Evaluation on the current status and comprehensive utilization prospect of associated cobalt resources in the Middle-Lower Yangtze River Valley metallogenic belt

Cobalt is a critical mineral resource that is extremely scarce in China. Most of the reported cobalt resources in our country's deposits are produced in associated forms, so it is necessary to estimate the associated cobalt resources and evaluate their comprehensive utilization prospects. Cobalt is commonly associated with iron deposits, copper deposits, and pyrite deposits in the Middle and Lower Reaches of the Yangtze River metallogenic belt, but research on the characteristics and differences of cobalt resources in different types of deposits, the amount and availability of cobalt resources, etc., has not been conducted. Currently, the comprehensive utilization level of most mines' associated cobalt is relatively low, and cobalt resources are wasted severely. This article comprehensively collects and summarizes relevant research data on the Middle and Lower Reaches of the Yangtze River metallogenic belt in recent years, systematically summarizes the occurrence states of cobalt in different types of deposits, clarifies the enrichment characteristics of cobalt in various types of deposits, estimates the associated cobalt resources, and evaluates the availability of associated cobalt. The research results show that the main cobalt-bearing minerals in iron deposits and pyrite deposits in the metallogenic belt are pyrite, with a small amount of magnetite, pyrrhotite, etc. The main cobalt-bearing minerals in copper deposits are pyrite and chalcopyrite, with a small amount of magnetite, bornite, etc. Independent cobalt minerals have been reported in all types of deposits, mainly including skutterudite, cobaltite, loellingite, nickeliferous pyrite, cobaltian pyrite, arsenopyrite, etc. Cobalt has been enriched to varying degrees in iron, copper, and pyrite deposits, with the silicon-calcium type iron deposit having the highest cobalt enrichment, reaching the associated cobalt boundary grade overall; the cobalt in the silicon-calcium type copper deposit mostly approaches or reaches the associated cobalt boundary grade, with a few not reaching the associated cobalt boundary grade; the cobalt enrichment is low in the magnetite-type iron deposit, the porphyry-type copper deposit, and the silicon-calcium and porphyry-type pyrite deposits, and generally does not reach the associated cobalt boundary grade. The associated cobalt resources in the metallogenic belt are abundant and have the resource conditions for the formation of medium to large cobalt deposits. The preliminary estimated scale of large deposits is three (Chengchao, Tieshan, and Luohe), and the scale of medium deposits is twenty-two (Longqiao, Zhuchong, Baixiangshan, Jinshandian, Anqing, Wushan, Chengmenshan, Fengshandong, Tonglushan, Tongshankou, Dabaizhuang, Xinqiao, Nihe, Gaocun, Meishan, Heshangqiao, Gushan, Shaxi, Charing, Yaojialing, Dongguashan, and Huangtun). The associated cobalt resources with good comprehensive utilization prospects are approximately 108000 tons, and the associated cobalt resources with a certain comprehensive utilization prospect are approximately 46000 tons, which can be used as potential replacements for the associated cobalt resources of approximately 125000 tons in the future. The main deposits in the metallogenic belt can obtain sulfur concentrate with cobalt content greater than 0. 20% through magnetic separation and flotation, and can obtain converter slag with cobalt content of up to 0.22% during the smelting process. For cobalt-containing sulfur concentrate or cobalt-containing converter slag, efficient recovery and utilization of cobalt can be achieved through processes such as flotation, pyrometallurgical smelting, wet separation, extraction, and microbial leaching, with a recovery rate of more than 80%, which is expected to generate good economic benefits. The research method in this article has important reference significance for the evaluation of associated cobalt resources in hydrothermal deposits. © 2023 Science Press. All rights reserved.