【作者】 吴伟丰；

【导师】 陈忠平；

【作者基本信息】 广州大学 ， 结构工程， 2020， 硕士

【摘要】 目前,处理矿山尾砂较为普遍的方法是制备尾砂充填体回填矿井采空区,不仅提高了矿石回采率,也保证了井下工作环境的稳定,同时也使尾砂固废得以回收利用。某铅锌矿通过旋流器对尾矿进行处理,得到分级尾砂和细尾砂。其中,分级尾砂可与水泥胶结进行矿山充填,但充填体的各方面性能不能够很好的满足充填生产要求,水泥成本日益增长,充填成本高居不下;而细尾砂90%以上颗粒粒径小于100um,难以回收利用,因而排放至尾矿库堆存。本文针对某铅锌矿山面临的充填问题,结合周边环境的固废资源现有情况,旨在解决矿山尾矿库退库,改善周边生态环境,以研制替代水泥充填的胶凝材料为目标,开展了研究工作。通过实地调研及理论分析,选择矿渣粉部分替代水泥的碱激发体系,采用XRD、SEM和微量热等测试方法,研究了胶凝材料及充填体的胶结机理及性能优势。最终开展现场工业试验验证其在实际充填中的可行性。同时,为研究细尾砂对新胶凝材料体系充填体的性能影响,通过利用细尾砂部分替代分级尾砂,制备充填体进行初步试验。研究表明:1)在矿渣粉部分替代水泥的体系中,添加适量的硫酸钠可以加快体系前期的水化反应速率,释放矿渣粉自身的活性成分,使体系在早期的水化过程中就能够产生较多的C-S-H凝胶等水化产物,从而缩短充填体的凝结时间和提高早期强度。2)室内试验和现场工业试验表明,生态胶凝材料与分级尾砂所制备的充填体的流动性能指标、强度指标及后期耐久性指标均能满足矿山要求。同时,选取适宜的充填配比参数制备满足井下不同采空区类型的充填体,可以减少充填体单方胶凝材料的消耗量。3)充填体制备工艺的改善,在一定程度上能够提高充填体的力学性能。在不同的搅拌速率下,高搅拌速率的试样早期强度较低搅拌速率的试样有较大幅度的提升,水泥体系和生态胶凝材料体系均表现一致的规律。4)采用细尾砂替代20%的分级尾砂,充填体的流动性能有所降低,力学性能有所提高。随着充填体细尾砂掺量的增加,在一定范围内,充填体的流动度呈下降趋势,而充填体的7d和28d抗压强度则得到进一步提高。5)工业试验的充填效果良好,根据工业试验的数据记录,与水泥充填进行成本对比,分析得生态胶凝材料用于胶面和矿房部位的单方充填成本相比水泥分别节约了29%和12%。更多还原

【Abstract】 At present,the common way to deal with mine tailings is to make up tailings backfill to fill the mined-out area,which not only improves the ore recovery rate but also ensures the stability of the underground working environment.Meanwhile,it enables the recovery and utilization of tailings solid waste.The tailings of a lead-zinc mine were treated by cyclone to obtain classified tailings and fine tailings.Among them,the classified tailings can be cemented with cement for mine filling,but the properties of the backfill cannot meet the requirements of filling production very well.The cement cost is increasing day by day,and the filling cost is high.More than 90% of the particle size of fine tailings is less than 100 um,which is difficult to be reused,so it is discharged to the tailings pond for storage.Aiming at the filling problems faced by a lead-zinc mine,combined with the existing situation of solid waste resources in the surrounding environment,the research work is carried out,aiming at developing cementitious materials to replace cement filling.It aims to solve the mine tailings depot withdrawal and improve the surrounding ecological environment.Based on the field investigation and theoretical analysis,the alkali excitation system of slag partially replacing cement was selected,and the cementation mechanism and performance advantages of cementitious materials and backfills were studied by means of XRD,SEM,and microcalorimetry.Finally,field industrial test was carried out to verify its feasibility in the actual filling.At the same time,to study the effect of fine tailings on the performance of the new cementitious material system,the classified tailings were partially replaced by the fine tailings to make up the fillings for preliminary tests.Research shows:1)In the system of partially replacing cement with slag,adding proper amount of sodium sulfate can accelerate the hydration reaction rate of the system and release the active ingredient of slag,so that the system can produce more C-S-H hydrates and other hydration products in the early hydration process.In this way,we could shorten the setting time and improving the early strength of the backfill.2)Laboratory tests and field industrial tests show that the flow performance index,strength index,and later durability index of the backfill made of ecological cementitious material and classified tailings can meet the mine requirements.At the same time,choosing appropriate filling ratio parameters to prepare backfill which meets different types of goaf can reduce the consumption of single cementitious material of backfill.3)The improvement of filling preparation technology can improve the mechanical properties of backfill to a certain extent.At different mixing rates,the early strength of the samples with high mixing rates was significantly improved compared with that of the samples with low mixing rates,and the cement system and the ecological cementitious material system showed the same law.4)The use of fine tailings instead of 20% classified tailings reduces the flow properties of the backfill and improves the mechanical properties.With the increase of the number of fine tailings in the backfill,the fluidity of the backfill showed a downward trend within a specific range,and the 7d and 28 d compressive strength of the backfill was further improved.5)The filling effect of industrial test is good.According to the data record of industrial test,comparing with the cost of cement filling,the cost of ecological cementitious material used in the single filling of glue surface and room is 29% and 12% less than that of cement respectively.更多还原