碳酸钠沉淀法制备氢氧化铝及其形成机理探讨.pdf

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碳酸钠沉淀法制备氢氧化铝及其形成机理探讣
黄静,夏举佩,罗中秋
(昆明理工大学化学工程学院,云南昆明650500)
摘要:以十八水碗酸铝LAl2(SO)1811?为沉淀前驱剂,饯酸(Na2CO3)为沉淀剂制备氢氧化铝,采用X射
线衍射(XIRD)、傅里叶变換红外光谱(HIIR)、热重分析(IGA)和扫描电子显微镜(SEM)探究硫酸铝水解
反应机理。硏究結果表明,75℃下0.02molL的硫酸铝溶液在pH=2.50时水解率为1.98%,pH=3.80时水解率为
100%。XRD、FTIR、TG-DTG和SLM结果表明,在Al1(SO4)溶液中滴加Na2CO;沉淀剂制备氢氧化铝的过程
中,pI起着重要作用。当溶液plIに3时,Ali以[Al(OI1)ず形式存在,随着溶液pⅡ的増加,[A(OI1)j水解
生成LAI(OH)(OH2)2」,LA(OH)4(OH2)」「在水化作用下脱水縮合为Al2(OH)s(OH2)2」2-,碱性增强
「Al(OH)s(OH2)2P转化为「Al2O(OH)2,最终形成氩氧化铝沉淀。pHI=3、5、7时,Al2(SO1)2水解所得产物为无
规则团聚的非晶态氢氧化铝;pIl=9、11时,氢氧化铝从非品晶态转变为晶态的勃姆石(y- AOOII)及少量拜尔石
La-Al(OH)」,且pH11时碗酸铝水解所得氮氧化铝结晶晶型较pH9时好。
关键词:氫氧化铝:沉淀法;勃姆石;拜尔石
中图分类号:TQ133.1
文献标志码:
文章编号:1000-6613(2017)(03-1120-06
DOI:10.16085.isa.1000-6613.2017.03.047
Preparation and growth mechanism of aluminium hydroxide by
precipitation method with sodium carbonate
HUANG ing, XIA pei, LUO Zhongyi
(Haculty of Chemical Ingineering, Kunming University of Science and'icchnology, Kunming 650500), Yunnan, China)
Abstract: Aluminum hydroxid was synthesized by onc-pot prccipitation mcthod using sodium carbonate
(Na2 O3 and aluminum sulfate A1 (0)3 18H O as precipi ator and precipitate precursor agents
respectively. Simultaneously, the rowth mechanism was investigated by X-ray diction(XRD), Fourier
transform infrared spectroscopy(FTIR), thermo gravimetric analysis(TGA )and scanning electron
microscopy (EM) The rcsults showed that the hydrolysis ratio of aluminum sulfate solution(0.02mol/L)
was 1. 98% and 100% under PH=2. 50 and 3.80 al 75 C, rcspcctivcly. The resulls OFXRD, FTIR, TG-DTG
and SEM showcd that PH played an important rolc in the preparation of aluminum hydroxic by the
dropwise addition o[ Na CO in A(:1)3. When PH was less than 3, Al kept a stable state as Al(OH2)
With the gradual increase of PH, [ Al(OH (OH, )] was generated hydrolyzed from Al(OH)and
subscqucntly dchydratcd-condcnscd into Al (OH (OH2)2 undcr thc cffcct of hydration. Thcn
Al(OH)(OH2)2 transformed into Al2 O(OH) with the increase of alkalinity. Finally, aluminum
hydroxide was generated. A ggregated and amorphous aluminum hydroxide could be obtained when PH was
3, 5 and 7. Under the PH of and II, amorphous aluminum hydroxide trans ormed into crystalline state of
boehmite (y-al0oh)and a little bayerite -Al(OH)3 Meanwhile, the crystal form of aluminum hydroxide
at PH=li was better than PH=9
Key words: aluminum hydroxide; precipitation method; boehmite; bayerite
收稿日期:2016-08-18:修改稿日期:2016-11-01
联系人:夏举佩,副教授,从事固体废弃物共伴生资源和用方面的研
第一作者:黃静(1991ー),女,硕士研究生,从事圖体废弃物共
究。F-mail:xjn661163.com
伴生资源利用方面的研究。上-mail:Huanging513401@163.com
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