Manganese economic importance

Steelmaking. Steelmaking is the most economically important slag refining process (see Steel). Pig iron contains up to 4% carbon, 1% manganese, 1%... 

Let us now consider the effects of Eh-pH conditions on the speciation state and solubility of manganese in aqueous solutions. Manganese complexes have been carefully studied in the last decade, owing to the discovery on ocean ffoors of economically important metalliferous deposits (nodules and crusts) in which Mn compounds are dominant. 

The major part of economically important metals from manganese nodules are alloys for steel production (Mn, Ni, Co, Mo). The production of steel is supposed to grow continuously in the next decades, because of the industrialization of underdeveloped countries. Thus, it can be expected that the prices of these metals will rise continuously, and the time will come when manganese nodules will be able to compete on the world trade market as a multi-element ore. Mez means it will be about the year 2000. 

Another important consideration pertains to the metal content of the deposit. A deposit with a content of iron of about 20% can have little value as an iron ore since there are several deposits with 30-50% iron. Earlier, a copper ore with a minimum of 5% copper was regarded or accepted as a copper ore. However, today, thanks to advancements in technology, rocks with as little as 0.5% copper are mined and processed economically despite the fact that the price of copper, in comparison with those of some other metals, might be showing a downward trend. It is possible that in the future, other resources, which are not considered to be worth exploiting today (such as the manganese nodules or the clays), would become acceptable ores for manganese, copper, nickel, cobalt, and aluminum. 

As in the case of igneous processes, the sedimentary processes of rock formation lead to the formation economic mineral deposits. Many valuable mineral deposits of iron, manganese, copper, phosphorus, sulfur, zirconium, the rare Earths, uranium and vanadium owe their origin to sedimentary processes. Some of these constitute special types of sedimentary rocks, while others form important constituents of sedimentary rocks. 

Of the numerous combinations of manganese with the halogens, and of the oxides with acids, the acetate, protochloride, and the sulphate of the protoxide are the only compounds which aro manufactured on the large scale or applied to economic purposes, and are, consequently, sufficiently important to claim consideration in a work on technology. 

During the 1980s interest in manganese nodules in exclusive economic zones (EEZs) started to increase. An important result of the Third Law of the Sea Conference, was the acceptance of a 200-nautical-mile EEZ in which the adjacent coastal state could claim any mineral deposits as their own. The nodules found in EEZs are similar to those found in adjacent parts of the International Seabed Area, and are of greatest economic potential in the EEZs of the South Pacific. 

Other sources of nickel, especially in deep-ocean polymetallic nodules (see Manganese) lying on the Pacific Ocean floor, will probably have an important economic role in the future. As a general rule, to be mineable, a nickel ore deposit must be able to produce annually at least 40,000 tonnes of nickel, that is, 800,000 tonnes for a period of 20 years. Annual world nickel production is 925,000 tonnes (2003), of which 70% is consumed for stainless steels. The world s largest nickel-producing countries are Russia, Canada, New Caledonia, and Australia. In 2005, the major nickel projects were the laterite deposit of Goro (New Caledonia, France) and the sulfide ore deposit of Voise/s Bay (Newfoundland, Canada). 

From a mining point of view, deposits of economic interest must contain manganese ores with more than 35 wL% Mn to be considered profitable, although some commercially mined deposits, especially in the CIS, India, and China, are well below this level. As well as the ore grade, mineral hardness and the presence of other elements such as copper, cobalt, phosphorus, sulfur, and arsenic is important in determining the viability of the ore body for development. 

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