The effect of Fe-Mn minerals and seawater interface and enrichment mechanism of ore-forming elements of polymetallic crusts and nodules from the South China Sea

摘要: Ferromanganese crusts and nodules are important submarine mineral resources that contain various metal elements with significant economic value. In this study, polymetallic obtained from the South China Sea (SCS) were determined by using X-ray power diffraction (XRD), Raman spectroscopy (RS), Fourier transform infrared (FTIR), photoelectron (XPS) to systematically investigate analyze mineralogical spectral characteristics of Fe-Mn minerals. XRD measurements revealed SCS composed vernadite, quartz, plagioclase. The also contained todorokite. Fe-phase minerals amorphous Fe oxide/hydroxide, Mn- Fe-phases exhibited relatively poor degrees crystallization. FTIR results showed in included a large number surface hydroxyl groups. These groups protons could provide reactive sites for complexation ore-forming seawater. XPS indicated surfaces mainly Fe, Mn, O. was present trivalent oxidation state, while which may several bivalent tetravalent states. compared Pacific seamount crusts, (-OH) numbered more than lattice oxygen (O2-). But This characteristic degree crystallization Ocean higher Sea. Comprehensive studies interface between seawater ferromanganese employed following enrichment mechanisms: (1) ion complexed form complexes, connected coordination bonds or stable inner-sphere complexes exchanged on surfaces; (2) charged cations formed outer-sphere made up electrostatic double layer, through adsorption; (3) isomorphously Mn ions structure.