EZ, Hoerde.
If in the acid and the basic Bessemer processes the molten pig iron is
taken direct to the converter from the blast furnace, there is the
disadvantage that the running of the individual blast furnaces can
hardly ever be kept so uniform as it is desirable should be the case
in order to secure regularity in the converter charges. In the
manufacture of Bessemer steel the variable proportions of silicon and
of carbon here come chiefly under consideration, while in the basic
process it is chiefly the varying proportions of silicon and of
sulphur; and in cases where either ores containing variable
percentages of phosphorus, or puddle slags, are treated, the varying
proportion of phosphorus has also to be considered. This disadvantage
of the irregular composition of the individual blast furnace charges
is obviated in a simple and effective manner by W.R. Jones's mixing
process. In this as much pig iron from the various blast furnaces of a
works as is sufficient for a large number of Bessemer charges, say
from seven to twelve charges, or, in other words, from 70 to 120 tons
of pig iron, is placed in a mixing vessel. Only a portion of pig iron
placed in the mixer is taken for further treatment for steel, while
new supplies of pig iron are brought from the blast furnace. In this
way homogeneity sufficient for practical purposes is obtained.
In the treatment of phosphoric pig iron, which is employed in the
production of basic steel, it is, however, not sufficient merely to
conduct the molten pig iron in large quantities to the converter in a
mixed condition, but the problem here is to render the proportion of
sulphur also independent of the blast furnace process to such an
extent that the proportion of sulphur in the finished steel is so low
that the quality of the steel is in no way influenced by it. The
question of desulphurization has, especially of late years, become of
the utmost importance, at any rate for the iron industry of the
Continent. By the great strike of 1889, the German colliers have
succeeded in greatly improving their wages; and with this increase in
wages not only is there a distinct diminution in the amount of coal
wrought, but, unfortunately, the coal produced since then is raised in
a much less pure condition than was formerly the case. Consequently
the proportion of sulphur in the coke has considerably increased.
Whereas formerly this proportion did not exceed one per cent., it has
now in
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