程晨,宋杨,臧静坤,等. 贵州普安矿区20号煤中锂的赋存状态及逐级化学提取实验研究[J]. 煤田地质与勘探,2022,50(10):44−53. DOI: 10.12363/issn.1001-1986.21.08.0430
引用本文: 程晨,宋杨,臧静坤,等. 贵州普安矿区20号煤中锂的赋存状态及逐级化学提取实验研究[J]. 煤田地质与勘探,2022,50(10):44−53. DOI: 10.12363/issn.1001-1986.21.08.0430
CHENG Chen,SONG Yang,ZANG Jingkun,et al. Occurrence modes and stepwise chemical extraction experiment of lithium in No.20 coal seam in Pu’an mining area, Guizhou Province[J]. Coal Geology & Exploration,2022,50(10):44−53. DOI: 10.12363/issn.1001-1986.21.08.0430
Citation: CHENG Chen,SONG Yang,ZANG Jingkun,et al. Occurrence modes and stepwise chemical extraction experiment of lithium in No.20 coal seam in Pu’an mining area, Guizhou Province[J]. Coal Geology & Exploration,2022,50(10):44−53. DOI: 10.12363/issn.1001-1986.21.08.0430

贵州普安矿区20号煤中锂的赋存状态及逐级化学提取实验研究

Occurrence modes and stepwise chemical extraction experiment of lithium in No.20 coal seam in Pu’an mining area, Guizhou Province

  • 摘要: 锂(Li)是一种重要的金属能源,近年来全球锂的需求持续增长。我国煤伴生型锂矿床的发现证明煤矿可能成为锂资源的潜在来源。以贵州普安矿区20号煤为研究对象,采用工业分析、镜下鉴定、X射线荧光光谱(XRF)、电感耦合等离子体质谱(ICP-MS)、激光剥蚀−电感耦合等离子体质谱(LA-ICP-MS)等方法,分析原煤及浮沉实验获得的密度分级试样的基本性质、矿物组成、元素组成及煤中Li的赋存特征。结果表明,原煤中Li含量达134.09 μg/g,在6个密度级样品中,Li含量随煤样密度级的增加而增加(>1.8 g/cm3密度级样品中Li含量最高为212 μg/g),重力分选可使煤中Li得到一定程度的预富集。原煤主要矿物组分包括黏土矿物、黄铁矿、方解石、石英等,基于Li与Al、Si等的相关性以及矿物微区元素含量(LA-ICP-MS)等分析,推测Li可能主要以吸附态赋存于黏土矿物中。逐级化学提取实验结果表明,煤中Li的赋存特征为水溶态(20.96%)、离子交换态(32.90%)、硅酸盐/铝硅酸盐态(22.80%)、碳酸盐/磷酸盐态(10.81%)、二硫化物态(3.92%)和残渣/有机态(2.58%),说明通过离子交换法可以从煤矸石中回收Li。该研究结果为下一步分离提取煤中Li提供了一定理论指导。

     

    Abstract: Lithium (Li) is an important energy metal, and the global demand for Li has grown rapidly in recent years. The discovery of coal-associated Li deposits in China proves that coal mines may serve as a potential alternative of Li resources. No.20 coal seam in Pu’an mining area in Guizhou province of China was selected as the study object. The basic properties, mineral composition, elemental composition, and occurrence modes of Li of the raw coal and six density-graded samples (obtained through a float-sink test) were determined by using coal proximate analysis, optical microscope, X-Ray fluorescence spectroscopy (XRF), inductively coupled plasma mass spectrometry (ICP-MS) and laser ablation-inductively coupled plasma mass spectrometry (LA-ICP-MS). The results show that the content of Li in the raw coal reaches 134.09 μg/g, and in the six density-graded samples the content of Li rises with the increase of density (e.g. the density-graded sample>1.8 g/cm3 has the highest Li content of 212 μg/g), which implies that gravity separation can preconcentrate Li in the coal to a certain extent. The main mineral components of raw coal include clay minerals, pyrite, calcite, quartz, etc. According to the correlation between Li and Al, Si, etc., as well as the elemental content in mineral micro-areas (by LA-ICP-MS), it is speculated that Li mainly occurs in aluminosilicate minerals in an adsorbed form. The results of the sequential chemical extraction test used to investigate the phase composition of Li in coal are as follows: water soluble form (20.96%), ion-exchangeable form (32.90%), silicate/aluminosilicate form (22.80%), carbonate/phosphate form (10.81%), disulfide form (3.92%) and residual/organic form (2.58%). This study provides a theoretical guidance for the extraction of Li resources from Li-rich coal.

     

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