Pb^(2+)、Cr^(3+)对煤基固废固化体性能及固化机理研究

Effects of Pb^(2+)and Cr^(3+)on Properties and Solidification Mechanism of Solidification Body Made of Coal-based Solid Waste

该文以屯兰矿区煤矸石、兴能矸石电厂粉煤灰和脱硫石膏为主要原料制备煤基固废固化体,研究了Pb^(2+)、Cr^(3+)的掺量对固化体抗压强度和固化率的影响,借助XRD、SEM-EDS、FTIR等分析方法研究了煤基固废固化体对重金属的固化机理。结果表明:Pb^(2+)、Cr^(3+)的掺加对煤基固废固化体的抗压强度都有减弱作用,重金属一定程度上抑制了固废胶凝体系的水化进程,2种重金属共同作用时明显影响固化体的力学性能。煤基固废固化体能很好地实现对Pb^(2+)、Cr^(3+)的固化,28 d时固化率达到93.92%~98.49%。研究表明,Pb^(2+)、Cr^(3+)以晶格离子取代、离子交换和水化反应等多种方式参与了煤基固废胶凝水化体系反应,生成稳定的水合硅酸铅钙、氢氧化铅、钙铬榴石和氧化铬铝水合物等新相。

Coal-based solid waste can be reused by the solidification method.In this case study,coal gangue from Tunlan Mine,fly ash and desulfurization gypsum from Xingneng Gangue Power Plant were used as the main raw materials,and the effects of adding Pb^(2+)and Cr^(3+)on the compressive strength and solidification rate of the solidification-body made from coalbased solid waste were investigated,and the solidified mechanism was studied by means of XRD,SEM-EDS,FTIR.As a result,the investigation presented that the compressive strength of the solidification-body such prepared was weakened by Pb^(2+)and Cr^(3+)as heavy metals such as Pb and Cr could inhibit the hydration process of the solid waste cementitious system,and the mechanical properties of the solidification body was affected significantly by the combined action of Pb^(2+)and Cr^(3+),which could be solidified effectively by the solidification body in 28 d,the solidification rates being ranging from 93.92%to 98.49%.With the cutting-edge analytic instruments it was found that Pb^(2+)and Cr^(3+)participated in the gelling hydration system reac⁃tion of coal-based solid waste in many ways,such as lattice ion substitution,ion exchange and hydration reaction,and generated the stable new phases,such as hydrated lead calcium silicate,lead hydroxide,uvarovite,and chromium aluminum oxide hydrate.