不同因素对超细尾砂胶结充填料流动性、强度和微观结构的影响

Effects of different factors on the fluidity, strength and microstructure of superfine tailings cemented paste backfill

  • 摘要: 为实现超细尾砂的高效利用,开展一系列实验研究了不同因素对超细尾砂胶结充填料流动性、强度和微观结构的影响。首先,研究了旋流器给料压力和沉沙口直径对超细尾砂浓度和产率的影响,并研究了超细尾砂的沉降特性。然后,通过单轴抗压强度测试、坍落度和流变测试以及扫描电镜对超细尾砂胶结充填料进行研究。结果表明,沉砂口直径和给料压力会显著影响尾矿的底流产率和浓度。絮凝剂剂量对尾砂沉降速率的影响较大,对最终浓度的影响不明显。料浆质量浓度越大,其流动性越差,且当质量浓度高于72%后,料浆的流动性显著变差。养护温度、养护时间以及配合比均会对超细尾砂胶结充填体的强度产生影响。低温环境下,充填体的水化进程缓慢,导致其水化产物少、结构松散且裂隙较多,这是造成充填体强度降低的根本原因。

     

    Abstract: To achieve efficient utilization of superfine tailings, a series of experiments were carried out to investigate the effects of different factors on the fluidity, strength and microstructure of the superfine tailing cemented paste backfill (SCPB). Firstly, the effects of cyclone feed pressure and sinker diameter on the concentration and yield of superfine tailings were explored and the settling characteristics of superfine tailings investigated, respectively. Then, the SCPB was investigated by uniaxial compressive strength tests, slump and rheological tests and scanning electron microscopy. The results show that the diameter of the sand settling port and the feed pressure significantly affect the bottom flow yield and concentration of tailings. The dosage of flocculant has a greater effect on the settling rate of tailings, and a less significant effect on the final concentration. The greater the mass concentration, the poorer the flowability of the slurry, which becomes significantly worse when the mass concentration is above 72%. Curing temperature, curing time and mix proportion will all affect the strength of SCPB. The slow hydration of the filler at low temperatures results in low hydration products, a loose structure and a high number of fissures, which is the underlying cause of the reduction of filler strength.

     

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