Characteristics of iron-manganese nodules containing nickel and cobalt in chromite deposits in Co Dinh, Thanh Hoa province

Along with the chromite ore bodies, very early on, geologists recorded the presence of cobalt (Co) and nickel (Ni) metal. The resource of cobalt and nickel is forecasted with over 3 million tons of Ni and over 260 thousand tons of Co metals. Until now, however, knowledge about the existence form and distribution of Ni and Co in chromite ore bodies is very limited. Researching the sludge in the chromite mines and in comparison with manganese nodules found in the ocean floor helps to detect the presence of particles of iron and manganese (Fe-Mn nodules) in granular sewage sludges and in primary chromite ore bodies. Fe-Mn hydroxides, including todorokite mineral, are believed to be the adsorption medium and forming of Ni and Co in the Co Dinh placer chromite. Determining the existence form and distribution of Ni and Co in chromite placer deposits has scientific and practical significance in sampling orientation, sample processing, geological exploration, and reserve and resource estimations, sorting and recovering technology of Co and Ni metals.