IMPROVEMENTS IN THE TREATMENT OF HEATING, PUDDLING, AND REPINERY IRON SLAGS OR CINDERS
Year: 1854

page_text: LETTERS PATENT to Frederick Crace Calvert, of the City of Manchester,
in the County of Lancaster, Professor of Chemistry, for the invention of
"IMPROVEMENTS IN THE TREATMENT OF HEATING, PUDDLING, AND REPINERY
IRON SLAGS OR CINDERS."
in the County of Lancaster, Professor of Chemistry, for the Invention or
"IMPROVEMENTS IN THE TREATMENT OF HEATING, PUDDLING, AND REPINERY
IRON SLAGS OR CINDERS."
Sealed the 30th January 1855, and dated the 18th August 1854.
PROVISIONAL SPECIFICATION left by the said Frederick Crace Calvert
at the Office of the Commissioners of Patents, with his Petition, on the
18th August 1854.
I, FREDERICK CRACE CALVERT, of the City of Manchester, in the County of
Lancaster, Professor of Chemistry, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN THE TREATMENT OF HEATING, PUDDLING, AND
REPINERY IRON SLAGS OR CINDERS," to be as follows:-
The purpose which I desire to attain is the production of a better quality
of cast and malleable iron from certain iron slags, known by the names of
puddling, refinery, and heating slags or cinders, than is effected at the present
day. It is necessary that I should state here that the usual way of applying
these slags or cinders on a blast furnace consists in adding them, either alone
or mixed with the ironstone, without submitting them to any previous pre-
paration; the consequence is, that as they descend in the furnace they are
soon carried to a bright red heat aud fused. A great portion of these slags is
not fluxed, and finds its way to that part of the furnace where cast iron is
being produced, and uniting with it, descends into the cupola of the blast

page_text: furnace. It is easy to understand how the above iron slags or cinders injure
the quality of the cast iron obtained in blast furnaces on which cinders are
used, for iron slags are composed of silicate, sulphuret, and phosphuret of iron,
which act most injuriously on the quality of cast and malleable iron.
I shall now explain how I intend to operate so as to effect the complete
fluxing of the above slags or cinders, and thus prevent the silica, sulphur, and
phosphorus arriving in contact with the cast iron which is being made.
The first process consists in reducing the above puddling; refinery, and
heating furnace slags or cinders into coarse powder, and mixing it with about
one-half its weight of slacked lime made into a thick paste. They are then well
mixed together, and the mass is made into lumps or bricks, which are dried or
not, according to circumstances, previously to adding them at the top of the
blast furnace; or the dried lumps of lime slag may be calcined in a separate
furnace, and then introduced at the top of the blast furnace; or the mass of
lime and slag inay be mixed with coal, coke, or charcoal, and calcined in
a furnace, or introduced into crucibles, and thus separate the iron it contains
previously to its addition on the blast furnace.
The second process consists in roasting or oxidizing the iron slags or
cinders before they are mixed with the slacked lime. To oxidise these slag's
or cinders I adopt two different processes. To carry out the first of these
processes, I reduce the slags into fiue powder, and introduce it into an
oxidising furnace, such as is used for roasting copper ores, such as sulphuret
of copper, and whilst the powder is carried to a dull red heat it is well stirred,
so as to transform the iron or the protoxide they contain into peroxide, the
silicum into silica, the phosphurets into phosphates, and the sulphur into
sulphurous acid. When the powder has assumed a bright red colour, and no
more sulphurous acid is produced, it is taken out of the furnace and mixed
with slack lime, as above described. I attain the same purpose by breaking
them into small fragments, and introducing them with a small amount of coal
into an ordinary kiln, or in one made of four walls, which have numerous
holes in the sides, the object of which is to admit freely the oxygen of the
atmosphere, and which holes are also employed to remove the oxidised slags.
These kilns are worked like ordinary lime ones, namely, the slags mixed with
a small quantity of coal are constantly added at the top, whilst the oxidised
slag is removed at the bottom of the kiln or furnace by the opening or openings
which exist there.
The third process to which I submit puddling, refinery, or heating slags or
cinders is to reduce them into a powder, and introduce it into furnaces or long
flues, into which are made to pass the volatile products given off from the

page_text: mouth of the blast furnace or of the coke oven. When the powdered slags or
cinders are not sufficiently heated by the gases for these to act upon the
component parts of the slags, a gentle heat is applied, so as to carry them to
a dull red heat; then the silicates of protoxide of iron are decomposed, and
metallic iron produced. When the operation is completed they are taken out
and allowed to cool in confined vessels. Such reduced slags are ready to be
mixed with slacked lime, as above described, made into masses or lumps,
which are employed as also above described.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Frederick Crace Calvert in the Great Seal Patent Office
on the 15th February 1855.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, FREDERICK
CRACE CALVERT, of the City of Manchester, in the County of Lancaster,
Professor of Chemistry, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Eighteenth day of August, in the year of our Lord
One thousand eight hundred and fifty-four, in the eighteenth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me, the
said Frederick Crace Calvert, Her special licence that I, the said Frederick
Crace Calvert, my executors, administrators, and assigns, or such others as I,
the said Frederick Crace Calvert, my exccutors, administrators, and assigns,
should at any time agree with, and no others, from time to time and at all
times thereafter during the term therein expressed, should and lawfully might
make, use, exercise, and vend, within the United Kingdom of Great Britain
and Ireland, the Channel Islands, and Isle of Man, an Invention for "IM-
PROVEMENTS IN THE TREATMENT OF HEATING, PUDDLING, AND REFINERY IRON SLAGS
OB CINDERS," upon the condition (amongst others) that I, the said Frederick
Crace Calvert, by an instrument in writing under my hand and seal, should'
particularly describe and ascertain the nature of the said Invention, and in
what manner the same was to be performed, and cause the same to be filed
in the Great Seal Patent Office within six calendar months next and imme-
diately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Frederick Crace Calvert, do hereby
declare the nature of my said Invention, and in what manner the same is
to be performed, to be particularly described and ascertained in and by the
following statement thereof; that is to say:-.

page_text: The effect which I desire to attain is the production of a better quality of
cast and malleable iron from certain iron slags or cinders, known by the names
of puddling, refinery, and heating slags or cinders, than is effected at the
present day. It is necessary that I should state here that the usual way of
applying these slags or cinders on a blast furnace consists in adding them,
either alone or mixed with ironstone, without submitting them to any previous
preparation, except sometimes burning them in a heap. The consequence is,
that as they descend in the furnace they are soon carried to a bright red heat
and fused, and get mixed with the various materials which compose the charge
of a blast furnace. A portion of these slags or cinders falling on mine or coke
are not fluxed, and thus gradually find their way to that part of the furnace
where cast iron is being produced, and uniting with it descends into the cupola
of the blast furnace. It is easy to understand how the above iron slags or
cinders mixing themselves with the cast iron injure its quality, for iron slags
or cinders are chiefly composed of silicate, sulphuret, and phosphuret of iron,
which act most injuriously on the quality of cast and malleable iron.
I shall now explain how I intend to operate so as to effect the complete
fluxing of the above slags or cinders, and thus prevent the silica, sulphur, and
phosphorus arriving in contact with the cast iron which is being produced.
The first process consists in reducing the above puddling, refinery, and heating
furnace slags or cinders into coarse powder, which I do by any of the ordinary
mills and grinding apparatus now in common use, and then adding to them
about one-half their weight of slacked lime made into a thick paste. They are
then well mixed together, and the mass is made into lumps or bricks of a con-
venient size, which are dried or not, according to circumstances, previously to
adding them at the top of the blast furnace; or the dried lumps of lime and
slag or cinders may be calcined in a separate furnace, and afterwards intro-
duced with ordinary mine at the top of the blast furnace; or the mass of lime
and slag may be mixed with coal, coke, or charcoal, and calcined in a furnace,
or introduced into crucibles, and thus separate the iron which it contains pre-
viously to its addition on the blast furnace. I may here state that heating
slags or cinders generally do not require roasting, but refinery and puddling
slags often do.
The second process consists in roasting or oxidizing the iron slags or
cinders before they are mixed with slacked lime. To oxidize these slags or g
cinders I adopt two different processes. To carry out the first of these pro-
cesses, I reduce the slags into fine powder and introduce it into an oxidizing
furnace, such as is used for roasting copper ores, such as sulphuret of copper,
and whilst the powder is carried to a dull red heat it is well stirred, so as to

page_text: transform the iron or the protoxide of iron it contains into peroxide, the silicum
into silica, the phosphurets into phosphates, and the sulphur into sulphurous
acid. When the powder has assumed a bright red color, and no more
sulphurous acid is produced, it is taken out of the furnace and mixed with
slacked lime, and applied as above described. I attain the same purpose
by breaking the slags or cinders into small fragments, and introducing them
with a small amount of coal into an ordinary kiln, or in one made of four
walls, which have numerous holes in the sides, the object of which is to admit
freely the
oxygen of the atmosphere, and which holes are also employed to
remove the oxidized slags or cinders. These kilns are worked like ordinary
lime kilns, namely, the slags or cinders mixed with a small quantity of coal
are constantly added at the top, whilst the oxidized slag or cinder is removed
at the bottom by the opening or openings which exist there, and then I treat
such prepared slags or cinders with slacked lime, as before described.
The third process to which I submit puddling, refinery, or heating slags or
cinders is to reduce them into a powder, and introduce them into furnaces
which communicate with the blast furnace by means of long flues, into which
are made to pass the volatile products given off' from the mouths of the blast
furnace or of the coke oven. When the powdered slags or cinders are not
sufficiently heated by the gases for these to act upon the component parts
of the slags or cinders, a gentle heat is applied, so as to carry them to a
dull red heat; then the silicates of protoxide of iron are decomposed, and
metallic iron produced. When the operation is completed they are taken
out and allowed to cool. Such reduced slags or cinders, having been made
into powder, are to be treated with slacked lime in manner before described.
And having now described the nature of my said Invention, and in what
manner the same is to be performed, I declare that I claim the use of hydrate
of lime or slacked lime in combination or intimately mixed with heating,
puddling, and refinery iron slags or cinders, both before and after calcining
the latter, in manner herein-before described.
In witness whereof, I, the said Frederick Crace Calvert, have hereunto
set my hand and seal, this Thirteenth day of February, One thousand
night hundred and fifty-five
F. CRACE CALVERT. (L.s.)