基于响应面法的超细矿渣粉-水泥胶凝材料开发及配比优化研究

针对某金矿超细尾砂胶结充填采用水泥胶凝材料经济效益低、充填效果差、充填体无法接顶等问题,利用当地成本低廉的粉煤灰、矿渣、脱硫石膏等工业固废开发低成本矿山充填胶凝材料。首先,在分析原材料物理化学性质的基础上,基于响应曲面法为依据的Box-Behnken试验设计,开展17组配比优化试验；其次,构建以充填体28 d抗压强度为响应目标的二次多项式预测模型,结合方差分析和响应曲面考察各试验因素对响应目标的影响主次关系,以优化胶凝材料最优配比；最后,借助X射线衍射分析(XRD)、傅里叶红外光谱分析(FT-IR)、扫描电镜分析(SEM)等微观检测手段,阐明复合胶凝体系中水化产物的类型及强度发展规律。试验结果表明：充填体抗压强度不仅受单一因素的影响,而且受多因素交互作用的影响。水泥与粉煤灰的交互作用影响显著,水泥与脱硫石膏的交互作用影响次之, 粉煤灰与脱硫石膏的交互作用影响不显著。胶凝材料最优配比为水泥添加量27%,粉煤灰添加量48%,矿渣添加量23%,脱硫石膏添加量2%,水玻璃添加量3.5%,芒硝添加量为1.5%,此条件下,充填体28 d抗压强度为3.58 MPa,满足矿山充填采矿要求。复合胶凝体系主导水化产物为钙矾石和C-S-H凝胶,随着水化反应的进行,二者交错黏结构筑成稳固的空间网络体系,使充填体保持较高的强度性能。

Development and Ratio Optimization of Ultrafine Slag Powder-Cement Cementitious Materials Based on Response Surface Methodology

In response to the problems of low economic efficiency, poor filling effect, and inability of the filling body to be capped by cement cementitious material for cementitious filling of superfine tailings in a gold mine, low-cost mine filling cementitious materials were developed by using local industrial solid waste such as fly ash, slag, and desulfurization gypsum. Firstly, based on the analysis of physical and chemical properties of raw materials, a Box-Behnken test design based on the response surface method was used to carry out 17 sets of ratio optimization tests; secondly, a quadratic polynomial prediction model with the 28-d compressive strength of the filler as the response target was constructed, and the primary and secondary relationships of the test factors on the response target were investigated by combining ANOVA and response surface to optimize the cementitious materials. Finally, the types of hydration products and strength development laws in the composite gelling system were elucidated by means of microscopic tests such as X-ray diffraction analysis (XRD), Fourier infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM). The test results show that the compressive strength of the filled body is not only influenced by a single factor, but also by the interaction of multiple factors. The interaction between cement and fly ash has a significant effect, followed by the interaction between cement and desulfurization gypsum, and the interaction between fly ash and desulfurization gypsum has no significant effect. The optimum ratio of cementing materials is 27% cement, 48% fly ash, 23% slag, 2% desulfurization gypsum, 3.5% water glass and 1.5% mannite, and the 28-d compressive strength of the filler is 3.58 MPa, which meets the requirements of mine filling and mining. The main hydration products of the composite gelling system are chalcocite and C-S-H gel, and with the hydration reaction, the interlocking viscous structure of the two forms a solid spatial network system, which makes the filling body maintain high strength performance.