煤系锂资源的分布赋存特征与提取分离研究进展

A review of in coal-based lithium resources:Distribution,occurrence characteristics,and extraction separation

锂是一种战略性金属,应用领域广泛,对国家安全、国民经济和科技发展具有极其重要的意义。目的目前,我国锂资源面临着供需不平衡的困境,急需寻找新的锂来源。我国煤中锂含量较高、分布广泛,煤系副产品煤矸石及粉煤灰中锂含量高,有望成为传统资源的替代物。从煤矸石和粉煤灰中回收锂可拓宽现有锂的生产渠道,并实现煤矸石和粉煤灰的资源化高值利用。方法本文综述了煤系锂元素分布特征、赋存状态和燃烧过程中迁移规律的最新研究进展,并对煤系锂元素的浸出提纯回收方法进行了总结,可为从煤系副产品中提取回收锂资源提供参考。结果我国华北与华南赋煤区内锂含量较高,主要载锂矿物是高岭石、伊利石等黏土矿物,部分矿区内煤层夹矸和顶底板中锂含量高于煤层;煤经燃烧后实现了锂元素的二次富集,锂主要与铝硅酸盐结合,赋存于玻璃相内,并倾向于富集在细粒飞灰中;浸出和分离是实现煤系锂资源回收利用的必要步骤,但现有工艺复杂,浸出液中锂浓度低,杂质离子对分离纯化环节干扰严重。结论未来煤系锂资源开发应在采选过程中强化矸石与煤中锂元素差异性富集,着重探明燃烧过程中锂的迁移转化规律,重视浸出的高效性和分离纯化过程的选择性。煤系锂资源的开发回收有助于煤炭资源高值化利用,促进绿色可持续发展。

Lithium is a strategical metal with broad areas of application,which is of great significance for national security,national economy and scientific and technological development.Objectives China’s lithium resources are facing the dilemma of imbalanced supply and demand,and there is an urgent need to find new lithium sources.The lithium content in Chinese coal is high and widely distributed.Coal gangue and coal fly ash,which are coalbased by products,have high lithium content and are expected to become alter-native resources for traditional resources.The recovery of lithium from coal gangue and coal fly ash can broaden the existing production routes of lithium,and realize the high value utilization of coal gangue and coal fly ash as resources.Methods This paper reviewed the current research progress on the distribution characteristics and modes of occurrence of lithium in coal deposit and migration laws of lithium elements in coal measures during combustion.It also summarized the leaching and purification recovery methods of coal-based lithium elements,which can provide reference for extracting and recovering lithium resources from coal-based by-products.Results The content of lithium was high in the coal-rich regions of North and South China,and the main lithium bearing minerals were clay minerals such as kaolinite and illite.In some mining areas,the lithium content of gangue-bearing coal,roof and floor was higher than that of coal seams.After coal combustion,the secondary enrichment of lithium was realized.Lithium mainly combined with alumino-silicate,occured in the glass phase,and tended to be enriched in fine fly ash.Leaching and separation were necessary way to realize the recycling of coal-based lithium resources.However,the existing process was complicated,with low lithium concentration in the leaching solution and severe interference from impurity ions in the separation and purification process.Conclusions The future development of coal-based lithium resources should strengthen the differential enrichment of lithium elements in gangue and coal during the mining and selection process,with a focus on exploring the migration and transformation laws of lithium during the combustion process,emphasizing the efficiency of leaching and the selectivity of separation and purification processes.The exploit and recovery of lithium from coal-based resources contribute to the highvalue utilization of coal resources and promote green and sustainable development.