No body among the metals and the metalloids (silicium, titanium,
tungsten, chromium, phosphorus, etc.) has occupied a more prominent
position in modern metallurgy than _manganese_, and it is chiefly due
to its great affinity for oxygen. When this substance was discovered,
more than a century ago (1774), by the celebrated Swedish chemist and
mineralogist, Gahn, by treating the black oxide of manganese in the
crucible, no one would have thought that the new element, so delicate
by itself, without any direct industrial use, would become, in the
middle of the nineteenth century, one of the most powerful and
necessary instruments for the success of the Bessemer process, as well
for its deoxidizing properties as for the qualities which it imparts
to steel, increasing its resistance, its durability, and its
elasticity, as has been shown elsewhere.
Without entering into a complete history (for it is beyond the task
which we have here assumed),[1] it will not be without interest to
recall how, when manganese was first obtained in a pure state, that it
was supposed that it would remain simply an object of curiosity in the
laboratory; but when its presence was proved in spiegeleisen and when
it came to be considered an essential ingredient in the best German
and English works for cutlery steel (where it is thrown into the
crucible as the peroxide), then we find that its qualities become
better and better appreciated; and it is surprising that no
technologist ever devoted his attention to the production of manganese
alloys.
[Footnote 1: See _Engineering_, May 27, 1881]
It was not till after the investigations of Dr. Percy, Tamm, Prieger,
and Bessemer, who employed crucibles for the production of these
alloys, that Hendersen received the idea of utilizing it in the
Siemens furnace. So important a compound could not remain unemployed.
The works at Terre Noire produced, by the Martin furnace, for a number
of years, ferro-manganese of 70 to 80 per cent. Shortly afterward,
when competition in the market was established, the works at Carniola
and at Carinthia, some English factories, and more especially the
works at Saint-Louis, near Marseilles, of Terre Noire, of Montluçon,
etc., successfully adopted the manufacture of _ferro-manganese with
the blast furnace_, which is without doubt the method best adapted for
the reduction of metallic oxides, as well in consideration of the
reactions as from an economical point of view. Before very long it was
possible to produce, by the blast furnace, alloys of 40, 60, 80, and
even 86 per cent., in using the hot air apparatus of Siemens, Cowper,
and Witwell, with the employment of good coke, and principally by
calculating the charges for the fusion in such a manner as to obtain
an extra basic and refractory slag.
Following in the same path, the Phoenix Co., of Ruhrort, sent, in
1880, to the Metallurgical Exposition of Dusseldorf, samples of
ferro-manganese obtained in a blast furnace, with an extra basic slag
in which the silica was almost entirely replaced by alumina. The works
of L'Esperance, at Oberhausen, exhibited similar products, quite pure
as to sulphur and phosphorus, and they had a double interest at the
exhibition, in consideration of the agitation over the Thomas and
Gilchrist process (see the discussions which were raised at the
meeting of the Iron and Steel Institute). This process unfortunately
requires for its prompt success the use of a very large quantity of
spiegel or of ferro-manganese, in order to sufficiently carburize and
deoxidize the burnt iron, which is the final product of the blowing.
The production of ferro-manganese by the blast furnace depends upon
the following conditions.