Queries. [Volume: 8, Issue: 1, 1888, pp. 21-28]

26

UNITED STATES ASSOCIATION OF

[VOL. 8,

The furnace was working well before the change was made and
has worked just as well since No increase in pressure of blast.
No decrease in the number of charges per day and no irregularities of any kind. The fuel used is } coke and f Lackawanna
anthracite.
During 1887, we ran our No. 5 furnace (70 feet X 19 feet) for
several weeks or 50 per cent. concentrated Chateaugay ore. When
we made this trial I anticipated a considerable increase in pressure
of blast and in order to meet this increased the proportion of coke to
one third. I afterwards concluded that this increase of coke was unnecessary, as the pressure of the blast went down considerably.
The furnace worked well on 50 per cent. concentrated ore and
showed no peculiarities.
None of the concentrated Chateaugay ore is coarser than what
will pass through a quarter-inch hole and most of it very much
finer.* As different blast furnaces work differently, I would recommend parties commencing the use of concentrated magnetite to try
a small proportion at first, say ~1th, and then gradually increase.
E. S. MOFFAT,
General Manager Lackawanna Iron and Coal Company,
Scranton, Pennsylvania.
QUERY No. 3.-What are the conditions governing the production
of different grades of pig iron?
The grade of iron is dependent upon the following conditions:
First. Upon the chemical composition of the individual ores.
A high manganese pig cannot be produced from an ore low in
manganese, or a low phosphorous pig from phosphoric ores.
Second. Upon the chemical composition of the whole mixture.
Reduction of manganese is facilitated by a strongly basic condition
of the slag-forming constituents of the mixture; sulphur is eliminated by a strongly basic slag. Moreover, the melting point of
the slag produced depends upon its chemical composition.
In general, the greater the amount of elements more difficult to
reduce than iron (silicon, manganese, etc.,) it is desired to reduce
*The concentrated Chateaugay ore referred to is the product of the works
described and illustrated in this issue. Some of this ore is used regularly
at the blast-furnaces of the Bethlehem Iron Company, the Edgar Thomson
Steel Works, etc..-ED.