铁尾矿微粉掺和料及其混凝土性能的研究

发布时间：2018-05-27 15:31

本文选题：铁尾矿微粉 + 混凝土　；参考：《北京建筑大学》2015年硕士论文

【摘要】：在铁矿石开采过程中,产生了大量尾矿固体废弃物,大量堆积不仅占用土地,污染环境,破坏生态,而且构成安全威胁。当前,我国铁尾矿的利用率还很低,急需寻求大量处理和利用的新途径。另一方面,我国混凝土用量巨大,2014年用量在70亿立方米以上,矿物掺和料每年需求量保守讲应该在8亿吨以上。由于粉煤灰、矿渣等工业废渣资源的分布不均匀,火力发电厂逐渐减少,粉煤灰等废渣产出量减少等原因,南方许多地区出现常规掺和料供应不足的情况,客观上需要开发新型掺和料进行补充。铁尾矿颗粒大多属于特细砂范畴,只有少量可以作为机制砂来利用。将铁尾矿磨细成微粉作为矿物掺和料在混凝土中利用,既可以缓解部分地区传统掺和料供应紧张的问题,又可以大规模消纳尾矿废弃物,有可观的经济和环境效益。本文主要研究磨细铁尾矿微粉作为混凝土矿物掺和料的适用性,明确铁尾矿微粉的技术要求及其对混凝土各性能的影响,以期形成铁尾矿微粉混凝土的应用技术要点,推进铁尾矿微粉在混凝土工程领域的广泛应用。课题针对铁尾矿微粉适宜的技术指标、在混凝土中合适的掺量、和易性、强度和耐久性等方面进行了系统研究,并通过扫描电镜试验,探讨分析微观组织结构和微粉上浮问题。结果表明:铁尾矿微粉细度控制在500m2/kg,亚甲蓝值低于1.0时,铁尾矿微粉与矿渣粉复掺比例在5:5至6:4范围,复合掺和料在胶凝材料中掺量不超过40%时,铁尾矿微粉掺入混凝土中,具有良好的和易性,强度满足混凝土等级要求,对耐久性影响与粉煤灰相当。铁尾矿微粉颗粒均匀分布于浆体中,抗上浮能力明显优于粉煤灰,耐磨性能优良。课题研究证明铁尾矿微粉作为混凝土掺和料使用具有技术可行性。
[Abstract]:In the process of iron ore mining, a large number of solid waste tailings are produced, which not only occupy the land, pollute the environment, destroy the ecology, but also pose a security threat. At present, the utilization rate of iron tailings in China is still very low. On the other hand, the amount of concrete in our country is huge, the consumption in 2014 is more than 7 billion cubic meters, the demand for mineral admixture should be more than 800 million tons per year. Due to the uneven distribution of industrial waste slag resources such as fly ash and slag, the gradual decrease in thermal power plants and the decrease in the output of waste slag such as fly ash, there has been a lack of supply of conventional admixture in many areas of southern China. Objectively, it is necessary to develop new admixture to supplement it. Iron tailings mostly belong to the category of ultrafine sand, only a few can be used as mechanism sand. The use of iron tailings as mineral admixture in concrete can not only alleviate the shortage of traditional admixture in some areas, but also absorb tailings waste on a large scale, with considerable economic and environmental benefits. This paper mainly studies the applicability of fine iron tailings as concrete mineral admixture, and clarifies the technical requirements of iron tailings and its influence on concrete properties, in order to form the main technical points of application of iron tailings fine powder concrete. Promote the wide application of iron tailings powder in concrete engineering field. Aiming at the appropriate technical index of iron tailings powder, this paper makes a systematic study on the appropriate content, ease, strength and durability of concrete, and analyzes the microstructure and floatation of fine powder by SEM test. The results show that when the fineness of iron tailings is controlled at 500m2 / kg, the methylene blue value is lower than 1.0, the ratio of iron tailings powder to slag powder is between 5:5 and 6:4, and when the amount of compound admixture is not more than 40%, the iron tailings fine powder is mixed into concrete. It has good and easiness, the strength meets the requirement of concrete grade, and the effect on durability is equal to that of fly ash. Iron tailings particles distribute evenly in the slurry, and the anti-floating ability is obviously better than that of fly ash, and the wear resistance of iron tailings is excellent. The technical feasibility of using iron tailings as concrete admixture is proved.
【学位授予单位】：北京建筑大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU528

【参考文献】