AN IMPROVED PROCESS AND APPARATUS FOR ELIMINATING PHOSPHORUS FROM IRON IN BESSEMER CONVERTERS
Year: 1880

page_text: PROVISIONAL SPECIFICATION left by William Robert Lake at the Office
of the Commissioners of Patents on the 31st March 1880. A communication
from abroad by Doctor Emil Pirath and Doctor Edward Pirath, both of
Frankfort on the Maine, in the Empire of Germany.
งา
WILLIAM ROBERT LAKE, of the Firm of Haseltine, Lake, & Co., Patent Agents,
Southampton Buildings, London. "AN IMPROVED PROCESS AND APPARATUS FOR
ELIMINATING PHOSPHORUS FROM IRON IN BESSEMER CONVERTERS." [A communi-
cation from abroad by Doctor Emil Pirath and Doctor Edward Pirath, both of
Frankfort on the Maine, in the Empire of Germany.]
This Invention relates to the de-phosphorization of crude or pig-iron by
employing the well known "Bessemer" process and introducing finely divided
magnesian salts or soda into a "Bessemer "converter.
This dephosphorization has hitherto been effected on a large scale only by lining
the converter with basic bricks, and this is attended with several disadvantages
notwithstanding its usefulness. For instance, the surface of the basic bricks
absorb phosphorus from the iron and soon becomes useless for any further
elimination of the former. The consequence is that these basic bricks produced by
costly workmanship and which in their preparation and manufacture require all
the skill of the chemist cannot be used to their full extent, as the de-phosphorization
will be effected more slowly the more the crust of the basic lining becomes
saturated with phosphorus.
A further disadvantage connected with this lining of basic bricks is that apart
from their chemical action they require by reason of their inferior strength to be
frequently renewed, and thus considerable interruption is caused in the manu-
facture which would occur much less frequently if the converter were lined with
ordinary fire-bricks.
In carrying this Invention into practico I de-phosphorize the crude or pig-iron
(using the "Bessemer" process) by introducing pulverized or otherwise finely
divided magnesian salt or soda into the converter (either through the blast-pipe
or by means of a separate arrangement), thoroughly mixing it with the molten
metal. Generally it will be most advantageous to introduce the magnesian salt
or soda which is to be employed into the blast-pipe in a burnt and finely powdered
state, so that being carried along with the blast and entering the converter
through the blast-pipe it will be intimately mixed with the crude or pig-iron

page_text: which ensures a perfect action of the magnesian salt or soda employed under any
circumstances.
The chief superiority of this method consists in the facts that it permits the
brick-lining of the Bessemer converter to consist of "Chamotte" or other fire-
bricks instead of basic bricks, and that by the direct introduction of an abundant
quantity of magnesian salt or soda the de-phosphorization will be certain, because
by reason of the fine division of the magnesian salt its chemical action must bo
perfect. It is obvious that this result cannot be attained by a basic lining becauso
the de-phosphorization with such a lining is dependent ontirely upon the chemical
action of the bricks which, as herein before stated, never can be certain.
To introduce the magnesian salt or soda I arrange at some suitable part of the
blast-pipe a funnel, in such a manner that its outlet opens into the said blast-
pipe. This funnel contains a sufficient quantity of the powdered inagnesian salt
or soda to serve for nearly two charges of the convertor, and it is provided with a
cover which closes the outlet air-tight by means of an india-rubber joint or other
suitable device. In the said outlet of the funnel there is a throttle-valve which
can be regulated from the side by means of a lever which may be fixed on a
quadrant by means of a screw in order to secure the valve in its exact position.
To prevent the pulverized magnesian salt or soda from sticking in or choking
the funnel, the latter is provided with a mechanical shaking apparatus of some
well known construction. The funnel may be suspended movably in a frame or
support by two radius bars, and is connected to its outlet-pipe by means of a
movable pipe connection, for instance, by a corrugated copper-pipe or by strong
leather or india-rubber hose.
A cam with three projections or some other well known arrangement produces
a jerking to and fro motion of the funnel, and by reason of the somewhat inclined
position of the radius-bars the funnel is always compelled to press against this cam.
An inclined plane serves to bring the charge into the funnel.
The operation is as follows, that is to say:-When the funnel is sufficiently filled
with the finely divided magnesian salt (dolomite or artificial mixtures) or soda, the
cover is put on and the blast applied in the ordinary manner as in the "Bessemer"
process. The throttle valve is at the same time placed in such a position that the
requisite amount of magnesian salt or soda is carried to the iron by the blast, and
the shaking-apparatus prevents any of the powderized inass from sticking in the
funnel. When the "Bessemer" process is completed the throttle-valve is closed
and the dephosphorized iron is subjected in the ordinary manuer to the next
manipulation.
The required opening of the throttle-valve can readily be ascertained by
practical experiments, and thus a means is provided for regulating exactly the
basic flux according to each sort of iron which has to be dealt with.
The apparatus may be modified as follows, that is to say:
On a blast-pipe leading from a separate blast I provide a pipe or cylinder which
is closed at the top by a stuffing-box. In this cylinder revolves a worm or screw,
the upper end of whose spindle works in a grooved bearing. The spindle also
passes through a lower bearing. This screw or worn is driven by bevel gear-
wheels which are driven by a cone-pulley at such a rate that the revolutions of the
screw or worm can be varied at pleasure within certain limits.
The upper part of the above described pipe or cylinder is filled with the required
magnesian salt or soda, and the screw or worm carries it in a suitablo manner into
the separate blast-pipe. The quantity of magnesian salt or soda which has to be
introduced into the "Bessemer" convorter can be regulated by the greater or
smaller number of revolutions of the said screw or worm, and this variation
in the revolutions can be readily effected by shifting the driving strap on the
said cone pulley.
The original or ordinary blast-pipe enters the "Bessomer" converter in the
hollow lower part, and the blast containing the magnesian salt or soda enters at
each side.

page_text: The last described apparatus for introducing the magnesian salt or soda by
means of a screw or worm may be placed directly on the ordinary blast-pipe
without cinploying a separate blast-pipe, and the hopper-arrangement hereinbefore
mentioned may also be used in connection with a separate blast-pipe.
The magnesian salt or soda used by this new method can either be produced
by artificial means, or I may use that which is found in a natural state, for
instance, dolomite. The reduction thereof to a finely divided state may be effected
in any desired manner, such as grinding, stamping, or the like.