| Pipeline transportation of filling slurry is an efficient,stable,safe and green transportation mode.This mode meets the requirements of the national "14th Five-year Development Plan" for ecological environment,and is also a crucial link of the construction of green mines.However,the stability of large capacity pipeline transportation of filling slurry and the safety problems caused by the wear of filling pipeline during transportation need to be solved urgently.This paper concentrated on the problems of serious pipeline wear and influence on mine safety production caused by high-concentration self-flow filling of coarse aggregate in Jinchuan Mine.The influencing factors of the wear of the filling pipeline,the wear mechanism of the pipeline and a new type of pipeline wear-resistant material were studied to lay the foundation for the safe,efficient and low-cost continuous backfill mining in Jinchuan Mine.Based on this,the following research was carried out.The investigation and analysis of the filling status such as the physicochemical properties of filling materials,filling system,filling process and the fluidity evaluation of filling slurry in Jinchuan Mine were carried out.The complex pipeline of the filling system,rod sanding and coarse aggregate of waste rock caused slurry segregation,fill drilling and pipelines wear.On the basis of the analysis of Jinchuan Mine filling status,studies were carried out to improve the fluidity and stability of coarse aggregate filling slurry during pipeline transportation.The influence law between the working characteristics of the filling slurry(collapse degree,consistency,delamination degree and bleeding rate)and the proportion factors(cement-sand ratio,slurry concentration and admixture amount)was analyzed.An optimization model for the transportation stability of the coarse aggregate filling slurry was established.The ways to reduce the pipeline transportation resistance of coarse-aggregate-filled slurry and the risk of pipeline wear were explored from different dimensions such as material selection and slurry ratio.The impact wear risk of coarse aggregate filling slurry gravity flow transportation on pipelines was studied.The risk assessment system of filling pipeline wear was established by catastrophe progression method,and the risk level of pipeline wear in Longshou Mine of Jinchuan was evaluated.The factors influencing the wear of coarse aggregate filling slurry gravity flow transportation on pipelines were analyzed,and on this basis,the influencing factors of pipeline wear were further tested to determine the main factors.ANSYS FLUENT software was used to analyze the influence of different solid particle density,flow velocity and mass concentration of slurry on the pipe wall of vertical pipe,elbow,horizontal pipe and other parts.The complex interaction between coarse aggregate and slurry in the flow process and the internal motion form of high-concentration mixed aggregate-filled slurry during transportation were studied.Momentum and energy were analyzed for different wear areas to explore the mechanism of pipeline wear.On the basis of exploring the mechanism of pipeline wear,the research on wear resistance of filling pipeline materials is carried out.Taking the filling pipeline as the main research object,the possibility of using Fe-Mn-Al-C light high manganese steel after explosion treatment as the pipeline material was explored.Research on microstructure and properties,and development of the materials with simple production process,low cost,high toughness,high strength and light weight were carried out to meet the performance requirements of high concentration filling for pipeline materials. |
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