高硫尾砂充填体强度变化规律实验研究

Experimental Study on the Strength Variation Law of High-sulfur Tailings Backfill

国内某铜矿尾砂含硫偏高,为论证该矿山能否采用尾砂胶结充填,通过尾砂充填配比实验研究高硫尾砂充填体强度变化规律。结果表明:高硫尾砂充填体在不密闭条件下养护,随龄期的增长逐渐开裂,强度先增加后逐渐减小;在密闭环境下养护,充填体未出现开裂现象,强度随龄期的增长逐渐增加至相对稳定。在不密闭条件下养护,充填体前期强度随料浆质量浓度和灰砂比的变化呈规律性增加或减小,后期强度随灰砂比或质量浓度的变化无明显规律;扫描电镜分析显示高硫尾砂充填体开裂主要是因充填体内含有大量的钙矾石和石膏等膨胀性物质。

In order to demonstrate whether tailings cemented filling with high sulfur content can be used in a copper mine in China, the strength variation of high-sulfur tailings filling body was investigated by adopting the tailings filling ratio experiment. The results showed that the high sulphur tailings filling body cracks gradually with the growth of curing age under unclosed environment, and its strength increases first and then decreases gradually. Under closed environment, the filling body does not crack, and its strength increases gradually to a relatively stable level with the growth of curing age. Under unclosed condition, the strength of filling body increases or decreases regularly with the change of slurry mass concentration and lime-sand ratio at the early stage, but it has no obvious variation law with the change of lime-sand ratio or mass concentration at the later stage. Scanning electron microscopy analysis shows that the cracking of high sulfur tailings filling body is mainly caused by the large amount of expansive materials such as ettringite and gypsum in the filling body.