Year: 1887

page_text: Date of Application, 23rd May, 1887
Complete Left, 23rd Feb., 1888
Complete Accepted, 23rd Mar., 1888
I, PERCY CARLYLE GILCHRIST of 9 Bridge Street in the City of Westminster,
Metallurgist, do hereby declare the nature of this invention to be as follows:-
This invention relates to an improved process for rendering pig iron suitable for use
in the basic Bessemer process when such pig is too high in silicon or phosphorus, it
is also applicable for use with any pig iron which can at present be used in the basic
Bessemer process.
A large proportion of the common phosphoric pig iron made whilst suitable as
regards its phosphorus, for use in the basic process is yet too high in silicon to be
advantageously employed directly in a basic lined Bessemer converter. When such
iron is employed it has in some cases been the custom to first blow the metal in an
acid lined Bessemer converter until the silicon has been completely oxidized and then
transfer the semi-blown metal to a basic lined Bessemer converter in which the blow
is finished. This however is seldom an economical method of working especially in
those cases in which molten metal direct from the blast furnace is unobtainable
as the waste of metal caused by first melting in a cupola, subsequently blowing in an
acid Bessemer and finally transferring to a basic one is very considerable. Even
when molten metal from the blast furnace is directly obtainable the necessity of
keeping one Bessemer vessel specially for desiliconizing is a serious drawback wheu
the plant is a small one. The loss of time also is very considerable and the output
consequently proportionately small.
The present invention consists in first treating the silicious pig in a basic or
neutrally lined Siemens' or other open hearth regenerative gas furnace and then
transferring the desiliconized metal to a basic lined Bessemer converter as hereinafter
described.
The open hearth furnace is brought to very nearly a steel melting heat and nearly
or quite all the lime that will be necessary to remove the phosphorus is charged
therein, this lime may be in the form of lime or limestone and should be in fairly
small pieces, a certain amount of iron ore (which may be phosphoric) or oxide of iron
or scale being mixed with the lime while the silicious and phosphoric pig iron is

page_text: charged on top of it. Some light scrap may if desired be charged in after the
pig. The gas is then turned on and the charge melted as rapidly as possible. It will
be found when the charge is melted that all or nearly all the silicon has been removed
from the metal together with a large amount of the carbon and sulphur and some of
the phosphorus. Or the pig may be first melted or molten pig run in from blast
furnace and iron ore and lime or limestone added until the charge is desiliconized but
the first described order is the one I prefer. The molten desiliconized charge is
tapped into a hot ladle, large enough to hold both metal and slag and the whole
charge transferred as quickly as possible to the basic Bessemer converters or
converter in which the blow is finished as usual and where it will be found that
owing to the fluid condition of the slag the duration of the "after blow
is very
largely diminished thus lessening considerably both the waste and the wear of the
Bessemer converter lining.
"
It will also be found that when working by the above described method the waste
of metal will be extremely small as in oxidizing the impurities in the pig by means of
iron ore, iron is reduced into the bath which compensates for the waste in working.
D
00
1
1005
PHILIP M. JUSTICE,
55 & 56, Chancery Lane, London,
Applicant's Agent.

page_text: I, PERCY CARLYLE GILCHRIST of 9 Bridge Street in the City of Westminster,
Metallurgist, do hereby declare the nature of this invention and in what manner the
same is to be performed, to be particularly described and ascertained in and by the
following statement :-
This invention relates to an improved process for rendering pig iron suitable for
use in the basic Bessemer process when such pig is too high in silicon or phosphorus,
it is also applicable for use with any pig iron which can at present be used in the
basic Bessemer process.
A large proportion of the common phosphoric pig iron made, whilst suitable as
regards its phosphorus, for use in the basic process is yet too high in silicon to be
advantageously employed directly in a basic lined Bessemer converter. When such
iron is employed it has in some cases been the custom to first blow the metal in an
acid lined Bessemer converter until the silicon has been completely oxidized and then
transfer the semi-blown metal to a basic lined Bessemer converter in which the blow
is finished. This however is seldom an economical method of working, especially in
those cases in which molten metal direct from the blast furnace is unobtainable, as
the waste of metal caused by first melting in a cupola, subsequently blowing in an
acid Bessemer and finally transferring to a basic one is very considerable. Even
when molten metal from the blast furnace is directly obtainable the necessity of
keeping one Bessemer vessel specially for desiliconizing is a serious drawback when
the plant is a small one. The loss of time also is very considerable and the output
consequently proportionately small.
The present invention consists in first treating the silicious pig in a basic or
neutrally lined Siemens or other open hearth regenerative gas furnace and then
transferring the desiliconized metal to a basic lined Bessemer converter as hereinafter
described.
The open hearth furnace is brought to very nearly a steel melting heat and nearly
or quite all the lime that will be necessary to remove the phosphorus is charged
therein, this lime may be in the form of lime or limestone and should be in fairly
small pieces, a certain amount of iron ore (which may be phosphoric) or oxide of iron
or scale being mixed with the lime while the silicious and phosphoric pig iron is
charged on top of it. Some light scrap may if desired be charged in after the pig.
The gas is then turned on and the charge melted as rapidly as possible. It will be
found when the charge is melted that all or nearly all the silicon has been removed
from the metal together with a large amount of the carbon and sulphur and some of
the phosphorus. Or the pig may be first melted or molten pig run in from the blast
furnace and iron ore and lime or limestone added until the charge is desiliconized,
but the first described order is the one I prefer. The molten desiliconized charge is

page_text: tapped into a hot ladle, large enough to hold both metal and slag and the whole
charge transferred as quickly as possible to the basic Bessemer converters or converter
in which the blow is finished as usual and where it will be found that owing to the
fluid condition of the slag, the duration of the "after blow" is very largely diminished,
thus lessening considerably both the waste and the wear of the Bessemer converter
lining.
It will also be found that when working by the above described method the waste
of metal will be extremely small, as in oxidizing the impurities in the pig by means
of iron ore, iron is reduced into the bath which compensates for the waste in working.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what I
claim is :-
The improvements in the manufacture of steel or ingot iron hereinbefore described
consisting in first treating the metal in a basic or neutrally lined open hearth furnace
and then completing the operation in a basic lined Bessemer converter substantially
as set forth.
PHILIP M. JUSTICE,
55 & 56, Chancery Lane, London,
Agent for the Applicant.