自流型矿渣基尾砂充填材料的研究

发布时间：2018-11-22 20:45

【摘要】：某矿山利用分级尾砂作为集料、外购胶结粉料制成灰砂比为1:10、固体浓度为68%的分级尾砂胶结充填料浆进行自流井下充填,存在充填材料凝结慢、早强低、充填浓度低及成本高等问题,亟需对充填材料配方进行优化。本文以矿渣作为充填材料胶结粉料的主要基材,利用单因素法分别研究了水泥、半水石膏、二水石膏、石灰用于矿渣基尾砂充填材料中的优缺点:单掺水泥激发矿渣基尾砂充填材料凝结时间长、各龄期强度都较低,不满足充填要求,需要添加其他组分复合激发矿渣;添加半水石膏可缩短凝结时间,提高接顶率,但会降低料浆流动性能和后期强度;添加二水石膏会提高早期强度,但后期强度增长较小;添加石灰能提高充填材料后期强度,但会延长凝结时间。因此,需要将上述几种激发剂复合使用以开发性能较优的自流型矿渣基尾砂充填材料。在单因素试验基础上,固定水泥掺量为15%,选取石膏掺量、半水石膏与二水石膏比例、石灰掺量三个因素,进行正交试验得到综合性能较优的矿渣基尾砂充填材料胶结粉料配比。在正交试验基础上,仅改变水泥与石膏的掺量优化正交最优配,结果发现矿渣基尾砂充填材料中不添加水泥是可行的,但早期强度受影响。因此研究在不添加水泥的矿渣基尾砂充填材料中分别掺加氢氧化钠、硅酸钠、硫酸钠及硫酸铝化学激发剂来提高强度,结果表明添加硫酸铝1.0%时效果最佳。得到的无水泥矿渣基尾砂充填材料胶结粉料的配比为:矿渣71.0%、半水石膏8.3%、二水石膏16.7%、石灰3.0%、硫酸铝1.0%,利用此配方配制的尾砂充填材料较原矿山尾砂充填材料工作性能得到明显的改善,终凝时间提前19.4%;3d、7d、28d强度分别提高32.1%、12.9%、16.3%。将无水泥矿渣基尾砂充填料浆浓度从68%提高到72%,分别研究了萘系高效减水剂(FDN)、氨基高效减水剂(A S F)及聚羧酸高效减水剂(PC)对其性能影响,研究表明:适当掺量的减水剂可增加流动度,在掺FDN0.7%、ASF0.27%、PC0.38%时可以满足72%浓度料浆自流充填;减水剂的加入增加了泌水率,延长了终凝时间,其中添加A SF的不利作用最小;FDN使3 d强度降低,ASF及PC在一定掺量范围内可增加3d强度,随龄期增长,三种减水剂对后期强度均有增加作用。综合来看,在无水泥矿渣基充填材料中使用0.27%的ASF性能最优。确定的自流型矿渣基尾砂充填材料配比为:利用无水泥矿渣基胶结粉料,外掺0.27%的ASF,灰砂比1:10,固体浓度72%。比原矿山充填材料浓度同比提高5.9%,泌水率同比减小30.1%,凝结时间提前19.4%,3d、7d及28d强度分别提高58.9%、39.5%及47.3%。利用XRD、SEM对无水泥矿渣基尾砂充填材料的微观形貌进行分析,结果表明:其主导水化产物为水化硅酸钙以及针棒状的钙矾石品体,这些水化产物或包裹在尾砂颗粒表面,或填充在尾砂颗粒之间,互相之间穿插、交联,使充填体强度增加。
[Abstract]:In a mine, graded tailings are used as aggregates, cemented powder is purchased, and grain-sand ratio is 1: 10 and solid concentration is 68%, which is used for filling under self-flowing well. There is slow condensation and low early strength of filling material. Due to the low concentration and high cost, it is necessary to optimize the filling material formula. In this paper, slag is used as the main base material for cementing powder of filling material. The cement, hemihydrate gypsum and dihydrate gypsum are studied by single factor method. The advantages and disadvantages of lime used in slag based tailings filling material are as follows: only cement is added to stimulate slag base tailings filling material, the setting time is long, and the strength of each age is lower, which does not meet the requirements of filling, so it is necessary to add other components to stimulate slag; The addition of gypsum hemihydrate can shorten the setting time and increase the topping rate, but it will reduce the fluidity of slurry and the later strength, and the addition of gypsum dihydrate can increase the early strength, but the later strength will increase slightly. The addition of lime can increase the later strength of the filling material, but it will prolong the setting time. Therefore, it is necessary to combine these activators to develop self-flowing tailings filling materials with better performance. On the basis of single factor test, fixed cement content is 15, gypsum content, ratio of hemihydrate gypsum to dihydrate gypsum, lime content are selected. The cemented powder ratio of slag based tailings filling material was obtained by orthogonal test. On the basis of orthogonal test, the orthogonal optimum combination of cement and gypsum is optimized only by changing the content of cement and gypsum. The results show that it is feasible not to add cement to the slag based tailings filling material, but the early strength is affected. Therefore, the strength was improved by adding sodium hydroxide, sodium silicate, sodium sulfate and aluminum sulfate in the slag based tailings filling material without cement. The results show that the best effect is when adding aluminum sulfate 1.0. The ratio of cemented powder obtained from cementless slag based tailings filling material is as follows: slag 71.0, hemihydrate gypsum 8.3, gypsum dihydrate 16.775, lime 3.0, aluminum sulfate 1.0. The working performance of the tailings filling material prepared by this formula is obviously improved than that of the original mine tailings filling material, and the final setting time is 19.443% earlier than that of the original mine tailings filling material. The intensity was increased by 32.1and 12.9for 28d, respectively. The concentration of cement free slag based tailings filling slurry was increased from 68% to 72%. The effects of naphthalene superplasticizer (FDN), amino superplasticizer (A S F) and polycarboxylic acid superplasticizer (PC) on their properties were studied respectively. The results show that the flow degree can be increased by adding water reducer with proper amount, and the slurry filling with 72% concentration can be satisfied when FDN0.7%,ASF0.27%,PC0.38% is added. The addition of superplasticizer increased the bleeding rate and prolonged the final coagulation time, and the adverse effect of adding A SF was the least. FDN decreased the strength of 3 days, ASF and PC increased the strength of 3 days in a certain range, and the three water reducers increased the strength of the later stage with the increase of age. In a word, 0.27% ASF is the best one in cement free slag based filling material. The ratio of self-flowing slag based tailings filling material is determined as follows: using cementless slag based cemented powder, adding 0.27% ASF, ash to sand ratio of 1: 10, solid concentration 72. Compared with the original mine, the concentration of filling material was increased by 5.9%, the bleeding rate was decreased by 30.1%, and the setting time was increased by 58.9% and 47.3%, respectively, and the setting time was increased by 19.4d ~ 3d ~ 7d and 28d, respectively. The microstructure of cementless slag based tailings filling material was analyzed by XRD,SEM. The results showed that the main hydration products were calcium silicate hydrate and ettringite, which were encapsulated on the surface of tailings. Or filling between tailing particles, intercalation, cross-linking, so as to increase the strength of the filling body.
【学位授予单位】：西安建筑科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TD853.34

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