Improvements relating to the Conversion of Metallic Lead into Lead Oxides.
Year: 1899

page_text: Date of Application, 24th Jan., 1899-Accepted, 4th Mar., 1899
COMPLETE SPECIFICATION.
[Communicated from abroad by ALBERT WILLETT SOUTHARD, of Newark, County,
of Essex, Mechanic, and GEORGE COOK, of Allendale, County of Bergan,
Lawyer, both in the State of New Jersey, and HERMAN ANSON CLARK, of
Sufferen, County of Rockland, and State of New York, Salesman, all in
the United States of America.]
Improvements relating to the Conversion of Metallic Lead into
Lead Oxides.
I, HENRY HARRIS LAKE, of the Firm of Haseltine, Lake & Co., Patent Agents,
45, Southampton Buildings, in the County of Middlesex, 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 and discovery is in the nature of improvements upon the inven-
tion for making oxide of lead, described in prior Letters Patent No. 25009
Dec. 31, 1895, granted to me as a. communication from abroad by Thomas
Benfield, of United States of America.
Previous attempts have been made by others, to produce an oxide of lead,
such as litharge, by grinding comminuted lead in the presence of air and
water, but I am not aware that it has been undertaken previous to my invention
to produce the hydroxide of lead in the manner hereinafter described, my im-
proved process consisting essentially in subjecting comminuted lead to agitation
in the presence of water, simultaneously forcing air into and throughout the
mass, then promptly withdrawing from the oxidizing tank a portion of the water
having the impalpable powder in suspension, then separating all of the metallic
lead from the hydroxide by a compound separator and then subjecting the
hydroxide to a filter press to expel the water therefrom, whereby the material
may be subsequently dried.
This submission of the water having the hydroxide in suspension, to the direct
action of the compound separator, and then to the filter press, secures an extra-
ordinary fineness of grain which enables the oxide produced by the action of air,
water and abrasion, to take up readily its proper volume of hydrogen and become
a true hydroxide.
And this peculiar richness and the other qualities of the hydroxide and its
exceeding fineness, enables it to readily assimilate the carbon of the carbon
dioxide when agitated in the carbonating tank, and thus produce very fine and
true hydrated oxy-carbonate of lead.
To enable others skilled in the art to make and practice my invention, I will
proceed to describe the construction and arrangement of a plant capable of
carrying out my improved process, and also the method of operating it, the one
hereinafter described and illustrated in the drawings, being such as I have used
in practice and found capable of producing from 700 to 1000 pounds of dry
hydrated oxy-carbonate of lead in twenty-four hours.
I would have it understood, however, that I do not limit my invention to the

page_text: detail construction and arrangement of parts forming the apparatus, nor the
proportions of materials specified, as such may be changed or varied in many
instances without departing from the spirit and scope of my invention.
There are five sheets of drawings and numerous figures, similar letters refer
to like parts. I find it convenient to use several floors of the factory so as to
discharge by gravity from one part of the apparatus to another.
Figure 1, shows the oxidizing tank and means of supplying it with atmo-
spheric air under pressure, which are on the top floor.
Figure 2 is a top plan view of the oxidizing tank, showing one half of the
cover or lid open.
Figure 3 is a vertical sectional view of the same.
Figures 4 and 5 are detail views showing the construction of the beater or
churning device.
Figure 6 is à side view of the compound separator and storage tank.
Figure 7 is a detail view of one part or portion of the separator.
.i
Figure 8 is a view in elevation of the carbonating tank and filter press, and
Figure 9 a detail view of one of the hollow arms for introducing gas into the
said tank.
Figure 10 is a view of the apparatus for forming the carbon-dioxide, and
Figure 11 shows the arrangement of the pipes in the cooling apparatus through
which the gas passes.
A is the oxidizing-tank, which in this plant, is about six feet internal diameter,
and about four feet deep with a tight lid. The tank I prefer to build of wood
staves, hooped, and its bottom, and about about two feet or more of its depth
is lined with copper. The tank A rests upon a platform.
In Figure 2, half of the cover is shown hinged and open for introduction of
the lead, and for inspection and cleaning. Cock 1, is the inlet cock to supply
ordinary water from the river, or other source. 2, 3 and 4 are outlet cocks for
drawing from the tank; they empty into an inclined sluice a, connected with
pipe b, which passes down through the floor and discharges upon the table of
the separating apparatus.
B, is the air-intake, which is above the roof, its sides are screened so as to
keep out dust. C, is a pump to draw in air from the intake and force it under
high pressure, through a tube T, into the beaters of the tank. D) is the gearing
under the tank, and F the driving pulley.
Figures 2, 3, 4 and 5 show details of the construction of the "beater" or
churning device which operates in the oxidizing tank.
This device is a beater revolving by means of its shaft c, driven by the gear-
ing D. The lower end of this shaft, as shown in Figure 1, is supported in the
step bearing c¹, the shaft being held in its vertical position by means of the
bearing, secured to the frame work. The upper end of the shaft c fits in a
stuffing box, and has secured thereto an air chamber or reservoir H.
From this hood there extends outward and downward, a number of radial
tubular beaters e each of which has at its lower end a hollow plough P, just
clearing the bottom of the tank, so as to lift up the lead and continue its vigorous
agitation; f, are several stationary breakers extending up from the floor of
the tank. Pump C forces air through tube T, into the pipe 1, then into the
chamber H, thence into the radial beaters e, down into, and out of the hollow
plough into the mass being agitated in the tank, the excess of air forced into
the mass in the tank A, escaping from said tank between the upper edge thereof
and the cover or lid. It is a distinctive feature that the air must be forced
under pressure into the mass at or near the bottom, so as to give the largest
volume of its oxygen to the agitated mass.
Figures 6 and 8 show the separating apparatus (and also a storage tank which
may be used when convenient to store, but which is not a necessary part of the
plant). This separator is arranged on the floor below that contained the parts
heretofore described.

page_text: The pipe 6 (also shown in Figure 1) discharges the fluid from tank A, upon
the distributing table E. Thence it falls into the vibrating screen S, which
catches the larger bits of metal. The water and oxide, and still smaller bits
which pass through screen S, drop upon the endless separating belt V, which
is made of rubber, and has a lip at each edge. The belt is inclined slightly
down towards the trough X from which leads a pipe X¹ to the storage tank
(when used) or to the carbonating tank on the floor below.
The belt travels over and around the frame VI provided with a series of
rollers V2, upon which latter the belt rests, said frame V being suspended by
means of the rods V3 secured at their upper ends to the stationary frame work V4,
this construction and arrangement of parts allowing the said "frame V₁ to be
moved or vibrated as hereinafter described. As the screen S is mounted upon
said frame V1, it will be evident that said screen also be moved or vibrated with
said frame. In order to produce the vibrating motion of the frame V1, the
belt V, and also of the screen S, I secure to said frame a cam-wheel V5, to which
is connected the rod or shaft V6, the opposite end of the latter being connected
with a shaft V, motion being transmitted from the latter through the shaft V6,
and cam 5 to the frame V
Above the belt V are located a number of feed jets J, discharging small jets
of water upon the belt between its higher end and the screen S. In order to
properly distribute the water over the belt, I prefer to give these jets a vibrat-
ing motion which may be accomplished in many ways well known to those
skilled in the art and which need not be described here in detail.
As the pipe b discharges the fluid from the tank A, over the distributing
table E and on to the screen S, the latter catches and retains the larger particles
of metal, the water and oxide passing through said screen on to the belt V,
which, as shown, is inclined from the frout or forward end toward the rear end,
said belt travelling in the same direction, that is, in a direction from its lower
end toward its higher end, as shown by the indicating arrow. As the water
and oxide, pass through the vibrating screen S onto the belt V, the water dis-
charged by the feed jets J together with the shaking or vibration of the belt
completely and perfectly separate the powdered oxide held in suspension from
any heavier particles of metal which may have passed through the screen S.
The heavy particles of metal adhere by gravity to the belt, and are. carried on
and by the same rearwardly into the pan Y, located below the higher end of
the belt and through which the belt travels. The pan or tank Y is partially
filled with water which, as said belt passes through it, washes off any of the
heavier particles of metallic lead which may be stuck or may adhere thereto.
The lighter particles of oxide thus completely separated from any metallic lead,
are washed down the belt by the water issuing from the jets J and carried down
the inclined belt by said water until they fall with the latter into the trough X,
from whence, as before described, they are led through the pipe X out into
the storage tank K, or to the carbonating tank O.
Figures 8 and 9, illustrate the carbonating apparatus, and filter press. This
part of the apparatus is arranged on the floor with the separating apparatus.
O is the carbonating tank which is of similar construction to that of oxidizing
tank A, and is provided with a similar, or other suitable beating apparatus,
although so great a degree of violence in agitation is not needed in this tank
where carbon dioxide is commingled with the oxide in suspension in the water,
as in tank A, where the abrasion of the lead pellets is an important result
to be accomplished by the violent beating. Carbon dioxide, commonly called
carbonic acid gas, is forced under high pressure by a pump into this tank, through
its beaters, one of which is illustrated in Figure 9, and is agitated with the
contents. From the storage tank K the water and oxide held in suspension
therein are drawn through the pipe K by means of the pump. K² and forced
through the inlet pipe K³ into said carbonating tank O, where, as before stated,
it is commingled with the carbon dioxide, the latter being fed into the tank

page_text: through the beaters from the supply pipe K³. The supply pipe K5 at its lower
end is provided with a T or outlet pipe from the bottom of the carbonating
tank O, and which communicates with the pipe K4, leading to the filter press Z,
valves or cut-offs and being provided in order that the oxide may be pumped
into the tank O or the carbonate from the tank to the filter press Z as desired.
The filter press Z may be of any desired construction or of any of the well
known styles now on the market, and hence need not be described here in detail.
Pipes K and K are respectively the steam inlet and discharge pipes to and
from the pump K².
Figures 10 and 11, illustrated that part of the plant in which the carbon-
dioxide is produced. Qis the furnace in which the consumption of coke and
chalk evolve large quantities of carbon-dioxide, which passes over into the
washing-tank, and thence into the reservoir R, where it is forced into the car-
bonating tank.
This I find a good apparatus for producing the carbon-dioxide,
but it is only one of several methods which may be adopted.
After the carbon-dioxide passes through the water in the washing tank L,
is passes out through the upper end of said tank through the outlet pipe L³ to
the compressor L', constructed in the usual manner, the latter forcing it through
the outlet pipes L2, through the pipes L, arranged as shown in Figure 11, that
is, in the bottom of the tank partially filled with water for the purpose of
cooling the gas, said coil of pipe L communicating with the pipe L5, leading to
the reservoir R, from which it passes through the pipe K5 to the carbonating
tank O, Figure 8, as before described, said reservoir R having an outlet pipe L'
from which gas may be taken at any time for the purpose of testing the same.
L7 represents a water inlet pipe for supplying the tank L with water from any
suitable source, a branch pipe L extending therefrom over the cover of the
tank L for the purpose of supplying water on to said cover and thereby prevent-
ing the heated gas within the top of the tank L from burning or destroying said
cover, another branch L of said water inlet extending down into the cooling
tank for the purpose of supplying water thereto.
The lead may be comminuted or converted into shot or pellets in any desired
way, as for instance by passing the same in a molten condition through a sieve
into a vessel of water located below the latter. However, as this step is well
understood by those skilled in the art, no detail description of the same is
required.
I will describe the operation of my invention in producing three commercial
products, or oxides, one of which I shall call hydroxide of lead, one minium,
and the other hydrated oxy-carbonate of lead.
I first form the hydroxide, and then filter, press and dry it, if it is intended
to be marketed in that form. If I wish to produce the hydrated oxy-carbonate,
then the hydroxide while in suspension in water, after separation, and before
it is pressed or dried, is carbonated as hereinafter described by a continuation of
the process. If I wish to produce minium or "red lead," I fuse in the usual
manner, either the hydroxide or the hydrated oxy-carbonate.
My operations are as follows: I first charge the oxidizing tank A, with about
five hundred pounds of the lead pellets, and about two hundred and fifty to three
hundred gallons of water at its normal temperature. At the same time atino-
spheric air is drawn through the screened intake B and forced at a pressure of
about five pounds or more per square inch into the beaters e, and out at the
bottom of the ploughs P. Power being applied, the beaters and ploughs rapidly
revolve and stir up, and violently agitate the entire contents of the tank,
striking the lead pellets against each other and the beaters and breakers, and
abraiding or grinding their surfaces which are slightly oxidized by the combined
action of the water and the excess of atmospheric air forced into the mass; about
six hours of this milling action will convert so large a percentage of the metallic
lead into an impalpable hydroxide as to impart a yellow colour to the fluid,
and add very materially to its density, and the temperature of the same will

page_text: b
increase by from 40 to 60 degrees. When the colour is right to the eye of the
operator, or the density of the water is increased say ten per cent. or more, I
begin to draw off a portion, through the cocks 2, 3 and 4 into the sluice a,
upon the table E of the separating apparatus, but it is not necessary to stop the
grinding.
When I have drawn off a suitable portion, I can feed in from time to time,
more lead and more water, and make the work continuous.
When the grinding in the tank A shows the proper colour or density, the
water therein will hold in suspension a large percentage of impalpable pure
hydroxide of lead. As before described, I then permit a portion of the contents
of the tank A to flow out of the tube b upon the table E thence upon the vibrating
screen S, and through the latter onto the inclined belt V. The water with
its contained lighter particles of impalpable hydroxide will flow down the in-
clined belt into the trough or tank X, the water issuing from the jets J assisting
to wash said lighter particles of the hydroxide down the belt. The heavier
particles or bits of metallic lead, however, which perchance have passed through.
the screen. S, will by gravity remain in contact with the belt, which, as before
described, travels in the direction of its ascent, thereby causing said heavier
particles of metal to be carried around the rear rolls V, whereupon they will
drop into the tank Y. Should any particles of metal adhere to the belt, they
will, of course, be detached therefrom as the said belt travels through the water
with which the tank Y is partially filled, as before described.
From this pan or tank Y, these particles of metallic lead, together with those.
which have remained upon the screen S, may be returned to the grinding tank A
for further grinding and oxidation.
I think that a substantial pellet like those I have described is of material aid
in the process, and is preferable to any other form of comminution for the
grinding process; they strike against each other, as well as against the beating
apparatus, the sides of the tub, and the water, and by this rapid abrasion greatly
hasten the complete oxidation of their surfaces, and the reduction of the result-
ing hydroxide to an impalpable powder which will long remain in a state of
suspension in the water.
If I intend to produce the hydroxide for the market as hydroxide of lead,
the fluid that passes from the separating process is then pumped into the filter
press Z, the residue left in the press is then taken out,, and dried, and when
desired is ground. It may then be sold as hydroxide of lead for various purposes
in the arts.
This hydroxide, and also the hydrated oxy-carbonate when properly fused
produces a high grade of minium or red lead, having a beautiful color. The
water may be returned from the press Z and used again in tank A, as it will
contain some of the hydroxide. When I intend to produce the hydrated oxy-
carbonate of lead (commonly called white lead) the process is the same, up to
and including the use of the separating apparatus. But, having done that,
the water from tank A, having the hydroxide in suspension, is fed into the
carbonating-tank O, instead of into the filter-press. In this tank 0, the carbon-
dioxide, which is forced through the beaters at a light pressure, supplies to the
impalpable molecules of hydroxide molecules of carbon, and in the course of
some six hours the hydroxide of lead is converted into hydrated oxy-carbonate
of lead, The contents of this tank 0 become of a pure whiteness, and of con-
siderable density, indeed, too long continued grinding will make it too thick.
When the contents show the desired color, or density, (about ten per cent.
increased density), I am ready to filter and dry. A force pump K2 then draws
off the carbonated fluid and forces it into the filter press; thence the residue
is taken out in cakes of stiff, damp hydrated oxy-carbonate of lead, and is ready
for the drying room, after which it may be dried or mixed with oil. The car-
bonated fluid from the press may be also re-used in tank A.
It will be noticed that throughout the processes described, no acid is used,

page_text: that no metallic lead is left in the products, that each entire process is con-
ducted in or under water, and that these circumstances secure a remarkable
degree of fineness and purity, and freedom from dirt or taint or other bodies,
and the fact that the lead is worked under water greatly lessens the danger
of lead poisoning to the operatives, is of importance.
Also that the process of making either the hydroxide or carbonate is a con-
tinuous process, that may be carried on without cessation.
I believe that the hydroxide produced as above described differs from any lead
oxide heretofore produced, and that its exceeding atomic fineness specially fits
it to take up atoms of carbon when it is subjected while in watery suspension
to the action of carbon dioxide under pressure and moderate agitation.
The hydrated-oxy-carbonate produced also appears to possess some distinctive
qualities; it is free from any acid; it is strictly amorphous, and non-crystalliz-
able, is exceedingly fine in texture and of great opacity and purity of color,
and its fineness of grain enables it to remain in suspension when ground in oil
a comparatively long time.
It is in point of fact a flour of lead, and I know of no other process by which
it can be produced, there is none on the market.
I understand that in the prior Patent No. 25009 A.D. 1895 it is stated that
the first tank partially oxidizes the lead, and that it is necessary to put the con-
tents drawn from this first tank into a second tank and there repeat the procedure
of the first tank. I have discovered that a better, and much quicker and cheaper
process is to use only the first oxidizing tank. and to continuously draw from it as
soon as the proper colour or density is reached. into the separating device, and
thence go from the separator directly to the filter-press, if I wish to produce
the hydroxide for the market or directly to the carbonating tank, if I wish
to produce the hydrated oxy-carbonate of lead.
The several features of my invention or discovery are all related to the art
of converting metallic lead into oxides, and it is believed may be included in
one patent for all these improvements in that art.
Having now particularly described described and ascertained the nature of
the said invention and in what manner the same is to be performed, as com-
municated to me by my foreign correspondent, I declare that what I claim is:-
-:
1. The process herein described for converting metallic lead into an hydroxide,
consisting in first agitating in a suitable vessel, metallic lead in a com-
minuted form in the presence of water, and simultaneously introducing air
into and throughout the mass; secondly, withdrawing a portion of the mass and
agitating the same for the purpose of separating the lighter hydroxide from
the heavier metallic lead by gravity, and thirdly, compressing the hydroxide
for exnelling the water therefrom.
2. The herein described process for converting metallic lead into an hydroxide.
consisting in first agitating in a suitable vessel, metallic lead in a comminuted
form in the presence of water and simultaneously introducing air into and
throughout the mass, and secondly, withdrawing a nortion of the mass on to
a suitable receptacle and agitating and simultaneously spraving the same with
water for the purpose of separating the lighter hvdroxide from the heavier
metallic lead by gravity and conveying said lighter hydroxide and metallic lead
to opposite ends of said receptacle.
Dated this 24th day of January 1898
HASELTINE, LAKE & Co.,
45, Southampton Buildings. London, W.C.,
Agents for the Applicant.