Nodulation

Manganese minerals are widely distributed oxides, silicates, and carbonates are the most common. The discovery of large quantities of manganese nodules on the floor of the oceans may become a source of manganese. These nodules contain about 24% manganese together with many other elements in lesser abundance. 

Alloys with other useful properties can be obtained by using yttrium as an additive. The metal can be used as a deoxidizer for vanadium and other nonferrous metals. The metal has a low cross section for nuclear capture. 90Y, one of the isotopes of yttrium, exists in equilibrium with its parent 90Sr, a product of nuclear explosions. Yttrium has been considered for use as a nodulizer for producing nodular cast iron, in which the graphite forms compact nodules instead of the usual flakes. Such iron has increased ductility. 

Thallium occurs in crooksite, lorandite, and hutchinsonite. It is also present in pyrites and is recovered from the roasting of this ore in connection with the production of sulfuric acid. It is also obtained from the smelting of lead and zinc ores. Extraction is somewhat complex and depends on the source of the thallium. Manganese nodules, found on the ocean floor, contain thallium. 

Ocean nodules Ocean raw materials Oceral Ocher... 

The earliest record of human usage of iron dates to ca 2000 BC (5) in Egypt, Asia Minor, Assyria, China, and India. It is almost certain, however, that the first iron to be used was not processed but was obtained from meteorites (1). One of the few places where native iron is found is in Greenland, where it occurs as very small grains or nodules in basalt (an iron-bearing igneous rock) that empted through beds of coal. 

The agglomerating methods typically used in the iron ore industry are pelletizing, sintering and, to a limited extent, briquetting and nodulizing (see Size enlargel nt). 

In the briquetting process, ore fines usually are mixed with a binder and are formed into compact masses between two rotating roUs. The roUs exert pressures of 1.5-4.2 t/cm in forming the briquettes. In the nodulizing process, which is relatively uncommon commercially, ore fines are heated in a rotary kiln to a temperature, usually 1250—1370°C, at which the ore begins to melt and bind. The ore balls in the kiln to form nodules that are discharged and cooled. 

Deep-Sea Manganese Nodules. A potentially important future source of manganese is the deep-sea nodules found over wide areas of... 

Table 7. Average Metal Content of Deep-Sea Nodules/ wt % Dry Basis ...

Deep-sea manganese nodules represent a significant potential mineral resource. Whereas the principal constituent of these deposits is manganese, the primary interest has come from the associated metals that the nodules can also contain (see Ocean rawmaterials). For example, metals can range from 0.01—2.0% nickel, 0.01—2.0% copper, and 0.01—2.25% cobalt (12). Recovery is considered an economic potential in the northwestern equatorial Pacific, and to a lesser degree in the southern and western Pacific and Indian Oceans (13—18). 

G. P. Glasby and G. L. Hubred, Comprehensive Bibliography of Marine Manganese Nodules, Memoir 71, New Zealand Oceanographic Institute, Wellington, 1976, p. 55. 

M. A. Meylan, B. K. Dugohnski, and L. Fortin, Bibliography and Index to Eiterature on Manganese Nodules, Key to Geophysical Records documentation No. 6, National Oceanic and Atmospheric Administration, Washington, D.C., 1874—1975, p. 365, p. 60 addendum. 

National Oceanic and Atmospheric Administration, description of Manganese Nodule ProcessingMctivitiesfor Environmental Studies, 3 Vols., NTlS, Springfield, Va., 1977, PB-274 913, PB-274 914, PB-274 915. 

In addition to the reported economic reserves, there are substantial nickel resources which could be amenable to mining and refining once appropriate technology becomes available. The single largest such resource is seabed nodules which contain ca 1% nickel and which could represent up to 800 X 10 t of nickel (see Ocean rawmaterials). 

Fig. 3. The stmcture of the nodulation (Nod) factors of i bium meliloti 2011 (44), where is 2 or 3, R is —H or—COCH, and R is C 2 as shown, C gT, or ie, a fatty acid chain having from 1 to 3 double bonds. The A/-acetyl glucosamine residues and an acyl moiety, R, are present ia all...

Although root nodules are the most common sites of N2-fixiag symbioses, some tropical legumes like Sesbania produce stem nodules ia associatioa Jp rhi bium caulinodans (55). la coatrast to root aodules, some stem aodules are photosyathetic and contain, ia the case oiPieschjnomene indica rhizobia themselves capable of photosyathesis (56). This close relatioaship of photosyathesis to fixatioa may ease the eaergy supply demand of nodules. 

Phi bium fixes only when the micro aetophilic conditions existing in the nodule ate simulated in a plant-free culture. Many other genera oxidize gases, such as H2 or methane, to derive the energy necessary for growth and fixation. 

E. B. Fred, I. L. Baldwin, and E. McCoy, Root Nodule Bacteria andEeguminous Plants, Studies in Science No. 5, University of Wisconsin Press, Madison, Wis., 1932. 

Ocean Basins. Ocean basins are primarily formed from oceanic basalts and maybe interspersed with continental remnants, ridges, seamounts, or volcanic islands rising from the depths. Average water depth is around 4000 m but the most significant mineralization is generally found at 5000 m for manganese nodules, 4000 m for biogenic oozes, and 3000 m for hydrothermal metalliferous sulfides. The area is poorly explored, however. 

---