IMPROVE- MENTS IN REMOVING IMPURITIES, SUCH AS SULPHUR AND PHOSPHORUS, PROM IRON AND OTHER ORES AND FROM COAL
Year: 1868

page_text: LETTERS PATENT to Thomas Rowan, of Glasgow, in the County of
Lanark, North Britain, Chemist, for the Invention of "IMPROVE-
MENTS IN REMOVING IMPURITIES, SUCH AS SULPHUR AND PHOSPHORUS, PROM
IRON AND OTHER ORES AND FROM COAL."
Sealed the 28th July 1868, and dated the 30th January 1868.
PROVISIONAL SPECIFICATION left by the said Thomas Rowan at
the Office of the Commissioners of Patents, with his Petition, on
the 30th January 1868.
I, THOMAS ROWAN, of Glasgow, in the County of Lanark, North
Britain, Chemist, do hereby declare the nature of the said Invention
for "IMPROVEMENTS IN REMOVING IMPURITIES, SUCH AS SULPHUR AND PHOS-
PHORUS, FROM IRON AND OTHER ORES AND FROM COAL," to be as follows, that is
to say :-
This Invention has for its object by a preliminary treatment of iron
and other ores to remove such impurities as sulphur and phosphorus, and
to thereby render such ores more suitable for subsequent manufacturing

page_text: processes. The Invention may also be applied for purifying coal so
as to render it or the coke formed from it more suitable for various
purposes.
The Invention consists in adding common salt or other chloride or
chlorides to the ore or coal, and then calcining or coking it, after which
the impurities are washed out with water in the form of soluble salts.
Fluorides, bromides, or iodides may be substituted for the chlorides, but
common salt (chloride of sodium) is to be preferred on account of its
lower cost. The proportion of chloride will depend upon the quantity
of the impurities existing in the ore or coal, but it should be in excess,
and with ores containing much phosphorus and little sulphur it may be
necessary to add sulphur along with the chloride, whilst it may in some
cases be advantageous to pass steam through the mass.
In carrying out the Invention the calcining or coking may be
conducted in the ordinary way, the salt being previously simply
sprinkled over or mixed with the raw ores or coal.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Thomas Rowan in the Great Seal Patent Office
on the 29th July 1868.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, THOMAS
ROWAN, of Glasgow, in the County of Lanark, North Britain, Chemist,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Thirtieth day of January, in the year
of our Lord One thousand eight hundred and sixty-eight, in the thirty-
first year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto me, the said Thomas Rowan, Her special licence that
I, the said Thomas Rowan, my executors, administrators, and assigns,
or such others as I, the said Thomas Rowan, my executors, adminis-
trators, 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 REMOVING

page_text: IMPURITIES, SUCH AS SULPHUR AND PHOSPHORUS, FROM IRON AND OTHER ORES AND
FROM COAL," upon the condition (amongst others) that I, the said Thomas
Rowan, 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 menths next
and immediately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Thomas Rowan, 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 in writing, that is to say :-
My said Invention has for its object by a preliminary treatment of iron
and other ores to remove such impurities as sulphur and phosphorus,
and to thereby render such ores more suitable for subsequent manu-
facturing processes. My Invention may also be applied for purifying
coal so as to render it or the coke formed from it more suitable for
various purposes.
My Invention consists in adding common salt or other chloride or
chlorides to the ore or coal, and after calcining or coking it washing out
the impurities with water in the form of soluble salts. Fluorides,
bromides, or iodides may be substituted for the chlorides, but common
salt (chloride of sodium) is to be preferred on account of its lower cost.
And in order that my said Invention and the manner of performing
the same may be clearly understood I now proceed to describe some
convenient arrangements for calcining ore with the addition of chlorides
for the purposes of purifying them.
In purifying iron ores which contain both sulphur and phosphorus
(such as the argillaceous orcs of the Cleveland district) it is only
necessary in some instances to add a proportion of salt (in the solid
form) to the mixture of ore and fuel previously to or during its erection
into a calcining heap or its being filled into a kiln. It will however
be found more suitable to arrange the calcining heap or kiln in com-
munication with a chimney by means of a flue so as to induce a draught
throughout the materials, and thereby assist the chemical action. A
series of rectangular chambers may, for example, be erected on both
sides of a main flue which leads to a chimney, each chamber having an

page_text: opening communicating with this flue. The side walls may be per-
manent, and the end walls farthest from the flue temporarily built up
previously to filling in so as to allow of being easily taken down for the
removal of the calcined ore from that point. The ore fuel (and salt if
it is thought advisable to add any in the solid form) may be tipped in
from trucks running. on rails across the tops of the chambers. With
this form of kiln it is unnecessary to break the pieces of ore on the
surfaces small, or to cover the surfaces with coal, slack, or the like, as is
usual in some heaps, and it also affords facilitics for carrying out my
improved process which will be readily understood. The kiln being fired
from the top, and the chlorides in the liquid form added as is herein-
after described. Otherwise a large calcining heap may be constructed,
by preference of a rectangular form (the length being considerably greater
than the width), having a main channel or flue running along the ground
or floor of the heap in the centre of it, and throughout its entire length,
and having other channels or flues leading into this main one, which is
led at one end into a chimney. The heap being built to the required
height (containing the proper admixture of ore and fuel, and if thought
advisable a quantity of salt throughout the heap), the surface may be
covered with coal slack or other suitable material to exclude as much
air as possible from all parts except the end farthest from the chimney,
at which point the heap is ignited, the chimney and flucs then inducing
a draught throughout the length of the heap, and carrying the cal-
cination in that direction. When calcination has fairly commenced, and
the materials of the kiln or heap have acquired a red heat for about six
feet from the part ignited I pump a solution of salt (or a supply of sea
water if at hand) upon that part, taking care to spread the water in
small streams or in spray. The solution should be a saturated one by
preference, and the addition of the salt water should be regulated so as
not to interfere with the progress of the calcination, the jets following as
calcination proceeds. The total quantity of chloride is to be pro-
portioned to the per-centage of impurities existing in the ore, and should
be in excess of the combining equivalents. The quantity of chlorido
will be most conveniently determined in practice by treating trial
quantities of the ore with different proportions, and by testing them
after treatment to ascertain how far the impurities have been eliminated.
The water in contact with the heated ore passes into steam, which
acting upon the sulphur produces sulphuretted hydrogen and other

page_text: products, while the salt in contact with the sulphur and steam (which
is always present, being produced by combustion even when not added
artificially) is decomposed, chlorine gas, hydrochloric acid, and soluble
and volatile chlorides (amongst other products) resulting. The phosphates
contained in the ore are decomposed by the gases, and chlorides of
phosphorus are formed which are readily removed by water. The
sulphur for the most part becomes sulphate of soda, which is also
soluble. In other cases salt may be mixed with the ore in the heaps
or kilns, and steam passed through the mass during the process of
calcination. In all cases I remove the resulting soluble products by
washing. This may be done in any convenient way, and it is immaterial
whether fresh or salt water be used. If the ore contains only sulphur
and no phosphorus, calcination with steam alone and without the
addition of chlorides may be resorted to, but the addition of salt assists
the purification from sulphur (besides fixing the sulphur so that it does
not pass off in the form of offensive gases), and therefore improves the
quality of the calcined ore.
In practising my Invention for purifying coal or for obtaining a
purified coke therefrom the salt or other chloride will generally be
most conveniently applied in the solid form, and in general it will
not be convenient to pass steam through the materials; at the same
time my Invention may be carried out by using solutions of chlorides
or steam along with solid chlorides if under any circumstances it should
be found convenient to do so. The salt may be roughly mixed with
the coals in any convenient way previously to their being coked,
the coking operation being conducted according to any existing system.
It is already customary to use water for cooling the coke, but in
practising my Invention the quantity of water employed must be
increased to what is in practice found to be sufficient for washing out
the impurities rendered soluble by the action of the salt in the coking
process. As in the case of the ores the salt should be in excess of
the chemical equivalents corresponding to the per-centage of impurities
existing in the coal.
Having thus particularly described my said Invention, and the
manner in which the same is to be performed, I have to state that
I do not restrict myself to the precise details herein-before referred
to, but that what I believe to be novel and original, and claim as
the Invention secured to me by the herein-before in part recited

page_text: Letters Patent is, the removing of such impurities as sulphur and
phosphorus from iron and other ores and from coal by washing them
out after converting them into soluble salts by means of chlorides,
fluorides, bromides, or iodides, substantially as herein-before described.
In witness whereof, I, the said Thomas Rowan, have hereunto set i
my hand and scal, this Twenty-seventh day of July, in the year
of our Lord One thousand eight hundred and sixty-eight.
Witness,
EDMUND HUNT,
Patent Agent,
Glasgow.
THOMAS ROWAN. (L.S.)