Experimental study on the strength deterioration of sulfidic paste backfill
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摘要: 高硫尾矿配制成的膏体表现出不同程度的强度劣化,高硫膏体强度劣化能引起充填体质量的巨大变化.通过不同硫含量的膏体强度劣化实验,同时结合X射线衍射物相分析和环境扫描电镜分析,对高硫膏体的劣化规律和劣化机理进行了分析.得出含硫尾矿在一定程度上能促进膏体早期强度增长,却抑制了后期强度发育,硫含量越高,膏体后期强度劣化越显著.硫化物氧化生成的硫酸盐能促进膨胀性钙矾石和石膏类物质的生成.同时酸性环境造成了C-S-H的脱钙和CH的分解,已形成的胶凝体系遭到破坏,进一步促进了充填体的劣化.通过孔隙计算模型对晶体膨胀应变和裂纹发育过程进行了分析,阐述了膨胀性物质的线弹性应变发育机理.Abstract: Paste made from high-sulfur tailings shows strength deterioration to different degrees and this can cause great changes in the quality of the filling body. The deterioration and degradation mechanism of high-sulfur paste with different sulfur contents was analyzed using XRD (X-ray diffraction) phase analysis and an ESEM. The results showed that sulfur tailings promoted the growth of early strength to a certain extent, but inhibited the development of later strength, and the greater the sulfur content, the more obvious the effect. In addition, sulfate produced by sulfide oxidation can promote the formation of expansive ettringite and gypsum. Meanwhile, the acidic environment caused decalcification of C-S-H and dissolution of CH, destroys the cementitious system and further promotes the degradation of the filling body. The crystal expansion strain and crack development process were analyzed using a pore calculation model. The linear development of elastic strain in swelling material was clarified.
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Key words:
- paste backfill /
- sulfide tailings /
- strength degradation /
- microstructure /
- pyrite
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