ZHOU Lei1, JU Dian-chun1,2, ZHOU Xia-zhi1, XU Yu-song1
(1. School of Metallurgy and Materials Engineering, Jiangsu University of Science and Technology, Zhangjiagang 215600, China;
2. Institute of Fine Metallurgy, Institute of Industrial Technology, Jiangsu University of Science and Technology, Zhangjiagang 215600, China)
Abstract: The deep-sea polymetallic nodules are mainly distributed in different sea areas such as the CP and CC zones in whichtheir surficial sediments are mainly siliceous clay on the sea floor. The polymetallic nodules in the CP zone,with general distribution abundance of over 15 kg/m2, have relatively low Cu+Co+Ni grade which is generally less than 1.8%. However, about45% polymetallic nodules in the CC zone,with distribution abundance of over 5 kg/m2, have relatively high Cu+Co+Ni grade which is more than 2.5%.They are basically distributed in form of the latitude zonal band in the central and southern parts of the CC zone. The Fe and Mncontents of the rim, intermediate, and core layers are 9.4%－12.8% and 39.7%－46.5%, respectively. The peak intensities of XRD diffraction spectra of main minerals such as birnessite, todorokite and δ-Mn2 in different layers of nodules show some certain differences. The nodule has a relatively thin rim layer , relatively thick intermediate layer with regular cracks, and core layer which has at least one nucleus. As various kinds of metal elements are containedin densely mixed various minerals of the polymetallic nodules, it is difficult to extract valuable metal elements such as Mn, Fe, Cu, Co, and Ni from those nodules. These polymetallic nodules can be treated byusing the pyrometallurgy,including smelting and direct reduction methods, to generally produce manganese-rich slag and alloy, or by usingthe acid/alkali leaching method toproduce metals such as Mn, Fe, Cu, Co, and Ni, with the basic leaching rate of over 85% and extreme rate of over 95%,or by using the biological method to extract elements such as Mn, Fe, Cu, Co, and Ni. In addition, the polymetallic nodules can also be effectively treated by using the smelting-corrosion and electrolysis methods.
Keywords: The deep-sea polymetallic nodule; distribution regulation; valuable elements; extraction process
ACTA MINERALOGICA SINICA Vol. 39, No. 6, 2019, page 649-656
