矿石中关键金属钴赋存状态研究方法流程的建立:以庐枞盆地龙桥富钴矽卡岩铁矿床为例  

Establishment of research methodology and workflow for the occurrence state of the critical metal cobalt in ore:A case study of the Longqiao cobalt-rich skarn iron deposit in the Luzhong Basin

作　　者：张一帆 范裕[1,2] ZHANG YiFan;FAN Yu(School of Resources and Environmental Engineering,Ore Deposit and Exploration Centre(ODEC),Hefei University of Technology,Hefei 230009,China;Anhui Province Engineering Research Center for Mineral Resources and Mine Environments,Hefei 230009,China)

机构地区：[1]合肥工业大学资源与环境工程学院,合肥工业大学矿床成因与勘查技术研究中心,合肥230009 [2]安徽省矿产资源与矿山环境工程技术研究中心,合肥230009

出　　处：《岩石学报》2023年第10期3156-3168,共13页Acta Petrologica Sinica

基　　金：国家自然科学基金项目(91962218);国家重点研发计划项目(2022YFC2903503);安徽省自然资源科技项目(2022-K-10)联合资助.

摘　　要：关键金属钴的赋存状态是研究关键金属成矿作用的核心问题之一。由于含钴矿物粒度较小,难以在矿床尺度查明关键金属矿物的种类、含量、粒度、分布特征以及与其他矿石矿物和脉石矿物的共生关系,因此亟需建立一套成本低且效率高的钴赋存状态研究流程。本次工作以龙桥铁矿床为例,建立了新的采样与制样流程,提高了样品的代表性,并大幅缩短了样品前处理与制样的时间。通过综合矿物分析技术(TIMA)分析,查明了不同钴含量的三类矿石样品中矿物的含量,在6个实验矿石样品中寻找到了辉砷钴矿、铁硫砷钴矿和硫铜钴矿三种钴矿物共753颗,并使用扫描电镜和能谱分析(SEM-EDS)对钴矿物进行了核验与半定量分析。最后,在同一个树脂靶上利用激光剥蚀-等离子体质谱仪(LA-ICP-MS)对磁铁矿和黄铁矿进行了原位点分析,进一步查明了样品中钴的赋存状态。本次研究建立了关键金属钴在矿石中赋存状态的研究方法和技术流程,具有制样简单便捷、分析时间短、分析费用低和分析精度高等诸多优点,为矿床尺度上关键金属空间分布规律和赋存状态研究提供了可靠的技术支撑。The occurrence state of the critical metal cobalt is one of the core issues in the study of critical metal mineralization.Due to the small grain size of the cobalt-bearing minerals,it is difficult to determine the types,contents,grain sizes,distribution characteristics and symbiotic relationships with other ore minerals and vein minerals of key metal minerals at the deposit scale.Therefore,there is an urgent need to establish a low-cost and efficient research process for the occurrence state of cobalt.In this study,taking the Longqiao iron deposit as an example,a new sampling and sample preparation process was established to improve the representativeness of the samples and significantly reduce the time required for sample pre-treatment and preparation.Through comprehensive mineral analysis using the Time-of-Flight Ion Microprobe Analysis(TIMA)technique,the content of minerals in three types of ore samples with different cobalt contents was determined.A total of 753 cobalt minerals,including skutterudite,arsenopyrite,cobalt-bearing pyrite and cobalt-bearing chalcopyrite,were identified in six experimental ore samples.Scanning Electron Microscopy with Energy Dispersive X-ray Spectroscopy(SEM-EDS)was used to verify and semi-quantitatively analyze the cobalt minerals.Finally,in situ spot analysis of magnetite and pyrrhotite was conducted using Laser Ablation-Inductively Coupled Plasma Mass Spectrometry(LA-ICP-MS)on the same resin target to further determine the occurrence state of cobalt in the samples.This study has established a research method and technical process for the occurrence state of key metal cobalt in ore,which has many advantages,such as simple and convenient sample preparation,short analysis time,low analysis cost and high analysis accuracy.It provides reliable technical support for the study of the spatial distribution patterns and occurrence states of key metals at the deposit scale.

关 键 词：钴 赋存状态 TIMA 龙桥铁矿床 分析流程 

分 类 号：P585.2[天文地球—岩石学] P618.62[天文地球—地质学]