矿山充填是保护土地资源、生态环境,实现矿山无废开采和消除重大安全隐患的理想途径。以某矿全尾砂为试验材料,在分析该矿全尾砂材料的化学成分、粒径级配组成等基本物理、化学特性基础上,借助XRD能谱分析和电镜扫描(SEM)方法,得到不同条件下的超细全尾砂材料胶凝成岩微观规律。对比以水泥、固结剂1#和固结剂2#分别为胶结剂时充填体的强度结果表明,在灰砂配比、浓度和龄期相同的条件下3种胶结材料充填体的强度大小为:固结剂1#〉固结剂2#〉水泥;固结剂1#可替代水泥作为矿山全尾砂胶结充填的胶结剂,且价格比水泥便宜,有利于降低矿山充填成本。对不同条件下的充填体强度曲线进行拟合,得到充填体的单轴抗压强度增长规律:在养护龄期28 d之内,充填体单轴抗压强度增长规律随龄期变化基本相同,皆遵循指数函数曲线增长规律;当以固结剂1#、2#分别作为胶结材料时,强度增长规律与水泥为胶结剂时相同;强度增长曲线趋势与灰砂配比、料浆浓度以及养护龄期正相关。
Mine backfill is an ideal approach to protect land resources, ecological environment, to achieve the mine mode of no-waste-discharged and eliminate the potential hazards. The unclassified tailings from a mine was used as experimental raw material, then the micro-mechanism of consolidating backfill body of super-fineness unclassified tailings and cementitious materials under different conditions by means of XRD and SEM were obtained after analyzing the physical and chemical properties, the chemical components and particle size composition of the unclassified tailings. The cementing agent type #1 and type #2 were taken to replace the regular cement and the uniaxial compressive strength (UCS) of backfill specimens were gained. The experimental results showed that the influence degrees of different cementing agents on the behaviors of UCS were different, when the external experimental conditions were same; and it almost obeyed the law: cementing agent type #1 〉cementing agent type #2〉cement. The study also demonstrated that the performance of the cementing agent type #1 were better than the others; and its price was cheaper; therefore, it can reduce the cost of mine backfill. The increasing curves of UCS of backfill samples at different curing times were obtained and it showed that the increasing laws of UCS at different curing conditions were unanimous, in accordance with the exponential function growth curve, although the cementing agents type were different. The cement-sand ratio, slurry concentration and curing time exhibit a positive correlation with the UCS growth curve.