IMPROVEMENTS IN OBTAINING IRON AND STEEL FROM CERTAIN ORES AND RESIDUAL PRODUCTS."
Year: 1862

page_text: LETTERS PATENT to William Henderson, of St. Rollox, in the City of
Glasgow, Chemist, for the Invention of "IMPROVEMENTS IN OBTAINING IRON
AND STEEL FROM CERTAIN ORES AND RESIDUAL PRODUCTS."
PROVISIONAL SPECIFICATION left by the said William Henderson at
the Office of the Commissioners of. Patents, with his Petition, on the
24th December 1862..
I, WILLIAM HENDERSON, of St. Rollox, in the City of Glasgow, Chemist,
do hereby declare the nature of the said Invention of "IMPROVEMENTS IN
OBTAINING IRON AND STEEL FROM CERTAIN ORES AND RESIDUAL PRODUCTS," to be
as follows:-
When.
In the manufacture of sulphuric acid from iron pyrites, the residue, consisting.
principally of oxides of iron, still contains from 3 to 9 per cent. of sulphur, and
cannot therefore be used with advantage for the manufacture of iron.
copper pyrites, or iron pyrites containing copper, are used for this manufacture
the residue contains copper besides a certain proportion of sulphur, which
renders it still more unfit for the manufacture of iron. By the process for
sulphuret copper ores, described in the Specification of my Patent, dated
20th December 1859, No. 2900, practically all the copper and sulphur are
extracted from these cupreous burnt ores, and a very pure oxide of iron or
uxides of iron remains as a residue. When found desirable iron pyrites

page_text: residues containing no copper may be treated in the same manner, and a very
pure oxide or mixture of oxides of iron will be the result if the pyrites have
been originally rich in sulphur. These residues, after treatment by my process
for the extraction of copper, are in a very fine state of division, and cannot be
used advantageously in a blast furnace for the production of cast iron. They
produce little or no slag, and pass rapidly through the furnace not properly
reduced, or choke the furnace, or are blown away by the blast.
These improvements relate, first, to a means of producing cast iron from
these residues, or a mixture of these residues with other. ores.
Second. To a method of obtaining steel from these residues, or a mixture of
these residues with other ores or other substances.
Third. To a method of obtaining malleable iron from these residues, or these,
residues mixed with other ores.
Fourth. To a method or methods of obtaining other qualities and compounds
of iron from these residues, either by themselves or by mixing with other ores
and other substances.
I proceed as follows:-To produce cast iron equal to best hematite pig.
I mix the residual oxides with from 25 to 30 per cent. of coal of a bituminous
quality, as free as possible from sulphur. and ash, 3 per cent. common salt,
3 per cent. lime, or 6 per cent, carbonate of lime, all in fine powder. These
substances are intimately incorporated with -the oxides of iron and fused in a
reverberatory furnace. If anthracite coal or coke is used, which will produce
a better iron, 22 to 25 per cent. will be sufficient, but an excess of carbona
ceous matter, when pig iron or other castings are to be produced, is always
advantageous and desirable. Charcoal in coarse powder may be substituted
for the coal or coke and will produce a better quality of iron. To produce
steel direct from these residual oxides of iron I use the same mixtures as
above described, preferring to use charcoal reduced to a coarse powder, but
only to the extent of from 19, to 22 per cent. by weight of the dry residues,
and with the addition of 2 to 5 per cent. of pure peroxide of manganese.
When intimately mixed the whole is charged into a reverberatory furnace
and melted as rapidly as possible in a reducing flame. To produce wrought
or malleable iron direct from these residues I mix them with from 16 to 25
per cent. of bituminous coal, with or without the fluxes mentioned above, and
charge them into a reverberatory furnace consisting of a balling or puddling
hearth and a long sloping bed or table having a hopper fixed at the top or
colder end. The mixture is charged into this hopper and is gradually moved
towards the flame bed of the balling hearth, the hopper is kept constantly
filled, and so is the back part of the furnace. The table or floor of this

page_text: extended furnace should be placed on such a slope as will ensure the mixture
descending to the furnace bed of its own accord, and be sufficiently capacious
to contain as much ore as will supply the furnace bed with a constant supply
of reduced ore and as fast as it can be worked up. The ore as it descends
against the flame is steadily reduced to a spongy mass and is withdrawn from
the furnace and rolled or hammered in the usual manner. Other compounds
of iron can easily be produced by mixing oxides or salts of manganese with
the ore and reducing agent, or other oxides or salts of other metals may be
reduced and combined with the iron or steel if desired. In localities where
blackband or other carbonaceous ore can be obtained, and if sufficiently free
from carthy impurities, they may be employed either wholly or in part as a
substitute for the coal, coke, or charcoal, due regard being paid to the proper
proportions. I take, for example, a blackband ore containing 25. per cent. of
carbonaceous matter and 40 per cent. of iron. To reduce the iron in this ore
from the state of protoxide to a metallic state only 10 to 12 per cent. of the
carbonaceous matter will be consumed, leaving 13 to 15 per cent. free. A
mixture, therefore, of ore of the above composition reduced to fine powder
in the proportion of two of blackband to one of the residues will produce
cast iron.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said William Henderson in the Great Seal Patent Office on
the 24th June 1863.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
HENDERSON, of Saint Rollox, in the City of Glasgow, Chemist, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters.
Patent, bearing date the Twenty-fourth day of December, in the year of our
Lord One thousand eight hundred and sixty-two, in the twenty-sixth year of
Her reign, did, for Herself, Her heirs and successors, give and grant unto
me, the said William Henderson, Her special licence that I, the said
William Henderson, my executors, administrators, and assigns, or such
others as I, the said William Henderson, my 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 Chaunel Islands, and Isle of Man, an Invention for

page_text: "IMPROVEMENTS IN OBTAINING IRON AND STEEL PROM CERTAIN ORES AND RESIDUAL
PRODUCTS," upon the condition (amongst others) that I, the said William
Henderson, 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
wás to be performed, 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 I, the said William Henderson, 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 thereof, that is to say :-
In the manufacture of sulphuric acid from iron pyrites, the residue, con-
sisting principally of oxides of iron, still contains from 3 to 9 per cent. of
sulphur, and cannot therefore be used with advantage for the manufacture of
iron. When copper pyrites, or iron pyrites containing copper, are used for.
this manufacture, the residue contains copper, besides a certain proportion of
sulphur, which renders it still more unfit for the manufacture of iron. By
treating burnt copper pyrites by the process for 'sulphuret copper ores, described
in the Specification of my Patent, dated 20th December 1859, No. 2900, prac-
tically all the copper and sulphur are extracted and a very pure oxide or
mixture of various oxides of iron remains as a residue. When found desirable
iron pyrites residues containing no copper may be treated in the same manner,
and a very pure oxide or mixture of oxides of iron will be the result if the
pyrites have been originally rich in sulphur. These residues, after treatment
by my process for the extraction of copper, are in a very fine state of division
and cannot be used advantageously in a blast furnace for the production of
cast iron; they produce little or no slag, and pass rapidly through the furnace
not properly reduced, choke the furnace, or are blown away by the blast.
My present Invention relates, first, to means of producing cast iron from
these residues, or a mixture of these residues with other ores.
Second. To a method or methods of obtaining steel from these residues, or a
mixture of these residues with other ores or other substances.
Third. To a method of obtaining malleable iron from these residues, or a
mixture of these residues with other ores.
Fourth. To a method or methods of obtaining other qualities or compounds
of iron from these residues, either mixed with other substances alone, or in
conjunction with other ores.
I proceed as follows:-To produce cast iron equal to best hematite pig, I

page_text: mix the residual oxides with 25 to 30 per cent. of bituminous coal, which
must be quite free from sulphur, and contain as small a proportion of ash as
can be obtained, also 3 per cent. of common salt, chloride of calcium, chloride
of manganese, or chloride of iron, and 3 per cent. of quicklime, all in fine
powder, intimately mixed and incorporated together. I prefer to grind and
mix them in a mortar mill, moistening with water, and make them into balls
or mould them into bricks, dry them thoroughly, and then charge them into a
reverberatory furnace with a bright red heat maintained for 3 or 4 hours and
an intense white heat afterwards till all is fused, when the metal is tapped into
sand and the furnace charged again. If anthracite coal or ground coke is
used, which will generally produce a better iron, 22 to 25 per cent. will be
sufficient. Charcoal in coarse powder may be used in the proportion of 20
to 22 per cent., and a still better quality of iron will be the result. In all
cases where pig iron or other castings are to be produced it is always better
to have an excess of carbonaceous matter. To produce steel direct from these
residues or a mixture of these residues with other pure ores of iron two methods
may be pursued. The ores are reduced to fine powder with from 19 to 22
per cent. of pure charcoal powder, a mixture of 100 parts of dry oxides of
iron, 22 of charcoal powder, 10 parts of carbonate of manganese, or 8 parts
of hydrated oxide, 2 parts of titanic iron ore, 3. parts of common salt, and
3 parts of lime, are all intimately incorporated together, moistened, made
into balls, bricks, or blocks, and dried. These bricks, blocks, or balls so
produced are gradually brought to bright redness in a close calcining furnace,
and are maintained at that heat till all the oxides are reduced or converted,
The furnace is then allowed to cool below redness and the reduced blocks or
fragments withdrawn. A few ounces of the reduced fragments are melted
in a covered crucible, and the degree of carburation ascertained. If too
much carbon the charge of converted or reduced metal can be oxidised to any
extent by heating to bright redness short of fusion and then admitting air
into the furnace, which may be then closed up and the charge rapidly melted.
Or even after melting the slag may be skimmed off and powdered peroxide
of manganese added, or the metal may be exposed to the air; however, the
oxidation is much more easily effected by exposure previous to melting.
If the converted metal shews a deficiency of carbon, charcoal or anthracite coal
free from sulphur must be sprinkled amongst the fragments of converted
metal and the charge melted as rapidly as possible.
By the second process I make a metal richer in manganese by increasing
the carbonate of manganese to 20 parts and the charcoal powder to 26 parts;
the other ingredients and mixture as already described. The dried balls are

page_text: smelted as rapidly as possible and the metal is run into metal mouids or such
moulds as will yield no sand adhering to the pigs. The pigs are broken up and
melted in a separate furnace and puddled into steel of any degree of mildness.
The presence of such a large proportion of manganese facilitates the operation
of puddling, and the degrees of oxidation or decarbonisation are well marked,
so that no difficulty exists in obtaining steel of any requisite degree
of hardness. To produce wrought or malleable iron direct from these
residual or other oxides of iron, I mix them with preferably 16 to 18 per
cent. of anthracite coal and 3 per cent. of common salt, crush fine, and
thoroughly mix, moisten, and mould into rough balls, dry and charge into
a reverberatory furnace, consisting of a balling or puddling hearth and a
long sloping bed or table having a hopper fixed at the top or colder end.
The prepared balls are placed in this hopper, which should be kept full, and
so should the back part of the furnace. The table or floor of the back part
of this furnace should be placed on such a slope as will ensure the mixture
descending to the furnace bed with little or no assistance. It must also be
sufficiently capacious to contain as much ore as will feed the furnace bed
with a constant supply of reduced ore and as fast as it can be worked up.
The ore as it descends against the flame is steadily reduced to a spongy mass,
and is brought to a welding heat on the lower hearth, where it is worked up
into balls and withdrawn from the furnace, hammered and rolled in the
usual manner. A very superior quality of iron is produced by substituting
charcoal powder in the same proportion for the anthracite coal, and the
addition of 4 or 5 per cent. of carbonate or hydrated oxide of manganese.
When it is found that through crevices in the furnace or other causes that the
reduced ore produces in balling too large a proportion of slag, this can be
readily corrected by adding more carbon to the mixture previous to grinding;
the proportion can be thus so regulated according to the working of the
furnace as to produce a maximum yield of iron consistent with quality. Other
pure oxide ores of iron, such as hematites, can be substituted for or mixed in
any proportion with the residual oxides for this purpose, and also for all the
other purposes described in this Specification.
"
•
I produce cast iron rich in manganese in the following manner:-I take
200 parts of dry oxide of iron, 100 parts of carbonate, or 72 parts of hydrated
oxide of manganese, 49 parts of charcoal powder, or 52 parts of anthracite
coal, 10 parts of chloride of sodium, of calcium, of manganese, or of iron, and
10 parts of quicklime, and intimately mix and reduce to fine powder. I
moisten the powder with water and mould the mass into bricks, balls, or
rough blocks, and dry. These bricks or balls are then subjected to a strong

page_text: red heat in a close furnace, retort, or oven, until all the oxides are converted
into metal. The contents are then raked out into a close chamber, or are
allowed to cool below redness in the furnace or retort, and are then withdrawn
and charged into a reducing reverberatory furnace and melted as rapidly as
may be with a reducing flame. The resulting pig iron, if the reduction
has been properly managed, will contain 20 to 25 per cent. of metallic
manganese.
I sometimes obtain cast iron containing a larger proportion of manganese-by
reducing in manner last described the following mixture:-100 parts of
oxides of iron, 100 parts of carbonate of manganese or a corresponding
proportion of hydrated oxide, 33 parts of charcoal powder, or 35 parts of
anthracite coal, 8 parts of common salt or other chloride previously men-
tioned, and seven parts of quicklime. By varying the above proportions the
quantity of manganese contained in the iron may be increased or diminished.
The method of reduction from the dried balls or bricks may also be varied.
The calcining or converting furnace may be dispensed with and the dried balls,
blocks, or fragments may be charged at once into the smelting furnace. The
heat is gradually brought up to and maintained at a cherry red for about
2 hours, the heat is then increased to a bright red for about 3 hours, and is
ultimately carried to an intense white heat until the whole is fused. In
localities where black band or other ore containing an excess of carbonaceous
matter over and above what is required to reduce its own contained iron
from the state of protoxide to that of metal, and when these ores are free or
nearly so from sulphur and phosphorous, and do not contain a large proportion
of ash, I employ them either wholly or in part as a substitute for the coal,
coke, or charcoal powder in the mixtures, due regard being paid to the proper
proportions.
The amount of carbon, or rather the reducing power of the blackband ore,
may be readily ascertained in the following manner :-A fair average sample
of a large heap having been obtained and reduced to very fine vler, 1 0.
grains are intimately mixed with 400 grains of dry carbonate of lead and
placed in a small fire-clay crucible, 100 grains more of carbonate of lead are
put on the top, and the crucible and contents heated for half an hour to bright.
redness. When all action has ceased the crucible is withdrawn, allowed to
cool, then broken, and the button of lead weighed. Every 108 parts of
metallic lead represent 6 parts of carbon or its equivalent in hydrogen, and
may be used in these proportions, wholly or in part, as a substitute for charcoal
powder or anthracite. I take, for example, a blackband ironstone containing
25 per cent. of iron and 40 per cent. of carbonaceous matter and mix with 100-

page_text: parts of raw blackband in fine powder, 170 parts of oxide of iron residue
and treat in manner already described, and I obtain all the iron contained in
both as cast iron, the fluxes already described being also used. In localities
where tar, pitch, or other hydrocarbon can be cheaply obtained, it may be
used, and I prefer to use it for reducing mixtures containing a large pro-
portion of manganese. I take the tar or pitch and melt it, and stir in the
dry hot mixture of oxides until the tar or pitch will not take any more and
remain fluid. I then ladle out into thin cakes, which, when cold, are reduced
to powder, and their reducing power ascertained, as has been already
described in the case of blackband. I then mix them with more oxides of
iron in the proportions already indicated, either wholly or in part, as a
substitute for charcoal, coal, or coke in the mixtures. The carbonate and
hydrated oxide of manganese are cheaply obtained from the waste chloride of
manganese solutions produced in the manufacture of bleaching powder from
the native peroxide of manganese and muriatic acid. To the waste acid
solutions I add a very slight excess of milk of lime, taking care to leave no
lime amongst the precipitated oxide. The chloride of calcium solutions are
run away and the precipitate well washed with water and used in the mortar
mill in the pasty state or of about the consistence of clay for making bricks,
care being taken to ascertain how much dry hydrated oxide it contains, as
all my mixtures are calculated as dry. The carbonate of manganese is
obtained from the same waste solutions by using carbonate of lime, heat and
pressure being necessary to complete the precipitation in this case. The
native black oxide of manganese may be used instead of the hydrated oxide or
carbonate, but it requires a much larger proportion of carbon, is more costly,
and far more difficult to reduce to the state of metal. I therefore prefer the
artificial protoxide or the carbonate for all purposes of reduction.
In all these smelting operations I. have spoken only of a reverberatory
furnace, but such furnaces as are commonly used in iron works will not
answer the purpose. Furnaces of the same construction as are used for
smelting copper orcs with the two additional protections of feeding the coals
to the fire uniformly by a hopper through the arch of the fire-place and with
a regulating damper or lid on the top of the chimney. If the furnace is
worked with a very close grate not much oxidation will take place, and nearly
uniform results will be obtained. In reducing iron ores either to steel or cast
iron all pass through the first stage of malleable spongy iron. In this state
the iron is extremely liable to oxidise or burn if exposed to currents of air or
currents having an excess of oxygen, and as iron requires a very high tempc-
rature to melt it, and as it has been found impossible to obtain an intense heat

page_text: in the common reberberatory furnace without a corresponding intensity of
draft, results are uncertain, and cannot be depended upon in reducing iron
ores by reverberatory furnaces of the best construction with coal fires. I
therefore employ for all the purposes of reduction a reducing flame obtained
from gas. Gas furnaces can be worked with a small amount of draft and
with indeed a pressure of gas inside them, and possess moreover the additional
advantage of affording complete control over the quality of the flame. The
most economical gas furnace with which I am acquainted and which I prefer
is Siemens' patent regenerative gas furnace.
And having now described the nature of my said Invention, and the
best means with which I am acquainted for carrying it into effect, I
declare that I do not confine myself to the exact mixtures herein specified nor
to the mode of mixing or smelting them; but I claim as my "Improvements
in Obtaining Iron and Steel from certain Ores and Residual Products,'
First. The manufacture of cast iron, wrought iron, and steel from oxides of
iron obtained from iron or cupreous iron pyrites, such pyrites or cupreous
pyrites having first been freed from copper and sulphur.
Second. The employment of artificial carbonate or oxide of manganese for the
purposes herein described.
Third. The processes herein described for manufacturing cast iron rich in
metallic or carburet of manganese.
Fourth. The employment of raw blackband ores and others containing an
excess of carbonaceous matters, as described, for the purposes of reduction by
mixing with oxide ores, either wholly or partially, as a substitute for coal, coke,
or charcoal.
Fifth. The employment of tar, pitch, or other hydrocarbon free from sulphur
for the purposes herein described.
And last. Manufacturing iron and steel from oxide and carbonate ores
previously prepared as before described, by the combined employment of a
reverberatory furnace as described, and of a reducing flame obtained from gas,
substantially in manner herein-before described.
In witness whereof, I, the said William Henderson, have hereunto set
my hand and seal, this Twenty-fourth day of June, One thousand
eight hundred and sixty-three.