Year: 1888

page_text: Date of Application, 11th Apr, 1888
Complete Specification Left, 11th Jan, 1889
Complete Specification Accepted, 16th Mar, 1899
I, THOMAS TWYNAM of 54 Minford Gardens West Kensington Park in the County
of Middlesex, Metallurgical Chemist, do hereby declare the nature of this invention
to be as follows
1
This invention relates to an improved process for the production of alkalies and
alkaline salts from the slag resulting from the purification of phosphoric pig iron
By my invention I remove the phosphorus contained in phosphoric pig iron by
adding in the furnace or converter in which the pig iron is to be purified a sufficient
amount of alumina to combine with and fix the phosphoric acid resulting from the
oxidation of the phosphorus in the pig iron I always prefer that the furnace or
converter employed should be lined with alumina (for which purpose bauxite may be
conveniently employed) a lining of shrunk dolomite or of magnesia or chrome iron
ore may however be employed The bauxite used as a lining material may or may
not be previously shrunk and should be rich in alumina and not too high in silica,
it may be made to cohere by mixing with it a small quantity of milk of lime, or fine
clay, or other suitable material such as an alkaline carbonate or hydrate or silicate or
aluminate of soda The mixture may be either made into bricks and fired or it may
be rammed into the furnace or converter direct
The alumina added in the vessel for fixing the phosphoric acid may be either bauxite
or other native form of alumina, but when possible I prefer the alumina recovered as
hereinafter described from the slags resulting from prior operations A small amount
of lime or soda or aluminate of soda may be also introduced with the alumina for
the purpose of rendering the alumina more fusible and to increase the basicity of
the slag
The operation of purifying the metal from the phosphorus is conducted in a
manner similar to that employed in the present basic dephosphorizing process

page_text: A
The resulting slag consists largely of phosphate of alumina mixed with some silica
and oxide of iron This slag is ground to a moderate degree of fineness and is then
used in the following manner for the production of alkalies and alkaline salts
mixture is made of the ground phosphate slag with salt and cohe dust which are well
mixed together under edge runners or otherwise, the mass being subsequently
moistened with water and made up into briquettes and dried
The briquettes are stacked in a cupola or other convenient furnace together with a
little coke to serve as fuel When the mass has attained a red heat a current of steam
(preferably superheated) is introduced, this together with the blast employed causes
reaction between the phosphate of alumina and salt resulting in the production
of phosphate of soda and aluminate of soda, hydrochloric acid gas being given off
When the reaction is finished the mass is withdrawn from the furnice, digested
with water and the dissolved phosphate and aluminate of soda separated by crystallı-
zation or otherwise The phosphite of soda may be converted in the ordinary way
into phosphate of lime and soda, the aluminate of soda may be also decomposed
preferably by a current of carbonic acid gas into alumina (which is reused) and
carbonate of soda
Instead of mixing chloride of sodium with the slag and coke, chloride of potassium
may be employed, in which case the resulting alkalies will of course contun potash
instead of soda
Dated the 11th --11000
PHILIP M JUSTICE,
55 & 56, Chancery Lane, London,
Applicant's Agent

page_text: COMPLETE SPECIFICATION
Improvements in the Production of Alkalies and Alkaline Salts
from the Slag Resulting from the Manufacture of Ingot Iron
and Steel
I, THOMAS TWYNAM, formerly of 54 Minford Gardens but now of 7 Marlborough
Crescent, Chiswick, in the County of Middlesex, 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
This invention relates to an improved process for the production of alkalies and
alkaline salts from the slag resulting from the purification of phosphoric pig iron
By my invention I remove the phosphorus contained in phosphoric pig iron by
adding in the furnace or converter in which the pig iron is to be purified a sufficient
amount of alumina or preferably alumina in combination with some basic body such
as lime or soda to combine with and fix the phosphoric acid resulting from the oxida-
tion of the phosphorus in the
Pig iron
I always prefer that the furnace or converter
employed should be lined with alumina (for which purpose bauxite may be conveniently
employed) a lining of shrunk dolomite or of magnesia or chrome iron ore or other
bodies may however be employed The bauxite used as a lining material may or
may not be previously shrunk and should be rich in alumina and not too high in
silica, it may be made to cohere by mixing with it a small quantity of milk of lime,
or fine clay, or other suitable material such as an alkaline carbonate or hydrate or
silicate or aluminate of soda The mixture may be either made into bricks and
fired or it may be rammed into the furnace or converter direct
The alumina added in the vessel for fixing the phosphoric acid may be either
bauxite or other native form of alumina, but when possible I prefer the alumina
recovered as hereinafter described from the slags resulting from prior operations
A small amount of lime or soda or aluminate of soda should be also introduced
with the alumina for the purpose of rendering the alumina more fusible and to
increase the basicity of the slag
The operation of purifying the metal from the phosphorus is conducted in a
manner similar to that employed in the present basic dephosphorizing process
It is sometimes preferable to remove only part of the phosphorus by means of
the alumina additions then to pour the slag and finish the dephosphorisation by
means of lime only as I find a difficulty in removing all the phosphorus by means of
alumina
The resulting slag consists largely of phosphate of alumina mixed with silica
oxide of iron &c This slag is ground to a moderate degree of fineness and is
then used in the following manner for the production of alkalies and alkaline salts
A mixture is made of the ground phosphate slag with salt and coke dust which are
well mixed together under edge runners or otherwise, the mass being subsequently
moistened with water and made up into briquettes and dried

page_text: The briquettes are stacked in
a little coke to serve as fuel
cupola or other convenient furnace together with
When the miss his attained red heat a current
of steam (preferably superheated) is introduced this together with the blast employed
causes a reaction between the phosphate of alumina and salt, resulting in the
production of phosphate of soda ind aluminate of soda hydrochloric acid gas being
given off
When the reaction is finished the mass is withdrawn from the furnace digested
with water and the dissolved phosphate and aluminate of soda separated by crystallı-
zation or otherwise The phosphate of soda may be converted in the ordinary way
into phosphate of lime and soda the iluminate of soda may be also decomposed
preferably by a current of carbonic acid gas into alumina (which is reused) and
carbonate of soda
Instead of mixing chloride of sodium with the slag and coke, chloride of potassium
may be employed in which case tho rosulting alkalies will of course contain potash
instead of soda
I would state that I do not claim the dephosphorisation of pig iron by means of
alumina, but
Having now particularly described and ascertained the nature of my sud inven-
tion and in what manner the same is to be performed I declare that what
I claim is
-
The production of alkalies and alkaline salts from the phosphatic slag obtained in
the purification of phosphoric pig iron by means of alumina or alumina with another
base substantially as described
1000
PHILIP M JUSTICE,
55 & 56, Chancery Lane, London,
Applicant's Agent