Dissolution kinetics and removal mechanism of kaolinite in diasporic bauxite in alkali solution at atmospheric pressure  

一水硬铝石型铝土矿中高岭石的常压碱溶动力学与溶出脱除机理（英文）

作　　者：Yan WU Xiao-lin PAN Yue-jiao HAN Hai-yan YU 吴艳;潘晓林;韩月娇;于海燕(东北大学冶金学院)

机构地区：[1]School of Metallurgy,Northeastern University,Shenyang 110819,China

出　　处：《Transactions of Nonferrous Metals Society of China》2019年第12期2627-2637,共11页中国有色金属学报（英文版）

基　　金：Project(2018YFC1901903) supported by the National Key Research and Development Program of China;Projects(51774079,51674075) supported by the National Natural Science Foundation of China;Project(N182508026) supported by the Fundamental Research Funds for the Central Universities,China

摘　　要：A new chemical pre-desilication process of kaolinite in diasporic bauxite in alkali solution at atmospheric pressure was proposed.The dissolution kinetics and mechanism were studied by chemical analysis,XRD and SEM.The kinetic results of dissolution process show that the kaolinite is symbiotic with diaspore but without cladding.The dissolution ratio of kaolinite is close to 100%at 100℃for 90 min.The dissolution kinetic equation is 1-(1-α)^1/3=7.88×10^6 exp[-64434/(RT)]t.With the low L/S(L/S=10:1),the dissolution ratio of kaolinite decreases to 55%.This is due to the formation of lamellar hydroxyl-sodalite(OH-SOD)which is deposited on the surface of kaolinite and hinders the further dissolution of kaolinite.Under the optimum conditions,the A/S(mass ratio of Al2 O3 to SiO2)of dissolved residues is increased to 8.55,while the A/S of the bauxite is only 4.97.提出一种一水硬铝石型铝土矿中高岭石的常压化学预脱硅新工艺。通过化学分析、XRD和SEM对溶出过程动力学及溶出机理进行研究。溶出动力学结果表明,高岭石与一水硬铝石虽嵌布共生,但并无包覆现象。因此,在100℃下,高岭石溶出90 min的溶出率可接近100%。溶出动力学方程为1-(1-α)^1/3=7.88×10^6exp[-64434/(RT)]t。低液固比(L/S=10:1)条件下,高岭石的溶出率降低到55%。这是由于形成层状羟基方钠石(OH-SOD),并沉淀在高岭石的表面,阻碍高岭石进一步被溶出。在最优条件下,可以将溶出渣的铝硅比提高到8.55,而原矿中铝硅比仅为4.97。

关 键 词：Bayer process KAOLINITE PRE-DESILICATION dissolution kinetics SODALITE 

分 类 号：P61[天文地球—矿床学]