摘要
以混合相磷石膏为主要原料,掺入矿渣、赤泥、偏高岭土、熟料制备混合相磷石膏基胶结材,通过抗压强度、p H和浸出毒性测试研究其早期性能,采用X射线衍射(XRD)、扫描电镜(SEM)和傅里叶变换红外光谱(FT-IR)测试分析水化机理。结果表明:53.76%(质量分数,下同)混合相磷石膏、9.68%矿渣、9.68%赤泥、16.13%偏高岭土和10.75%熟料可制备出性能最优的混合相磷石膏基胶结材,其3、5、7 d抗压强度分别达到8.93、10.99、13.14 MPa,p H碱性低于传统水泥基材料,总磷、氟化物浸出浓度均满足污水综合排放标准要求;磷石膏在400℃下煅烧60 min形成半水-无水混合相磷石膏,其中半水石膏和无水石膏的相对含量分别为31.7%和68.3%。混合相磷石膏基胶结材水化生成的水化硅酸钙凝胶、钙矾石和透钙磷石等物质形成致密结构,提升材料强度,阻隔污染物F^(-)、PO_(4)^(3-)浸出。混合相磷石膏基胶结材具有良好的力学性能和环境相容性,可为磷石膏规模化消纳提供新途径。
Mixed phase phosphogypsum was used as the main raw material,and slag,red mud,metakaolin and clinker were added to prepare mixed phase phosphogypsumbased cementing material.Its early performance was studied by compressive strength,pH and leaching toxicity tests,and the hydration mechanism was elaborated by X-ray diffraction(XRD),scanning electron microscope(SEM)and Fourier transform infrared spectroscopy(FT-IR)tests.The results showed that 53.76%(mass fraction,the same below)of mixed phase phosphogypsum,9.68%of slag,9.68%of red mud,16.13%of metakaolin and 10.75%of clinker could prepare the mixed phase phosphogypsum cementing material with optimized performance,and its compressive strength at the 3,5 d and 7 d were 8.93,10.99 MPa and 13.14 MPa respectively.Its pH alkalinity was lower than that of traditional cementbased materials,and the leaching concentration of PO_(4)^(3-) and F^(-) were lower than the limit ofthe integrated wastewater discharge standard.The results of microscopic analysis showed that phosphogypsum was calcinedat 400 ℃ for 60 min to form hemihydrateanhydrate mixed phase phosphogypsum,in which the relative contents of hemihydrate and anhydrate gypsum were 31.7% and 68.3% respectively.The hydrated calcium silicate gel,ettringite and brushitegenerated by hydration of mixed phase phosphogypsumbased cementing materials formed dense structures,which wouldimprove the strength of materials and block the leaching of pollutants.The mixed phase phosphogypsumbased cementingmaterial had good mechanical properties and environmental compatibility,which provided a new potential way for the largescale consumption of phosphogypsum.
作者
王茹霆
赵小蓉
黄绪泉
王豪杰
薛菲
蔡家伟
WANG Ruting;ZHAO Xiaorong;HUANG Xuquan;WANG Haojie;XUE Fei;CAI Jiawei(Engineering Research Center of Eco-environment in Three Gorges Reservoir Region,Ministry of Education,China Three Gorges University,Yichang 443002,China;College of Hydraulic&Environmental Engineering,China Three Gorges University,Yichang 443002,China;Yichang Key Laboratory of Solid Waste Disposal and Resource Utilization,China Three Gorges University,Yichang 443002,China;Hubei Province Enterprise-college Cooperation Innovation Center for Comprehensive Utilization of Phosphogypsum,Yichang 443002,China)
出处
《无机盐工业》
CAS
CSCD
北大核心
2024年第3期98-104,154,共8页
Inorganic Chemicals Industry
基金
三峡库区生态环境教育部工程研究中心开放基金课题项目(KF2022-11)
宜昌市自然科学研究项目(A23-2-020)。
关键词
磷石膏
混合相
胶结材
浸出毒性
微观结构
phosphogypsum
mixed phase
cementing material
leaching toxicity
micro structure
