全固废膏体关键性能指标的多目标优化

Multiple response optimization of key performance indicators of cemented paste backfill of total solid waste

在全尾砂膏体充填的基础上提出了全固废膏体充填,将全尾砂、废石、水淬渣等固废制备成膏体料浆充填至井下采空区,实现采空区垮塌、尾矿库溃坝和废石场滑坡的协同治理,达到“全废治三害”的效果.为此,研究了固体质量分数、废石掺量和胶固粉耗量对全固废膏体的塌落度、屈服应力、单轴抗压强度和泌水率的影响.根据国家标准规定的技术指标范围,对全固废膏体的关键性能指标进行了多目标优化.研究发现,全固废膏体的关键性能指标和全尾砂膏体相似,具有良好的流动性、输送性能与力学性能,并具有一定的泌水性.固体质量分数、废石掺量和胶固粉耗量对全固废膏体的关键性能指标具有显著的影响,其中固体质量分数对塌落度和屈服应力影响最大,胶固粉耗量对单轴抗压强度和泌水率的影响最大.通过研究,最终多目标优化所得最优参数是固体质量分数为79.31%、废石掺量为18.86%(质量分数)、胶固粉耗量(胶固粉质量与全尾砂和废石质量之和的比值)为3∶20,对应的塌落度为25.45 cm、屈服应力为100.49 Pa、单轴抗压强度为3.55 MPa、泌水率为1.50%.多目标优化结果可为实际应用提供参考,而总评归一值模型也可应用于其他矿山膏体的多目标优化.

Tailings and waste rock produced in metal mines are the most common industrial solid wastes all over the world,resulting in serious environmental and safety issues.Cemented paste backfill(CPB)is widely used for tailings management and stope treatment.CPB of total solid waste(TSW-CPB)was proposed on the basis of CPB of full-tailings.In the TSW-CPB process,thickened full-tailings,waste rock,and slag are mixed to prepare a paste that is filled into the stope.TSW-CPB can avoid the collapse of a stope,failure of the tailings storage facility,and landslide of a waste-rock yard,achieving the goal of“total waste to cure three harms.”The effects of solid fraction(SF),waste rock dosage(WRD),and glue powder dosage(GPD)on the slump(S),yield stress(τ0),uniaxial compressive strength(UCS),and bleeding rate(BR)were investigated through orthogonal experiments.According to the scope of technical indicators specified in the National Standard of the People’s Republic of China“Technical specification for the total tailings paste backfill(GB/T 39489-2020),”the overall desirability function approach was used to conduct multiple response optimization of key TSW-CPB performance indicators.TSW-CPB was shown to have similar fluidity,transportation performance,mechanical properties,and bleeding performance to the CPB of full-tailings.The SF,WRD,and GPD affect the S,τ0,UCS,and BR of TSW-CPB considerably.The SF has the most important influence on S andτ0,while GPD has the most substantial impact on UCS and BR.Multiple response optimization yielded SF=79.31%,WRD=18.86%,and GPD=3:20,with S=25.45 cm,τ0=100.49 Pa,UCS=3.55 MPa,and BR=1.50%as the corresponding responses.The optimal results can provide references for practical application,and the overall desirability function approach can be used in other mines to optimize multi objective CPB.