拜耳法赤泥低钙烧结提铝反应机理研究  

Study on Reaction Mechanism of Alumina Recovery from Bayer Red Mud by Low Calcium Sintering

作　　者：陈颖 陈延信[1] 赵博[1] 宋强[1] Chen Ying;Chen Yanxin;Zhao Bo;Song Qiang(College of Materials Science and Engineering,Xi’an University of Architecture and Technology,Xi’an,Shaanxi 710055)

机构地区：[1]西安建筑科技大学材料科学与工程学院,陕西西安710055

出　　处：《非金属矿》2021年第4期80-84,共5页Non-Metallic Mines

摘　　要：本试验采用低钙烧结法从拜耳法赤泥中提取氧化铝,在钙比为1.0的情况下,考察配料碱比、烧结温度和烧结时间对熟料中氧化铝溶出的影响。结果表明,在碱比为1.1、烧结温度为1150℃、烧结时间为1.5 h的条件下,熟料中氧化铝溶出率可达到86.07%。利用热重-差热(TG-DTG)、傅里叶红外光谱(FTIR)、X射线衍射(XRD)和扫描电镜(SEM)分析了拜耳法赤泥低钙烧结反应机理。结果表明,700℃时,水钙铝榴石、高岭石转变为Na_(2-x)Al_(2-x)Si_(x)O_(4);750℃时,Na_(2)CaSiO_(4)开始出现;800℃时,钙霞石消失;随着烧结温度的升高,Na_(2-x)Al_(2-x)Si_(x)O_(4)在Ca和Na的作用下逐渐向NaAlO_(2)转变,至1200℃,完全转化为NaAlO_(2),同时生成Na2CaSiO4。Alumina was extracted from Bayer red mud by low calcium sintering method in this experiment.The effects of alkali ratio,sintering temperature and sintering time on alumina dissolution in clinker were investigated with calcium ratio of 1.0.The results showed that the alkali ratio was 1.1,the sintering temperature was 1150℃and the sintering time was 1.5 h,the dissolution rate of alumina in clinker could reach 86.07%.The sintering mechanism of low calcium of Bayer red mud was analyzed by TG-DTG,FTIR,XRD and SEM.The results showed that hydrotalcite and kaolinite were transformed into Na_(2-x)Al_(2-x)Si_(x)O_(4)at 700℃,Na_(2)CaSiO_(4)appeared at 750℃.Cancrinite disappeared at 800℃.Na_(2-x)Al_(2-x)Si_(x)O_(4)gradually transformed into NaAlO_(2)under the action of Ca and Na with the increase of sintering temperature.Na_(2-x)Al_(2-x)Si_(x)O_(4)was completely transformed into NaAlO_(2)at 1200℃,and Na2CaSiO4 was formed at the same time.

关 键 词：拜耳赤泥 低钙烧结 铝硅酸钠 氧化铝 

分 类 号：TF802.6[冶金工程—有色金属冶金]