PROVEMENTS IN TREATING IRON ORES
Year: 1857

page_text: "IM-
LETTERS PATENT to Henry Bessemer, of Queen Street Place, New
Cannon Street, in the City of London, for the Invention of
PROVEMENTS IN TREATING IRON ORES."
Sealed the 22nd January 1858, and dated the 5th November 1857.
PROVISIONAL SPECIFICATION left by the said Henry Bessemer at the
Office of the Commissioners of Patents, with his Petition, on the 5th
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 TREATING IRON ORES," to be as follows:-
This Invention consists, firstly, in roasting or calcining iron ores by the direct
action thereon of superheated steam or other highly heated gaseous matters in
close vessels or chambers, such ores being out of contact with and not heated by
any ignited fuel during such roasting process; for this purpose the ores of iron
are to be put into a close or nearly closed chamber or vessel, which may be so
constructed as to hold a certain charge of ore, which may be removed there-
from by a suitable door or opening after it has been operated upon in the
manner hereafter described; or the materials may be made to descend at
intervals or continuously through the said chamber or vessel, which may if
desired, be made to revolve on an axis, so as to equalize as near as may be the
heat and chemical action of the elements present in such chamber or vessel.
In whatever manner the said vessels or chambers are constructed, I introduce
therein superheated steam of a very high temperature, keeping it by preference
in such vessels under, considerable pressure. I also prefer to allow the ingress

page_text: or egress of such superheated steam to be made at opposite ends or sides of
the vessel or chamber alternately, so as to equalize the action of it on the ore,
and so that the temperature of such superheated steam shall be of itself
sufficient to roast or calcine the said ores of iron. At any time during the
calcining operation, hot, blast may be used, alone or mixed with the superheated
steam; the air or superheated steam may also, if desired, be passed over or
among coal or other carbonaceous matters before entering the calcining
chamber, should the ore be of such a nature as to require the pressure of gaseous
carbon in order to facilitate the removal of its impurities; the heated products
which escape from the roasting chamber, I prefer to pass through any suitable
heating apparatus, through which also other portions of steam or air are
allowed to pass from a steam boiler or from a blowing, machine, such air or
steam passing through other pipes or channels, so that the heat which would
otherwise be wanted may be usefully employed in heating fresh portions of
steam or air prior to the final and more complete heating thereof in any con-
venient form of hot blast apparatus; or the heated matters escaping from the
roasting chamber may be employed in a suitable tubular boiler for generating
steam to be afterwards employed in the process. In this roasting process,
chloride of lime, chloride or muriate of soda, chlorine gas, or the elements
necessary for the formation of chlorine gas, may be put into the vessel, or the
gas may be supplied by pipes to the roasting chamber, and so in like manner
any gaseous or solid matter that may be found to act beneficially on the ores
may be employed. I also in some cases employ a condenser, and by such
means am enabled to form a partial vacuum in the roasting chamber, in order
to facilitate the liberation of gaseous matters from and amongst the ore; and
when I desire to use any gas or chemical agent that is costly, I prefer to do
so after having made such partial vacuum, so that such chemical agent may be
in a less diluted state, and I prefer in such cases to entirely close the vessel or
chamber for such a period as I consider necessary for the said gaseous or other
matters to operate on the ore.
The second part of my said. Invention consists in saturating iron ores, roasted
as above described, with a solution of chloride of sodium or a solution containing
chlorine or chloride of lime, potash, or other alkaline salt, and the smelting of
the ores of iron so heated with desulphurized coke or coal in an ordinary blast
furnace.