MANGANESE (Neo-Lat. manganesium, an arbitrary variant of magnesium, magnesium). A metallic element first isolated by Gahn in 1774. It is generally accepted that Pliny was ac quainted with pyrolusite, or manganese dioxide, and assuming it to be a variety of magnetic iron ore, which was called lapis magnesius, he called 'the manganese compound magnesia. Basil Valentine and later chemists regarded the com pound as an ore of iron, and mentioned its use in glass-making under the name of lapis man go nensis. That the compound really contains no iron was first shown by Pott in 1740, and later researches by Scheele and Bergman estab lished the fact of its being a distinct chemical species. The name magnesium, at first applied to its isolated metal, was changed to manganese by Buttmann in 1808.
Manganese ores are found in many parts of the United States, notably in California. Colorado, Arkansas, Georgia, Michigan, New Jersey, and Virginia, hut the deposits have nowhere proved to be sufficiently extensive to supply the domestic requirements. One of the largest mines, situated near Crimora, Augusta County, Va., has been operated for nearly fifty years and is still pro duetive. The ore occurs in pockets in a thick led of clay, and is mined by the hydraulic process. There are similar occurrences of manganese in Bartow County. Ga., and at other localities along the Appalachian Mountain system. Colo rado is an important producer of man ganese ores which carry a large percentage of iron. The total output of the United States in 1901 was 11.995 long tons, valued at $110,722. In addition there was a production of 574,439 long tolls of manganiferous iron ore. Enormous deposits of manganese are found in Southern Russia and in the State of Minas Geraes, Brazil. Small quantities of manganese are also present in certain mineral waters, in many plants, espe cially the cereals and vegetables used as human food, and it is a constituent of the sun's atmos phere. The metal itself is readily obtained by reducing the oxide with carbon, or by heating manganese chloride with metallic sodium. Man ganese (symbol Ain; atomic weight, 55) is a very hard, grayish-white metal with a reddish lustre. It takes a high polish and is not mal leable. Its specific gravity varies between 6.89 and 7.99. Its melting point is about 1897° C. (about 3447° F.). The metal itself has no uses, but forms valuable alloys with aluminum, copper, iron, and mercury. Those with iron, containing from S to SO per cent. of manganese, are used in the manufacture of steel under the names of Spiegeleisen and ferromanganese. The presence of manganese in iron and steel is said greatly to increase their elasticity and hardness. and
even one per cent. of manganese will render east steel more tenacious.
With oxygen manganese forms several oxides, including a monoxide (11110), a sesquioxide a dioxide (Mn00, a trioxide (11n0,), and a heptoxide Besides these, a number of intermediate oxides are believed to exist. The most important of the oxides is the dioxide or peroxide, which occurs native as pyrolusite and is the 'black manganese' of com merce, a substance largely used in the manufac ture of chlorine (q.v.), and in the preparation of oxygen (q.v.), as well as in the making of black enamel for pottery, and in the manufac ture of glass. The sesquioxide of manganese, or manganie oxide, occurs in nature as the mineral braunite, or, in a hydrated form as the mineral manganite. The monoxide of man ganese, or manganous oxide, occurs in nature as the mineral manganosite, or, in a hydrated form as the mineral pyrochroite. It is the manganese salts corresponding to this oxide that are found, always together with iron salts, in mineral water and in the organisms of animals and plants. For the trioxide of manganese, see MANGANIC AND PERMANGANIC ACIDS.
While salts have been obtained corresponding to several of the oxides of manganese, many of those salts are unstable and hardly deserve men tion. Jlanganous chloride, is obtained as a by-product in the manufacture of chlorine by the action of hydrochloric acid on manganese dioxide. To isolate the chloride from the solu tion thus obtained, the latter is evaporated until it contains no more free hydrochloric arid, then part of it (about one-quarter) is precipitated with an excess of sodium carbonate, the precipi tate (mauganous carbonate) is washed with water and added to the rest of the solution, and the latter is kept boiling for some time. On cooling, the solution is filtered, and the filtrate fs allowed to evaporate, hydrated manganese chlo ride separating out in the crystalline state. When freed from its water of crystallization, man gallons chloride forms pink crystals that may be distilled in a. current of chlorine. The chloride is used for the production of a brown color in calico printing and is employed, in small quan tities, in certain operations of analytical chem istry. Manganous sulphate, MnSO,, or rather the hydrated form, MnSO, 4H.D. may he obtained by the action of sulphuric acid on manganese dioxide. It is used in dyeing and is official in the pharmacopceia. For other important com pould of manganese. see MANGANIC AND PER 3IAM,ANIC ACIDS.