(1. 中國科學院綠色過程與工程重點實驗室，中國科學院過程工程研究所，北京 100190；
2. 戰(zhàn)略金屬資源綠色循環(huán)利用國家工程研究中心，中國科學院過程工程研究所，北京 100190；
3. 中國科學院大學，北京 100049；
4. 東北大學 冶金學院，沈陽 110819)
摘 要: 二次鋁灰是電解鋁工業(yè)產(chǎn)生的一種含鋁危險廢棄物，由于成分復雜，其中的鋁資源尚未得到有效利用。通過二次鋁灰與硫酸銨混合焙燒形成易浸取的硫酸鋁銨，可實現(xiàn)二次鋁灰中鋁資源的高效回收。本文采用熱重-紅外聯(lián)用儀、XRD、SEM和HSC等研究了二次鋁灰與硫酸銨焙燒提鋁過程機理。結(jié)果表明：二次鋁灰中主要含鋁物相為Al2O3、AlN、Na3AlF6、Al和NaAl11O17，二次鋁灰與硫酸銨混合物料的熱分解過程可分為六個階段。在30~215 ℃階段，主要為物理水揮發(fā)；在215~300 ℃階段，(NH4)2SO4分解為NH4HSO4并產(chǎn)生NH3；在300~337 ℃階段，NH4HSO4開始分解為SO2、NH3、H2O；在337~437 ℃階段，Al2O3與(NH4)2SO4反應生成NH4Al(SO4)2并產(chǎn)生NH3、H2O，含量相對較少的含鋁物相(Al、AlN和NaAl11O17)及氟化物(Na3AlF6、CaF2)逐漸與硫酸銨反應生成相應的硫酸鹽；在437~556 ℃階段，NH4Al(SO4)2分解生成Al2(SO4)3、SO2、NH3、H2O；在556~900 ℃階段，Al2(SO4)3分解生成Al2O3和SO2。因此，二次鋁灰硫酸銨焙燒提鋁優(yōu)化溫度區(qū)間為300~500 ℃。
關(guān)鍵字: 二次鋁灰；鋁資源；硫酸銨焙燒；過程機理
（1. CAS Key Laboratory of Green Process and Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China;
2. National Engineering Research Center of Green Recycling for Strategic Metal Resources, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China;
3. University of Chinese Academy of Sciences, Beijing 100049, China;
4. School of Metallurgy, Northeastern University, Shenyang 110000, China）
Abstract:The secondary aluminum dross is one of Al-bearing hazardous wastes produced in the electrolytic aluminum industry. Due to the complex chemical composition of secondary aluminum dross, its aluminum resources have not been effectively utilized. The aluminum resources of secondary aluminum dross can be efficiently recovered by roasting with ammonium sulfate to form ammonium aluminum sulfate, which can easily dissolve into the water. In this paper, the process mechanism of aluminum extraction from secondary aluminum dross through roasting with ammonium sulfate was investigated by thermogravimetric-infrared spectroscopy, XRD, SEM and HSC. The results show that Al2O3, AlN, Na3AlF6, Al and NaAl11O17 are the main Al-containing phases in secondary aluminum dross. The thermal decomposition process of secondary aluminum dross and ammonium sulfate mixture can be divided into six stages. In the stage of 30-215 ℃, physical water gradually volatilizes. In the stage of 215-300 ℃, (NH4)2SO4 is decomposed into NH4HSO4 and NH3. In the stage of 300-337 ℃, NH4HSO4 decomposes and produces SO2, NH3, and H2O. In the stage of 337-437 ℃, Al2O3 reacts with (NH4)2SO4 to produce NH4Al(SO4)2, NH3, and H2O. Besides, Al-containing phases (Al, AlN and NaAl11O17) and fluorides (Na3AlF6, CaF2)) reacts with (NH4)2SO4 to form corresponding sulfates. In the stage of 437-556 ℃, NH4Al(SO4)2 is decomposed into Al2(SO4)3, SO2, NH3, and H2O. In the stage of 556-900 ℃, Al2(SO4)3 is decomposed into Al2O3 and SO2. Therefore, the optimum temperature range of the process is from 300 ℃ to 500 ℃.
Key words: secondary aluminum dross; aluminum resources; ammonium sulfate roasting; process mechanism
