本文關鍵詞： 高嶺土 白炭黑 吸附 鈣、鎂離子　出處：《內蒙古工業(yè)大學》2015年碩士論文　論文類型：學位論文

【摘要】：白炭黑是一種外表呈白色、質輕、蓬松的非晶質二氧化硅,具有表面多孔結構,組成可用Si O2·n H2O來表示,其中n H2O是以表面羥基形式存在的。白炭黑常用的制備方法包括氣相法、沉淀法和硅酸鹽礦物分解法。前兩種方法的原材料通常為硅酸鈉、四氯化硅、正硅酸乙酯,成本都較高,而非金屬礦則價廉易得,是一種理想的原材料。高嶺土中含有的二氧化硅經高溫煅燒可轉化為非晶態(tài)二氧化硅,因此廉價的高嶺土可以作為合成白炭黑的硅源,既降低了生產成本,又實現了高嶺土的資源化、精細,提高了其附加價值。本文以高嶺土為原料,高溫煅燒后可與氫氧化鈉溶液反應,絕大多數非晶態(tài)二氧化硅與堿液反應而進入溶液中。實驗重點考察了高嶺土煅燒溫度、堿浸反應的堿液濃度、反應溫度和反應時間對提硅效果的影響。通過單因素實驗研究確定了最佳提硅條件為:煅燒溫度:960℃,堿液濃度:20%,反應溫度90℃;反應時間90 min。在此工藝條件下,提硅率可達60.50%。然后以提硅液為原料沉淀法制備得到了白炭黑,考察了提硅液中二氧化硅濃度、碳化溫度、反應時間及陳化時間等對白炭黑的產率及DBP值的影響,得出最適反應條件:提硅液中二氧化硅濃度為12 g/L,碳化溫度為90℃,反應時間為90 min,陳化時間為2 h,在此條件下合成的白炭黑DBP吸油值在2.8 m L/g以上,比表面積達到127.4 m2/g,符合國家標準。同時采用紅外光譜、X射線衍射、掃描電鏡等分析手段對高嶺土及制備白炭黑的組成及形貌進行了表征,通過場發(fā)射掃描電鏡圖可以看出白炭黑粒徑大約40~50 nm。以合成的白炭黑為吸附劑,考察了不同條件下,白炭黑對水溶液中鈣、鎂離子去除能力的影響。白炭黑用量、接觸時間和溶液初始濃度對去除效果影響較大,同時反應溫度、搖床轉速也對鈣鎂離子的去除有一定的影響。常溫下,當鈣離子濃度為200 mg/L,白炭黑投加量為4 g/L時,去除率達到94.99%,當鎂離子的濃度為100 mg/L時,白炭黑投加量為8 g/L時,去除率才達到62.32%,可見,合成的白炭黑對鈣離子的去除能力明顯高于鎂離子。
[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，

本文編號：1519499