Manganese crustal abundance

The major part of elements are enriched in manganese nodules due to adsorption processes on hydroxides. The limited number of analyse does not allow the conclusion in which phase these elements are concentrated. Table 1 shows factors of enrichment of a number of elements in nodules, compared with the crustal abundance of these elements. 

Lithium s average crustal abundance is only 20 ppm, which means that it is rarer than other metals vital for electrochemical energy storage systems, such as manganese, cobalt and nickel. Although lithium is foimd in many rocks and several natural brines, its concentration is rather low, making commercial exploitation possible in only a few... 

Occurrence. In order of abundance in the earth s crustal rocks, it is the third within the transition elements (after Fe and Ti) and the 12th in the general order of all the elements. It occurs in several minerals such as primary deposits of silicates and as secondary deposits (commercially more important) of oxides and carbonates as pyrolusite, Mn02, hausmannite, Mn304, rhodochrosite, MnC03, etc. Large amounts of manganese are present in the deep sea nodules located over certain areas of the ocean floor. 

The abundances in the Earth s crust of both the d-block transition metals and the f-block inner transition metals vary considerably, as shown in Table 1.2. Iron is the most common of the transition metals (6.30% by mass of the crustal rocks) and this reflects the high yield of iron from element synthesis reactions in stellar supernovae. Titanium (0.66%) and manganese (0.11%) are also quite abundant, but some of the heavier... 

As the twelfth most abundant element in the earth s crust (0.106% in crustal rocks), manganese is found in over 250 different minerals of which some 10-15 are of commercial importance. In primary hydrothermal deposits the metal occurs as silicates, but as it is readily depleted from igneous and metamorphic rocks by weathering, particularly under acid conditions, it is normally found in commercially useful ores as oxides or carbonates, deposited, as are iron and aluminum, under alkaline conditions [9]. 

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