Geotechnical and Mineralogical Properties of the Recently Exposed Black Mud Deposits along the Northeastern Shore of the Dead Sea

Along the recently evacuated shores of the retreating Dead Sea black mud deposits have been exposed and hence subjected to head ward erosion resulting in landslides and land collapses threatening herewith the infrastructure in the area. The geotechnical and mineralogical characterization of the black mud show the presence of a variety of clays including smectite, kaolinite, illite, montmorollinite and muscovite with a natural water content near the liquid limit. These geotechnical and mineralogical properties indicate that the mud is prone to rapid erosion and sliding, which actually hit the area and have until now caused damages and degrading topography and geology in the area. The study also refers the origin of the black mud and its organic content to the erosion and deposition of Upper Cretaceous-Tertiary oil shale deposits formerly covering the whole surrounding areas of the Dead Sea. The study suggests engineering solutions to the geologic degradation processes in the area, before further damage to the infrastructure takes place.

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

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

Volcanic Event Layers——A Marker Bed of Correlation of Coal Measures

Upper Carboniferous-Lower Permian volcanic event deposits from two cross sections in Nanpiao, Liaoning Province, and the Daqing Mountains, Inner Mongolia, were examined by systematic rock and mineral identification, differential thermal analysis, X-ray diffraction, scanning electron microscopy and trace element and rare earth element quantitative analysis. According to the results, twelve sequences of volcanic event deposits have been distinguished from bottom to top, including 34-39 volcanic event layers. As these layers each have their own distinctive petrological, mineralogical and geochemical characteristics and were derived from the same source, they provide new evidence for further ascertaining the distribution characteristics of volcanic event deposits on the northern margin of the North China plate and carrying out the stratigraphic correlation using volcanic event layers as marker beds.

A quantitative investigation on consolidation of titanium-containing pellets during roasting process

The measurement method and quantitative indexes of iron ore consolidation characteristic temperature(CCT)during roasting,including consolidation starting temperature,highest consolidation rate temperature,and consolidation termination temperature,were improved based on previous research.The mineral properties of V-Ti magnetite(Panzhihua)were analyzed,and the CCT of V-Ti magnetite was calculated.To investigate the effect of mineral types on CCT,a series of trials were carried out by using various ores,including high-grade magnetite ore,high silicon iron ore,and V-Ti magnetite ore.The greatest shrinkage of V-Ti magnetite was 6.7%,the consolidation starting temperature was 991℃,and the termination temperature was 1384℃.The results of X-ray diffraction analysis indicated that the V-Ti magnetite ore was composed of titanomagnetite,peridotite,and other minerals,which is more complicated than conventional magnetite.As a result,the temperature at the maximum rate of consolidation and the temperature at the termination of consolidation are the greatest.FeTiO_(3) and MgFe_(2)O_(4) in V-Ti magnetite may inhibit the creation of sinter necks between hematite particles.Liquid phase occurs inside the pellet when the temperature surpasses 1250℃,which may accelerate particle growth and the formation of a sintering neck within the pellets.