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Manganese oxide minerals Crystal structures and economic and environmental significance

wallpapers News 2021-04-25
Most people's description of manganese oxide is the dirty black interior of a dry battery. In fact, however, the manganese oxide/hydroxide (collectively called manganese oxide) mineral is found in a variety of geological environments and is almost ubiquitous in soils and sediments. They occur in the form of fine-grained aggregates, veins, Marine and freshwater nodules and concretions, crusts, dendrites, and other mineral particles, and coatings on rock surfaces (such as desert varnish). Since manganese oxides are usually formed at the interfaces between the lithosphere and the hydrosphere, the atmosphere and/or the biosphere, they can provide environmentally relevant insights into some types of interactions between these systems and may serve as long-term monitoring of changes within the system.
Manganese oxide has been mined since ancient times as an ore. In particular, pyrolusite (MnO2) is thought to be a pigment that can remove the greenness that iron gives to glass. By the mid-19th century, manganese had become an important component in steelmaking, used as a deoxidizer, a desulfurized and in the manufacture of hard steel alloys. Manganese oxide is the main ore mineral in most commercially important manganese deposits today. It is usually formed by weathering of manganese-rich carbonate or silicate, oxidized or dissolved in situ and then migrated and reprecipitated. About 80-90% of the world's manganese ore production is currently consumed by the steel industry; On average, steels contain about 0.6% of Mn by weight, but high strength steels may contain 10% or more Mn. Other uses include the production of special aluminum alloys, chemicals containing Mn, catalysts, water purifiers, livestock feed additives, plant fertilizers, brick colorants, and batteries. Natural manganese oxides (mainly manganese oxides) are used as cathode materials in zinc-carbon dry batteries. In recent years, however, alkaline batteries, using synthetic, electrolytic manganese oxides, have increasingly dominated the market.