IMPROVEMENTS IN THE MANUFACTURE OF IRON
Year: 1857

page_text: LETTERS PATENT to Sir Francis Charles Knowles, of Lovell Hill, in the
County of Berks, Baronet, for the Invention of "IMPROVEMENTS IN THE
MANUFACTURE OF IRON."
Sealed the 5th January 1858, and lated the 10th July 1857.
PROVISIONAL SPECIFICATION left by the said Sir Francis Charles
Knowles at the Office of the Commissioners of Patents, with his
Petition, on the 10th July 1857.
I, Sir FRANCIS CHARLES KNOWLES, of Lovell Hill, in the County of Berks,
Baronet, do hereby declare the nature of the said Invention for "IMPROVE-
MENTS IN THE MANUFACTURE OF IRON," to be as follows:-
My Invention consists, first, in the employment in the blast furnace of
kaolin, together with lime or magnesian lime (quick or stone), as a flux for
aiding in producing iron from the ore; and, secondly, in the employment in
the puddling furnace of kaolin, together with nitrate of soda, nitrate of lime,
or nitrate of potash, if desirable, for the purpose of purifying the iron. When
the nitrate of soda is used quicklime should be added.
In applying my Invention, the average amount of silica, sulphur, and
phosphorous which are usually present in the pig or smelted iron at any
particular works where the Invention is to be applied must first bo
ascertained; and then the quantity of nitrate to be used must be estimated,

page_text: a sufficient quantity being employed to oxidize these substances and the
carbon in the iron. The freed silica being known, and also the phosphoric
acid due to the phosphorous, the kaolin must be so estimated that its silica and
the freed silica shall be exactly neutralized by the alumina and the lime and
soda, and the surplus alumina suffice to take up the phosphoric acid. I
recommend that the metal be directly conveyed into the puddling from the
blast furnace to save fuel and time, but the ordinary process answers well,
particularly if sand moulds be avoided; and I employ either method or both
methods.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Sir Francis Charles Knowles in the Great Seal Patent
Office on the 8th January 1858.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, Sir FRANCIS
CHARLES KNOWLES, of Lovell Hill, in the County of Berks, Baronet, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Tenth day of July, in the year of our Lord One
thousand eight hundred and fifty-seven, in the twenty-first year of Her
reign, did, for Herself, Ier heirs and successors, give and grant unto me, the
said Sir Francis Charles Knowles, Her special licence that I, the said
Sir Francis Charles Knowles, my executors, administrators, and assigns,
or such others as I, the said Sir Francis Charles Knowles, my executors,
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 "IMPROVEMENTS IN THE MANUFACTURE OF IRON," upon
the condition (amongst others) that I, the said Sir Francis Charles Knowles,
my executors or administrators, by an instrument in writing under my, or
their, or one of their hands and seals, 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 immediately after the date
of the said Letters Patent.
NOW KNOW YE, that I, the said Sir Francis Charles Knowles, do
hereby declare the nature of my said Invention, and in what manner the same

page_text: is to be performed, to be particularly described and ascertained in and by the
following statement thereof, that is to say:-
My Invention consists, first, in the employment in the blast furnace of
kaolin, together with lime or magnesian lime (quick or stone), as a flux for
ailing in producing iron from the ore or cinders, or both; and, secondly, in
the employment in the puddling furnace of kaolin, together with nitrate of
soda, nitrate of lime, or nitrate of potash, if desirable, for the purpose of
purifying the iron. When the nitrate of soda or of potash is used, quicklimo
should be added.
In applying my Invention, the average amounts of silicon, sulphur, and
phosphorus which are usually present in the pig or smelted iron at any
particular works where the Invention is to be applied must first be ascertained,
and then the quantity of nitrate to be used must be estimated, a sufficient
quantity being employed to oxidize these substances and part at least of the
carbon in the iron. The freed silica being known, and also the phosphoric
acid due to the phosphorus, the kaolin must be so estimated that its silica and
the freed silica shall be exactly neutralized by the alumina (all but a small
surplus) therein and the lime and soda, so as to form a true silicate or glass,
and the small surplus alumina suffices to take up the phosphoric acid. I
recommend that the metal be directly conveyed into the puddling from the
blast furnace, if possible, to save fuel and time, but the ordinary process
answers well, particularly if sand moulds be avoided; and I employ either
method or both methods. The method, however, which I recommend in
preference to all is to remelt the pig iron in a cupola, using the same as far
as may be as a refinery, with appropriate detersive fluxes, and thence to
convey the hot metal as a charge into the puddling furnace, so that the heats
of the latter may succeed each other without losing the time and heat at
present lost while the metal is melting, and without the greater wear and
tear of the furnace itself from the alternations of temperature and tho
corresponding expansion and contraction of the masonry.
And having now described the naturo of my said Invention, and in what
manner the same is to be performed, I declare that I claim,-
First, the employment of kaolin as a flux, with quicklime or limestone in
the smelting of iron ores or cinders, or both, in the blast furnace, such lime
or limestone being either of the ordinary kind or derived from the dolomite
or magnesian limestone.
And, second, the employment of kaolin, nitrate of soda, or potash, or lime,
and lime, common or magnesian (the latter in preference where obtainable),

page_text: in proportions determinable, as above described, from the impurities present
in the pig iron or metal, and the composition of the nitrates and kaolin used.
I do not claim the use of kaolin and the nitrates and lime by intermixing
the same with iron as it flows from, or while in a transition state, from a
melting or remelting furnace of any kind, but solely in the puddling furnace
to purify and bring to nature the iron as soon as possible, to deprive it of its
liquid condition and to form it into blooms, as at present done in the ordinary
way of manufacture.
I do not preclude myself from using, in addition, other substances, if desirable,
for any special purpose in combination with the substances enumerated in the
preceding claims, but I claim the use of them whether alone or mixed with
any other ingredients the use of which is at present known and published.
In witness whereof, I, the said Sir Francis Charles Knowles, have
hereunto set my hand and seal, this Seventh day of January, One
thousand eight hundred and fifty-eight.
FRANCIS CHARLES KNOWLES.. (L.S.)