锂云母、锂瓷土中铁的测定

探讨锂云母、锂瓷土中铁的测定方法,用原子吸收光谱仪测定能得到满意的结果。     

锂云母中提取锂的方法初步研究

研究了从锂云母中提取锂的方法，即将粉碎至150-180μm的云母粉与质量分数为50％的硫酸溶液以1：2的质量比在118—122℃下反应8h左右，以两倍于反应液体积的水浸取，得到含锂的硫酸溶液。用ICP—AES法对硫酸溶液中的锂、钾、钠、铝、硅、镁、铁等金属离子进行检测，结果表明，锂云母中锂的提取率达95％以上。     

Enhanced lithium leaching from lepidolite in continuous tubular reactor using H2SO4+H2SiF6 as lixiviant

An acidic mixture of sulfuric and fluosilicic acid (H₂SO₄+H₂SiF₆) was employed as lixiviant to enhance leaching of lithium from lepidolite. The H₂SiF₆ 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/H₂SO₄/H₂SiF₆, concentrations of H₂SO₄ and H₂SiF₆, leaching temperatures (40−80 °C) 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/H₂SO₄/H₂SiF₆ mass ratio of 1:0.8:1.6, 80 wt.% H₂SO₄, 15 wt.% H₂SiF₆, 80 °C, 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 H₂SO₄ and H₂SiF₆ in a continuous tubular reactor shows potential as an alternative process to extract lithium from lepidolite.     

卢氏锂辉石-锂云母型稀有多金属矿石工艺矿物学研究

深入研究了卢氏锂辉石-锂云母型稀有多金属矿石的工艺矿物学特征,为矿石选冶工艺提供理论基础和科学依据。查明了矿石中锂辉石、锂云母、绿柱石、铌钽铁矿、锑钽矿、细晶石和铯榴石等稀有金属矿物可供回收利用,石英和长石亦可综合回收,有用矿物占矿物量的94.3%。铌钽矿物与锂云母和锂电气石关系密切,铷无独立矿物、载体矿物为长石和锂云母。锂辉石和锂云母粒度较粗,铌钽铁矿和绿柱石粒度细小。铌钽铁矿主要呈粒柱状、绿柱石主要呈柱状和晶簇状集合体分布于粒间隙及微裂隙中。     

Na2SO4-H2SO4混合焙烧中低品位锂云母提锂研究

采用Na2SO4-H2SO4混合焙烧法处理宜春地区中低品位锂云母（Li2O=1.2-1.4%）,研究了酸浓度、焙烧后粒径、硫酸钠添加量等工艺条件对浸出率的影响。采用TG、XRD、SEM、元素成分分析等方法对焙烧过程进行了分析,探讨了Na2SO4对浸出过程的影响。研究结果表明：在800℃-1000℃的温度下,酸浓度70%、矿粒径80目、硫酸钠添加量100g时,浸出率达到90.0%,优于传统H2SO4法的浸出率（73.0%）。本工艺具有优异的固硅、固铝效果,可大幅度缩减传统工艺浸出过程中除硅、除铝工序;焙烧后的硅渣主要成分为SiO2和Al2O3;硫酸钠的加入加剧了锂云母矿原有结构的破坏,可以大幅度提升锂浸出率     

锂云母复合盐焙烧-水浸提取锂铷铯

采用复合盐焙烧-水浸工艺从锂云母中提取锂、铷、铯,研究了焙烧工艺参数及浸出工艺参数对锂、铷、铯浸出率的影响。结果表明,锂云母精矿焙烧时,复合盐焙烧效果优于单一盐添加剂,CaCl₂+Na₂CO₃组合添加剂具有焙烧时氯气排放少、焙烧矿浸出效果好等优点。从锂云母中回收锂、铷、铯,较佳的焙烧-浸出工艺条件为: CaCl₂+Na₂CO₃组合为焙烧添加剂,锂云母精矿∶CaCl₂∶Na₂CO₃(质量比)=1∶0.5∶0.2,锂云母精矿焙烧温度900 ℃、焙烧时间2 h,对焙烧矿进行室温水浸,浸出时间1 h、液固比2∶1,此时锂、铷、铯浸出率分别为86.64%、92.58%、85.37%。含锂浸出液经2次调节pH值净化除钙,升温至95 ℃后加入饱和Na₂CO₃溶液,结晶得到碳酸锂,样品纯度为99.08％,产品纯度及杂质含量达到一级碳酸锂标准。沉锂母液采用溶剂萃取法分离铷、铯,铯萃取率达到99%以上,铷洗脱率达到96%左右。     

锂云母酸浸液萃取除杂

锂云母酸法浸出液含有大量杂质金属,使用传统化学沉淀法会引起大量产物损失。为了降低浸出液除杂过程中的产物损失,使用溶剂萃取法进行萃取除杂工艺研究。通过对不同萃取剂组合萃取除杂效果的研究,确定使用P204作为萃取剂。考察了萃取过程中不同因素的影响,并使用H2O2预氧化水相里的Fe2+,强化萃取效果。结果表明：在有机相组成为30%P204+70%磺化煤油、料液初始pH为2.4、相比O/A=1、萃取时间10min和振荡频率300 r/min的单级萃取最佳条件下,铁除杂率为99.89%、铝除杂率为31.23%、锂和铷的萃取率分别为7.63%和14.85%。相比于化学沉淀法,锂和铷的回收率得到了30%左右的提高。