本文選題：氧化鋁前驅(qū)體　切入點(diǎn)：硫酸鋁銨　出處：《河北科技大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

【摘要】：氧化鋁是一種重要的化工原料,由于具有多種晶型,因而用途十分廣泛,可用于電解鋁、陶瓷、醫(yī)藥、電子、機(jī)械等眾多行業(yè)行業(yè)。氧化鋁多是由煅燒其前驅(qū)體制得,其前驅(qū)體的制備有酸法、堿法、硫酸銨法。硫酸銨法因污染小、產(chǎn)品品質(zhì)高而優(yōu)于前兩種方法,但是該方法存在的問題之一是通過硫酸鋁銨制備的氫氧化鋁的顆粒小、濾餅含水量高,造成過濾困難和后續(xù)過程能耗過高。本論文針對(duì)硫酸銨法存在的問題,以硫酸鋁銨為原料,開展氧化鋁前驅(qū)體生成過程的實(shí)驗(yàn)研究,探索制備較大粒徑氧化鋁前驅(qū)體的方法和條件。首先對(duì)硫酸鋁銨與堿直接沉淀反應(yīng)制備氧化鋁前驅(qū)體進(jìn)行實(shí)驗(yàn)研究,探討堿源、滴加方式、反應(yīng)溶液的p H值、反應(yīng)溶液的溫度、滴加速度、陳化時(shí)間、硫酸鋁銨溶液的濃度、晶種用量等條件對(duì)所得產(chǎn)品的影響。結(jié)果表明,在優(yōu)化的實(shí)驗(yàn)條件下,可以制得粒徑為300~400nm、濾餅含水量為70%左右的氫氧化鋁樣品。采用加入襯底溶液的方法對(duì)堿直接沉淀法進(jìn)行改進(jìn)。分別加入硫酸銨及硫酸鈉做襯底溶液,硫酸鈉做襯底溶液時(shí)又分單注法和雙注法,進(jìn)行直接沉淀反應(yīng)實(shí)驗(yàn)研究,制得了粒徑大并且濾餅含水量低的產(chǎn)品。以硫酸鋁銨與氨水直接沉淀反應(yīng)制備的氧化鋁前驅(qū)體為原料,采用水熱生長法對(duì)其處理,對(duì)水熱操作條件進(jìn)行考察,制得了粒徑達(dá)500nm,含水量降低至60~70%的氧化鋁前驅(qū)體。在上述實(shí)驗(yàn)研究的基礎(chǔ)上,本論文嘗試了在水熱條件下原位合成氧化鋁前驅(qū)體即水熱合成法。經(jīng)過實(shí)驗(yàn)操作條件的優(yōu)選,獲得了適宜的制備條件為水熱時(shí)間為9小時(shí)、水熱溫度為150℃、水熱合成環(huán)境為弱堿性,晶種的適宜加入量為5.0g/L,氨水與尿素配比為1:40,添加劑為硫酸鉀。在此操作條件下,制得的氧化鋁前驅(qū)體粒徑為450~550nm,濾餅含水量降低到了40~50%,可有效降低生產(chǎn)氧化鋁過程的能耗,提高經(jīng)濟(jì)效益。
[Abstract]:Alumina is an important chemical raw material, because of its many crystal forms, it can be used in many industries such as electrolytic aluminum, ceramics, medicine, electronics, machinery and so on. The precursor was prepared by acid method, alkali method and ammonium sulfate method. The ammonium sulfate method is superior to the former two methods because of its low pollution and high product quality. However, one of the problems in this method is the small size of aluminum hydroxide prepared by ammonium aluminum sulfate. The high moisture content of filter cake causes the difficulty of filtration and the energy consumption of subsequent process is too high. Aiming at the problems existing in ammonium sulfate process, this paper carried out an experimental study on the formation process of alumina precursor with ammonium aluminum sulfate as raw material. Firstly, the preparation of alumina precursor by direct precipitation of ammonium aluminum sulfate with alkali was studied, and the alkali source, the method of dropping and the pH value of the reaction solution were discussed. The effects of temperature, droplet acceleration, aging time, concentration of ammonium aluminum sulfate solution and amount of crystal seed on the product were studied. The aluminum hydroxide sample with the diameter of 300nm and the water content of filter cake is about 70%. The direct alkali precipitation method is improved by adding substrate solution. Ammonium sulfate and sodium sulfate are added as substrate solution, respectively. When sodium sulfate was used as substrate solution, it was divided into single injection method and double injection method to study the direct precipitation reaction. The product with large particle size and low water content of filter cake was prepared. The alumina precursor prepared by direct precipitation reaction of ammonium aluminum sulfate with ammonia water was used as raw material. The alumina precursor with a diameter of 500 nm and a water content of 60 ~ 70% was prepared by hydrothermal growth method and the conditions of hydrothermal operation were investigated. In this paper, the hydrothermal synthesis of alumina precursor in situ under hydrothermal conditions is attempted. The optimum preparation conditions are obtained as follows: hydrothermal time is 9 hours, hydrothermal temperature is 150 鈩，

本文編號(hào)：1556308