Full resolution (JPEG) - On this page / på denna sida - VI. Mining and Metallurgical Industry. General Survey. By C. Sahlin - 2. Iron and Steel Industry. By J. A. Leffler
<< prev. page << föreg. sida << >> nästa sida >> next page >>
Below is the raw OCR text
from the above scanned image.
Do you see an error? Proofread the page now!
Här nedan syns maskintolkade texten från faksimilbilden ovan.
Ser du något fel? Korrekturläs sidan nu!
This page has never been proofread. / Denna sida har aldrig korrekturlästs.
-286
vi. mining and metallurgical industry.
chanically separated from the reducing agent. The silicon and phosphorus
impurities in the latter remain unreduced, and the bulk of the sulphur is bound
with lime and is removed along with the ashes, as well as the impurities
mentioned.
Spongy iron made from the above-mentioned Gällivare slick contains 96’6 %
of metallic iron, 1’6 % of ferrous oxide, O’oio % to 0’030 % of sulphur and O.013
% of phosphorus. The specific gravity of the spongy iron is 2 to 2’6, and it
thus contains up to 70 % of pores. By severe pressure the specific gravity
can be raised to 4’6 or 5.
Spongy iron is used with advantage as a substitute for wrought iron
scrap in Siemens-Martin furnaces. Moreover, rather extensive experiments
have been made to smelt it in Lancashire hearths. Attempts have also
been made in German chemical factories to use the spongy iron for
reducing purposes.
The supplies of coal which the Höganäs Company has available for the
immediate future for the preparation of spongy iron, will probably allow
of an annual output of up to 200 000 tons.
The Manufacture of Wrought Iron.
The production of wrought iron in Sweden during the last 35 years is
shown by the Table 55.
It will be seen from the Table that the output of wrought iron has
diminished in the course of the last 25 years. The reasons of this
decrease are firstly that this industry is entirely dependent on the price
of charcoal, which is constantly rising, secondly, that the soft ingot metal
(Bessemer and Martin) has entirely or partially ousted wrought-iron for
a number of uses.
However, if the wrought iron industry has declined, it is not for lack
of efforts to keep it alive. On the contrary, much labour has been
expended and much interest has been lavished both on the production
of the pig iron intended for the fining (hotter blast, more basic slag,
richer charges and faster driving of the blast furnaces) and also on the
actual finery process. With regard to the latter, the Lagerwall machine
(1895) for breaking up the iron mass (first used at Laxå) effected quite
a revolution in the Lancashire process. These machines rendered possible
the use of hotter blast and larger charges, without entailing heavier
Table 55. Output of Wrought Iron in Siveden.
Annually Tons
1876-80 .... 1881-85 .... 1886—90 .... 1891—95 .... 116 125 153 495 205 945 215 770
1
1896-00 .... 192 147
1901-05 .... 183 031
1906—10 .... 155 468
1911 ............146 722
1912 ...... 148828
1913 ...... 153 400
<< prev. page << föreg. sida << >> nästa sida >> next page >>
