IMPROVEMENTS IN THE PRODUCTION OF IRON AND STEEL, AND OF OXIDE OF IRON
Year: 1871

page_text: LETTERS PATENT to Henry Larkin, of Theydon Gernon, in the
County of Essex, Andrew Leighton, of No. 16, South Castle Street,
Liverpool, in the County of Lancaster, and William White, of
No. 30, Thurlow Road, Hampstead, in the County of Middlesex, for
the Invention of "IMPROVEMENTS IN THE PRODUCTION OF IRON AND STEEL,
AND OF OXIDE OF IRON."
PROVISIONAL SPECIFICATION left by the said Henry Larkin, Andrew
Leighton, and William White at the Office of the Commissioners of
Patents, with their Petition, on the 8th June 1871.
We, HENRY LARKIN, of Theydon Gernon, in the County of Essex,
ANDREW LEIGHTON, of No. 16, South Castle Street, Liverpool, in thẹ
County of Lancaster, and WILLIAM WHITE, of No. 30, Thurlow Road,
Hampstead, in the County of Middlesex, do hereby declare the nature of
the said Invention for "IMPROVEMENTS IN THE PRODUCTION OF IRON AND STEEL,
AND OF OXIDE OF IRON," to be as follows:-
In the Specification of the Patent dated the 30th November 1870,
No. 3139, we have described arrangements for obtaining purified oxide
:
'

page_text: of iron by first dissolving crude iron or any suitable ore of that metal
in hydrochloric acid in order to convert the contained iron into ferrous
chloride, then purifying the same by subsidence and crystallisation, and
afterwards recovering the acid by the action of aqueous vapor on the
heated chloride.
In the Provisional Specification filed by us and dated the Twentieth
May, One thousand eight hundred and seventy-one, No. 1357, we have
also described a modification of this process, in which oxygen or atmo-
spheric air is substituted for the aqueous vapour with the production of
free chlorine instead of hydrochloric acid, in each case a purified oxide
of iron being the residue left by the operation.
In order to facilitate these operations we have devised the following
improvements in the methods of carrying them out:-In the first place
we obtain the solution of ferrous chloride by causing the aqueous
hydrochloric acid to pass upwards through a suitable vessel or vessels
containing the ore or metal to be dissolved. And in order to obtain the
solution as thoroughly saturated as possible, and at the same time to
obtain the maximum yield from any given material, we provide a series
of such vessels arranged as the vats in alkali works, so that the raw acid
may first pass through the vessel containing the nearly exhausted
material, and after passing through any convenient number of inter-
mediate vessels at last issue from one containing an altogether, fresh
charge.
Having thus obtained a solution of ferrous chloride, we in some cases
before proceeding to crystallise the same precipitate such extraneous
substances as would be of sufficient value to pay the cost of such
recovery, or would be deleterious even in minute quantities to the iron or
steel ultimately produced. Thus, if copper be contained in the solution
we precipitate it in the metallic state in the usual way by means of scrap
iron, if phosphorus we precipitate it as ferrio phosphate, which may be
done by the addition of ferric chloride and a suitable acetate, and if
arsenic we precipitate it as ferric arsenate by the addition of ferric
chloride, and then heating the solution, or hydro-sulphuric acid may be
passed through the solution to precipitate the arsenic as sulphide. We
then proceed to crystallise rapidly by means of a long evaporating tank
similar to that used in crystallising common salt, but in addition to
having a fire below one end of the tank for the purpose of boiling off
the superfluous water, we provide at the other end, which is made

page_text: shallower and considerably wider than the heated end, an arrangement
for increasing the rapidity of cooling, such as jets of cold water or a
blast of cold air beating against its under surface. We also provide
a horizontal diaphragm passing through the tank to enable us to secure
a continuous circulation of the contained liquor from the heated end to
the cool, and from the cool end to the heated.
By this arrangement we cause a continual flow of the hot saturated
solution towards the cool end of the tank, where as it becomes cooled
down it deposits crystals in consequence of the chloride being less
soluble in cold than in hot water, after which it passes downwards to
the hot end to be again concentrated by boiling, when it again passes
on to deposit a fresh crop of crystals, and so on in continual succession.
The crystals are continually raked out as they form by means of a
scraper into a vessel provided to receive them. After the ferrous
chloride has thus been sufficiently crystallised out, the molten liquor,
should it contain any other ingredients of commercial value, may be
treated by any known methods for their recovery.
In order to facilitate the decomposition of the ferrous chloride and
recovery of the chlorine, either as free chlorine or as hydrochloric acid,
we first dry it and reduce it to powder, and then cause it to fall through
a scattering furnace similar to that described in the Provisional Specifi-
cation of a Patent dated Twentieth May, One thousand eight hundred
and seventy-one, No. 1357, for the manufacture of bleaching powder,
in which furnace it is met by a highly heated current of steam of
oxygen or atmospheric air, or of hydrogen. When steam is thus used
we obtain hydrochloric acid and oxide of iron; when oxygen or atmo-
spheric air is used we obtain free chlorine and oxide of iron, and when
hydrogen is used we obtain hydrochloric acid and metallic iron; or
we recover the hydrochloric acid by mixing the chloride with rotted
peat, wood sawdust, or other suitable deoxydizing substance and a
sufficient quantity of water, and place them in a retort or suitably
constructed furnace, in which the mixture is brought as rapidly as
possible to a low red heat, by which means the hydrochloric acid is
driven off to be collected and again used, leaving a residue of oxide
of iron and carbon, which residue may then be raised to a sufficient
heat to reduce the oxide to a pasty metallic condition, when it may
be cooled down and removed. Any excess of carbon which may bo
contained in the metal obtained by this or by other similar method

page_text: -
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Henry Larkin, Andrew Leighton, and William
White, in the Great Seal Patent Office on the 8th December 1871.
TO ALL TO WHOM THESE PRESENTS SHALL COME, we, HENRY
LARKIN, of Theydon Gernon, in the County of Essex, ANDREW
LEIGHTON, of No. 16, South Castle Street, Liverpool, in the County of
Lancaster, and WILLIAM WHITE, of No. 30, Thurlow Road, Hampstead,
in the County of Middlesex, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her;
Letters Patent, bearing date the Eighth day of June, in the year of
Our Lord One thousand eight hundred and seventy-one, in the thirty-.
fourth year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto us, the said Henry Larkin, Andrew Leighton, and
William White, Her special license that we, the said Henry Larkin,
Andrew Leighton, and William White, our executors, administrators,
and assigns, or such others as we, the said Henry Larkin, Andrew
Leighton, and William White, our 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 PRODUCTION
OF IRON AND STEEL, AND OF OXIDE OF IRON," upon the condition (amongst
others) that we, the said Henry Larkin, Andrew Leighton, and William
White, our executors or administrators, by an instrument in writing
under our or their hands and seals, or under the hand and seal of one
of us or them, should particularly describe and ascertain the nature
of the said Invention, and in what manner the same was to be por-
formed, 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 we, the said Henry Larkin, Andrew Leighton,
and William White do hereby declame the
..
10

page_text: and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement thereof,
that is to say :-
In the Specification of the Patent, dated the Thirtieth of November
1870, No. 3139, we have described arrangements for obtaining purified
oxide of iron by first dissolving crude iron or any suitable ore of that
metal in hydrochloric acid in order to convert the contained iron into
ferrous chloride, then purifying the same by subsidence and crystal-
lization, and afterwards recovering the acid by the action of aqueous
vapour on the heated chloride.
In order to facilitate these operations we have devised the following
improvements in the method of carrying them out:-In the first place
we obtain the solution of ferrous chloride by causing the aqueous
hydrochloric acid to pass upwards (by an arrangement herein-after
described) through a suitable vessel or vessels containing the ore or
metal to be dissolved. The acid solution thus obtained is then slowly
boiled in a cast-iron or other suitable vessel with scrap or other iron,
as long as hydrogen continues to be evolved. This operation has the
effect not only of neutralizing the excess of acid, but also of reducing
the whole or nearly the whole of any ferric chloride contained in the
solution into ferrous chloride, besides precipitating the copper, if any
should be contained therein.
Having thus obtained a solution of ferrous chloride we convey the
same into a settling tank or tanks, which may be constructed of wood;
where, when necessary or desirable, we precipitate such extraneous sub-
stances as would be of sufficient value to pay the cost of such recovery,
or would be deleterious even in minute quantities to the iron or steel
ultimately produced. Thus, if phosphorus exist therein we precipitate
it from the neutralized solution as ferric phosphate by the addition of
ferric chloride and any suitable acetate, as acetate of sodium; if
sulphur we precipitate it as sulphate by adding the chlorides of calcium
and of barium, the details of all which operations are well known and
commonly practised by chemists. We then allow the solution thus
treated, according to the nature of the extraneous substances it may
contain, to remain in the settling tanks until the precipitates formed,
with all other substances held in mechanical suspension, have sufficiently
subsided, when the clear liquor is drawn off into an evaporating tank.

page_text: which may
be made of iron, and in which the superfluous water may.
be rapidly boiled off.
In order to facilitate this operation we provide a long shallow tank
similar to those used in crystallizing common salt. When the boiling
liquor has been sufficiently concentrated, which may be known by its 5
beginning to crystallize on its surface, it is run off into a crystallizing
tank, in which it is allowed gradually to cool. As the liquor cools it
deposits well formed crystals, which may be readily removed. The
mother liquor is then again concentrated by boiling, and a further
crop of crystals obtained. After the ferrous chloride has thus been 1
sufficiently crystallized out, the mother liquor, should it contain any
other ingredients of commercial value, may be treated by any known
methods for their recovery. In some cases, however, in which the
solution is already sufficiently purified, this process of crystallization.
may be dispensed with.
In order to facilitate the decomposition of the ferrous chloride and
recovery of the chlorine, either as free chlorine or as hydrochloric acid,.
we first dry it and reduce it to powder, and then cause it to fall
through a scattering furnace similar to the scattering chamber described
in the Specification of the Patent dated 20th May 1871, No. 1357, :
for the manufacture of bleaching powder, in which furnace it is met by
a highly heated current of steam of oxygen or atmospheric air or of
hydrogen. When steam is thus used we obtain hydrochloric acid and
oxide of iron; when oxygen or atmospheric air is used we obtain free
chlorine and oxide of iron, and when hydrogen is used we obtain ?
hydrochloric acid and metallic iron; or we recover the hydrochloric
acid and obtain metallic iron or steel by mixing the aqueous crystals
or any sufficiently purified solution of the chloride with broken or
powdered peat, or wood sawdust, or other suitable hydro-carbonaceous
substance, and place them in a retort similar to an ordinary gas retort,.
in which the mixture is brought as rapidly as convenient to a low red
heat. By this means hydrogen from the peat or wood sawdust and
from the water mingled with the chloride is made to unite with the
chlorine to form hydrochloric acid, which is conveyed from the retort
and collected in the usual manner by means of an ordinary condensing
tower, leaving a residue consisting chiefly of iron, oxide of iron, and
carbon intimately mingled. The proportion of hydro-carbonaceous
matter mixed with the chloride may vary considerably, but it is desirable
]

page_text: that it should not greatly exceed what would be sufficient to absorb
the water of crystallization given out on heating the crystals or that
contained in the solution used. When the acid has thus been removed
we cause atmospheric air to pass slowly through the retort, which is still
kept at a red heat. This is continued until the residual carbon is
sufficiently burnt out, which may be roughly known by carbonic oxide
ceasing to be evolved. And we prefer stopping the operation at such
point as to leave a small excess of carbon. When the carbonic oxide.
ceases or nearly ceases to be evolved the contents of the retort are
carefully raked into a closed pit or chamber connected with the retort,
in which pit it is allowed to cool without access of atmospheric air.
When the whole mass is sufficiently cooled it is taken out, crushed into.
a fine powder, and thoroughly mixed. A portion of the material is then
taken and tested to ascertain if there is an excess of carbon.
If the proportions of iron, oxide of iron, and carbon are found to be
correct to produce steel of the required hardness it will only be necessary:
to mix with the powdered material a sufficient quantity of any suitable
flux to dissolve out the ash left by the charcoal, and either melt the
whole down in crucibles similar to those used in the production of cast:
steel, or else heat it in a deoxydized furnace to a high welding heat,.and
then hammer or compress it by the usual well known methods. If an
excess of carbon be found on testing it may be removed by adding an
equivalent proportion of oxide of iron or any other suitable oxydizing
material. In a similar manner iron free from carbon may be obtained
if desired.
.
When the ore to be operated on contains a valuable per-centage of
copper in a readily soluble condition, as in the case of roasted or burnt'
cupreous pyrites, we first dissolve out the copper with a weak solution
of acid (say about one measure of ordinary commercial acid to four
of water, which has little or no action on the iron), and then dissolve.
the iron by means of a strong undiluted solution. In both cases we
prefer to act on the ore by an upward percolation of the acid, and for
this purpose we use an arrangement of tanks and apparatus of which
Figure 1 in the accompanying Drawing shews an elevation, and
Figure 2 a plan.
.
a and a¹ are two strong wooden frames supported by the uprights 6;
c, c, are a series of twelve tanks or tubs for holding the crushed ore for.
the purpose of dissolving out the iron, and c¹, c¹, a series of six similar:

page_text: tanks or tubs for dissolving out the copper. The aqueous acid flows
in the one case through the supply tube d, and in the other through
the supply tube d¹. From the supply tubes it flows into perpen-
dicular tubes e and e¹, which may be made of ordinary stoneware,
and which pass down through the ore and through the perforated
bottoms and f³, and then percolates upwards through the crushed
ore, thereby loosening and gently agitating the whole mass. By this
means the necessity of continual stirring is obviated. As the acid more
or less charged with metal rises to the surface it runs off through the
inclined tubes g and g¹ (which may be made of prepared caoutchouc)
into the next tank or tub, where it takes up a further quantity of
metal, and so on until it has passed through the whole series, and
is discharged through the exit tubes hand h³ in a highly concentrated
condition into large receiving tanks to be provided for the purpose.
When the acid is observed to flow from the first tank c as free from
metal as it entered, thereby proving that all the available metal is
dissolved out, the remaining acid is drawn off and the tank removed
to be emptied of the insoluble residue and replenished with a fresh
supply of ore. When the first tank c has thus been removed the
whole series is moved upwards by means of the endless chain i until
the second tank takes its place, leaving a vacancy at the lower end of
the series. The same explanation applies to the diluted acid passing
through the tanks c¹ for the solution of the copper. When the copper
has been dissolved out of the first or upper tank c¹ the weak acid is
drained off, and the tank still containing the iron ore is lifted across
to fill the vacancy occasioned, as described at the lower end of the
series c, c. The remaining five tanks c³, c², are then moved upwards by
means of the endless chain 2, leaving a vacancy at the lower end of the
copper series, which vacancy is then supplied by a tank containing an
altogether fresh charge of ore. By this arrangement the raw acid in
both the iron and the copper series is always made to pass first through
the tank containing the almost exhausted material, and after passing
through any sufficient number of intermediate tanks to issue at last
from one containing the richest or least exhausted material. The tanks
or tubs c, c, and c¹, c', are placed upon moveable carriages / and k¹,
which rest upon the cross rods 7 and P. To these rods are fitted a series
of bearing rollers m and m³, which bear and roll on the inclined planes n
and n², which pass the whole length of the wooden frames a and a¹.
There are also ratchet catches o and o¹ to prevent the tanks from

page_text: slipping downwards; p and p' are clutches fixed to the revolving shaft q,
and working into the square drums or pulleys r, by which the drums
and by them the endless chains i and it may be moved or stopped at
pleasure.
Having thus described the nature of our said Invention, and the
manner of performing the same, we would have it understood that we
claim as our improvements in the manufacture of iron and steel and
oxide of iron,—,
1. The method of and apparatus for dissolving iron or iron ore in
hydrochloric acid so as to obtain a chloride from which metallic iron or
steel is obtained, substantially as described.
2. The treatment of the liquor obtained by dissolving iron or iron
ore in hydrochloric acid by boiling it with metallic iron so as to obtain
a neutralized solution of ferrous chloride free from ferric chloride,
from which solution metallic iron or steel is obtained, substantially as
described.
3. The purification of such ferrous chloride solution by the precipi-
tation of the phosphorus which it may contain, and the production
of iron or steel from such purified solution by means substantially as
described.
4. The treatment of the ferrous chloride by heating it with peat or
other hydro-carbonaceous substance, so that hydrochloric acid is driven
off and recovered for re-use, whilst the ferrous chloride is decomposed
and prepared for the production of iron and steel therefrom by means
substantially as described.
5. The production of iron and steel by means substantially as described.
In witness whereof, we, the said Henry Larkin, Andrew Leighton,
and William White, have hereunto set our hands and seals, this
Seventh day of December, in the year of our Lord One thousand
eight hundred and seventy-one.
HENRY LARKIN.
(L.S.)
ANDREW LEIGHTON. (L.S.)
WILLIAM WHITE.
(L.S.)