Transactions of Nonferrous Metals Society of China The Chinese Journal of Nonferrous Metals

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中国有色金属学报

ZHONGGUO YOUSEJINSHU XUEBAO

第26卷    第7期    总第208期    2016年7月

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文章编号:1004-0609(2016)-07-1523-08
焙烧气氛对含砷铁精矿球团中砷挥发行为的影响
游志雄,文佩丹,李光辉,张元波,姜 涛

(中南大学 资源加工与生物工程学院,长沙 410083)

摘 要: 对含砷铁精矿球团在中性、氧化和还原性气氛以及预氧化-还原焙烧过程中砷的挥发行为进行研究;并结合热力学分析,揭示不同气氛下砷挥发的机理。结果表明:含砷铁精矿球团在中性、弱还原性气氛或经预氧化-弱还原焙烧,均能实现砷的有效挥发。将含砷铁精矿球团在850 ℃、100% N2气氛下焙烧10min,砷挥发率达到79.33%,砷含量由0.11%降低至0.023%;在950 ℃、5%H2、9.5%CO、85.5%CO2(体积分数)的弱还原气氛下焙烧10 min,砷挥发率为82.47%,残余砷含量仅为0.020%;球团在空气气氛下经750 ℃预氧化10 min后,再经950 ℃、5%H2、9.5%CO、85.5%CO2条件下还原20 min后,砷的挥发率达到81.76%,残余砷含量为0.021%。砷挥发机理的研究表明,砷在不同气氛下能够以As2(g)、As4(g)或As2O3(g)的形式挥发;但是氧化或还原气氛过强将分别生成砷酸铁和砷化铁影响砷的脱除。

 

关键字: 砷;含砷铁精矿;焙烧;气氛;挥发

Effect of roasting atmosphere on arsenic volatilization behavior of As-bearing iron concentrate pellet
YOU Zhi-xiong, WEN Pei-dan, LI Guang-hui, ZHANG Yuan-bo, JIANG Tao

School of Minerals Processing and Bioengineering, Central South University, Changsha 410083, China

Abstract:Arsenic volatilization behavior of As-bearing iron concentrate pellet was studied in various atmospheres, such as neutral, oxidation, reduction and by preoxidation-weak reduction roasting. The results show that arsenic can be volatilized by roasting in the above mentioned atmosphere except oxidation atmosphere. The results show that arsenic volatilization ratio of 79.33% is obtained when roasted at 850 ℃ for 10 min in N2 atmosphere and the residual As content decreases from 0.11% to 0.023%. Under the conditions of 950 ℃ for 10 min in reduction atmosphere of 5% H2 and 10% CO/(CO+CO2), As volatilization ratio and residual As content are 82.47% and 0.020%, respectively. When the pellet was preoxidized at 750 ℃ for 10 min in air and subsequently reduced at 950 ℃ for 20 min with 5% H2 and 10% CO/(CO+CO2), As volatilization ratio of 81.75% is achieved and the residual As content decreases to 0.021% correspondingly. The volatilization mechanisms of arsenopyrite reveal that As is capable of being volatilized in the form of As2(g), As4(g) as well as As2O3(g). However, FeAsO4 and FeAs are likely generated at higher oxidation and reduction potential, respectively, which will inhibit the volatilization of As.

 

Key words: arsenic; arsenic-containing iron concentrate; roasting; atmosphere; volatilization

ISSN 1004-0609
CN 43-1238/TG
CODEN: ZYJXFK

ISSN 1003-6326
CN 43-1239/TG
CODEN: TNMCEW

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