Ix- PROVEMENTS IN THE TREATMENT OF THE SULPHIDES OF LEAD, ZINC, AND ANTIMONY, AND IN THE SEPARATION OF SILVER AND COPPER FROM THE LEAD
Year: 1875

page_text: LETTERS PATENT to William White, of No. 30, Thurlow Road,
Hampstead, in the County of Middlesex, for the Invention of "Ix-
PROVEMENTS IN THE TREATMENT OF THE SULPHIDES OF LEAD, ZINC, AND
ANTIMONY, AND IN THE SEPARATION OF SILVER AND COPPER FROM THE
LEAD."
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PROVISIONAL SPECIFICATION; left by the said William White at
the Office of the: Commissioners of Patents, with his Petition, on
⚫the 24th December 1875.
..
.
I, 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 TREATMENT OF THE SULPHIDES OF LEAD, ZINC, AND
ANTIMONY, AND IN THE SEPARATION OF SILVER AND COPPER FROM THE LEAD,” to be
as follows:-
.
I
It is well known that lead may be reduced from its sulphide by
-means of iron, and ferric oxide has also been employed for that purpose
with the addition of coal or other carbonaceous matter. Neither of
Price Sd.1

page_text: these methods has however been carried out very successfully, partly by
reason of the cost of iron, and partly from the slowness of the action of
iron on sulphide of lead when the iron is not in regular and intimate
contact with the sulphide, which contact can only be ensured when
the iron is reduced from finely divided ore and kept in a state of
powder.
Thus in order to effect the reduction of galena with economy and
certainty very careful and exact treatment is required, and such treat
ment it is the object of my Invention to secure. I proceed as follows :—
The galena is picked as clean as possible, or fused if it cannot be readily
separated from gangue, and then crushed to fine powder, the mass of
powder for the time under treatment being well intermixed to produce
uniformity. The crushed ore is then sampled and analysed, so as to
ascertain the proportion of sulphide of lead and gangue it contains; and
according to the character and quantity of gangue appropriate fluxes
are provided. According to the quantity of galena to be operated upou
I add iron powder, obtained by the reduction of rich iron ore in retorts,
with some powdered carbonaceous matter to counteract oxidation of
metal whilst under treatment. These matters, all in a state of powder.
the galena, the fluxes, the iron, and carbon, are intimately mixed
together, so that the fluxes may come into contact with the gangue and
the iron with the sulphide of lead, for on the close commingling of the
materials and the accuracy of their adjustment the rapidity and per-
fection of the ensuing reaction depend.
Any rich oxide cf iron may be used in a similar way instead of the
iron powder, with the addition of powdered carbon for deoxidation and
flux for earthy matter. The mixture thus prepared may be spread on
the hearth of a reverberatory furnace and subjected to adequate heat, in
which case it should be covered with a layer of coke or coal dust to
protect it from oxidation; or the reaction may be conducted in closed
retorts, or ovens, or pots. The iron is thus made to combine with the
sulphur of the galena, forming sulphide of iron, and the lead is liberated.
When the reaction is complete the heat is allowed to subside, when the
lead is drawn off, and the sulphide of iron is reserved for conversion into
sulphate or for other purposes.
Galena usually contains more or less silver, and sometimes copper,

page_text: of the powdered galena due account is taken of the silver or copper, or
both, which may be present, and to either of the mixtures described is
added a quantity of zinc answering to the ascertained proportion of
silver or copper, or both. It may be added either as metallic zinc,
oxide of zinc with carbon, or sulphide of zinc with iron, but always in
powdered condition. In the course of the reaction the zinc unites with
the silver and copper, and in cooling separates as a crust from the lead in
common with the sulphide of iron. Thus in the course of the operation
the lead is simultaneously desilverised and decopperised. By these
means lead smelting is accomplished with economy and despatch, and
without noxious fumes.
The same process of accurate assay and of accurate and intimate
mixture in powder with appropriate fluxes, iron, or oxide of iron with
carbon, is applicable to the reduction of the sulphides of zinc and
antimony, and with similar advantages.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said William White in the Great Seal Patent Office
on the 23rd June 1876.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
WHITE, of No. 30, Thurlow Road, Hampstead, in the County of Mid-
dlesex, 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 seventy-five,
in the thirty-ninth year of Her reign, did, for Herself, Her heirs aud
successors, give and grant unto me, the said William White, Her
special license that I, the said William White, my executors, admi-
nistrators, and assigns, or such others as 1, the said William White,
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 Channel Islands, and Isle of Man, an Invention for
"IMPROVEMENTS IN THE TREATMENT OF THE SULPHIDES OF LEAD, ZINC, AND

page_text: ANTIMONY, AND IN THE SEPARATION OF SILVER AND COPPER FROM THE LEAD,"
upon the condition (amongst others) that I, the said William White,
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 months next and immediately
after the date of the said Letters Patent.
NOW KNOW YE, that I, the said William White, 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 thereof, that is to say :-—
It is well known that lead may be reduced from its sulphide (galena)
by means of irou, and ferric oxide has also been employed for the same
purpose, with the addition of coal or other carbonaceous matter. Neither
of these methods has been worked out very successfully, partly by
reason of the cost of the iron, whether scrap or granulated, and partly
from the slowness of the action of iron on sulphide of lead when the
irou is not in regular and intimate contact with the sulphide. Such
contact is ensured when iron and galena are mixed in fine powder, and
fine iron powder is cheaply obtained when finely divided iron ore is
deoxidised by carbon. There are numerous rich powdery ores of iron
unsuitable for smelting in the blast furnace, which when mixed with
charcoal and submitted to a red heat under cover are readily deoxidised
without fusion.
In order to effect the reduction of galena with economy and efficiency
I thus proceed-The galena is picked as clean as possible, or fused if it
cannot easily be separated from gangue, and then crushed to fine
powder, the mass of powder for the time under treatment being well
intermixed to produce uniformity. If the crushed ore has not been
cleansed by fusion it is sampled and analysed, so as to ascertain tho
proportion of sulphide of lead and gangue it contains, and according to
the character and quantity of gangue appropriate fluxes are provided.
In either case, according to the quantity of galena to be operated upon,
iron powder reduced from ore as described is added, with some fino
charcoal to prevent oxidation of metal whilst under treatment. These
matters, all in a state of powder, the galena, the fluxes, the iron, and

page_text: the carbon, are intimately mixed together, so that the fluxes may
come into contact with the gangue and the iron with the sulphide of
lead, for on the close commingling of the materials and the accuracy
of their adjustment the rapidity and perfection of the ensuing reaction
depend.
Any rich oxide of iron in fine powder and flux for earthy matter may
be used in a similar way instead of iron powder, with the addition of a
sufficient quantity of carbonaceous matter for its deoxidation. The
mixture thus prepared may be spread on the hearth of a reverberatory
furnace, and subjected to adequate heat, in which case it should be
covered with a layer of coke or coal to protect it from oxidation; or the
reaction may be conducted in closed retorts, or ovens, or pots. The iron
is thus made to combine with the sulphur of the galena, forming
sulphide of iron, and the lead is liberated. When the reaction is
complete the heat is allowed to subside, and the lead is run off. The
sulphide of iron is reserved for conversion into sulphate or for other
purposes.
Galena usually contains more or less silver and sometimes copper,
which it is desirable to eliminate from the lead, and the separation may
be effected with facility in the course of the process just described. In
the preliminary assay of the powdered galena due account is taken of
the silver or copper, or both, which may be present, and a quantity of
zinc is added corresponding to the ascertained proportion of silver and
copper. It may be added as metallic zinc, oxide of zinc with carbons
or sulphide of zinc with iron, but always in powdered condition. In the
course of the general reactions the zinc unites with the silver and
copper, and in cooling separates as a crust from the lead, along with the
sulphide of iron. Thus in the course of the operation the lead is simul-
taneously reduced, desilverised and decopperised. By these means lead
smelting is accomplished with economy and despatch and without
noxious fumes.
The same process of accurate assay, and of accurate and intimate
mixture with oxide of iron and carbon or iron powder, is applicable to
the native sulphide of zinc, known as blende and black jack, and with
similar advantages. The zinc ore is powdered and mixed with the iron,
and a suitable flux for the gangue, when it is ready for reduction and
distillation. The like is true of antimony, the chief ore of which is a
sulphide. This when powdered, mixed, and fused with oxide of iron.

page_text: and carbon or iron powder is reduced as readily as either the sulphide of
lead or of zinc.
Having thus described my Invention, and means which I adopt in
carrying the same into effect, I would have it understood that what 1
claim as my improvements in the treatment of the sulphides of lead,
zinc, and antimony, and in the separation of silver and copper from the
lead are,-
First. The reduction of galena (sulphide of lead) by iron powder or
powdered oxide of iron and carbon, with simultaneous desilverization
and decopperisation by zinc, or oxide of zinc, or sulphide of zinc, as
described.
Second. The reduction of the sulphides of zinc and antimony by iron
powder or oxide of iron and carbon, as described.
In witness whereof, I, the said William White, have hereunto
set my hand and seal, this Twenty-second day of June, in the
year of our Lord One thousand eight hundred and seventy-
six.
Witness,
1
J
WILLIAM BROOKES,
62, Chancery Lane,
London.
WILLIAM WHITE. (L.S)