Manganese

Elemental ManganeseMn

Unfortunately most manganese oxide minerals tend to be black.

The History SaysThe word manganese comes from the Latin word magnes which means magnet, because when manganese is alloyed with other metals like aluminum, copper and antimony, the end product is magnetic.

The Present ScenarioDeep-sea nodules of manganese and other metals are scattered on the ocean floor. They form when the hot waters from hot springs (called black smokers) on the ocean bottom meet the cold, deep ocean water.

Manganese is named from a corruption of the latin word for magnestism; magnes, in allusion to its prinicple ore's magnetic properties. However, manganese crystals have yet to be found in nature and therefore it is technically not a mineral, although laboratory grown specimens can look like a natural stone.

The element manganese is an essential element in people's daily food consumption and has several industrial uses. Manganese is used in steel alloys to increase many favorable characteristics such as strength, hardness and durability. In fact steel can not be produced without manganese; it is an essential ingredient in the process. Manganese is also used to color glass an amethyst color. That is not so surprising since manganese is the trace element responsible for quartz's purple variety, amethyst.

Manganese coloring ability in minerals is well known and appreciated. Manganese is chiefly responsible for the wonderful colors in rhodochrosite, purpurite, rhodonite, serandite and spessartine to name a few. Unfortunately most manganese oxide minerals tend to be black. Manganese is extracted from the ore minerals pyrolusite and rhodochrosite. Manganese nodules on the sea floor may one day provide an economic source as well.

ClassCrystal System

Specific Gravity

Colour

Transparency

LusterField Indicators

Elements

isometric

7.44

steel or silver grey

opaquemetallic

color and density

Manganese is gray-white metal with a pinkish tinge, and a very brittle but hard metallic element. Its atomic number 25. In 1774, while heating the mineral pyrolusite (MnO2, manganese dioxide) in a charcoal fire, the Swedish scientist Johann Gahn discovered manganese. The heat and carbon in the charcoal separated oxygen from the pyrolusite, leaving a metallic manganese residue. This chemical reaction is called a reduction reaction.

Manganese is a reactive element that easily combines with ions in water and air. In the Earth, manganese is found in a number of minerals of different chemical and physical properties, but is never found as a free metal in nature. The most important mineral is pyrolusite, because it is the main ore mineral for manganese.

Trace amounts of manganese are very important to good health. It makes bones strong yet flexible, and it aids the body in absorbing Vitamin B1. It also is an important activator for the body to use enzymes. As little as 0.00002% Mn in the human body is essential. Studies have shown that a lack of manganese leads to infertility in animals.

SourcesOver 80% of the known world manganese resources are found in South Africa and Ukraine. Other important manganese deposits are in China, Australia, Brazil, Gabon, India, and Mexico. The United States imports manganese ore because the manganese resources in the U.S. are relatively low in manganese content per ton of ore. Importing these ores is presently more economic than mining them locally.

Most manganese ore imported to the United States is used to manufacture intermediate manganese ferroalloy products and electrolytic manganese for use in dry-cell batteries. Only a small amount of the ore is directly used in the steel making process.

Some manganese is recovered through the reprocessing of scrap metals and steel slag, or the materials left over from the steel-making process. Though considered waste in terms of its steel content, slag often contains significant amounts of other elements that can be recovered.

Deep-sea nodules of manganese and other metals are scattered on the ocean floor. They form when the hot waters from hot springs (called black smokers) on the ocean bottom meet the cold, deep ocean water. The elements in the hot volcanic waters precipitate as nodules. Though rich in manganese (nearly 25% manganese) they are very deep in the ocean and it would cost too much to make them worth retrieving. This may prove to be an important source of manganese in the future should reserves in the Earth's crust be depleted and cost-effective deep-sea mining methods are discovered.

UsesSteel becomes harder when it is alloyed with manganese. It has similar applications when alloyed with aluminum and copper. Hardened steel is important in the manufacture of construction materials like I-beams (24% of manganese consumption), machinery (14% of manganese consumption), and transportation (13% of manganese consumption).

Manganese dioxide is used to: manufacture ferroalloys; manufacture dry cell batteries (it's a depolarizer); to "decolorize" glass; to prepare some chemicals, like oxygen and chlorine; and to dry black paints. Manganese sulfate (MnSO4) is used as a chemical intermediate and as a micronutrient in animal feeds and plant fertilizers. Manganese metal is used as a brick and ceramic colorant, in copper and aluminum alloys, and as a chemical oxidizer and catalyst. Potassium permanganate (KMnO4) is used as a bactericide and algicide in water and wastewater treatment, and as an oxidant in organic chemical synthesis.

Mineral Photos - Manganese

Manganese: essential to iron and steel production. The U.S., Japan, and Western Europe are all nearly deficient in economically mineable manganese. South Africa and the Ukraine have over 80% of the world's reserves.

Manganite - Mii Photo

Background

Manganese is gray-white metal with a pinkish tinge, and a very brittle but hard metallic element. Its atomic number 25. In 1774, while heating the mineral pyrolusite (MnO2, manganese dioxide) in a charcoal fire, the Swedish scientist Johann Gahn discovered manganese. The heat and carbon in the charcoal separated oxygen from the pyrolusite, leaving a metallic manganese residue. This chemical reaction is called a reduction reaction.

Manganese is a reactive element that easily combines with ions in water and air. In the Earth, manganese is found in a number of minerals of different chemical and physical properties, but is never found as a free metal in nature. The most important mineral is pyrolusite, because it is the main ore mineral for manganese. When manganese is alloyed with other metals like aluminum, copper and antimony, the end product is magnetic.

Trace amounts of manganese are very important to good health. It makes bones strong yet flexible, and it aids the body in absorbing Vitamin B1. It also is an important activator for the body to use enzymes. As little as 0.00002% Mn in the human body is essential. Studies have shown that a lack of manganese leads to infertility in animals.

Name

The word manganese comes from the Latin word magnes which means magnet.

Sources

Over 80% of the known world manganese resources are found in South Africa and Ukraine. Other important manganese deposits are in China, Australia, Brazil, Gabon, India, and Mexico. The United States imports manganese ore because the manganese resources in the U.S. are relatively low in manganese content per ton of ore. Importing these ores is presently more economic than mining them locally.

Most manganese ore imported to the United States is used to manufacture intermediate manganese ferroalloy products and electrolytic manganese for use in dry-cell batteries. Only a small amount of the ore is directly used in the steel making process.

Some manganese is recovered through the reprocessing of scrap metals and steel slag, or the materials left over from the steel-making process. Though considered waste in terms of its steel content, slag often contains significant amounts of other elements that can be recovered.

Deep-sea nodules of manganese and other metals are scattered on the ocean floor. They form when the hot waters from hot springs (called black smokers) on the ocean bottom meet the cold, deep ocean water. The elements in the hot volcanic waters precipitate as nodules. Though rich in manganese (nearly 25% manganese) they are very deep in the ocean and it would cost too much to make them worth retrieving. This may prove to be an important source of manganese in the future should reserves in the Earth’s crust be depleted and cost-effective deep-sea mining methods are discovered.

Uses

Steel becomes harder when it is alloyed with manganese. It has similar applications when alloyed with aluminum and copper. Hardened steel is important in the manufacture of construction materials like I-beams (24% of manganese consumption), machinery (14% of manganese consumption), and transportation (13% of manganese consumption).

Manganese dioxide is used to: manufacture ferroalloys; manufacture dry cell batteries (it's a depolarizer); to "decolorize" glass; to prepare some chemicals, like oxygen and chlorine; and to dry black paints. Manganese sulfate (MnSO4) is used as a chemical intermediate and as a micronutrient in animal feeds and plant fertilizers. Manganese metal is used as a brick and ceramic colorant, in copper and aluminum alloys, and as a chemical oxidizer and catalyst. Potassium permanganate (KMnO4) is used as a bactericide and algicide in water and wastewater treatment, and as an oxidant in organic chemical synthesis.

Substitutes and Alternative Sources

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Manganese Ore

We specialize in offering a vast assortment of Manganese, a mineral/chemical denoted by Mn with atomic number 25. It has the key property of being very brittle yet can be easily oxidized. Further, it is a free element and is considered as a metal along with important uses for metal alloys. Recognized as a grey white metal, it is quite similar to iron.

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Pyrolusite Mineral Facts:Chemical Formula: MnO2

Manganese Dioxide, a principal ore of manganese. Commonly contains a little water.

Colors: Iron-black color and streak.

Hardness: 2-2.5, often soiling the fingers.

Density: 4.75

Cleavage: Perfect on 110, Splintery fracture.

Crystallography: HexagonalCrystals are radiating columnar to fibrous, also granular or massive; often in reniform coats. Crystals probably always pseudomorphous after manganite.

Luster:. Metallic and opaque.

.

Composition, Structure and Associated Minerals:Pyrolusite is a secondary mineral. Manganese is dissolved out of the crystalline rocks, in which it is almost always present in small amounts, and redeposited under various conditions, chiefly as pyrolusite. Dendritic coatings of pyrolusite are frequently observed on rock surfaces, coating pebbles, etc. Nodular deposits of pyrolusite are found on the sea bottom. Nests and beds of manganese ores are found inclosed in residual clays, derived from the decay of manganiferous limestones. As the rock has weathered and its soluble constituents -been taken away, the manganese content has been concentrated in nodules and masses composed chiefly of pyrolusite. Also found in veins with quartz and various metallic minerals.

Identification and DiagnosticsThe manganese minerals are easily distinguished from other minerals by the violet color they give to the borax bead and by the green product obtained when they are fused with sodium carbonate. Gives oxygen in closed tube, and which will cause a splinter of charcoal to ignite when placed in tube above the mineral and heated.  In hydrochloric acid, chlorine gas evolved. Pyrolusite is distinguished from manganite by its physical properties, and from polianite by its softness.

 

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Occurrence, Localities and Origins:Pyrolusite, together with the other manganese ores with which it is mixed, is the source of nearly all the manganese compounds employed in the industrial arts. Some of the ores, moreover, are argentiferous and others contain zinc. From these silver and zinc are extracted. Themost important use of the mineral is in the iron industry. In this industry, however, much of the manganese employed is obtained from manganiferous iron ores. The alloys spiegeleisen and ferro-manganese are employed very largely in the production of an iron used in the steel industry for casting car wheels and other items. It is also employed in making various alloys with copper, zinc, aluminium, tin, lead, etc. It is extremely hard and tough. The manganese minerals are also used in glass factories to neutralize the green color imparted to glass by the ferruginous impurities in the sands from which the glass is made. Pyrolusite is also used as a decolorizer of glass, and in electric cells and batteries. Manganese is also used as a coloring material in bricks, pottery, glass, etc. giving black, brown and violet colors to pottery. Some of its salts are used to make potassium permanganate, while some are valuable mordants.

Pyrolusite has been mined at Elgersberg, near Ilmenau in Germany; at Vorder Ehrensdorf and at Flatten in the Czech Republic also in Australia, Japan, India and New Brunswick, Nova Scotia. In the US it has been mined at Cartersville, Ga.; at Batesville, Ark., California and in the Valley of Virginia. A manganiferous silver ore containing considerable quantities of pyrolusite was mined in the Leadville district, Colorado, and large quantities of manganiferous iron ores are obtained in the Lake Superior region. 

 

Manganese Ore

Manganese is one of the most needed strategic minerals, used in the metallurgical industry for manganese steels.

Never found in nature in native state. Because of its great affinity for oxygen usually present as oxides and also the silicate and carbonate. The ore of this mineral mainly used in industry is the pyrolusite (MnO2), 63% of manganese, but others are used as braunite (MEs abundant in the crust. Among its natural combinations include oxides, silicates and carbonates: pyrolusite or manganese, rhodochrosite or dialogita are the most important and others less important are hausmannite, psilomelana (manganomelana), manganite, rhodonite, braunite [3Mn2O3.MnSiO3] hubnerite (MnWO4). have discovered large quantities of manganese nodules in the ocean bottom in the future will be important for obtaining the metal. These nodules containing more than 24% manganese together with minor amounts of other elements in the form of hydrated oxides.

The metal oxide obtained by reduction with sodium, magnesium or aluminum or by electrolysis of salt solutions. Obtaining pure metal does not matter, as it has suitable properties and its applications are limited. Usually (90% of the production) is obtained alloyed with iron from ore mixtures of both metals and coke. nS12O3) of 69%, rhodonite, the rodocrusita, etc.

The chemical composition of manganese ore determines its industrial uses. Manganese is consumed mainly in the steel industry in the manufacture of dry batteries, and chemical use in the production of steel, ferro-manganese alloys and as a purifying agent, for its great avidity for oxygen and sulfur, are takes to rid the iron ore of these impurities, bleaching glass, obtaining manganese salts, among others.

THE MINERAL PYROLUSITE Chemical Formula: MnO2, Manganese Oxide Class: Oxides and Hydroxides Group: Rutile Uses: a major ore of manganese and as a mineral specimen Specimens

Pyrolusite is the most common manganese mineral and is an important ore. Manganese is a strategically valuable metal since it is an essential ingredient in steel and other alloys. The mining term "wad" is used to indicate ores that are a mixture of several manganese oxides such as pyrolusite, psilomelane and others that are difficult to distinguish.

Pyrolusite is an oxidation product of weathered manganese minerals and also forms from stagnant shallow marine and freshwater bog and swamp deposits. Minerals such as rhodochrosite, rhodonite and hausmannite are often replaced by pyrolusite.

Pyrolusite has some interesting habits despite its common occurrence as dull, sooty, black masses and/or earthy forms. Possibly its most popular form is its dendritic habit that forms wonderfully detailed, fern-like patterns on the surfaces of rocks such as sandstone. These dendrites are so amazing that they have often been mistaken for fossil plants. Another popular habit is its acicular or hair-like crystal aggregates that produce nice tufts of "hair", or meadows of shiny black pyrolusite fibers. Often specimens of pyrolusite are very difficult to distinguish from other manganese oxides. Thus, as a consequence of its more abundant distribution, pyrolusite is the default name for black, hair-like manganese crystals or powdery black alteration products of manganese minerals in general.

PHYSICAL CHARACTERISTICS:

Color is steel gray to a solid black in earthy specimens. Luster is metallic to dull in weather or thinly crusted specimens. Transparency crystals are opaque, translucent in only thin splinters. Crystal System is tetragonal; 4/m 2/m 2/m Crystal Habit is typically massive and compact forms, but also fibrous, acicular,

columnar, concretionary, scaly and earthy forms are well known. A thin dendritic habit is commonly seen encrusted on sandstones and siltstones and will form wonderful fern or tree like patterns that are often mistaken for fossil plants. A variety with large, easily visible crystals is called polianite, and occurs as minute prismatic crystals with a square or rectangular cross-section and a wedge-shaped terminations.

Cleavage is good in two directions forming prisms, but rarely seen except in rare large crystals.

Fracture is conchoidal to uneven.

Hardness is 6 in individual crystals, but aggregates can be as soft as 4 or 5 and massive or earthy forms will mark paper and leave powder on fingers (a hardness under 2).

Specific Gravity is 4.4 - 5.1 (average for metallic minerals) Streak is black. Associated Minerals are limonite, hematite, quartz, manganite, psilomelane and

other manganese and iron oxide minerals. Notable Occurances include nice specimens from Germany; iron mines in Minnesota

and Michigan and at Lake County, New Mexico, USA. Pyrolusite is mined in many countries around the world with the most productive countries being Georgia and Ukraine of the former USSR, India, China, South Africa, Brazil, Australia and Gabon. Polianite occurs in abundance at the Kisenge Mine, in Zaire.

Best Field Indicators are habits, luster, softness, color and streak.

Pyrolusite From Wikipedia, the free encyclopediaJump to: navigation, search

Pyrolusite

Pyrolusite mineral with dendrite (height of sample ~ 9 cm).

GeneralCategory Oxide mineralsChemical formula

MnO2

Strunz classification

04.DB.05

Identification

ColorDarkish, black to lighter grey, somethimes bluish

Crystal habitGranular to massive: botryoidal and dendritic. Crystals rare

Crystal system TetragonalTwinning {031}, {032} may be polysyntheticCleavage Perfect on 110Fracture BrittleMohs scale hardness

6–6.5, 2 when massive

Luster Metallic, dull to earthyStreak Black to bluish-blackSpecific gravity 4.4–5.06Refractive index OpaqueReferences [1][2][3]

Major varietiesPolianite pseudomorphic after manganite [4]

Pyrolusite is a mineral consisting essentially of manganese dioxide (Mn O 2) and is important as an ore of manganese. It is a black, amorphous appearing mineral, often with a granular, fibrous or columnar structure, sometimes forming reniform crusts. It has a metallic luster, a black or bluish-black streak, and readily soils the fingers. The specific gravity is about 4.8. Its name is from the Greek for fire and to wash, in reference to its use as a way to remove tints from glass.[3]

Contents

1 Occurrence 2 Use 3 Variations in crystal habit 4 See also

5 References

Occurrence

Pyrolusite and romanechite are among the most common manganese minerals. Pyrolusite occurs associated with manganite, hollandite, hausmannite, braunite, chalcophanite, goethite and hematite under oxidizing conditions in hydrothermal deposits. It also occurs in bogs and often results from alteration of manganite.[3]

Use

The metal is obtained by reduction of the oxide with sodium, magnesium, aluminium, or by electrolysis. Pyrolusite is extensively used for the manufacture of spiegeleisen and ferromanganese and of various alloys such as manganese-bronze. As an oxidizing agent it is used in the preparation of chlorine; indeed, chlorine gas itself was first described by Karl Scheele in 1774 from the reaction products of pyrolusite and hydrochloric acid. Natural pyrolusite has been used in batteries, but high-quality batteries requires synthetic products. Pyrolusite is also used to prepare disinfectants (permanganates) and for decolorizing glass. When mixed with molten glass it oxidizes the ferrous iron to ferric iron, and so discharges the green and brown tints (making it classically useful to glassmakers as a decolorizer). As a coloring material, it is used in calico printing and dyeing; for imparting violet, amber, and black colors to glass, pottery, and bricks; and in the manufacture of green and violet paints.

Variations in crystal habit

Botryoidal

Dendritic

Acicular radiating

crystal structure of pyrolusite

Mangan Idi na: navigacija, traži

Mangan

[Ar] 3d54s225Mn

       

                               

                               

                                                                                                                                               

        ↓                                                            

        ↓                                                            

→                                                            

→                                                            

Periodni sistem elemenata

Općenito

Hemijski element, Simbol,

Atomski brojMangan, Mn, 25

Serija Prijelazni metali

Grupa, Perioda, Blok 7, 4, d

Izgled srebrenasti metal

Zastupljenost 0,09 %

Atomske osobine

Atomska masa 54,938049 u

Atomski radijus (izračunat) 140 (161) pm

Kovalentni radijus 139 pm

Van der Waalsov radijus - pm

Elektronska konfiguracija [Ar] 3d54s2

Broj elektrona u energetskom

nivou2, 8, 13, 2

Izlazna energija 4,1 eV

1. energija ionizacije 717,3 kJ/mol

2. energija ionizacije 1509 kJ/mol

3. energija ionizacije 3248 kJ/mol

4. energija ionizacije 4940 kJ/mol

5. energija ionizacije 6990 kJ/mol

6. energija ionizacije 9220 kJ/mol

7. energija ionizacije 11500 kJ/mol

Fizikalne osobine

Agregatno stanje čvrsto

Mohsova skala tvrdoće 6,0

Struktura kristala

α-Mn:kubična prostorno

centrirana

β-Mn:kubična primitivna

Gustoća 7470 kg/m3

Tačka topljenja 1517 K (1244 °C)

Tačka ključanja 2235 K (1962 °C)

Molarni volumen 7,35 · 10-6 m3/mol

Toplota isparavanja 226 kJ/mol

Toplota topljenja 12,05 kJ/mol

Pritisak pare 121 Pa kod 1517 K

Brzina zvuka 5150 m/s kod 293,15 K

Specifična toplota 480 J/(kg · K)

Specifična električna

provodljivost0,695 · 106 S/m

Toplotna provodljivost 7,82 W/(m · K)

Hemijske osobine

Oksidacioni broj 1, 2, 4, (5), 6, 7

Elektronegativnost 1,55 (Pauling-skala)

Izotopi

Sigurnosno obavještenje

Oznake upozorenja

Prah

FLako zapaljivo

Obavještenja o riziku i

sigurnosti

R: 11 (prah)

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Ukoliko je moguće i u upotrebi, koriste se SI osnovne jedinice.

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uslovima.

Mangan (Mn, latinski - manganium) je metal VIIB, grupe. Ima 15 izotopa čije se atomske mase nalaze između 49-62. Postojan je samo jedan- 55, koji čini skoro 100% sastava izotopa mangana koji se javljaju u prirodi.

Zastupljenost [uredi]

Zastupljen je u zemljinoj kori u količini od 950 ppm (eng. parts per million) u obliku rude koju čine mješavine nekoliko vrsta oksida. Važniji minerali su: braunit, piroluzit i hausmanit. Sva tri su oksidi mangana. Mangan je 1774 otkrio J.G. Gahna. Najpoznatiji spoj mangana je kalijum permanganat KMnO4, koji ima baktericidne osobine, a koristi se i za borbu protiv gljivičnih oboljenja kože.

Rastvor kalijum-permanganata

Biološki značaj [uredi]

Mangan je sastojak mnogih enzima. Njega bi trebalo dnevno unositi u količini od najmanje 1 miligram. U velikim količinama soli mangana su toksične.

Osobine [uredi]

Mangan je tvrd, srebrnast i krt metal. Vrlo je reaktivan, na vazduhu se pali. Rastvara se u kiselinama uz izdvajanje vodika. Mangan ima slične osobine kao i alkalni metali. Mangan se masovno koristi kao dodatak čeliku smanjujući njegovu temperaturu topljenja i popravljajući mehaničke osobine.