IMPROVEMENTS IN THE SMELTING OR REDUCING OF LEAD ORES, AND IN THE REFINING AND SOFTENING OF LEAD
Year: 1864

page_text: LETTERS PATENT to John Henry Johnson, of 47, Lincoln's Inn Fields, in
the County of Middlesex, Gentleman, for the Invention of "IMPROVEMENTS
IN THE SMELTING OR REDUCING OF LEAD ORES, AND IN THE REFINING AND
SOFTENING OF LEAD." -A communication from abroad by Professor
Alexander Hill Everett, of New York City, in the United States of
America.
Sealed the 13th October 1864, and dated the 7th July 1864.
PROVISIONAL SPECIFICATION left by the said John Henry Johnson at
the Office of the Commissioners of Patents, with his Petition, on the
7th July 1864.
I, JOHN HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County of
Middlesex, Gentlemen, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN THE SMELTING OR REDUCING OF LEAD ORES, AND IN THE
REFINING AND SOFTENING OF LEAD," a communication to me from abroad by
Professor Alexander Hill Everett, of New York City, in the United States of
America, to be as follows:-
This Invention relates, firstly, to the smelting or reducing of sulphuretted
lead ores; and, secondly, to the refining and softening of lead containing the
metals that are usually present in lead reduced from the native ores.

page_text: According to the first part of this Invention it is proposed to employ refuse
scraps of "tin plate" in any suitable or well-known reverberatory furnace
used in the smelting of lead, for the purpose of assisting the reduction of lead
from the sulphuret of lead to the metallic state, whereby a larger per-centage
of an improved quality of lead is obtained at a less expense than heretofore.
The furnace having been first heated to a red heat is to be charged with, say,
250 lbs. of "tin-plate" scraps, which should be spread evenly over the bed,
and so soon as the scraps have attained a white heat, 2000 lbs. of sul-
phuretted lead ore in a pulverised state are to be evenly spread over the
heated "tin-plate" scraps. When the ore has become heated to nearly a
dull red, a further supply of, say, 250 lbs. of "tin-plate" scraps is to be intro-
duced and evenly spread over the heated surface of the ore. The whole mass
is then brought to a bright red heat, which is to be maintained during a
period of about 15 minutes, after which the mass is to be well raked and
stirred. This raking or stirring is to be repeated every 15 minutes during a
period of about 2 hours, by which time the entire mass will have assumed a
fluid state, and the whole of the lead will have been reduced, and may now
be tapped and cast into ingots. The furnace is then cleared of the slags, and
the operation above described repeated with a fresh charge. Although
.definite proportions of "tin-plate" scraps and sulphuretted ore have been
given as having been found in practice to yield the best results, other propor-
tions may be employed, according to the nature of the ore to be treated.
In carrying out the second part of this Invention it is proposed to employ
metallic sulphurets, or sulphur in mechanical combination with organic pro-
ducts, in a reverberatory furnace, with a view to the separation from lead of
copper, zinc, antimony, iron, and other metals, which it is the object of the
refiner to remove from lead in order to render it of prime quality. The
furnace employed may be the ordinary reverberatory furnace used in the
reduction of lead ores, but having a hard cast-iron bed. The unrefined lead
is to be fused in this furnace, and when it is in a melted state sulphuret of
lead, or other metallic sulphuret, or sulphur alone finely pulverised and mixed
with hydrocarbon (to prevent the oxidation of the lead) are to be evenly
spread over the surface of the melted metal. The sulphur immediately unites
with the metallic impurities and forms sulphurets, which float on the surface
of the lead, and are easily removed by an iron rake or hoe. The refined
metal may now be tapped and re-cast into ingots.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said John Henry Johnson in the Great Seal Patent Office on.
the 7th January 1865.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County of Middlesex,
Gentleman, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Seventh day of July, in the year of our Lord One
thousand eight hundred and sixty-four, in the twenty-eighth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me,
the said John Henry Johnson, Her special license that I, the said
John Henry Johnson, my executors, administrators, and assigns, or such
others as I, the said John Henry Johnson, my executors, administrators, or
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 SMELTING OR REDUCING OF LEAD ORES,
AND IN THE REFINING AND SOFTENING OF LEAD," a communication to me from
abroad by Alexander Hill Everett, of New York City, in the United States
of America, upon the condition (amongst others) that I, the said John
Henry Johnson, my executors or administrators, by an instrument in writing
under my hand and seal, or under the hand and seal of one of them, 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 months next and imme-
diately after the date of the said Letters Patent.
:
- NOW KNOW YE, that I, the said John Henry Johnson, do hereby
declare the nature of the said Invention, and in what manner the same
is to be performed, to be particularly described and ascertained in and by
the following statement, reference being had to the accompanying Drawings;
and to the letters and figures marked thereon, that is to say :-
.:
The said Invention relates, firstly, to the smelting or reducing of sul-
phuretted lead ores; and, secondly, to the refining and softening of lead
containing the metals that are usually present in lead reduced from the
native ores.
According to the first part of this Invention it is proposed to use refuse
scraps of "tin plate" in a reverberatory furnace for assisting the reduction of

page_text: lead from the sulphuret of lead to the metallic state, by which a larger per-
centage of an improved quality of lead is obtained at less expence for reducing
agents, fuel, and labor than by the processes heretofore practiced. In practice
the reverberatory furnace now commonly constructed for smelting lead may
be employed. As this is illustrated and described in most standard works on
metallurgy it is deemed unnecessary to describe it here. In working this
process the reverberatory furnace is first heated to a red heat, two hundred.
and fifty pounds of "tin plate" scraps are then spread evenly over the bed,
the doors are next closed for a few minutes until the "tin plate" scraps have
attained a bright red heat. The doors are then opened and two thousand
pounds of the sulphuretted lead ore pulverized are evenly spread over the
heated "tin-platė" scraps. When this has been done the doors of the
reverberatory furnace are re-closed, and so left until the ore has become
heated to nearly a dull red heat, when the doors are again opened and two
hundred and fifty pounds more of the "tin-plate" scraps are carefully and
When this has been
evenly spread over the heated surface of the ore.
accomplished the doors are closed, and the whole mass is brought to a bright
red heat. The doors are still kept closed for about fifteen minutes, and care
is exercised to keep the heat of the reverberatory furnace at a constant
uniform temperature during this time. When the fifteen minutes have
expired the doors are again opened, and the whole mass is raked and well
stirred for two or three minutes, while care is exercised to keep the mass at
as uniform a thickness as practicable. This stirring operation should be
repeated every fifteen minutes for about two hours. At the expiration of two
hours the whole mass will have assumed the fluid state, when the whole of the
lead will have been reduced. The tap at the side of the reverberatory
furnace there provided leading into a kettle is drawn, and the lead is ready
to be cast into ingots. The furnace is next cleared of the slags, and the
operation just described is repeated. The time required to reduce sul-
phuretted ores by the old processes on the scale named is never less than
between three and four hours, whilst by the process above described the same
quantity of ore is reduced in from two and a half to three hours, thus effecting
a saving of one-third of the time employed, and a proportionate saving o
labor and fuel. Practical experience has demonstrated, also, that a superio
quality of lead is obtained with a larger yield from the ore. Definite pro
portions of
"tin plate
scraps and sulphuretted ore have been given which
have been found in practice to yield the best results, but it is obvious tha
the proportions may be varied according to the nature of the ore to b
treated.
"

page_text: The second part of this Invention consists in a new and useful improvement
in refining and softening lead containing the metals that are usually present
when it is reduced from the native ores.
Before describing this improvement I would remark that the process now'
generally practised for the purposes to which this improved mode relates"
consists in fusing the lead to be refined in a reverberatory furnace of the same
construction as that in which it was reduced from the ore, with the exception
of having a cast-iron bed, and allowing it to remain exposed to the oxidizing
influence of the heated air of the furnace until the metals constituting the
impurities become oxidized, and therefore float on the surface of the melted
metal, when this "dross" is raked off with an iron rake; the duration of
time required to complete this process depending upon the nature and amount
of foreign metals present in the lead. The shortest time, however, under the
most favorable circumstances is not less than twelve hours, whilst in some
instances several days are necessary.
A considerable loss of lead occurs from
L
oxidation in the practise of this process.
The object of this part of the said Invention is to lessen the time required
by the old processes, and thereby to reduce the expense of fuel and labor,
and the cost for building furnaces and other attendant provisions to refine
large quantities of metal, as well as to reduce the loss from oxidation of lead. >
According to the second part of this Invention metallic sulphurets, or
sulphur in mechanical combination with organic products, are used in a
reverberatory furnace for the purpose of effecting the separation of copper,
zinc, antimony, iron, and other metals which it is the object of the refiner to
remove from lead to make it of prime quality. The furnace used may be the
ordinary reverberatory for reducing lead ores, except in place of the fire-brick
or tiles forming the bed, hard cast iron must be employed. Into this furnace
the unrefined lead to be operated upon is placed, the doors of the furnace are
closed, and the walls heated to a red heat, when the metal will have been
melted. The doors are re-opened and sulphuret of lead, or other metallic
sulphuret, or sulphur itself finely pulverized and mixed with hydrocarbon are
evenly spread over the surface of the melted metal. The sulphur immediately
unites with the metallic impurities and forms sulphurets, which float on the
surface of the lead, and are easily withdrawn by an iron rake or hoe. When
these conditions have been complied with the tap provided at the side of the
furnace is drawn, and the refined lead is re-cast into ingots.. I have not
designated the proportions of sulphur to the bydrocarbon, nor the quantity of
the compound to be employed for refining a given quantity of lead. The
former will depend upon the source from which it has been obtained, and the

page_text: physical nature of the hydrocarbon, and the latter upon the quantity of
foreign metals to be removed. Generally one part of sulphur to five of hydro-
carbon by weight will be found to answer, and one hundred pounds of this
mixture will be sufficient to refine two thousand pounds of lead. Charcoal,
when convenient, may be used, but I prefer the use of anthracite siftings or
coal dust obtained at the coal yards, on account of their cheapness. The time
ordinarily required for performing an operation is one hour.
Having now described and particularly ascertained the nature of the said
Invention, and the manner in which the same is or may be used or carried
into effect, I would observe, in conclusion, that what I consider to be novel
and original, and therefore claim as the Invention secured to me by the
berein-before in part recited Letters Patent, is,
First, the peculiar process for smelting, or reducing sulphuretted lead ores,
as herein-before described.
Second, the application and use to and in the refining and softening of lead
of sulphur, or metallic sulphurets combined with the melted lead in a
reverberatory furnace, substantially in the manner and for the purpose herein-
before described.
Third, the refining and softening of lead by the employment of hydro-
carbon in combination with sulphur for the purpose of preventing the oxida-
tion of the lead, substantially as herein-before described.
In witness whereof, I, the said John Henry Johnson, have hereunto set
my hand and seal, the Sixth day of January, One thousand eight
hundred and sixty-five.
J. HENRY JOHNSON.
(L.B.)