984 IRON 



Spiegeleisen is at present made, on the large scale, in Germany, Russia, and Sweden, 

 and curiously enough, the ores from which it is reduced are of extremely different and 

 distinct characters in each of these countries. In Germany it is made chiefly from 

 the manganiferous spathic carbonate of iron ; in Russia, it is reduced from ferruginous 

 oxides of manganese ; and in Sweden, it is produced by smelting a mixture of 

 knebelite and manganiferous garnet, both of which minerals are compound silicates of 

 iron and manganese. In one point, however, they all agree, which is, that in all these 

 ores the oxides of manganese and iron, if not in actual combination as compound 

 silicates, or carbonates, are at any rate in a very intimate admixture with one another, 

 and therein lies one of the most important points connected with this manufacture ; 

 for it would appear, wherever true ores of manganese have been added to the usual 

 charge of the blast-furnace, in the expectation of obtaining spiegeleisen rich in man- 

 ganese, that this has net succeeded, or at most, that only a small fraction of the 

 manganese added has combined with the iron, the major part having been carried off 

 in the slag ; for which reason, when it is desired to produce a cast iron containing 

 much manganese, it is requisite that this metal should be added to the charge in the 

 shape of some strongly ferruginous compound, thereby facilitating the process of re- 

 duction, since a mixture of the two oxides of manganese and iron is much more easily 

 reduced to the metallic state, and so enabled to unite with the iron from the rest of 

 the charge than oxide of manganese alone, which unless the heat is very intense, and 

 the reducing action of the furnace nearly perfect, is extremely apt to go into the slag in 

 the state of silicate from which it subsequently cannot, or can only with great difficulty, 

 be recovered. The oxides of manganese are, it must be remembered, infinitely less 

 easily reduced, and require more time as well as a much higher temperature than the 

 oxides of iron ; and from what has already been said, it will naturally follow that in 

 making spiegeleisen particular attention should be paid to the following points : 



1 . The mineral used as a source of manganese should be in itself highly charged 

 with iron, so as to facilitate and ensure the reduction of as large an amount of the 

 manganese contained in it as possible. 



2. The charge of the furnace should be highly basic, or, in other words, an excess 

 of limestone or, preferably, burnt lime, should be used. 



3. The working of the furnace should be much slower than is usual in iron smelting, 

 in order to allow more time for the reduction of the oxides of manganese. 



4. The temperature of the blast-furnace should be as high as possible, using as hot 

 a blast as can be obtained ; and, as coke admits of the use of a sharper blast, and 

 affords a greater heat, it is to be preferred to charcoal in this manufacture. 



In Russia, the spiegeleisen produced at Nischne-Tagilsk is smelted with charcoal, 

 and is known for its good character, it is reduced from a mixture of the native oxides 

 of iron, which in themselves contain some manganese with ferruginous Braunite, which 

 contains about 40 per cent, metallic manganese, with 10 per cent, metallic iron, in inti- 

 mate admixture. 



In order to increase the amount of manganese in grey pig-iron, which already con- 

 tained 1*2 per cent, of manganese, so as to obtain a spiegeleisen, trials have been made 

 at Wotkinski, by re-melting this pig-iron in a cupola, with the addition of from 12 to 

 15 per cent, of clean native oxide of manganese (manganite or pyrolusite), which have 

 resulted in making a spiegeleisen containing between 5 and 6 per cent, metallic 

 manganese. 



In Sweden, spiegeleisen has been produced in several parts but principally at 

 Schisshyttan and Ramshyttan, in Dalecarlia, where it is obtained by smelting a 

 mixture of knebelite and manganiferous garnet, which contains an average of about 

 42 per cent, iron with 13 per cent, manganese, in the blast-furnace (which is 47 feet 

 high, and has two tuyeres) with as hot a blast as could be obtained from an iron-pipe 

 apparatus. The fuel employed is a mixture of half charcoal half coke, and the ore is 

 fluxed with 30 per cent, of its weight of limestone. The ore frequently contains 

 visible specks of galena, pyrites, and zinc blende, but it is stated that no sulphur is 

 found in the spiegeleisen, although the slag which, when the furnace is working well, 

 has a peculiar yellowish green colour, is said to contain 4 per cent, sulphur up to as 

 much as 16 per cent, oxide of manganese. 



The ordinary spiegeleisen obtained at Schisshyttan contains an average of 13 per 

 cent, manganese, with about 4 per cent, carbon, or 5 per cent, carbon, silicon, &c. 

 Occasionally it has been as high as 17 per cent. Mr. Alexander Keiller, the manager 

 of these works, found that some which averaged 15 per cent, of manganese with only 

 2 per cent, carbon was altogether different in appearance, and could not, be made to 

 assume the crystalline bladed reflecting fracture, peculiar to spiegeleisen, and from 

 which its name is derived, and in consequence, was regarded with prejudice in the 

 market by the buyers, who judge from appearance alone. Ho also stated that he had 

 latterly succeeded in producing a cast iron, containing as much as 23 per cent, of man- 



