Improvements in the Process of and Apparatus for the Manufacture of White Lead.
Year: 1891

page_text: Date of Application, 9th May, 1891
Complete Specification Left, 18th Jan., 1892-Accepted, 20th Feb., 1892
PROVISIONAL SPECIFICATION.
Improvements in the Process of and Apparatus for the Manufacture
of White Lead.
We ANDREW HONMAN of Electra Street Williamstown in the Colony of
Victoria, Surgeon, and VICTOR VULLIEZ of Osborne Street, Williamstown afore-
said, White Lead Manufacturer do hereby declare the nature of this invention to
be as follows:-
This invention relates to a method of manufacturing white lead in which the
roasted ore is subjected to the action of lead acetate the clear solution from which
has a stream of carbonic acid passed through it and its object is to obtain white
lead which is in finer crystals and more uniform in quality than when manufactured
by the ordinary process.
It consists first and mainly in preserving the basic acetate of lead at a uniform
temperature of about 120 degrees Fahrenheit throughout the whole of the operation
and secondly in the conversion into white lead of the sulphate of lead produced in
the roasting by first dissolving it in a solution of caustic soda, caustic potash or
ammonium acetate and then precipitating the white lead by means of a solution of
carbonate or bi-carbonate of sodium, or potassium, or ammonium.
In carrying our process into operation we have invented certain novel apparatus
which will be understood by the following description. In manufacturing white
lead by our process we take the ordinary galena and crush and wash it as in the
ordinary manner. We then roast it in a reverberatory furnace which has a more
than ordinarily large area of sole relatively to the fire place and this latter is
provided with a boiler arranged immediately above it for the purpose of providing
a supply of steam which is conducted through a pipe or pipes just beyond the bridge
so as to discharge a series of steam jets in the direction of and above the galena in
course of roasting. The galena is roasted in this furnace at a low red heat for a
sufficient time to drive off the greater part of its sulphur. When this has been
accomplished we remove it from the furnace and place it in one of a series of tinned
copper cylinders each having a man-hole door through which the material is fed, a
perforated false bottom covered with coarse linen and a manhole door for removing
the contents after they have been treated. A stream of hot neutral lead acetate is
conducted into this cylinder and is then conveyed (after it has then been converted
into basic lead acetate) to a settling tank constructed as hereinafter described. The
hot lead acetate is supplied to this cylinder at about 15 B. and is continued until it
ceases to have any effect on the material under treatment which is ascertained by
testing the solution as it is being discharged.
The settling tank just mentioned is divided into two parts by a vertical partition
one part of which contains a series of baffle plates for the purpose of preventing the
stream of liquid rising too rapidly to the top and by compelling it to pursue a
circuitous course to give greater opportunities for it to deposit any solid matter it
nay hold in suspension. The overflow from this half passes into the second half in
which there is a discharge pipe made of india-rubber or other flexible material and
aving its mouth supported by floats so as to receive only the purer liquid which is
t the upper part of the vessel. The clear solution basic lead acetate thus being
lischarged is conveyed into a vat lined with tinned copper and having its bottom
nade so as to converge towards the centre. This we prefer to effect by filling up a
ortion of the vat with cement. To the centre of this vat we connect a discharge
ipe which we provide first with a plug and secondly, with a stop cock so that both
ust be operated before the liquid can escape. To the plug is attached a rod

page_text: having a rack at the top with which gears a pinion by operating which the said
plug may be either opened or closed. This vat has a lid or
cover which is
securely fastened down by means of two or more right and left hand screw-
threaded rods provided each with a correspondingly screw-threaded link whereby
the two parts of said rods may be drawn closer together or vice-versa as will be well
understood.
The solution in this vat is kept at an even and regular temperature of 120 degrees
Fahrenheit or thereabouts by means of a worm through which steam passes. In
this vat we also provide a worm arranged spirally so as to be parallel to the
cemented sides of the vat. This worm is perforated throughout its whole length so
as to admit of the escape of a stream of carbonic acid which is conveyed to it from
any suitable source by means of pipe which of course is provided with a stop cock
to cut off the supply whenever needed. By preference we force the stream of
carbonic acid through said worm by means of a pump and the result of this
proceeding is to cause the basic lead acetate to precipitate lead carbonate (white
lead). When the solution which is at first about 18 B. decreases to 15 B. the
supply of carbonic acid is cut off and a few minutes allowed for the precipitate to
settle down to the bottom, from whence it is drawn through a pipe and is then
immediately replaced by a fresh quantity of clear basic lead acetate from the above
mentioned settling tank so as to bring the solution again to the density of about 18 B.
when the supply of carbonic acid is again turned on and the same operation repeated.
The lead carbonate (white lead) which is thus discharged together with its
accompanying solution is conducted to a settling tank where the white lead deposits
itself and the clear solution at the top is pumped back to a cylinder containing lead
oxide and when said oxide has been entirely dissolved the sulphate of lead which
forms portion of the residue is dissolved by a solution of caustic soda, caustic
potash, or ammonium acetate the solution thus made is conveyed to a tinned copper
pan wherein it is preferably maintained at a fairly high temperature in order that
finer crystals may be produced than would otherwise be the case and wherein the
white lead is precipitated by means of a solution of carbonate of soda, or potash, or
ammonium. The white lead thus produced either from the decomposition of the
sulphate of lead or from the discharge from the vat above mentioned is first
thoroughly washed and then dried in an apparatus which consists of a cast iron pan
say 50 feet long and eight inches deep supported upon a thin bed of bricks beneath
which are two heating flues. This apparatus is provided with metal lids which are
inclined at about 45 degrees. The ends of these lids rest in a groove or channel sc
that as the vapour condenses on said lids it runs down into this channel and is
conveyed away outside the pan. The pasty white lead should be spread upon this
pan about three or four inches deep and must be kept there until it is completely
dried. When dried it is broken up pressed through fine sieves mixed with oil and
packed ready for transport.
It will be obvious that that portion of our process which relates to the conversion
of sulphate of lead into lead carbonate is applicable not only to the sulphate of lead
produced by our process of converting galena into white lead but is also applicable
to sulphate of lead no matter how produced. If however the sulphate of lead
were sufficiently pure it would be a simpler plan to transform it directly into
lead carbonate by boiling it in a solution of carbonate of soda or potash or
ammonium.
The apparatus employed for washing the carbonic acid used in the manufacture
of carbonate of lead to remove any dirt or foreign matters which might get into it
from either the lime or fuel in the lime kiln in which said carbonic acid is
manufactured consists of a cylindrical vessel having several compartments whose
floors are perforated to allow the carbonic acid to bubble up whilst preventing the
wash water from passing through. This wash water can only escape from one floor
on to the next below by overflowing down pipes whose upper ends project slightly
above each of the floors so that there will always be a certain depth of wash water

page_text: on said floors through which the carbonic acid will be caused to pass as above
stated.
D
1 1
T
1. 1801
ANDREW HONMAN.
VICTOR VULLIEZ,
COMPLETE SPECIFICATION.
Improvements in the Process of and Apparatus for the Manuacture
of White Lead.
We, ANDREW HONMAN, of Electra Street, Williamstown, in the Colony of
Victoria, Surgeon, and VICTOR VULLIEZ, of Osborne Street, Williamstown afore-
said, White Lead Manufacturer, 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 :-
This invention relates to a method of manufacturing white lead in which the
roasted ore is subjected to the action of lead acetate, the clear solution from which
has a stream of carbonic acid passed through it, and its object is to obtain white
lead which is in finer crystals and more uniform in quality than when manufactured
by the ordinary process.
It consists first and mainly in preserving the basic acetate of lead at a uniform
temperature of about 120 degrees Fahrenheit throughout the whole of the operation,
and secondly in the conversion into white lead of the sulphate of lead produced in
the roasting by first dissolving it in a solution of caustic soda, caustic potash or
ammonium acetate, and then precipitating the white lead by means of a solution of
carbonate or bi-carbonate of sodium or potassium or ammonium.
In carrying our process into operation we have invented certain novel apparatus
which will be understood by the following description and by reference to the
accompanying drawings.
In manufacturing white lead by our process we take the ordinary galena and
crush and wash it as in the ordinary manner. We then roast it in a reverberatory
furnace which has a more than ordinarily large area of sole relatively to the fire-
place and this latter is provided with a boiler arranged immediately above it for
the purpose of providing a supply of steam which is conducted through a pipe or
pipes just beyond the bridge, so as to discharge a series of steam jets in the
direction of and above the galena in course of roasting. This construction of
reverberatory furnace is clearly shewn in Figures 1, 2, 3, and 4 which are
respectively a front elevation, a horizontal section, a transverse vertical section
and a longitudinal central section thereof. In these figures A represents the fire-
place or furnace, B the sole, C the boiler over the furnace, C¹ the pipe leading
therefrom passing through the masonry and running behind the bridge B',
D-D hoppers for feeding the material to the furnace, and E-E doors for
introducing air and raking the material as is customary. The galena is roasted in
this furnace at a low red heat for a sufficient time to drive off the greater part of
its sulphur. When this has been accomplished we remove it from the furnace, and
place it in one of a series of tinned copper cylinders such as is shewn in Figure 5
of our drawings, F being a man-hole door through which the material is fed,
and G being a perforated false bottom covered with coarse linen, and H a man-hole
door for removing the contents after they have been treated. I is a pipe for
conducting a stream of hot neutral lead acetate into this cylinder, and J is a pipe
at the bottom for the purpose of conveying this stream (which has then been
converted into basic lead acetate) to a settling tank shewn in Figures 6 and 7.
The hot lead acetate is supplied to this cylinder at about 15 B. and is continued
until it ceases to have any effect on the material under treatment which is ascer-
tained by testing the solution discharged through pipe .J.

page_text: The settling tank which is represented in section and plan at Figures 6 and 7, is
divided into two parts by a vertical partition L, one part of which contains a series
of baffle plates for the purpose of preventing the stream of liquid rising too
rapidly to the top and by compelling it to pursue a circuitous course to give greater
opportunities for it to deposit any solid. matter it may hold in suspension. The
overflow from this half passes into the second half in which there is a discharge
pipe M made of india-rubber or other flexible material, and having its mouth
supported by floats m so as to receive only the purer liquid which is at the upper
part of the vessel. The clear solution of basic lead acetate thus being discharged
through pipe M is conveyed into a vat constructed as shewn in Figure 8, said vat
being lined with tinned copper, and its bottom being made so as to converge towards
the centre. This we prefer to effect by filling up that portion of the vat marked O
with cement. To the centre of this vat we connect a discharge pipe P which we
provide first with a plug Q and secondly with a stop-cock Q' so that both must be
operated before the liquid can escape. To the plug Q is attached a rod q having a
rack gl at the top, with which gears a pinion q² by operating which, the plug Qmay
be either opened or closed. This vat has a lid or cover R which is securely
fastened down by means of two or more right and left hand screw-threaded
rods, provided each with a correspondingly screw-threaded link ¹ whereby the
two parts of said rods may be drawn closer together or vice-versa, as will be well
understood.
The solution in this vat is kept at an even and regular temperature of 120 degrees
Fahrenheit or thereabouts by means of a worm S into which steam enters at s and
the exhaust from which finds its exit at s¹. In this vat we also provide a worm T
This worm
arranged spirally so as to be parallel to the cemented sides of the vat.
is perforated throughout its whole length so as to admit of the escape of a stream
of carbonic acid which is conveyed to it from any suitable source by means of pipe t,
which of course is provided with a stop-cock t' to cut off the supply whenever
needed. By preference we force the stream of carbonic acid through said worm by
means of a pump, and the result of this proceeding is to cause the basic lead acetate
to precipitate lead carbonate-white lead. When the solution which is at first
about 18 B. decreases to 15 B. the supply of carbonic acid is cut off and a few
minutes allowed for the precipitate to settle down to the bottom, from whence it is
drawn through the pipe P and is then inmediately replaced by a fresh quantity of
clear basic lead acetate from the settling tank, shown in Figures 6 and 7, so as to
bring the solution again to the density of about 18 B. when the supply of carbonic
acid is again turned on and the same operation repeated. The lead carbonate-
white lead-which is thus discharged through pipe P, together with its accompanying
solution, is conducted to a settling tank, where the white lead deposits itself, and
the clear solution at the top is pumped back to a cylinder, such as is illustrated in
Figure 5, and when the oxide therein has been entirely dissolved the sulphate of
lead which forms portion of the residue is dissolved by a solution of caustic soda,
caustic potash, or ammonium acetate. The solution thus made is conveyed to a
tinned copper pan, such as is shewn in Figure 9, wherein it is preferably maintained
at a fairly high temperature in order that finer crystals may be produced than would
otherwise be the case, and wherein the white lead is precipitated by means of a
solution of carbonate of soda or potash or ammonium. The white lead thus
produced either from the decomposition of the sulphate of lead or from the
discharge from the vat, shewn in Figure 8, is first thoroughly washed and then
dried in an apparatus which we have invented, and which is represented in
Figures 10 and 11, and which consists of a cast iron pan, say 50 feet long and
8 inches deep supported upon a thin bed of bricks beneath which are two heating
flues v. This apparatus is provided with metal lids W, which it will be seen
are hinged at w and are inclined at about 45 degrees. The ends of these lids rest
in a groove or channel X so that as the vapour condenses on the lids W it runs
down into this channel and is conveyed away outside the pan. The pasty white

page_text: lead should be spread upon this pan about three or four inches deep and must be
kept there until it is completely dried. When dried it is broken up, pressed through
fine sieves, mixed with oil and packed ready for transport.
It will be obvious that that portion of our process which relates to the conversion
of sulphate of lead into lead carbonate is applicable not only to the sulphate of
lead produced by our process of converting galena into white lead, but is also
applicable to sulphate of lead no matter how produced. If however, the sulphate.
of lead were sufficiently pure, it would be a simpler plan to transform it directly
into lead carbonate by boiling it in a solution of carbonate of soda or potash or
ammonium.
The apparatus illustrated in Figure 12 is employed for washing the carbonic
acid used in the manufacture of carbonate of lead, the object being to remove any
dirt or foreign matters which might get into it from either the lime or fuel in the
lime kiln in which said carbonic acid is manufactured. This said apparatus consists
of a cylindrical vessel Y having several compartments, whose floors y-y are
perforated as shown, so as to allow the carbonic acid to bubble up, whilst
preventing the wash water from passing through. This wash water can only
escape from one floor on to the next below by overflowing down the pipes y¹ whose
upper ends project slightly above each of the floors, as shown, so that there will
always be a certain depth of wash water on said floors through which the carbonic
acid will be caused to pass, as above stated.
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 :-
In that process of manufacturing white lead in which the roasted ore is subjected
to the action of lead acetate, and the clear solution from which is subjected to the
action of carbonic acid.
First. Preserving the basic acetate of lead thus produced at a uniform temperature
of 120° Fahrenheit or thereabouts throughout the whole operation as and for the
purposes herein described and explained.
Second. Converting sulphate of lead into white lead by first dissolving it in a
solution of caustic soda, caustic potash or ammonium acetate, and then precipitating
the white lead by means of a solution of carbonate of sodium or potassium or
ammonium, substantially as herein described and explained.
Third. In apparatus for the manufacture of white lead the employment of a
cylinder provided with two man-holes, one (such as F) through which lead oxide
can be fed into and the other (such as H) through which the residue can be with-
drawn from said cylinder, which is moreover provided with a perforated false botttom
(such as G) as well as with inlet and outlet pipes (such as I-J) for the lead acetate,
substantially as and for the purposes herein described and explained and as illustrated
in Figure 5 of our drawings.
Fourth. In apparatus for the manufacture of white lead the employment of a
settling tank divided into two compartments, in one of which is arranged a series of
horizontal baffle plates (such as 1) whilst in the other is arranged a flexible tube
(such as M) having a conical or trumpet-shaped mouth supported just beneath the
level of the liquor by floats (such as m) substantially as and for the purposes
herein described and explained and as illustrated in Figures 6 and 7 of our
drawings.
Fifth. In apparatus for the manufacture of white lead the combination with a
tank having its sides inclined towards a discharge tube (such as P) of a coiled steam
pipe (such as S) and a perforated carbonic acid delivery pipe (such as T) together
with an inlet pipe for delivering basic lead acetate into said tank, said discharge
tube being provided with a plug (such as Q) as well as a stop-cock (such as Q¹)
substantially as and for the purposes herein described and explained and as illus-
trated in Figure 8 of our drawings.

page_text: Sixth. In apparatus for the manufacture of white lead the combination with a
comparatively long shallow tray or receptacle (such as V) having flues (such as v¹)
leading from a furnace or fire-place running underneath it of a lid or lids (such
as Warranged at an inclination of about 45° across said tray or receptacle and
resting in a gutter or channel (such as X) substantially as and for the purposes
herein described and explained and as illustrated in Figures 10 and 11 of our
drawings.
Sevento. In the manufacture of white lead the employment of an apparatus for
washing carbonic acid gas consisting essentially of a cylinder (such as Y) provided
with a series of perforated floors (such as y) arranged one above the other and
having tubes (such as y¹) projecting slightly above each of said floors and extending
down to the floor next below substantially as and for the purposes specified and as
illustrated in Figure 12 of our drawings.
Dated this Fourteenth day of December One thousand eight hundred and
ninety-one.
ANDREW HONMAN.
VICTOR VULLIEZ.