宜春锂云母提锂渣的火山灰活性及其对水泥混凝土性能的影响研究

发布时间：2018-05-14 00:38

本文选题：锂渣 + 火山灰活性　；参考：《南昌大学》2017年硕士论文

【摘要】：江西宜春钽铌矿伴生锂云母矿是世界上最大的锂云母矿资源,锂云母经提锂处理后会产生大量的固体废渣(简称锂渣),开发锂渣在水泥及混凝土材料中的应用,对大量存放的锂渣的资源化利用,变废为宝和保护环境都具有十分重要的资源和环境意义。本文采用不同的评价方法研究对比了锂渣与几种常用混合材料的火山灰活性,探讨了单掺锂渣、复掺锂渣(锂渣+矿渣、锂渣+粉煤灰)对水泥及混凝土性能的影响,研究了锂渣对普通混凝土收缩性、抗氯离子渗透性、抗碳化性以及耐磨性的影响,采用扫描电镜观察分析了锂渣混凝土的界面结构,并采用正交试验优化了锂渣混凝土的配合比,制备了C70高强混凝土试样。得到以下研究结论:(1)锂渣的主要化学成分为SiO_2和Al_2O_3,XRD分析表明:锂渣主要物相为方沸石。采用火山灰性试验、对比强度法、结合水率法、选择性溶解法以及TG-DTA同步热分析法评价了锂渣的火山灰活性,发现锂渣比煅烧煤矸石、粉煤灰以及花岗岩粉拥有更强的火山灰活性。(2)锂渣会明显增加水泥的需水量,延长水泥的凝结时间;锂渣对水泥强度贡献超过粉煤灰,但低于矿粉;锂渣与矿粉复合掺时,具有比单掺锂渣或单掺矿粉更好的增强效果。(3)少量的锂渣掺入具有增稠作用,可改善混凝土的流动性、粘聚性和保水性,当锂渣的掺量高于20%时,随锂渣掺量的增加,混凝土的流动性会呈现逐渐降低的趋势。(4)锂渣是优质的混凝土掺合料,当锂渣掺量为20%时,制备的混凝土具有最佳的力学性能。(5)在锂渣掺量不超过20%时,随着锂渣掺量的增加,混凝土的抗收缩性、抗氯离子渗透性以及耐磨性都有所增加,但混凝土的抗碳化性随锂渣掺量的增加而下降。(6)锂渣能有效改善普通混凝土的界面结构,掺锂渣20%的混凝土与未掺试样比较,界面区CH数量明显减少并富集生长了大量的C-S-H凝胶,界面结构更加致密。
[Abstract]:The spodumite ore associated with Yichun tantalum and niobium deposit in Jiangxi Province is the largest spodumite ore resource in the world. After lithium extraction from spodumite, a large amount of solid waste slag (lithium slag for short) will be produced, and the application of lithium slag in cement and concrete materials will be developed. It has very important resource and environmental significance for the utilization of a large amount of lithium slag, the conversion of waste to treasure and the protection of the environment. In this paper, the pozzolanic activity of lithium slag and several common mixed materials are studied by using different evaluation methods, and the effects of lithium slag and lithium slag (lithium slag, lithium slag fly ash) on the properties of cement and concrete are discussed. The effects of lithium slag on shrinkage, chloride ion permeability, carbonation resistance and wear resistance of ordinary concrete were studied. The interface structure of lithium slag concrete was observed and analyzed by SEM. The mixture ratio of lithium slag concrete was optimized by orthogonal test, and C 70 high strength concrete sample was prepared. The main chemical constituents of the lithium slag are SiO_2 and Als _ 2O _ 3C _ (XRD). The results show that the main phase of the lithium slag is analite. The pozzolanic activity of lithium slag was evaluated by pozzolanic test, contrast strength method, water rate method, selective dissolution method and TG-DTA simultaneous thermal analysis. Fly ash and granite powder have stronger pozzolanic activity. The lithium slag can obviously increase the water demand of cement and prolong the setting time of cement. The contribution of lithium slag to cement strength is higher than fly ash, but lower than that of mineral powder. A small amount of lithium slag has thickening effect and can improve the fluidity, agglomeration and water retention of concrete. When the content of lithium slag is higher than 20%, the content of lithium slag increases with the increase of lithium slag content. The fluidity of concrete will decrease gradually.) Lithium slag is a high quality admixture of concrete. When the amount of lithium slag is 20, the prepared concrete has the best mechanical properties. 5) when the amount of lithium slag is not more than 20%, with the increase of the content of lithium slag, The shrinkage resistance, chloride ion penetration resistance and wear resistance of concrete are all increased, but the carbonation resistance of concrete decreases with the increase of lithium slag content. The lithium slag can effectively improve the interface structure of ordinary concrete. Compared with unadulterated concrete with 20% lithium slag, the amount of Ch in the interface region is obviously reduced and a large number of C-S-H gels are enriched and grown, and the interface structure is more compact.
【学位授予单位】：南昌大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ172.44;TU528

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