Enhanced lithium leaching from lepidolite in continuous tubular reactor using H_(2)SO_(4)+H_(2)SiF_(6) as lixiviant  

锂云母连续管式反应器中混酸H_(2)SO_(4)+H_(2)SiF_(6)体系强化溶出锂

作　　者：Hui GUO Ge KUANG Huan LI Wen-tao PEI Hai-dong WANG 郭慧;旷戈;李欢;裴文涛;王海东(郑州大学化工学院,郑州450001;福州大学石油化工学院化学工程技术研究所,福州350108;中南大学资源加工与生物工程学院,长沙410083;Western Australian School of Mines:Minerals,Energy and Chemical Engineering,Curtin University,Perth,WA 6102,Australia)

机构地区：[1]School of Chemical Engineering,Zhengzhou University,Zhengzhou 450001,China [2]Institute of Chemical Technologies,College of Chemical Engineering,Fuzhou University,Fuzhou 350108,China [3]School of Minerals Processing and Bioengineering,Central South University,Changsha 410083,China [4]Western Australian School of Mines:Minerals,Energy and Chemical Engineering,Curtin University,Perth,WA 6102,Australia

出　　处：《Transactions of Nonferrous Metals Society of China》2021年第7期2165-2173,共9页中国有色金属学报（英文版）

基　　金：the financial supports from Natural Science Foundation of Henan,China(No.212300410278);Henan Provincial Key Research and Development Program,China(No.212102310371);Henan Postdoctoral Foundation,China(No.202002020);China Postdoctoral Science Foundation(No.2020M682353).

摘　　要：An acidic mixture of sulfuric and fluosilicic acid(H_(2)SO_(4)+H_(2)SiF_(6))was employed as lixiviant to enhance leaching of lithium from lepidolite.The H_(2)SiF_(6) was obtained as a byproduct of anhydrous hydrofluoric acid production,aiming to provide HF molecules.It was found that the HF molecules were the main reaction component and played a key role in strengthening the dissolution of lepidolite.Different factors,including mass ratio of ore/H_(2)SO_(4)/H_(2)SiF_(6),concentrations of H_(2)SO_(4) and H_(2)SiF_(6),leaching temperatures(40−80℃)and time(15−75 min),were investigated.Moreover,an efficient tubular reactor was employed to improve this acid leaching system.Under the optimal conditions(ore/H_(2)SO_(4)/H_(2)SiF_(6) mass ratio of 1:0.8:1.6,80 wt.% H_(2)SO_(4),15 wt.% H_(2)SiF_(6),80℃,15 min),97.9% of Li,96.4% of K,97.6% of Rb,96.7% of Cs and 81.4% of Al(mass fraction)were leached.Additionally,a two-step thermal process was proposed to remove fluorine of leaching slurry.This acid treatment using an acidic mixture of H_(2)SO_(4) and H_(2)SiF_(6) in a continuous tubular reactor shows potential as an alternative process to extract lithium from lepidolite.采用硫酸(H_(2)SO_(4))和氟硅酸(H_(2)SiF_(6))的混酸浸出剂强化锂云母中锂的浸出。氟硅酸(H_(2)SiF_(6))作为氢氟酸的副产物,可以提供反应所需的氟化氢(HF)分子。而氟化氢是氟硅酸实际参与反应的主要成分,对锂的强化溶出具有关键作用。探究矿石/硫酸/氟硅酸质量比、硫酸和氟硅酸浓度、浸出温度(40~80℃)、浸出时间(15~75 min)等因素对锂浸出的影响。采用连续管式反应器进一步强化酸浸体系。确定酸浸最优条件为:矿石/H_(2)SO_(4)/H_(2)SiF_(6)质量比1:0.8:1.6、H_(2)SO_(4)浓度80%(质量分数)、H_(2)SiF_(6)浓度15%(质量分数),97.9%的锂、96.4%的钾、97.6%的铷、96.7%的铯和81.4%的铝(质量分数)在80℃下仅需反应15 min即可得到有效浸出。此外,提出两步热处理工艺对反应浆料进行脱氟。研究结果表明,采用管式反应器加含氟混酸浸出剂(H_(2)SO_(4)+H_(2)SiF_(6))可实现锂云母的高效提锂。

关 键 词：LEPIDOLITE lithium extraction continuous tubular reactor fluosilicic acid fluorine chemical method 

分 类 号：TF826.3[冶金工程—有色金属冶金]