Improvements in the Manufacture of Oxides of Lead and Apparatus therefor.
Year: 1894

page_text: Date of Application, 16th Feb., *1894
Complete Specification Left, 15th Nov., 1894-Accepted, 16th Feb., 1895
PROVISIONAL SPECIFICATION.
Improvements in the Manufacture of Oxides of Lead and
Apparatus therefor.
SEBASTIAN ZIANI DE FERRANTI, 27, Charterhouse Square, in the County of
London, Electrical Engineer, and JOHN HENRY NOAD, 14 Stafford Road,
East Ham, in the County of Essex, Chemist, do hereby declare the nature of this
invention to be as follows:-
Our invention has for its object an improved process of manufacturing litharge
and red lead. According to our invention we take molten lead, preferably from a
reducing furnace, or if the process is started on pig lead we melt the lead separately
and by means of a blast of air spray this molten lead in a very finely divided state
through a heated chamber, supplied with hot air, during which time it is more or
less oxidised and falls out mostly in the form of litharge into a receiving chamber
at the other end of the heated chamber.
The nozzle through which the lead is sprayed by means of the blast may be made
in various ways. According to one plan it consists of a pipe dipping into a pot of
molten lead, and is formed as an ejector. A current of air, or in some cases steam,
produces a vacuum, sucking up the lead from the pot into the nozzle and spraying it
out with considerable force.
According to another method we run the lead out of a pot or containing chamber
through a fine orifice and it is then caught in an air or steam blast, being
eventually driven forward in a finely divided state. The projection of the lead may
also take place through a heated retort, or muffle, and this may be supplied with
heated air so as to furnish sufficient oxygen for oxidising the fine particles of lead
in their passage through the heated chamber. This chamber may be placed
horizontally and the lead spray driven through it with a considerable blast. Or it
may be placed somewhat with a falling inclination so that there may be less likeli-
hood of the lead particles or litharge choking in the chamber.
According to another method we use a vertical hot chamber or retort and either
drive the lead upward allowing it to fall by gravity round about and oxidise in
ascent. Or we place the lead pot at the top of a vertical retort chamber of
sufficient height, spraying the lead by means of a blast from the under side so that
in falling to the bottom of the chamber it is oxidised.
At the receiving end of the retort we form a chamber in which the lead oxide is
caught and from which it may be extracted.
When it is desired to more fully oxidise the lead than is required for litharge
making, we may take the litharge formed by the first process and by means of a
blast ejector blow it through a second or third chamber under the same conditions
as above mentioned, so that the oxidation may be made very complete. In certain
circumstances we may grind the product between these operations.
According to another method we sift the lead oxide from the top through a
vertical retort chamber so that in falling it may come in contact with heated air
and so be more thoroughly oxidised.
When we desire to make a superior quality of litharge or red lead we may take
carbonate of lead and either blow it or sift it as above explained through a chamber
of sufficient length or sufficiently often to produce the desired result.
In some cases we allow the large supply of hot air to the heated chamber to be
drawn in with the spray of lead. Or with the lead oxide or carbonate falling from

page_text: the upper part of the chamber. In other cases we put a hot air blast in the
opposite direction to encounter the particles of lead oxide or carbonate in their
descent to diminish the velocity in their falling, keeping them longer in the presence
of the oxygen.
The heated chamber may be formed of an earthenware retort or it may be of a
metal retort or pipe where the temperatures required are not too great for metal.
This may be heated by means of a fire or burning gases circulating round about it,
which may also be used to heat the air blast and the lead to be acted upon.
Where ore is being reduced in a reverberatory furnace for the purpose of
supplying lead for the above process the same furnace may serve the purpose of
reducing the ore, heating the chamber, heating the air blast, and, if necessary,
heating the lead at the point at which it is sprayed. The heating of the air for
the blast may be done in any of the well known ways.
Dated this Cintaanth day of Fahru 1804
S. Z. DE FERRANTI.
JOHN H. NOAD.
W. P. Thompson & Co.,
Liverpool, Manchester, Birmingham, and London, Patent Agents.
Improvements in the Manufacture of Oxides of Lead and
Apparatus therefor.
We SEBASTIAN ZIANI DE FERRANTI of 27 Charterhouse Square in the County
of London, Electrical Engineer, and JOHN HENRY NOAD of 14 Stafford Road,
East Ham in the County of Essex, 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 :-
Our invention has for its object an improved process of manufacturing litharge,
and red lead.
It is best described by aid of the accompanying drawings, showing vertical
sections of five variations of our apparatus.
In these
:
A is a furnace B, annular flue: C, chamber surrounded by said flue, in which
the lead oxide or red lead is made: D, reservoir of melted lead: E, tube leading
from a reservoir of compressed air or, in some cases, steam: F, pipe from lead
reservoir D G, spraying nozzle: H, chamber for receiving the oxidised lead.
According to our invention, we take molten lead, preferably from a reducing
furnace, or, if the process be started on pig lead, we melt the lead separately, and
by means of a blast of air or oxygen spray this molten lead in a very finely divided
state through a heated chamber, supplied with hot air, from any convenient source,
or, in some cases, we may allow the gaseous products of combustion, largely admixed
with air or oxygen, as in Figure 3, to pass through this chamber, or by heating the
chamber sufficiently, may accomplish our purpose by supplying air or oxygen at
ordinary atmospheric temperature. During this spraying, the lead is more or less
oxidised and falls out mostly in the form of litharge into a receiving chamber at
the other end of the heated chamber.
The nozzle, through which the lead is sprayed by means of the blast, may be
made in various ways.
According to one plan, it consists of a pipe F dipping into a pot of molten
lead D, and is formed as an ejector, as sketched in Figure 6. A current of air, or in
some cases steam, entering by pipe E, produces a vacuum, sucking up the lead from
the pot into the nozzle spraying it out with considerable force.

page_text: According to another method, we run the lead out of a pot or containing
chamber through a fine orifice, and it is then caught in an air or steam blast, being
eventually driven forward in a finely divided state.
The projection of the lead may also take place through a heated retort or muffle,
and this may be supplied with heated air so as to furnish sufficient oxygen for.
oxidising the fine particles of lead in their passage through the heated chamber..
This chamber may be placed horizontally and the lead spray driven through it
with a considerable blast, as in Figure 4: or it may be placed somewhat with a
falling inclination, so that there may be less likelihood of the lead particles or
litharge choking in the chamber as in Figure 5.
According to another method, we use a vertical hot chamber or retort, and
either drive the lead upward, allowing it to fall by gravity round about and oxidise in
ascent, as in Figure 1: or we place the lead pot at the top of .a vertical retort
chamber of sufficient height, spraying the lead by means of a blast from the under
side, so that, in falling to the bottom of the chamber, it is oxidised, as in Figure 2.
At the receiving end of the retort, we form a chamber H in which the lead
oxide is caught and from which it may be extracted.
When it is desired to more fully oxidise the lead than is required for litharge
inaking, we may take the litharge formed by the first process, and by means of a
blast ejector blow it through a second or third chamber containing air or oxygen
under the same conditions as above mentioned, but always with the aid of heat, so
that the oxidation may be made very complete. In certain circumstances, we
may grind the product between these operations.
According to another method, we sift the lead oxide from the top through a
vertical retort chamber, so that, in falling, it may come in contact with heated air
or oxygen and so be more thoroughly oxidised.
When we desire to make a superior quality of litharge or red lead, we may take
carbonate of lead and either blow it or sift it as above explained through a chamber
containing highly beated air or oxygen of sufficient length or sufficiently often to
produce the desired result.
In some cases we allow the large supply of hot air to the heated chamber to be
drawn in with the spray of lead; or with the lead oxide or carbonate falling from
the upper part of the chamber.
In other cases we put a hot air blast in the opposite direction to encounter the
particles of lead oxide or carbonate in their descent to diminish the velocity in
their falling, keeping them longer in the presence of the oxygen.
The heated chamber may be formed of an earthenware retort, or it may be of
a metal retort or pipe where the temperatures required are not too great for metal.
This may be heated by means of a fire or burning gases circulating round about
it, which may also be used to heat the air blast and the lead to be acted upon.
Where ore is being reduced in a reverberatory furnace for the purpose of
supplying lead for the above process, the same furnace may serve the purpose of
reducing the ore, heating the chamber, heating the air blast and, if necessary,
heating the lead at the point at which it is sprayed. The heating of the air for the
blast may be done in any of the well known ways.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed, we declare that what
we claim is :
1. The process of manufacturing litharge, consisting in aspirating, spraying or
showering melted lead or carbonate of lead in finely divided form through an
atmosphere containing free oxygen with sufficient heat and length of travel to
produce the oxidation.
2. The variation in or addition to the process described in Claim 1, which
consists in passing the product of the process as described in Claim 1 one or more
times through hot gases containing free oxygen with or without previous grinding
until sufficiently oxidised.

page_text: 3. The apparatus applicable for working the herein described process consisting
in an atomising device fed by steam, air, oxygen or like propelling medium or in
case carbonate of lead be used other ejecting device a supply of liquid lead or
finely divided carbonate of lead to such device, a chamber containing heated air or
oxygen into which such device ejects and a place in which the finely divided lead 5
oxide can settle.
Dated this 14th day of November 1894.
WM. P. THOMPSON & Co.,
Of Liverpool, Manchester, Birmingham, and London, Patent Agents.