IMPROVE- MENTS IN THE TREATING AND SMELTING OF IRON ORES, AND IN OBTAINING PRODUCTS THEREFROM
Year: 1857

page_text: LETTERS PATENT to Henry Bessemer, of Queen Street Place, New
Cannon Street, in the City of London, for the Invention of "IMPROVE-
MENTS IN THE TREATING AND SMELTING OF IRON ORES, AND IN OBTAINING
PRODUCTS THEREFROM."
Sealed the 16th April 1858, and dated the 13th November 1857.
PROVISIONAL SPECIFICATION left by the said Henry Bessemer at the
Office of the Commissioners of Patents, with his Petition, on the
13th November 1857.
I, HENRY BESSEMER, of Queen Street Place, New Cannon Street, in the
City of London, do hereby declare the nature of the Invention for "IMPROVE-
MENTS IN THE TREATING AND SMELTING OF IRON ORES, AND IN OBTAINING PRODUCTS
THEREFROM," to be as follows:-
The various ores of iron used for smelting in Great Britain are composed
of several elemental substances combined with iron in different proportions,
and I have found on examination that the greater part of them contain
phosphate of lime, phosphoric acid, or phosphorous in some other state of
combination, and in such quantity as greatly to influence the quality of the
crude metal obtained therefrom. I have also found that phosphorous, when

page_text: combined with metallic iron in the form in which it exists in crude or pig
iron, is extremely difficult to remove in the after processes to which such
crude metal is subjected in order to convert it into malleable iron or steel.
Now, the object of my present Invention is the separation or removal from
the ores of iron of phosphate of lime, phosphoric acid, or phosphorous in any
of its various combinations that are soluble in acid prior to the smelting
thereof. For this purpose I take the ore in its raw or natural state, or after
it has been roasted in the usual manner, or after it has been calcined or
treated according to the mothods in part described in the Provisional Speci-
fication of a Patent for "Improvements in Treating and Smelting the Ores of
Iron," registered by me on the 5th day of November 1857. The ore may be
reduced to lumps of a suitable size, or it may be stamped or crushed into
powder by such means as are now generally employed in the stamping or
crushing of other metallic ores. In either case the ore is to be put into large
vessels or tanks, into which is also put as much dilute muriatic or other acid
as will be necessary to dissolve or take up the phosphate of lime or other
combined phosphorous. To facilitate the desired chemical action the materials
may be agitated by any suitable apparatus, or steam may be blown in for that
purpose, as well as for heating the materials in the tanks or vessels, if desired;
and after a lapse of one or more days, or such time as-is found necessary, the
matters may be allowed to subside and the acid liquor be drawn off, after
which the ore is to be well washed with fresh water, with or without steam.
Any remaining trace of acid may be neutralized, if desired, by the addition
of an alkali or alkaline earth. The acid liquor may be then treated in another
vessel with powdered lime or other matter capable of precipitating phosphoric
acid, and which may be employed as manure, or for the manufacture of
phosphorus, or for other useful purposes, while the acid liquor first drawn
off may be mixed with a fresh portion of a like acid solution, and be again
employed on other portions of ore.
For the purpose of smelting any ores of iron so treated, I use desulphurized
coal, coke, or artificial fuel that has been separated from pyrites and other
impurities, by washing such pulverized coal after the manner employed to
separate tin ores in the running buddle or rotating buddle, or by any other
suitable means that are already known or practised.
In some cases I prefer to combine the washed or purified coal powder with
as much pulverized ore (that as been treated by acid, as before described,) as
may be necessary to hold or cement the combined matters together by the
process of coking, and I also add to such compound of coal and ore, or mixed
ores, as much lime, clay, silica, chloride of sodium, oxide of manganese,

page_text: alkaline salts, or other matters or fluxes as are already known or as have
before been used in the manufacture or smelting of iron, as the peculiar
nature and constituents of the ore or mixed ores may render desirable for the
economical fusion or for the purification thereof. The purified or washed
coal may be used in sufficient quantity for the complete smelting of the ore,
or the addition of other portions of washed or purified fuel may be made in
the smelting process, which may be carried on in a blast furnace as usual.
And so in like manner, when ore treated as above described with acid, and is
not combined with coal to form coke, the ore may be used in the usual manner
with purified coke or coal in a blast furnace, hot or cold blasts being used in
either case as may be found most desirable.
The crude metal obtained by smelting the ores of iron so treated as above,
or treated in combination with a process provisionally registered as aforesaid,
may be used for all the various purposes of founding in iron, or may be
converted into malleable iron or steel by any of the various methods of
decarbonizing or partially decarbonizing crude metal already known and
practised. But such iron will be especially suitable for and is intended to
be used for the direct production of malleable iron and steel, by the forcing
of air, steam, or, other gaseous or solid matters into or on to such crude
metal, and thereby rendering the same malleable whilst still retaining the
fluid state.