Improvements in or relating to the Purification of Steel or of Iron During its Conversion into Steel.
Year: 1892

page_text: being date of first Foreign Application (in 21st Jan., 1892
Belgium),
Date of Application (in United Kingdom), 6th May, 1892
Complete Specification Left, 26th Sept., 1892-Accepted, 29th Oct., 1892
Belgium),
Date of Application (in United Kingdom), 6th May, 1892
Complete Specification Left, 26th Sept., 1892-Accepted, 29th Oct., 1892
PROVISIONAL SPECIFICATION.
Improvements in or relating to the Purification of Steel or of Iron
During its Conversion into Steel.
I, ERNEST HENRY SANITER of 11 New Market Street, Wigan, in the County
of Lancaster, Analytical and Metallurgical Chemist, do hereby declare the nature
of this invention to be as follows :-
The invention forming the subject matter of this application was covered by an
application for a Patent in Belgium No. 98005 dated the 21st day of January 1892
but not yet issued to me, and I now apply for an English Patent under the
Convention for the said invention.
Many experiments by myself and others have been tried by the addition of
various chemicals to effect the separation of sulphur and other metalloids from
iron and steel, but they have, I believe, until lately, as far as I am aware, entirely
failed. I have, however, found that, if a chloride of an alkaline earth be added
to molten iron in presence of a very large excess of alkaline earth oxide, a
reaction does take place and the sulphur is in a great part eliminated, and would
probably be entirely eliminated if the reaction were allowed sufficient length
of time.
My invention is based upon this new reaction which I have discovered, and
consists in bringing the chloride of an alkaline earth into contact with the metal in
presence of lime or other alkaline earth oxide, carbonate or hydrate, the reaction
taking place by contact while the materials are in a highly heated fused condition.
In its simplest form as used for purifying steel from a melting furnace, I mix
calcium chloride and lime or equivalent of carbonate with or without oxide of iron
together in suitable proportion, say 2 to 3 of calcium chloride to 3 of lime, or
equivalent of CaCO, preferably in their anhydrous condition, and either place the
mixture loosely on the bottom of a suitable receiver, or cause it to be solidified by
partial fusion after placing on the bottom, or the powder may be kept down by a
grating of iron or any suitable substance which will keep the mixture in position
till the whole of the iron is in the receiver, or it can be allowed to float on the
metal, or bars of iron or other rigid material may be coated or their hollows filled
with the mixture and forced below the surface of the metal and stirred about.
Then about 40 to 80 times the weight of the mixture of raw iron is run into the
receiver, which gradually melts the mixture and is acted upon by it. The receiver
may be lined with any refractory substance, whether of a basic, neutral or acid
character.
In carrying out my invention for the basic open hearth steel process, the cast
iron and scrap are charged with a sufficient quantity, say about 150 kilogrammes
of lime-stone, or an equivalent quantity of lime, to 1000 kilogrammes of metal.
The charge is then melted and a sufficient quantity of calcium chloride, say 1 to
10 per cent., added to the bath of metal and allowed to remain in contact with it for
a sufficient period, say 30 minutes. Feeding with oxide of iron is then commenced
A

page_text: and the charge worked in the ordinary way, care being taken to keep the slag very
basic by means of lime or magnesia.
The quantity of lime-stone required varies with the composition of the metal
used, but should be sufficient to produce a very highly basic slag, say 50 per cent.
of lime. By these means, the sulphur has been reduced from 5% to 06% and
from 2% to 018%
In applying the process to the basic Bessemer converter, the metal is run into
the converter and 10 to 20 per cent. of lime and 1 to 10 per cent. of calcium chloride
are added the blast is then turned on and the blow proceeded with as usual. The
calcium chloride may be added at a later stage during the conversion together with
any necessary further additions of lime.
In working the process, I do not confine myself to the use of a ready formed
chloride of an alkaline earth, a mixture of material may be added to form the
chloride in the furnace, such, for instance, as chloride of iron (refuse from
galvanising works) and lime.
Where, too, it is desirable to remove or reduce the amount of silicon-in-the-metal,
oxide of iron can be added separately or mixed with the chloride of calcium and
lime or their equivalent as aforesaid.
I may use an alkaline earth fluoride instead of an alkaline earth chloride in the
above process.
WM. P. THOMPSON & Co.,
Of 6, Lord Street, Liverpool, Patent Agents for the Applicant..
COMPLETE SPECIFICATION.
Improvements in or relating to the Purification of Steel or of Iron.
During its Conversion into Steel.
I, ERNEST HENRY SANITER of 11 New Market Street, Wigan in the County
of Lancaster, Analytical and Metallurgical Chemist, 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 :--
In the manufacture of steel by the basic Bessemer process, it has been suggested
to add chloride of calcium or other halogen salts of lime with lime to assist the
dephosphorisation by promoting the fluidity of the slag. Iu all these cases,
however, the slag has consisted of from 35 to 45 per cent. lime. Now I have
found that, with these fluid slags containing up to 45 per cent. of CaO it is quite
impossible to extract the sulphur, and I believe there is no instance on record
of the percentage of sulphur being reduced by this means. I have found,
however, that, if the slags be kept so basic as to contain about 0 to 60 per cent.
of lime, in which state it is in a very thick viscous condition, the addition of
chloride or even of a fluoride of an alkaline earth has the property of causing.
the sulphur to leave the iron and join the slag.
This invention has for its object the purification of iron, during its conversion.
into steel or homogeneous metal, from sulphur.
The process consists in bringing into contact with the molten iron or steel a
chloride of an alkaline earth metal, together with an alkaline earth metal oxide,
carbonate or hydrate, under the conditions to be hereafter described, for the
purpose of removing, sulphur.
In working the process, I do not confine myself to the use of a ready formed
chloride of an alkaline earth metal, a mixture of materials may be used to form
the chloride in the vessels or furnaces, such, for instance, as chloride of iron,
(refuse from galvanising works) and lime, or a corresponding fluoride can take.
the place of chloride.

page_text: By the above described process, pig iron containing 75 per cent. of sulphur has
been converted into steel containing 08 per cent. and using iron with 20 per cent. of
sulphur has been reduced to 018 per cent. in the steel.
In applying the process to the basic Bessemer converter, it is necessary to insure
that an exceedingly basic slag, containing from 50 to 60 per cent. of CaO, is formed
in conjunction with the calcium chloride which is added either before the
commencement of the blow or at a somewhat later period with any necessary
addition of lime.
I have not fully satisfied myself of the exact chemical reactions that occur, but
believe that the following is correct-
When there is only 35 or 40 per cent. of lime, this lime exists in the slag mainly
as a silicate, aluminate or phosphate of lime while the sulphur is in combination
with the iron, if, however there be 50 to 60 per cent. of lime, there is a quantity of
caustic lime in the slag, and this, being much more powerful, takes the sulphur
from the iron and retains it as long as the lime is thus in excess.
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 :-
1. In the process of purifying iron from sulphur during its conversion into steel,
adding to the molten metal in the furnace a mixture of chloride or fluoride of an
alkaline earth and of the oxide, hydrate or carbonate of an alkaline earth, the
latter in sufficient quantity to form and maintain a slag having from 50 to
60 per cent. of lime.
2. In the process of purifying iron from sulphur during its conversion into steel,
adding a halogen salt of an alkaline earth or of iron to the molten metal in the
presence of an excess of lime and maintaining that excess so that the slag shall
contain from 50 to 60 per cent. of lime.

page_text: 3. The process of purifying steel from sulphur which consists in causing it to
stand in the fluid condition in sufficiently prolonged contact with a mixture of
chloride of calcium and lime or their respective chemical equivalents herein
mentioned...
Dated this 24th day of September 1892.
WM. P. THOMPSON & Co.,
Of Liverpool, Manchester, Nottingham, and London, Patent Agents..