A treatise on chemistry. Vol. II, Metals. Part II / by H.E. Roscoe & C. Schorlemmer ...

  • Henry Enfield Roscoe
Date:
1880
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Licence: Public Domain Mark

Credit: A treatise on chemistry. Vol. II, Metals. Part II / by H.E. Roscoe & C. Schorlemmer ... Source: Wellcome Collection.

Provider: This material has been provided by University of Bristol Library. The original may be consulted at University of Bristol Library.

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    MUTALLIC MANGANESE. occurring in them in small quantity. Thus, for instance, most silicates contain manganese, which frequently imparts to them tlieir peculiar colour. By means of these minerals the metal manganese passes into the soil, whence it is absorbed in smaU. quantities into the bodies of plants and animals. 314 Preparation of Metallic Manganese. The higher oxides of manganese are reduced to manganese monoxide when they are heated to redness, the metal not being formed either when the o.videis heated alone or mixed with charcoal in a current of hydro • gen, until the temperature rises to a white-heat. The original method of preparing the metal, proposed by John,^ depends upon this fact. Einely-divided oxide of manganese, obtained by the calcination of the carbonate in a covered crucible, is well mixed with carbon, and the mixture formed into a paste with oil; the paste is then introduced into a cruoible lined with charcoal, and the upper portion completely filled with powdered charcoal. The crucible is first heated to redness for half-an-hour to solidify the mass, after which the cover is carefully luted down, and the whole exposed in a wind furnace for an hour-and-a-half to the highest temperature which the crucible can support without fusing. The regulus thus prepared contains both carbon and silicon derived from the ashes of the wood charcoal. By igniting the metal a second time in a charcoal crucible with some borax it was ob- tained by John in a more fusible and brilliant state, and so free from carbon that it left no black residue when treated with an acid<v Deville's** method consists in mixing red manganese oxide, MugO^, prepared by heating the artificial dioxide, with sugar char- coal insufficient in quantity for complete reduction. The mixture is placed in a doubly-lined crucible and heated to whiteness. The regulus obtained is coated with a violet crystalline mass which appears to be calcium-manganese spinelle, CaO,Mn03. Hugo Tainm,-' who has made a number of experiments on the preparation of the metal on the large scale, suggests the follow- ing as the best method of preparation. A flux is prepared of twenty parts of powdered soda-lime glass and seven parts of fluor-spar; six parts of this ndxture are then added to one part of lampblack and eleven parts of powdered black oxide of manganese. The mass is heated in a plumbago crucible which has been lined with a mixture of three parts of graphite and one part of fire-clay, and this is then intensely ignited in a wind ' Gohlen'fl Jnnrn. Chnn. Phij.i. iii. 452. ' Ann. Chim. Phys. [3], xlvi. 182. » C/wm, News, 1872, 111. 1*—2
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