矿精粉中关键金属元素赋存状态研究方法流程的建立:以长江中下游成矿带富钴硫矿精粉为例

长江中下游成矿带作为我国矿床学研究程度和矿产利用技术水平最高的成矿带之一,大部分矿床中除了主要成矿元素铜、金、铁和硫等,还伴生潜在可利用的关键金属资源镉、钴、硒、碲和铼等。由于目前矿山主要选矿回收铜、铁、硫、铅、锌、金和银等主要矿种,在不改变选矿工艺的条件下,矿山产品矿精粉中关键金属的分布特征和可利用性是当前关键金属资源利用的核心问题之一。本文对成矿带内玢岩型铁矿床、矽卡岩型铁矿床、矽卡岩型铁铜矿床、矽卡岩型铜金矿床、斑岩型铜金矿床和角砾岩筒型铜金矿床等六类矿床的矿山产品(铜金粉、硫精粉、铁精粉和金精粉)进行了系统化学成分分析,发现目前的矿山产品中关键金属元素含量普遍不高,但矽卡岩型铁矿床中的龙桥铁矿床硫精粉中富集钴,具有综合回收利用钴资源的潜力。在此基础上,本次工作利用综合矿物分析技术(TIMA),扫描电镜(SEM)和激光剥蚀-等离子体质谱仪(LA-ICP-MS)三种测试方法,系统开展了富钴硫精粉中钴的赋存状态研究。结果表明,龙桥硫精粉中钴矿物为辉砷钴矿、铁硫砷钴矿和硫铜钴矿,分别占硫精粉中总钴含量的9.93%、0.64%和0.01%。黄铁矿晶格中类质同象形式产出的钴占总量的81.97%,此外还有7.46%的钴赋存在其他矿物中。通过对比研究,初步建立了矿精粉中关键金属元素赋存状态的研究方法流程,为矿精粉中钴的回收利用提供了依据。

Establishment of a research workflow for occurrence state of critical metal in ore concentrate powder: A case study of the cobalt-rich sulfur ore concentrate powder from the Middle-Lower Yangtze River Valley Metallogenic Belt, China

The Middle-Lower Yangtze River Valley Metallogenic Belt is one of the metallogenic belts with well-studied economic geology research and comprehensive mineral utilization technology in China. In addition of the main ore-forming elements Cu, Au, Fe and S, most deposits are associated with potentially available critical element resources, such as Cd, Co, Se, Te and Re. At present, the mines processed and recovered Cu, Fe, S, Pb, Zn, Au, Ag and other major products. Without changing the mineral process, the key problems in the utilization of critical element resources are the understanding of the occurrence of critical metals in ore concentrations. We have conducted a systematic chemical composition analysis of the mine products (i.e., copper concentrate powder, sulfur concentrate powder, iron concentrate powder and gold concentrate powder) of six types of deposits in the metallogenic belt, including apatite-magnetite Fe deposit, skarn Fe deposit, skarn Fe-Cu deposit, skarn Cu-Au deposit, porphyry Cu-Au deposit and breccia-hosted Au deposit. It is found that the contents of critical elements (Cd, Co, Se, Te and Re) in those mine products are generally low, except Co enriched in sulfur concentrate powder of Longqiao skarn iron deposit, which has the possibility of recovery and utilization of cobalt resources. In this study, the occurrence of cobalt in Co-rich sulfur concentrate powder was analyzed by Tescan Integrated Mineral Analyzer (TIMA), Scanning Electron Microscope (SEM) and Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS). The analyses results show that the cobalt independent minerals in Longqiao sulfur concentrate powder are cobaltite, glaueodot and carrollite, which account for 9.93%, 0.64% and 0.01% of the total cobalt in sulfur concentrate powder, respectively. The amount of cobalt occurs as isomorphic form in pyrite lattice accounts for 81.97% of the total. In addition, 7.46% of cobalt exists in other unknown minerals. Research workflow of critical elements deportments in ore concentrate powder is established initially, which provides a theoretical basis for the recovery and utilization of cobalt in ore concentrate powder.