An Improved Method and Appliances for the Production of Litharge from Metallic Lead.
Year: 1891

page_text: Date of Application, 29th July, 1891
Complete Specification Left, 30th May, 1892-Accepted, 2nd July, 1892
PROVISIONAL SPECIFICATION.
An Improved Method and Appliances for the Production of Litharge
from Metallic Lead.
I, ADOLPH GUTENSOHN, of the Globe Works, Ford Road, Old Ford, in the
County of London, E., Chemist, do hereby declare the nature of this invention to be
as follows:-
My invention relates to the dry metallurgical production of litharge from
metallic lead and to the appliances employed in such process, whereby the rate of
production of the said litharge is greatly increased as compared with known process
and the amount of attention and manual labour is much reduced.
In the present usual mode for producing litharge from metallic lead, air is
admitted to the surface of a molten bath of lead. The bath of lead must be
constantly rabbled to cause fresh surface to be exposed and the oxide of lead or
litharge must be removed as quickly as it is formed to prevent it being reduced
again to lead or getting fused. This known process thus requires constant
attention and manual labour.
To carry out my improved method I melt the lead in a suitable vessel or chamber
(an iron pot or crucible) and blow air or preferably furnace gas which contains
carbonic acid right through the molten lead which is kept preferably at low red
heat. The employment of furnace gas with only a moderate percentage of oxygen
available prevents waste of lead by burning off as would be the case with pure air.
To prevent the metal from flying about and being lost I construct a special
vessel, pot, or crucible, as follows:-
I divide the vessel into a lower pot provided with a wide flange inclined upwards
so that all metal thrown outwards will fall back into the pot, and close this pot by
an upper hood resting on the said flange.
The injecting air or gas I bring in by a pipe through an orifice in the top of the
hood, which latter is arranged so that the hood may be raised by a chain or chains
to skim or examine the molten metal, without unshipping the pipe of air supply, or
vice-versa, so that the air pipe may be withdrawn without the hood being removed.
The injection air or gas pipe passes down below the level of the molten lead and
extends into a bell-mouth so that the ascending air or gas may be distributed over
a wide area as it rises through the molten metal.
The ascending current of air or gas affords a sufficient agitation of the molten
metal without rabbling and the oxide of lead or litharge is formed many times
more quickly than in a surface bath, thus saving time and labour.
It is important however that special arrangements be made that the litharge so
formed, which floats on the top of the bath, shall be prevented from reducing back
into metallic lead or from fusing.
For this purpose I provide special orifices through the hood just above the
surface of the molten metal through which air or steam is admitted or forced upon
the litharge on the surface of the bath and the oxide or litharge can thus be
allowed to remain some time on the surface, before removal by skimming, without
risk of reconversion or loss.
In order to prevent the lead from splashing out of such air orifice, I prefer to fit
them with elbows or bends passing through the hood so that splashes of lead will
Irop back into the pot.
The litharge thus obtained by my improved method and appliances, in an
exceedingly cheap and rapid manner, is a commercial product ready for use in
many known ways.
If the litharge is to be used for making nitrate, acetate, or other salts of lead,

page_text: particles of lead mixed with the litharge are no drawback and sifting is enough;
but if the litharge required pure the usual method of treatment for purification
may be resorted to.
Dated this 29th day of July 1801
FELL & WILDING,
1, Queen Victoria Street, London, E.C., Agents for the Applicant.
COMPLETE SPECIFICATION.
An Improved Method and Appliances for the Production of Litharge
from Metallic Lead.
I, ADOLPH GUTENSOHN of the Globe Works, Ford Road, Old Ford, in the
County of London, E., Chemist, do hereby declare the nature of this invention,
and in what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement :-
My invention relates to the dry metallurgical production of litharge from
metallic lead, and to the appliances employed in such process, whereby the rate of
production of the said litharge is greatly increased as compared with known
processes and the amount of attention and manual labour is much reduced.
In the present usual mode for producing litharge from metallic lead, air is
admitted to the surface of a molten bath of lead. The bath of lead must be
constantly "rabbled," to cause fresh surface to be exposed, and the oxide of
lead or litharge must be removed as quickly as it is formed, to prevent it being
reduced again to lead or getting fused. This known process thus requires constant
attention and manual labour. And in order that my invention may be the better
understood, I now proceed to describe the same, reference being had to the
accompanying drawings and to the letters and figures marked thereon.
Figure 1 is a sectional elevation of my apparatus.
To carry out my improved method, I melt the lead in a suitable vessel or chamber
(an iron pot or crucible) A and blow air or preferably furnace gas, which contains
carbonic acid, right through the molten lead B, which is kept preferably at low
red-heat. The employment of furnace gas with only a moderate percentage of
oxygen available, prevents waste of lead by burning off, as would be the case
with pure air.
To prevent the metal from flying about and being lost, I construct a special
vessel, pot, or crucible as follows."
I divide the vessel into a lower pot A provided with a wide flange C, inclined
upwards so that all metal thrown outwards will fall back into the pot, and close
this pot by an upper hood D, resting on the said flange C.
The injecting air or gas I bring in from the air or gas main F by a pipe F,
through an orifice in the top of the hood D, which latter is arranged so that the
hood may be raised by a chain or chains e, to skim or examine the molten metal,
without unshipping the pipe of air or gas supply E, or vice-versá, so that the air
pipe may be withdrawn by disengagement of the bayonet or union joint G without
the hood being removed.
The injection air or gas pipe E passes down below the level of the molten lead,
and extends into a bell mouth or preferably a three way mouth H so that the
ascending air or gas may be distributed over a wide area as it rises through the
molten metal.
The ascending current of air or gas affords a sufficient agitation of the molten
metal without rabbling, and the oxide of lead or litharge is formed many times
more quickly than in a surface bath, thus saving time and labour.
It is important however that special arrangements be made that the litharge so
formed K which floats on the top of the bath, shall be prevented from reducing
back into metallic lead or from fusing.

page_text: For this purpose I provide special orifices through the hood just above the
surface of the molten metal, or utilize the upper orifice of the hood D through
which air or steam is admitted or forced upon the litharge, on the surface of the
bath, by a pipe L, connected to the main by a cock and bayonet or union joint M
for easy disengagement; the oxide or litharge can thus be allowed to remain some
time on the surface, before removal by skimming, without risk of re-conversion
or loss.
In order to prevent the lead from splashing out of such side air or steam orifices,
where I use such, I prefer to fit them with elbows or bends passing through the
hood, so that splashes of lead will drop back into the pot.
The litharge thus obtained by my improved method and appliances in an
exceedingly cheap and rapid manner, is a commercial product ready for use in
many known ways.
I find also that finely disintegrated lead blown out by the air or gas blast, collect
and adhere at N to the inside of the hood D, and such finely disintegrated lead,
when collected and removed, is a valuable bye-product, for carrying out any wet
process of making white lead, or lead salts, as it offers to the acids an enormous
surface, and is consequently readily dissolved.
If the litharge is to be used for making nitrate, acetate, or other salts of lead,
particles of lead mixed with the litharge are no drawback and sifting is enough.
To carry out this sifting and prevent clogging, I drop the skimmings into a
sieve, which is suspended in a tank over water, and thus the skimmings passing
through the sieve into the water are cooled, and thus remain as finely divided as the
fineness of the sieve permits.
If the litharge is required absolutely pure the usual method of treatment for
purification may be resorted to.
I use the word litharge as a general expression for all degrees of oxidised lead.
Having now particularly described and ascertained the nature of my inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
1st. An improved process for the production of litharge or other oxides of lead,
from metallic lead, consisting of an injection of air or furnace gas under the surface
of the bath of lead, when molten in a suitable vessel at low red heat, subjecting the
said scum or oxide to the blast of air or steam jets to maintain its degree of
oxidation when standing, the skimming and sifting of the litharge or lead oxide
floating on the surface of the molten lead; a bye-product of finely divided lead being
collected from the inner surface of the hood of the vessel or crucible, substantially
as described.
2nd. In an improved process for the production of litharge or other oxides of lead
from metallic lead by the injection of air or furnace gas under the surface of the
bath, resulting in a scum of litharge or oxide of lead, the sifting of the said scum by
pouring it through a sieve into water to prevent it clogging with, and to separate it
from, particles of metallic lead mixed therewith.
3rd. For carrying out an improved process for the production of litharge or
other oxides of lead, from metallic lead, a crucible with an upper extended flange,
and a suspended hood thereon, in combination with a pipe passed through the said
hood, and dipping below the said lead bath, with a trumpet shaped or double ended
Tmouth, for the injection of air; and with other pipes passing through the
bottom edge or upper orifice of said hood, for the admission of air and steam; all
adapted so that the hood can be raised or lowered without disturbing the said pipe
connections.
FELL & WILDING,
1, Queen Victoria Street, E.C., Agents for the Applicant.