宁东矿区气化渣基膏体充填材料性能优化研究

宁东矿区作为黄河流域的9个亿吨煤基地之一,年产出煤基固废近2×108 t且气化渣堆存量大、规模化利用困难、简单填埋处理空间有限,充填开采能解决空间堆存难题,但成本高、性能亟待优化。根据响应面法设计气化渣在固体中的掺量(A)、气化渣与水泥质量比(B)、料浆含量(C)3因素3水平共17组中心组合实验,对气化渣基膏体充填材料的坍落度、扩展度、7和14 d单轴抗压强度等性能进行了对比优化研究。实验前使用X射线衍射仪(XRD)和扫描电镜(SEM)对原料的成分及微观形态进行观测分析,试块单轴压缩后通过SEM观测分析水化作用特点,揭示强度形成机制。综合强度和流动性得到最优配比及其性能特征为：A为48%,B为3,C为80%,脱硫石膏∶煤矸石∶炉底渣的质量按2∶1∶1配制,其7、14 d强度分别为1.15、2.41 MPa,坍落度为133 mm,扩展度为325.5 mm,坍落度与扩展度的比值为0.41。进一步基于响应面法分析得到7、14 d强度的单影响因素按显著性排序分别为：B>C=A、B>A>C;7、14 d强度的交互影响因素按显著性排序分别为：BC>AB>AC、AB&g...

Study on performance optimization of gasification slag based paste filling materials in Ningdong mining area

As one of the nine coal bases at hundred million ton level in Yellow River Basin, Ningdong Mining Area has nearly 2×108 t of coal-based solid waste produced annually, and faces to the problems of large stock of gasification slag, difficulty in scaled utilization, and limited space for simple landfill. Filling mining could solve the problem of stockpiling, of which the cost is high and the performance needs to be optimized. According to the response surface method, 17 groups of central composite experiments were designed for the three factors at three levels: the mixing amount of gasification slag in solid (A), the mass ratio of gasification slag to cement (B), and the slurry concentration (C). Meanwhile, comparative optimization research was conducted for the slump, expansion, 7 d and 14 d uniaxial compressive strength and other properties of gasification slag based paste filling materials. Before the experiment, the composition and micromorphology of the raw materials were observed and analyzed by XRD and SEM. Besides, the test block was observed by SEM and had its hydration characteristics analyzed after uniaxial compression, thereby revealing the strength formation mechanism. By integrating the strength and fluidity, the following optimum mixing ratio and performance characteristics of the filling material were obtained: 48% for A, 3 for B and 80% for C. Meanwhile, the desulfurized gypsum, coal gangue and bottom slag should be mixed at the mass ratio of 2∶1∶1 to reach the 7 d and 14 d strengths of 1.15 MPa and 2.41 MPa respectively, the slump of 133 mm, the expansion of 325.5 mm, and the slump to expansion ratio of 0.41. According to the further analysis based on response surface method, the single influencing factors of 7 d and 14 d strength are B>C=A and B>A>C, the interaction influencing factors of 7 d and 14 d strength are BC>AB>AC and AB>AC>BC, and the single influencing factors of slump and expansion are C>B>A and C>A>B respectively according to the significance. On this basis, the proportioning scheme and parameters were optimized for the 3 different functional requirements, including the strict control of surface settlement, rapid filling to reduce pipe plugging, and control of strength and cost. Generally, the research results provide important basic parameters and optimization direction for the ecological protection and low damage coal mining in Yellow River Basin.