铁矿尾矿料微观结构与压缩特性试验研究

Experimental study on microstructure and compressibility of iron ore tailings

针对马鞍山青山尾矿库铁矿尾矿料,开展了一系列压缩试验,对铁尾矿的压缩特性进行了分析;对试验完成后的试样开展了扫描电镜试验(SEM)和压汞试验(MIP),从定性和定量两个角度分析了铁尾矿微观结构对压缩特性的影响。试验结果表明:铁矿尾矿料在单向压缩和等向压缩下表现出基本一致的压缩特性,初始干密度对压缩曲线的影响只体现在初始孔隙比的不同,单一级配的试样压缩性更强。SEM和MIP试验表明,铁尾矿试样颗粒间孔隙结构多样,孔径主要分布在10~0.1μm的孔隙组;初始干密度和试验固结围压均会对尾矿料的总孔隙率产生影响,其中围压的影响更为剧烈。研究成果可为尾矿库的设计运营维护提供参考。

A series of compression tests are conducted on iron ore tailings taken from Qingshan tailings impoundment to analyze the compression deformation behavior.Furthermore,the scanning electron microscopy(SEM)tests and mercury intrusion porosimetry(MIP)tests are carried out on post-test specimens to study the effects of microstructure on compression deformation properties of iron ore tailings.The compression test results show that the iron ore tailings exhibit basically consistent compression behavior during uniaxial compression and isotropic compression.Different initial dry densities are found to have few effects on the shape and slope of compression curve but change the initial void ratio.The specimens with single size gradation show stronger compressibility than those with design size gradation.The microscopic tests results show that pore structure of the iron ore tailings is various and complicated,and the pore sizes are mainly distributed in the interval of 10 to 0.1μm.Both the initial dry density and the consolidation pressure affect the total porosity of the iron ore tailings,and the later one has more severe effect.The research results may provide reference for the design,operation and maintenance of tailings impoundment.