钢渣吸附性能的改进及其资源化应用的研究

发布时间：2018-11-16 09:35

【摘要】：铅具有生物毒性,含铅废水进入环境后不能被微生物降解,只能发生形态间的相互转化、分散和富集,并且沿生物链传递,通过皮肤、消化道、呼吸道进入人体体内与多种器官亲和积蓄。但铅是自然界分布很广的元素,常被用作制造业的原料。若不妥善安全处置含铅废水必然会给环境带来极大的危害。因此,需寻找一种安全可靠且经济有效的方式处理含铅废水。钢渣是炼钢过程中排出的熔渣,分为转炉渣、平炉渣、电炉渣三种,长期以来被作为固体废物处置。本实验用XRF、XRD、SEM、BET等测试方法观察转炉渣的成分及微观形貌,可知,钢渣表面粗糙多孔,具有一定的吸附能力；钢渣的化学成分主要有CaO、SiO2;钢渣置于水中呈碱性,对水溶液中的铅离子具有一定的化学沉淀作用；钢渣的矿物成分主要有C2S、C3S,与硅酸盐水泥熟料相似,可作为混合材料制备钢渣水泥。故利用钢渣处理含铅废水,探索吸附铅离子钢渣制备钢渣水泥用作建筑材料的可行性。针对高浓度含铅废水,本论文用氧化铝助改、高温活化、酸浸三种改性方法对钢渣改性,提高钢渣的吸附性能。硫酸对钢渣的改性效果最好,最佳改性条件为氢离子浓度0.32mol/L。通过静态实验对改性钢渣处理高浓度含铅废水的操作条件进行了优化选择。结果表明：钢渣的投加量、反应时间、反应温度对吸附效果有较大影响,铅离子与钢渣的最佳投加比仅为1：6,在200min时达到吸附平衡,最佳反应温度为25℃。溶液初始浓度和初始pH对吸附效果影响不大。结合吸附等温线模型、吸附动力学模型、化学沉淀原理、实验现象及表征分析,探讨了钢渣处理含铅废水的作用机理。钢渣吸附铅离子的过程属于单分子层吸附,符合Langmuir模型和伪二级动力学模型。钢渣处理含铅废水的机理主要包括化学沉淀和离子交换作用。本文重点解决了吸附铅离子钢渣稳定化、无害化、资源化处理的难题,将吸附重金属铅离子钢渣混合材制备成钢渣水泥,寻找了一个经济、低碳、环保的废渣资源化利用新途径。通过对钢渣水泥的物理性能测试、XRD、SEM表征、水化热、孔结构分析以及水泥中铅离子浸出毒性测试,研究其作为建材应用的可行性。结果表明：钢渣水泥的各项物理性能均满足GB 175-2007《通用硅酸盐水泥标准》：掺杂10%钢渣时,水泥强度能达到52.5R；掺杂40%钢渣时,水泥强度能达到42.5R；未出现异常水化产物；吸附有铅离子的钢渣未导致水泥水化延迟；且钢渣水泥中的铅离子在酸性和中性环境下的浸出浓度均满足GB5085.3-2007《危险废物鉴别标准-浸出毒性鉴别》标准。
[Abstract]:Lead is biotoxic, and lead-containing wastewater cannot be degraded by microorganisms when it enters the environment. It can only be transformed, dispersed and enriched by morphology, and is transmitted along biological chain through the skin and digestive tract. Respiratory tract enters the human body and a variety of organs affinity savings. But lead is a widely distributed element in nature and is often used as a raw material for manufacturing. If the waste water containing lead is not disposed properly and safely, it will bring great harm to the environment. Therefore, it is necessary to find a safe, reliable and economical and effective way to treat waste water containing lead. Steel slag is a kind of slag discharged in steelmaking process. It is divided into converter slag, flat slag and electric slag. It has been used as solid waste disposal for a long time. In this experiment, the composition and microstructure of the converter slag were observed by means of XRF,XRD,SEM,BET and other testing methods. The results show that the steel slag surface is rough and porous, and it has certain adsorption ability. The main chemical composition of steel slag is that CaO,SiO2; steel slag is alkaline in water and has certain chemical precipitation effect on lead ion in aqueous solution. The mineral composition of steel slag is mainly C _ 2S _ 2 C _ 3S, which is similar to Portland cement clinker and can be used as a mixed material to prepare steel slag cement. Therefore, using steel slag to treat lead-containing wastewater and to explore the feasibility of preparing steel slag cement by adsorption of lead-ion steel slag as building material. In order to improve the adsorption performance of steel slag, three modification methods, alumina modification, high temperature activation and acid leaching, were used to improve the adsorption properties of steel slag. The effect of sulfuric acid on the modification of steel slag is the best, and the optimum modification conditions are as follows: hydrogen ion concentration 0.32 mol 路L ~ (-1). The operation conditions of modified steel slag for treatment of high concentration lead-containing wastewater were optimized by static experiment. The results show that the addition amount of steel slag, reaction time and reaction temperature have great influence on the adsorption effect. The optimum addition ratio of lead ion to steel slag is only 1: 6, the adsorption equilibrium is reached at 200min, and the optimum reaction temperature is 25 鈩，

本文编号：2335153