IMPROVEMENTS IN THE SMELTING AND MANUFACTURE OF, PIG IRON
Year: 1873

page_text: PROVISIONAL SPECIFICATION left by James Cane Coombe at the
Office of the Commissioners of Patents, with his Petition, on the
18th October 1873.
I, JAMES CANE COOMBE, of 18, Lesley Street, Barnsbury, in the
County of Middlesex, Chemist, do hereby declare the nature of the
said Invention, for." IMPROVEMENTS IN THE SMELTING AND MANUFACTURE OF,
PIG IRON," to be as follows:-
;
▸
These improvements consist in the use and employment of purified
or nearly pure materials for producing pig iron in the smelting furnace,
or in purifying such materials whilst in the smelting furnace. A good
pig is the foundation of, all successive operations, be the requirement
whatever it may, from wrought iron to steel of all qualities., Therefore.
my.
Invention consists in subjecting the raw materials, coke or ore, a
to such a purifying process that on withdrawal from the furnace or ;
clamp the sulphur, phosphorus, arsenic, silicon, and the like shall be
expelled, and to do this I make use of certain well-known materials,
namely, hydrochloric acid, chlorine, carbon highly subtilized, and nitro-
genized steam, water, and atmospheric air, that is to say, I subject
the ores to the action of water, and water-containing hydrochloric
F
:

page_text: acid in solution, and I likewise adopt the same agents in the purifi-
cation of the coke employed in the reduction of the ore and the
production of heat. I also select the purest limestone, chalk, or lime
procurable, but should the materials employed in the furnace be not
wholly free from objectionable constituents the blast of air that feeds
the furnace may be made to convey a mixture of carbonic acid gas,'
chlorine gas with some highly subtilized carbon or nitrogenized carbon
(in proportions herein-after to be recommended) right through, over
or into the heated mass till the remaining portions of the silicon,
sulphur, and phosphorus are removed.
To obtain a cheap and pure coke I employ water and hydrochloric
acid, which agents are made use of in the following way:-During
the process of cokeing from coal, and whilst the coke remains in a
heated state; sprinkle over or pass through the heated mass certain
quanties of water which of itself, as is well known, discharges large
amounts of sulphur and other impurities; -I then add to the water
a certain amount of hydrochloric acid, and treat the coke in the same
way again, which latter process completes the expulsion of the hostile
constituents.
.
'
:
As regards the ore it is desirable to roast it in some suitable furnace, a
kiln, or vessel, instead of clamping it, as is usually done; but should
it be found more convenient to resort to the open roasting process
or clamping, then I use the frequent distribution in the form of
sprinkling or otherwise of diluted hydrochloric acid, and especially
when it is at or above a red heat. I prefer however to roast the
ore in a kiln or other suitable furnace, and when all that is possible
of the volatile constituents have been driven off I pass through, over,
or into the heated ore the same constituents that were employed in the
purification of the coke.
As the object of this Invention is to ensure purity of result by
purity of materials no lime or limestone or flux are advantageously
available unless they are wholly or nearly free from obnoxious con-
stituents.
J
I also in certain cases (dependant on the composition of the ore
and its gangue) employ certain common fluxing and reducing materials, a
such as manganese, fluor spa, sal amononiac, and certain cyanogen
compounds in various stages and states of existence. These fluxes

page_text: and reducers may sometimes be introduced through the tuyeres (having
been previously rendered very subtil by pulverization) with the blast,
and with certain ores a very rapid and efficient reduction is accom-
plished.
I prefer a mixture of the carbonic acid gas with chlorine, herein-
before referred to, in the proportion of four to one of the former to
the latter, and this is found to answer well with ores containing
small per centages of silica; but where an ore contains above an
average amount of silica, I vary the proportions so that there shall
be a larger per centage of the chlorine, according to the dominancy
of the silica.
As regards the subtilized, as also the nitrogenous carbon, in my
experiments I have usually found that 14 pounds to a ton of ore will
be sufficient, but this must be considered subject to variation, according
to the quality of the ore.