AN IMPROVEMENT IN PROCESS OF AND APPARATUS FOR DESILVERING And REFINING LEAD
Year: 1874

page_text: LETTERS PATENT to Gustave Luce, of the Firm Luce, Son, and
Rozan, of Marseille (France), Manufacturers, for the Invention of
"AN IMPROVEMENT IN PROCESS OF AND APPARATUS FOR DESILVERING And
REFINING LEAD."
Sealed the 11th September 1874, and dated the 11th May 1874.
PROVISIONAL SPECIFICATION left by the said Gustave Luce at the
Office of the Commissioners of Patents, with his Petition, on the
11th May 1874.
I, GUSTAVE LUCE, of the Firm Luce, Son, and Rozan, of Marseille
(France), Manufacturers, do hereby declare the nature of the said
Invention for "AN IMPROVEMENT IN PROCESS OF AND APPARATUS FOR DESILVERING
AND REFINING LEAD," to be as follows:-
In the Specification of a Patent granted to C. D. Abel, dated the
15th November, 1869, No. 3292 (being a communication from Gustave
Luce, Son, and Rozan) was described an improved process and apparatus
for refining and desilvering lead, wherein steam was forced through the

page_text: melted lead contained in a cauldron in order to oxidise the impurities
and produce an ebullition of the lead, whereby the greater portion of the
lead was made to crystalize. The portion remaining uncrystalized con-
tained the greater proportion of silver and was run off and subjected to
the cupelling process.
The present Invention consists in employing compressed air or other
compressible gas containing oxygen in place of steam for effecting
the oxidation of the impurities and the ebullition and consequent
crystalization of the lead. In place of the pipe passing vertically down
through the cauldron for the introduction of the steam, as described in
the before-mentioned Specification, the cauldron containing the molten
lead is provided near its bottom with a pipe passing horizontally through
the side thereof to its centre, through which pipe the air or other gas or
steam, as described in the before-mentioned Specification, is forced into
the cauldron, a plate being fixed over the orifice of the pipe in order to
distribute the incoming air, gas, or steam equally throughout the molten
lead. The said pipe is provided externally with a cock or valve by
means of which the supply of air, gas, or steam may be regulated or
cut off when the process of crystalization is complete.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Gustave Luce in the Great Seal Patent Office on
the 6th October 1874.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, GUSTAVE
LUCE, of the Firm Luce, Son, and Rozan, of Marseille (France),
Manufacturers, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Eleventh day of May, in the year
of our Lord One thousand eight hundred and seventy-four, in the
thirty-seventh year of Her reign, did, for Herself, Her heirs and suc-
cessors, give and grant unto me, the said Gustave Luce, Her special
license that I, the said Gustave Luce, my executors, administrators,
and assigns, or such others as I; the said Gustave Luce, my exc-
cutors, administrators, and assigns, should at any time agree with,
and no others, from time to time and at all times thereafter during the

page_text: 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 "AN IMPROVE-
MENT IN PROCESS OF AND APPARATUS FOR DESILVERING AND REFINING Lead,” upon
the condition (amongst others) that I, the said Gustave Luce, 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 Gustave Luce, 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, reference being had to the accompanying
Sheet of Drawings, and to the figures and letters marked thereon, that
is to say :-
In the Specification of a Patent granted to C. D. Abel, dated the
15th November, 1869, No. 3292 (being a communication from Gustave
Luce, Son, and Rozan) was described an improved process and apparatus
for refining and desilvering lead, wherein steam was forced through the
melted lead contained in a cauldron in order to oxidise the impurities
and produce an ebullition of the lead, whereby the greater portion of the
lead was made to crystallize. The portion remaining uncrystallized
contained the greater proportion of silver and was run off and subjected
to the cupelling process.
The present Invention consists in employing compressed air or other
compressible. gas containing oxygen in place of steam for effecting
the oxidation of the impurities and the ebullition and consequent
crystallization of the lead. In place of the pipe passing vertically down.
through the cauldron for the introduction of the steam, as described in
the before-mentioned Specification, the cauldron containing the molten
lead is provided near its bottom with a pipe passing horizontally through
the side thereof to its centre, through which pipe the air, or other gas, or
steam, as described in the before-mentioned Specification, is forced into
the cauldron, a plate being fixed over the orifice of the pipe in order to
distribute the incoming air, gas, or steam equally throughout the molten

page_text: DESCRIPTION OF THE DRAWINGS.
Fig. 1 shews an elevation of the said apparatus for desilvering and
refining lead; Fig. 2 shews a longitudinal section; Fig. 3 shews a plan;
and Fig. 4 shews a transverse section.
A is the crystallizing vat, and H is the upper melting cauldron, which
is of cast iron or other suitable metal, and is provided with a pipe I
through which the melted lead is discharged into the vat A. F and f
are the fire-grates for heating the cauldron H and vat A. The
crystallizing vat H is of a cylindrical form, and is constructed of cast
iron or other suitable metal. It is provided near its bottom with a
horizontal tube t which serves for the introduction either of steam, as
described in the Specification to the before-mentioned previous Patent,
or of compressed air, or other compressible gas. According to the present
Invention, the pipe t has at its outer end a cock or valve C, by pre-
ference of steel, worked by means of the hand wheel E. The means for
closing the discharge pipes K, K, of the vat A, as also the pipe I of the
cauldron H, consists of a lever N pivotted at O and fitting accurately
against the faced flange of the pipe, against which it is kept by
means of the guide S secured by bolts a, a, to the flange of the pipe.
By raising the lever N the aperture of the pipe is opened more or less so
as to regulate the outflow of the melted lead. The operation takes
place as follows:-The crude argentiferous lead is melted down in the
cauldron H and is then allowed to flow through the pipe I into the
vat A, and when this is full steam or compressed air, or other com-
pressible gas is forced in through the pipe t, whereby a violent ebullition
is produced which induces the crystallization of the lead, while at the
same time the oxydation of any oxydizable foreign metals contained in
the lead is effected. The oxides rise in a pulverulent state to the
surface of the lead, whence they are removed to be treated in the
ordinary manner. The steam, air, or gas is made to enter the vat
beneath a distributing plate x. As soon as the proportion of crystals
appears sufficient the supply of steam, air, or gas is stopped by closing
the cock C, and the pipes K. are opened. The liquid lead, in which is
concentrated the greater proportion of the silver is received by the ingot

page_text: moulds G, G. As soon as all the liquid lead has run off the pipes Kare
closed. While the crystallization is taking place in the vat A another
charge of lead is melted down in the cauldron H equal in quantity to
that run into the moulds, and having a per centage of silver approxi-
mating as nearly as possible to that of the crystals in the vat A.
Immediately upon the closing of the pipes K. the pipe I is opened so as
to allow the lead to flow from H into A, and the crystals in the latter
are thereby dissolved. Steam, air, or gas is then again introduced
through the pipe t, and the above described operation is repeated until
there has been produced, on the one hand, merchant lead by the
successive decrease of per centage of silver in the crystals, and on the
other hand, lead suitable for cupelling.
++
The above process is distinguished from the so-called "Pattinson's
process," or
" zinc
process," in that Spanish or other suitable leads may
in the above described apparatus be desilvered and refined without any
preparatory purification and without the addition of zinc. Also the
Pattinson's process requires special skilled and robust workmen, whereas
the above described process can be carried on by any ordinary workmen,
who are enabled to superintend the operation without fatigue, and whose
only labour is to open and close the several pipes for discharging the
lead and for introducing the steam, air, or gas. The duration of one
operation for 12 to 13 tons of argentiferous lead is from 2 to 3 hours.
With the above described apparatus the loss of lead and silver is less
than with the usual processes, the operation is more rapid and
economical, and a better result is obtained. In fact the lead for
cupelling is by the above process enriched by about 2.2 per cent. of
silver, while the silver retained in the merchant lead amounts to from
124 to 150 grains per ton, whereas the loss by the usual processes is
about double that quantity.
Having thus described the nature of my Invention and in what
manner the same is to be performed, I wish it to be understood that I
do not claim the before described process and apparatus for refining and
desilvering lead, in so far as it is the same as described in the Specifica-
tion to the before-mentioned previous Letters Patent, but I claim,―
First. The use of compressed air or other compressible gas for
effecting the shullition and crustallization of the malted load

page_text: Second. The use of the horizontal tube t.for the introduction of steam,
compressed air, or other compressible gas into the crystallization vat.
In witness whereof, I, the said Gustave Luce, have hereunto set
my hand and seal, this Twenty-ninth day of September, in
the year of our Lord One thousand eight hundred and seventy-
four.
GUSTAVE LUCE. (L.S.)
Witness,
ALBERT CAHEN,
Civil Engineer,
of Boulevard Magenta, No. 32,
at Paris.