This section is from "Scientific American Supplement Volumes 275, 286, 288, 299, 303, 312, 315, 324, 344 and 358". Also available from Amazon: Scientific American Reference Book.
By M.V. Deshayes.
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.
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.
1. A high temperature.
2. On a proper mixture of the iron ores and the manganese.
3. On the production of slag rich in bases.
These different conditions may be obtained with but slight variations at the different works, but the condition of a high temperature is one of the most important considerations, not only for the alloys of manganese, but equally as well for the alloys of iron, manganese, silicium, those of chromium, of tungsten, etc. It is also necessary to study the effects produced either in the crucible or in the blast furnace, and to examine the ores which for a long while have been regarded as not reducible.
The works of Terre Noire especially made at the same time, in the blast furnace, ferro-silicon with manganese, alloys which are daily becoming more important for the manufacture of steels tempered soft and half soft without blowing.
These alloys, rich in silicon, present the peculiarity of being poor in carbon, the amount of this latter element varying with the proportions of manganese. In addition to the alloys used in the iron and steel industry, we shall proceed to relate the recent progress obtained in the metallurgy of other materials (especially copper) by the use of cupro-manganese:
|A||18 to 20||2 to 3||10 to 12||Traces|
|Extra Quality for soft metals.|
|B||15 to 18||3.00||10 to 8||Medium Quality.|
|C||15 to 10||3.25||8 to 6|
|D||5 to 10||3.50||4 to 6||Ordinary for hard metals.|
The first alloys of manganese and copper were made in 1848, by Von Gersdorff; soon after Prof. Schrötter of Vienna made compounds containing 18 or 20 per cent. of manganese by reducing in a crucible the oxides of copper and manganese mixed with wood charcoal and exposing to a high heat.
These alloys were quite ductile, very hard, very tenacious, and capable of receiving a beautiful polish; their color varies from white to rose color, according to the respective proportions of the two bodies; they are particularly interesting on account of the results which were obtained by adding them to certain metallic fusions.
It is well known that in the fining of copper by oxidation there is left in the fined metal the suboxide of copper, which must then be removed by the refining process, using carbon to reduce the copper to its metallic state. M. Manhès, taking advantage of the greater affinity of manganese for oxygen, found that if this last element was introduced into the bath of copper during the operation of refining, the copper suboxide would be reduced and the copper obtained in its metallic condition. For this purpose during these last years real cupro-manganese has been prepared, occupying the same position to copper as the spiegel or the ferro-manganese does toward the manufacture of steel. M. Manhès used these same alloys for the fusion of bronze and brass, and recommended the following proportions:
|3||to||4||kilog. of||cupro-manganese||for 100 kilog. of||bronze.|
In every case the alloy is introduced at the moment of pouring, as is the case in the Bessemer or Martin process, taking care to cover the fusion with charcoal in order to prevent the contact with air, together with the use of some kind of a flux to aid in the scorification of the manganese.
According to M. Manhès a slight proportion of manganese added to bronze appears to increase its resistance and its ductility, as is shown in the following table, provided, however, that these different alloys have been subjected to the same operations from a physical point of view; that is, pouring, rolling, etc.