Na_(2)SO_(4)溶液作用下碱激发钨尾矿强度和微观特性研究  

Study on strength and microscopic characteristics of alkali-activated tungsten tailings under the action of Na_(2)SO_(4)solution

作　　者：李善梅[1,2] 曹佳豪 夏炜燕 曹贤发[1,2] 蒙剑坪[1,2] LI Shanmei;CAO Jiahao;XIA Weiyan;CAO Xianfa;MENG Jianping(College of Civil Engineering and Architecture,Guilin University of Technology,Guilin 541004,China;Guangxi Key Laboratory of Geomechanics and Geotechnical Engineering,Guilin University of Technology,Guilin 541004,China)

机构地区：[1]桂林理工大学土木工程学院,广西桂林541004 [2]桂林理工大学广西岩土力学与工程重点实验室,广西桂林541004

出　　处：《混凝土》2025年第2期105-110,114,共7页Concrete

基　　金：国家自然科学基金(52268055);广西科技计划项目(2023GXNSFBA026269)。

摘　　要：沿海城市和盐碱地的土木工程建设无法避免材料受Na_(2)SO_(4)的侵蚀。为研究碱激发钨尾矿的抗Na_(2)SO_(4)侵蚀性能,以NaOH、KOH、Na_(2)SiO_(3)、K_(2)SiO_(3)为激发剂,测试不同浸泡龄期的试样无侧限抗压强度。试验结果表明:随浸泡龄期增长,NaOH和KOH激发钨尾矿的强度均先增大再减小,K_(2)SiO_(3)和Na_(2)SiO_(3)·9H_(2)O激发的钨尾矿的强度减小。结合XRD、SEM、FTIR和ICP等微观测试结果可知,Na_(2)SO_(4)对该类材料的危害并非石膏和钙矾石导致,而是由于溶液与凝胶体系之间离子交换和扩散导致。离子间相互作用导致凝胶形貌和组构均发生改变,高钙低钠容易形成膜状凝胶,高钠易形成碎屑状、球状和三维网状凝胶,K^(+)替代凝胶中的Na^(+)易形成溶蚀孔。膜状凝胶对强度提高的贡献最大,团粒状次之,碎屑状、球状和三维网状次次小,溶蚀孔最小。Civil engineering construction in the coastal cities and the saline-alkali lands cannot avoid material erosion by Na_(2)SO_(4).In order to study the anti-Na_(2)SO_(4)erosion performance of alkali-excited tungsten tailings,Na OH,KOH,Na_(2)SiO_(3)and K_(2)SiO_(3)were used as initiators to test the unconfined compressive strength of samples at different immersion ages.The experimental results showed that the strength of tungsten tailings activated by NaOH and KOH increased and then decreased with the increase of immersion age,and the strength of tungsten tailings excited by K_(2)SiO_(3)and Na_(2)SiO_(3)·9H_(2)O decreased.Combined with the microscopic test results of XRD,SEM,FTIR,and ICP,it can be seen that the hazard of Na_(2)SO_(4)to such materials is not caused by gypsum and alumina,but by ion exchange and diffusion between the solution and the gel system.The interaction between ions led to changes in gel morphology and composition,high calcium and low sodium were easy to form membrane-like gels,high sodium was easy to form chip-like,spherical and three-dimensional reticular gels,and the dissolution pores formed when K^(+)replaces Na^(+)in the gel.The contribution of the film gel to the strength is the largest,followed by the agglomerates,debris,globular,and three-dimensional reticular,and the dissolution pore is the smallest.

关 键 词：碱激发 钨尾矿 微观特性 离子扩散 

分 类 号：TU528.041[建筑科学—建筑技术科学]