utilized low-level radioactive rare earth residue and fly ash as raw materials to prepare geopolymers under the action of a composite alkali activator.The effects of rare earth residue content,liquid-to-solid ratio,solidification temperature,SiO_(2)/Al_(2)O_(3)molar ratio,and Na_(2)O/Al_(2)O_(3)molar ratio on the compressive strength of the geopolymers were investigated.In this study,geopolymers were prepared by using low-level radioactive rare earth residue and fly ash as raw materials under the action of a composite alkali activator.An orthogonal experiment was conducted to optimize the preparation conditions of the geopolymer-based solidification material,and a toxicity leaching test was performed to verify its safety.The results indicate that when the solidification temperature is 75℃,the liquid-solid ratio(mL/g)is 0.33,the molar ratio of SiO_(2)/Al_(2)O_(3)is 4.0,the molar ratio of Na_(2)O/Al_(2)O_(3)is 0.9,and the content of rare earth residue is 5%(mass fraction),the highest compressive strength of rare earth residue geopolymers is achieved,and reaching 30.47 MPa.In the 7-day toxicity leachate,the cumulative leaching concentrations of Th and U are both below 0.1μg/L,which is lower than the standard for radioactive element content in industrial effluents.

关 键 词：稀土废渣 地质聚合物 力学性能 粉煤灰 

分 类 号：TF042[冶金工程—冶金物理化学]