钴的地球化学行为、矿床成因类型、资源分布及研究展望

Geochemical Behavior,Genetic Type,Resource Distribution,and Research Prospect of the Cobalt Deposits

基于钴的化学性质及在岩浆、热液和表生作用过程中的地球化学行为,系统梳理了全球和我国钴矿产特征和资源分布,将钴矿床成因划分为11个四级类型。研究显示:在镁铁-超镁铁质岩浆中,早期以类质同象分散到造岩矿物和副矿物中,随后在岩浆体系中逐渐下降进入硫化物中;在热液中以含氯化物、氢氧化物和二硫化氢的水溶液络合物形式发生运移,受流体性质、温度和盐度等因素影响;在表生作用中主要包括镁铁-超镁铁质岩石风化作用和现代海底铁锰结核和结壳化学沉积作用;建立钴的来源-分配-迁移-沉淀富集机制。建议在今后工作中,应进一步细化钴成矿类型,追溯钴金属来源,识别关键控矿因素,精细刻画钴的迁移沉淀机制,尤其是硫化物矿床岩浆期后叠加改造对矿体的二次富集作用。同时,提升钴矿产的选矿工艺,加大钴资源的综合利用。

As a new key metal mineral resource,the research on cobalt mineralization mechanism,exploration meth-ods,and utilization technology has risen to the national strategic level of developed economies in the world.As a major global cobalt consumer,China's cobalt resource supply and demand situation is severe.Based on the chemical properties of cobalt and its geochemical behavior in the process of magma,hydrothermal,and epigenesis,this paper systematically combs the characteristics and resource distribution of cobalt minerals in the world and in China,and divides the genesis of cobalt deposits into 11 fourth-order types.The research shows that in the mafic-ultramafic magma,it was dispersed in the diagenetic minerals and accessory minerals in the form of isomorphism in the early stage,and then gradually de-creased in the magma system and entered into the sulfide.The migration occurs in the form of aqueous solution complex containing chloride,hydroxide and hydrogen disulfide in the hydrothermal solution,which is affected by many factors such as fluid properties,temperature and salinity.Supergenesis mainly includes weathering of mafic-ultramafic rocks and chemical deposition of modern seafloor ferromanganese nodules and crusts;The mechanism of source-distribution-mi-gration-precipitation and enrichment of cobalt was established.It is suggested that in the future work,the type of cobalt mineralization should be further refined,the source of cobalt metal should be traced,the key ore-controlling factors should be identified,and the migration and precipitation mechanism of cobalt should be carefully described,especially the secondary enrichment of sulfide deposits after magmatic superimposed transformation on ore bodies.At the same time,improve the beneficiation process of cobalt minerals and increase the comprehensive utilization of cobalt resources.