Removal of AlN from secondary aluminum dross by pyrometallurgical treatment  

采用火法工艺去除二次铝灰中的氮化铝

作　　者：WANG Jian-hui ZHONG Ye-qing TONG Yue XU Xun-lin LIN Gao-yong 王建辉;钟叶清;仝悦;徐勋林;林高用(School of Materials Science and Engineering,Central South University,Changsha 410083,China;Key Laboratory of Nonferrous Materials Science and Engineering(Ministry of Education),Central South University,Changsha 410083,China)

机构地区：[1]School of Materials Science and Engineering,Central South University,Changsha 410083,China [2]Key Laboratory of Nonferrous Materials Science and Engineering(Ministry of Education),Central South University,Changsha 410083,China

出　　处：《Journal of Central South University》2021年第2期386-397,共12页中南大学学报（英文版）

基　　金：Project(2017YFB0306001)supported by National Key R&D Program of China。

摘　　要：A new process of AlN removal from secondary aluminum dross(SAD)by pyrometallurgical treatment with added cryolite was applied for solving the problem of recycling the secondary aluminum dross.The response surface methodology(RSM)was used to design experiments and optimize parameters.The results show that adding the appropriate amount of cryolite can effectively promote the oxidation of AlN in the SAD,and too much cryolite will reduce the promotion effect.The effects of roasting temperature and cryolite on the denitrification rate are the most significant(p<0.0001)followed by holding time.Predicted values of the denitrification rate are found to be in good agreement with experimental values(R^(2)=0.9894 and R_(adj)^(2)=0.9775),which confirms the validity of the model employed.The optimum conditions of roasting temperature of 750°C,holding time of 194 min,mass fraction of cryolite of 17.7%are obtained according to the quadratic model.Under these conditions,the maximum actual denitrification rate reaches 94.71%and the AlN content in the SAD is only 0.55 wt%.The unfired brick with compressive strength of 18.62 MPa(GB/T 2542−2012)was prepared based on the roasted SAD.为了促进二次铝灰的再生利用,采用添加冰晶石并高温焙烧二次铝灰的火法工艺以去除其中的氮化铝。采用响应面法进行实验设计和参数优化。结果表明,添加适量冰晶石可以有效促进二次铝灰中氮化铝的氧化,但是过量的冰晶石会降低这种促进作用。相比于保温时间,焙烧温度和冰晶石质量分数对脱氮率的影响较为显著(p<0.0001)。脱氮率的预测值与实验值吻合较好(R^(2)=0.9894,R_(adj)^(2)=0.9775),验证了模型的有效性。根据二次模型,确定了最佳工艺参数为焙烧温度750°C,保温时间194 min,冰晶石质量分数17.7%。在此条件下,最大实际脱氮率达到94.71%,二次铝灰中氮化铝质量分数仅为0.55%。以处理过的二次铝灰为主要原料,制备的免烧砖抗压强度达到18.62 MPa(GB/T 2542−2012)。

关 键 词：secondary aluminum dross(SAD) ALN pyrometallurgy treatment denitrification rate response surface methodology(RSM) 

分 类 号：TF821[冶金工程—有色金属冶金]