高岭土制备白炭黑及应用其吸附钙、镁离子的实验研究

发布时间：2018-02-20 16:54

  本文关键词： 高岭土 白炭黑 吸附 钙、镁离子　出处：《内蒙古工业大学》2015年硕士论文　论文类型：学位论文

【摘要】：白炭黑是一种外表呈白色、质轻、蓬松的非晶质二氧化硅,具有表面多孔结构,组成可用Si O2·n H2O来表示,其中n H2O是以表面羟基形式存在的。白炭黑常用的制备方法包括气相法、沉淀法和硅酸盐矿物分解法。前两种方法的原材料通常为硅酸钠、四氯化硅、正硅酸乙酯,成本都较高,而非金属矿则价廉易得,是一种理想的原材料。高岭土中含有的二氧化硅经高温煅烧可转化为非晶态二氧化硅,因此廉价的高岭土可以作为合成白炭黑的硅源,既降低了生产成本,又实现了高岭土的资源化、精细,提高了其附加价值。本文以高岭土为原料,高温煅烧后可与氢氧化钠溶液反应,绝大多数非晶态二氧化硅与碱液反应而进入溶液中。实验重点考察了高岭土煅烧温度、碱浸反应的碱液浓度、反应温度和反应时间对提硅效果的影响。通过单因素实验研究确定了最佳提硅条件为:煅烧温度:960℃,碱液浓度:20%,反应温度90℃;反应时间90 min。在此工艺条件下,提硅率可达60.50%。然后以提硅液为原料沉淀法制备得到了白炭黑,考察了提硅液中二氧化硅浓度、碳化温度、反应时间及陈化时间等对白炭黑的产率及DBP值的影响,得出最适反应条件:提硅液中二氧化硅浓度为12 g/L,碳化温度为90℃,反应时间为90 min,陈化时间为2 h,在此条件下合成的白炭黑DBP吸油值在2.8 m L/g以上,比表面积达到127.4 m2/g,符合国家标准。同时采用红外光谱、X射线衍射、扫描电镜等分析手段对高岭土及制备白炭黑的组成及形貌进行了表征,通过场发射扫描电镜图可以看出白炭黑粒径大约40~50 nm。以合成的白炭黑为吸附剂,考察了不同条件下,白炭黑对水溶液中钙、镁离子去除能力的影响。白炭黑用量、接触时间和溶液初始浓度对去除效果影响较大,同时反应温度、摇床转速也对钙镁离子的去除有一定的影响。常温下,当钙离子浓度为200 mg/L,白炭黑投加量为4 g/L时,去除率达到94.99%,当镁离子的浓度为100 mg/L时,白炭黑投加量为8 g/L时,去除率才达到62.32%,可见,合成的白炭黑对钙离子的去除能力明显高于镁离子。
[Abstract]:Silica is a kind of amorphous silica with white appearance, light weight and fluffy shape. It has porous surface structure and its composition can be expressed by Sio 2 路n H 2O. The preparation methods of silica include gas phase method, precipitation method and silicate mineral decomposition method. The raw materials of the first two methods are usually sodium silicate, silicon tetrachloride, ethyl orthosilicate. The cost is high, and the non-metallic ore is cheap and easy to obtain, so it is an ideal raw material. The silica contained in kaolin can be converted into amorphous silica after high temperature calcination, so cheap kaolin can be used as a source of silicon for the synthesis of silica. In this paper, kaolin is used as raw material and can react with sodium hydroxide solution after high temperature calcination. Most amorphous silica reacts with alkali solution and enters the solution. The experiment focuses on the calcination temperature of kaolin and the concentration of alkali solution in alkali leaching reaction. The effects of reaction temperature and reaction time on the effect of silicon extraction were studied by single factor experiments. The optimum conditions of silicon extraction were determined as follows: calcination temperature: 960 鈩，

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