ISSN 1000-3665 CN 11-2202/P

    基于碱性抑制的矿山帷幕注浆材料配比优化研究

    Optimization of material ratio of curtain grouting based on alkali suppression

    • 摘要: 某大水型金属矿山帷幕注浆工程中应用的黏土-水泥浆液水化反应后的pH值高达13,表现为强碱性,构成对地下水及地表水的潜在污染风险。为探究低碱性外加剂对该矿山水害防治帷幕注浆工程中黏土-水泥浆液性能的调控机制,采用正交试验设计,系统分析了不同配比条件下浆液的流变特性,包括流动性、泵送性能、凝结时间及pH值的变化规律。通过分别引入磷石膏、粉煤灰及降碱外加剂(substance of Jin Pin,SJP),探讨不同材料在降低浆液碱性方面的有效性。试验结果显示:磷石膏能够将浆液pH值有效降低至11,同时延长凝结时间;粉煤灰虽在降低浆液碱度方面效果有限,却改善了浆液的泵送性能并缩短了泵送期限;SJP外掺剂在降低pH值和延长泵送期方面表现突出,当掺量由2.5%增加至3.5%时,浆液pH值显著降低至8。基于试验数据,优化了SJP外掺剂-粉质黏土-磷石膏-水泥(CCAS)配方,并通过正交试验确定最优配比:复合酸式盐0.5%、硫铝酸盐1.5%、磷石膏10%、黏土50%。该优化配方制备的浆液pH值降低至10,流动度保持在18~23 cm,泵送期延长至100~220 min,充分满足工程应用需求。研究结果可为帷幕注浆工程中通过控制浆液碱性以减少环境污染提供了科学依据。

       

      Abstract: To investigate the regulatory mechanisms of low-alkalinity additives on the performance of clay-cement slurry in mine water hazard prevention and curtain grouting engineering, this study employed an orthogonal experimental design. The rheological properties of the slurry, including flowability, pumpability, setting time, and pH evolution, were systematically analyzed under varying mix conditions. By introducing phosphogypsum, fly ash, and the SJP additive, the effectiveness of these materials in reducing the alkalinity of the slurry was evaluated. The results reveal that phosphogypsum effectively reduced the pH to 11 and prolonged extending the setting time. Although fly ash showed limited efficacy in alkalinity reduction, it significantly enhanced the pumpability of the slurry and shortened the pumping period. The SJP additive demonstrated outstanding performance in both pH reduction and pumpability extension, with the pH decreasing notably to 8 when the dosage was increased from 2.5% to 3.5%. Based on experimental data, an optimized formulation of the SJP additive, clay, phosphogypsum, and cement (CCAS) was developed. Orthogonal tests identified the optimal proportions as follows: composite acid salt 0.5%, calcium sulfoaluminate 1.5%, phosphogypsum 10%, and clay 50%. The optimized slurry achieved a significant reduction in pH to 10, maintained a flowability of 18-23 cm, and extended the pumpability window to 100-220 minutes, fully meeting the engineering application requirements. This study provides a scientific basis for controlling slurry alkalinity in curtain grouting projects, thereby mitigating environmental pollution.

       

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