【作者】 耿磊；

【导师】 俞马宏；

【作者基本信息】 南京理工大学 ， 环境工程， 2010， 硕士

【摘要】 钢渣是一种工业废渣,堆放它们会压占大量的土地资源,造成水体和空气污染。对钢渣进行回收利用不仅可以保护环境,还能充分利用自然资源,提高利用率。本课题的研究目的是通过实验寻找能处理利用钢渣的工艺,解决钢厂的固体废弃物污染问题。针对本课题所用钢渣的特性,寻找合理的应用方法。为寻找合理的应用方法,首先要了解钢渣的性质,尤其是化学成分、化学性质和矿物学成分,所以在实验之前,必须对钢渣进行相关的测试,经测定知道本钢渣中铁、铝、硅、钙是主要元素,它们主要以各种矿物的形式存在,如硅酸二钙(C2S)、硅酸三钙(C3S)、铁铝酸钙、水化硅酸钙(CSH)和氢氧化钙(CH)等,它们具有一定的水化胶凝特性,可以用于工程建设。针对钢渣的胶凝特性,可以将钢渣用作熟料制备钢渣水泥,石膏对其胶凝特性具有一定的激发能力,按照水泥熟料的各种指标设计各物质间的配比,并参照国家标准GB／T 17671-1999规定的测试方法测试相关性能,通过分析发现钢渣已经发生一定程度的水化,胶凝性能明显减弱,各项强度远小于国家标准的要求。所以利用钢渣生产钢渣水泥的方法不可行,必须寻找其他利用方式。由钢渣的化学成分可知,可以利用钢渣制备絮凝剂,但是在合成絮凝剂之前必须使铁、铝溶解出来。经过参阅有关文献可知盐酸是最好的溶剂,并考查固液比、酸浸温度以及酸浸时间对浸出率的影响,通过实验找到最佳浸出条件,即1g钢渣加入3mol/L的盐酸16mL在60℃的条件下浸取2h,此时铁、铝的浸出率最大。然后外加一定聚合度的硅酸进行聚合,即可制备絮凝剂。分别考察Si:(Fe+Al)、熟化聚合温度和聚合pH值对絮凝剂性能的影响,通过单因素实验和正交试验,发现最佳聚合工艺,即Si:(Fe+Al)为3(摩尔比),聚合温度为60℃,聚合pH值为1.5,聚合时间为2h以上。在水处理中,絮凝剂的投加量和水样的pH值都是影响絮凝效果的主要因素,为寻找最佳使用条件分别考察絮凝剂对模拟废水以及大蒜废水的处理效果,主要考察指标有浊度和COD的去除率。此次制备的絮凝剂聚硅酸氯化铝铁的最佳投加量为120mg/L,适用pH值在7.0～8.0之间,是一种非常经济的水处理剂。利用工业废物生产工业产品实现以废制废的目的,不仅节约成本还可以治理环境污染,是一种非常有潜力的方法。更多还原

【Abstract】 Steel slag as one of industrial waste took up large quantities of land resources, and caused water and air pollution. The recycling of steel slag can not only protect the environment, but also make use of natural resources effectively and promote utilization ratio of resources. The research purpose of this paper is to look for the reasonable method of reusing the steel slag comprehensively through the experiment, and then solve the pollution problem.In order to find a reasonable method of application, we must first understand the various properties of steel slag, especially the chemical composition, chemical properties and mineralogical composition. So before the experiment, relative testing on the slag must be conducted. By the determination it shows that iro、aluminum、silicon and calcium are the main elements which are mainly in the form of various minerals, such as calcium silicate(C2S)、. tricalcium silicate(C3S), calcium silicate hydrate(CSH) and calcium hydroxide(CH), et al. These elements have some cementitious properties of hydration and can be used in building material industry.Because of its cementitious properties, steel slag can be used as clinker to prepare the steel slag cement. Cementitious properties of steel slag can be activated to a certain degree by gypsum. According to various indicators of cement, the proportion of each substance was determined. Compressive strength and flexural strength was tested in accordance with state Standard GB/T 17671-1999. The results showed that steel slag had hydrated to a certain degree. Its activity reduced significantly and the intensity is much less than the national standard. Therefore, using steel slag to produce slag cement is not feasible, we must look for some other ways.As the chemical composition of steel slag, it can be prepared for flocculant, but before that, iron and aluminum must be dissolved out. Referring to the literature, the best method was using hydrochloric acid. Then the influence of solid-liquid ratio, leaching temperature and leaching time on leaching rate was examined, and then the best leaching conditions was found, that was, under the condition of 60℃and 2h, adding 3 mol/L of hydrochloric acid to 1g slag, aluminum and iron leaching rate was the highest. Flocculant could be prepared after a certain degree of polymerization of silicic acid was added. Many flocculant performance parameters was studied, such as Si:(Fe+Al), curing polymerization temperature and polymerization pH value. Through single factor experiments and orthogonal test, the best polymerization process was found, namely Si:(Fe+Al) was 3 (molar ratio), polymerization temperature was 60℃, pH was 1.5 and polymerization reaction time was more than 2h.In water treatment, the dosage of flocculants and pH value of water sample are the main factors which affect flocculation. In order to search for the best condition, the experiment study using steel slag flocculant to process simulated wastewater and garlic wastewater respectively. The indicators turbidity and COD removal efficiency were studied. Results show the best dosage of flocculant (PAFCSi) is 120mg/L, pH range from 7.0 to 8.0, so it is a very economical water treatment agent.Turning waste into industrial products can achieve the purpose of using waste to treat environmental pollution, it is also a kind of economic and effective method which has great significance.更多还原