Improvements in the Manufacture of Oxide of Lead and Means used therefor.
Year: 1896

page_text: Date of Application, 22nd July, 1896
Complete Specification Left, 22nd May, 1897-Accepted, 3rd July, 1897
PROVISIONAL SPECIFICATION.
Improvements in the Manufacture of Oxide of Lead and Means
used therefor.
I, ADOLF GUTENSOBN, of 24 Bloomfield Road, Burdett Road, E. in the County of
Middlesex, Metallurgical Chemist, do hereby declare the nature of my invention to be
as follows:-
My invention relates to the manufacture of oxide of lead of superior quality in one
operation, and consists in the treatment of molten metallic lead by oxygen or air
enriched by oxygen, to convert the same directly into an oxide or oxides of lead, the
means employed being specially adapted to prevent the too rapid destruction thereof
by the high temperature of the process and by the action of any fuzed portion of the
lead oxide.
To carry out my manufacture into effect, I smelt metallic lead to about a bright
red heat, and may then directly convert it into an oxide or oxides of lead by blowing
oxygen or air enriched with oxygen over the service of, or into, the molten lead; the
oxide being almost entirely driven off as vapour owing to the high temperature and
violent combination resulting. The said lead oxide vapour may be collected in the
usual well known manner for collection of lead fumes.
In this case the re-action is very rapid and violent, where pure or a large proportion
of oxygen is supplied at pressure, and many precautions must be taken.
The crucible or receptacle containing the molten lead should be of very refractory
material such as plumbago, as also the pipe conveying the oxygen to or into the
lead.
The latter pipe must be provided with a valve at some distance from the lead
receptacle, to control the supply of oxygen, or to reduce the pressure and check any
counter pressure or entry of oxide.
As under ordinary circumstances it will be impossible to prevent the formation of
a portion of fuzed oxide of lead on the surface of the molten lead bath when oxidising,
nor can such fuzed oxide be removed in the ordinary way, sufficiently quickly, by
skimming I adopt the following special arrangement of crucibles to prevent the
serious destruction of any crucibles where such fuzed oxide is present.
I employ two pots, one communicating with the other, the first melting pot being
situated higher than the second oxidising pot or vessel and thus adapted to keep the
lower oxidising pot or vessel always overflowing with molten lead. The oxygen blast
may be blown through or plays on the surface of the lower pot or vessel and any
oxide fuzed upon the surface at once flows over with the overflowing lead without
touching or attacking the crucible or vessel.
The overflowing lead is collected for reworking.
Where the oxygen or enriched air is blown over the surface of the molten lead,
this may be accomplished in a long and shallow overflowing receptacle for the lead,
so as to give the largest surface to the action of the oxygen.
Alternately, instead of blowing the oxygen into or over the molten lead, I may
connect the lead receptacle to a long cylinder or chamber, supplied with oxygen, and
permit the molten lead, at red heat, to fall in a finely divided condition through the
oxygen and thus be burned into oxide until the oxygen is used up. The oxide
vapour condensing and being conveniently collected in the said chamber. Or I may
supply constant re-charges of oxygen to the chamber as it is used up by the lead.

page_text: In this case, the surface of the molten lead in the melting pot, is prevented from
oxidation by a layer of charcoal or oxidation preventing flux.
The oxygen chamber described above must be sufficiently large and strong to
admit of expansion of the internal gas by the high temperature of combination and it
should be provided with a safety valve.
FELL & JAMES,
1 Queen Victoria Street, London, E.C.,
Agents for the Applicant.
Improvements in the Manufacture of Oxide of Lead and Means
used therefor.
I, ADOLF GUTENSOHN, of 24 Bloomfield Road, Burdett Road, E. in the County of
Middlesex, Metallurgical 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 :-
The various methods of manufacturing Oxide of Lead may be divided into two
groups, viz. (1) Those in which air is blown on to the liquid molten lead, whereby
the surface of the latter is converted into Oxide of Lead, and (2) those in which the
lead is vapourized and compressed air is blown among the finely disintegrated particles
thereof.
My method of producing Oxide of Lead differs from those aforesaid in so far, that I
blow oxygen, or air enriched with oxygen, on to the surface or into the mass of molten
lead which has previously been heated to redness, and cause the liquid oxide of lead
which forms on the surface, to flow into a vessel placed at a lower level than the
crucible or pot in which the oxidation takes place, immediately after the formation
of the said liquid oxide, while the gases or vapours rising from the liquid mass are
collected and condensed in the known manner.
By employing oxygen or air enriched with oxygen I attain actual combustion of
the lead, the gases forming the product of such combustion yielding oxide in a state
requiring no further preparation for being marketable, and, as it is not dissolved like
ordinary litharge and readily absorbs carbonic acid, it is the better adapted for con-
version into white lead without being completely dissolved, as is indispensable in the
so called wet process of manufacturing white lead.
As in all other known methods of producing oxide of lead, which are based upon
forced oxidation of surfaces, a liquid mass of oxide will form on said surfaces during
the process; this liquid mass does not escape in the form of products of combustion,
but so destructively attacks the crucibles or smelting pots that no material, however
refractory it may be, can resist its decomposing effects. In order to obviate this
grave disadvantage, I use a special arrangement or disposition of crucibles which
forms part of my present invention.
The aforesaid arrangement of crucibles consists in placing the oxidising crucible
between two others, one, serving as smelting crucible, is placed on a suitably higher
level, and the other intended to receive the liquid oxide of lead overflowing from the
oxidising crucible, is placed on a somewhat lower level than the latter.
In order to render the said arrangement of crucibles more readily understood I have
hereunto attached a sheet of drawings upon which the aforesaid arrangement is shown
in projection.
(A) is the smelting crucible placed on the highest level and connected by a pipe
C with the oxidising crucible B, the said pipe C running from the bottom portion of
crucible into the corresponding portion of crucible B. The latter is provided at its

page_text: upper rim with a circumferential gutter-like trough, into which the liquid oxide of
lead overflows, and is thence led by a conveniently disposed pipe or gutter into the
lowest crucible I. The liquid mass of oxide, which invariably contains a certain
limited quantity of molten lead, steadily overflows into the circumferential gutter of
crucible B, in proportion to the supply of molten lead passing from crucible A
through pipe C into the lower part of crucible B. The overflow may be regulated in
conformity with the supply of molten lead to crucible B, by means of a stop-cock or
the like provided in pipe C, or in other convenient manner. It is of importance
that the temperature of the material should be nearly equal in both crucibles, so as
to prevent the contents of crucible B being cooled down by the cooler influx from
crucible A and thus retard the process of oxidation.
Oxygen or air enriched with oxygen, is blown on to the surface, or into the mass of
the lead contained in crucible B in any efficient and convenient manner.
The gases rising from crucible B are collected in the supposed inverted funnel and
drawn off through pipe Finto the condenser (f.
The heat required by crucibles A & B may be supplied by suitably disposed
furnaces, indicated by D and E in the drawing.
The liquid oxide of lead collecting in the lowermost crucible H, is skimmed off and
treated like ordinary litharge, for conversion into oxide of lead, immediately after its
being generated, from oxidising crucible B, which would he rapidly destroyed by the
said material remaining there. I wholly or partly prevent such destruction, and a
hitherto very expensive process of manufacture is thus made practical and
advantageous.
Having now particularly described and ascertained the nature of this invention
and in what manner the same is to be performed, I declare that what I claim is :-
Apparatus for and method of producing oxide of lead by means of blowing oxygen
or air enriched with oxygen on to or through molten lead heated to redness, the
oxidation taking place in a crucible B which is so disposed that the liquid oxide
forming on the surface is made to continually overflow into another receptacle H
placed on a lower level, while fresh lead is continually supplied in liquid form to the
oxidation crucible B from a third crucible or smelting pot A placed on a higher level
than the said oxidation crucible B, the gases or vapours being drawn off through
pipe into the condenser G substantially as set forth and illustrated in the
accompanying drawing.
Dated this 00nd do of 1007