Improvements relating to the Manufacture of Lead Salts.
Year: 1894

page_text: Date of Application, 30th Jan., 1894
Complete Specification Left, 27th Nov., 1891-Accepted, 30th Jan., 1895
[Communicated from abroad by JOHN BLEECKER TIBBITS, of Hoosac, New
York, United States of America, Clergyman.]
Improvements relating to the Manufacture of Lead Salts.
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 to be as follows:-
This invention relates to improvements in the manufacture of lead salts by
electrolysis which is described in the Specification of British Letters Patent
No. 18076 A.D. 1889.
The object of the present invention is to obtain hydrated carbonate of lead or
"white" lead which is shaded or coloured.
The chief feature of my invention is that the colour of the hydrated carbonate
of lead is produced while the said carbonate is being manufactured.
In the Specification No. 18076 A.D. 1889 of the Letters Patent above cited a
process for manufacturing white lead by electrolysis of a solution with leaden
anodes is described. According to the present invention I modify said process so
as to produce shaded or coloured hydrated carbonate of lead as I now will proceed
to explain.
In one method of carrying out my invention I provide in the process above
referred to, a supplementary anode of a metal other than lead. Said supplementary
anode is used in conjunction with the ordinary lead anode. The precipitated
carbonate is then generally not white but is shaded or coloured, the tint depending
on the metal used for the supplementary anode. In this process it is obvious that
no metal which has a detrimental effect on lead carbonate can be used unless some
change be made in the electrolytic solution or bath which will counteract the
injurious effect of the metal. Many metals are however not prejudicial and I
preferably use one of these metals to produce the colour.
Another method of carrying out my present invention is to add a mineral dye to
the electrolytic solution or bath. The precipitated carbonate will then be dyed in
accordance with the dye added. It is important that the dye should be added
before electrolysis takes place and any carbonate is precipitated since the carbonate
is not permanently dyed unless the dyeing takes place during the formation of said
carbonate. If the dye is merely mixed with the carbonate after precipitation the
colour is not fixed but liable to change.
1
T
1001
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.

page_text: Improvements relating to the Manufacture of Lead Salts.
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 :-
This invention relates to improvements in the manufacture, by electrolysis, of
lead salts and particularly of hydrated carbonate of lead or "white" lead which
is shaded or coloured.
The chief feature of my invention is that the colour of the hydrated carbonate
of lead is produced while the said carbonate is being manufactured.
In the Specification of the Letters Patent No. 18076 A.D. 1889 a process for
manufacturing white lead by electrolysis of a solution with lead anodes is described.
According to the present invention I modify such process so as to produce shaded or
coloured hydrated carbonate of lead as I will now proceed to explain.
In one method of carrying out my invention I provide in the process above
referred to, a composite electrode that is to say an electrode made of amalgam or
an alloy or mechanical mixture of lead with another metal. The second metal
forms a supplementary electrode. The precipitated carbonate is then shaded or
coloured or tinted, the tint depending on the metal used for the supplementary
electrode. In this process it is obvious that no metal which has a detrimental
effect on lead carbonate can be used unless some change be made in the electrolytic
solution or bath which will counteract the injurious effect of the metal. Many
metals are however not prejudicial and I preferably use one of these metals to
produce the colour.
Another method of carrying out my present invention is to add a dye to the
electrolytic solution or bath. The precipitated carbonate will then be dyed in
accordance with the dye added. It is important that the dye should be added
before electrolysis takes place and any carbonate is precipitated since the carbonate is
not permanently dyed unless the dyeing takes place during the formation of said
carbonate. If the dye is merely mixed with the carbonate after precipitation the
colour is not fixed but liable to change.
These methods may be combined that is to say, a composite electrode may be
used in conjunction with a dye which is dissolved in the electrolyte.
In order that my invention may be clearly understood I have shewn in the
accompanying drawings a simple apparatus adapted to carry my invention into
practice which I will now explain.
Figure 1 is a vertical section of the precipitating tank taken transversely to the
plates which form the electrodes.
Figure 2 is an under plan of the gas distributing tubes, and
Figure 3 is an end elevation of the same.
Figure 4 is a front elevation of one of the electrodes, and
Figure 5 is a side elevation of the same.
Like letters indicate corresponding parts throughout the drawing.
A is a vat or tank which is not affected by electric action and which holds the
electrolytic solution and receives the lead precipitate. The electrolytic solution is
preferably alkaline but may be otherwise if the character of the electrodes
requires it. A system of tubes for introducing into and diffusing through this
solution carbon dioxide is shown in Figures 1, and 3, which consists of a piece
of rubber or glass tubing B bent substantially to the shape shown, that portion
which traverses the tank beneath the electrodes being provided with lateral

page_text: arms B', B which have small perforations or diffusing apertures B³, B' opening
downwardly thereout so as to effect a uniform diffusion of the gas through the bath.
C, C are bars spanning the top of the tank and from them the electrodes D and E
are suspended alternately. These electrodes may be of metallic lead or of lead
alternating with other substances, or one or both may be an amalgam or an alloy,
changes in the composition of one or both of then being accompanied by a change
in the characteristics of the product or precipitate produced.
For example in Figures 4 and 5 a composite electrode is shewn consisting of a
plate G to which strips H of another metal are mechanically connected.
The apparatus is rendered effective by connecting all the anodes with each other
and with the positive pole of a suitable current generator, and the cathodes are
similarly connected with each other and with the negative pole of the generator.
The gas distributing pipe B is then connected with the source of supply of the
carbon dioxide by one or both of its terminals and enough pressure is applied to
the entering column of gas to effect its circulation through the bath. To procure
a coloured precipitate of carbonate of lead a diversity of expedients or agencies
may be brought into requisition, but those most efficacious for the purpose, consist
in connecting with one or the other of the electrodes either by contact, fusion,
amalgamation or otherwise, a supplemental substance of which metals seem to be
the best adapted to the purpose, or by introducing into the electrolytic solution
the substance relied on to impart to the precipitate the desired qualification of
colour, or by employing both such agencies in conjunction. The electrolytic
decomposition and reaction which is thus set up in the bath by the electric current
results in the precipitation therein of a shaded or coloured product. In this
product the principal substance of the anode forms the base, and is chemically
united with products of the electrolytic action upon the other substances connected
with the electrodes or held in solution in the bath.
As examples of the improved process, to obtain a product of a light-blue
shade, a composite anode consisting of 90% lead and 10% copper may be
employed; to obtain a brown product an alloy of lead with a small amount of tin
may be employed for the anode, picric acid being dissolved in the electrolyte to
obtain a purple product, a composite anode of lead and iron may be employed with
cochineal mixed in an alkaline electrolyte.
The electrode which furnishes the precipitated pigment may be an amalgam, an
alloy or two metals in mechanical contact, but however connected or combined I
designate such electrode as "composite" and "basic."
My improved process may be used for the colouring of salts of lead other than
the carbonate or the basic carbonate, for example it may be used to colour lead
sulphates and lead sulphites in the process of manufacture of such salts by
electrolysis.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, as communicated to ine by
my foreign correspondent, I declare that what I claim is :-
1. The herein described process of manufacturing lead pigments which consists
in electrolytically dissolving in an alkaline solution a composite electrode formed
of an amalgam or alloy containing lead while supplying the solution with carbon
dioxide.
2. The herein described process of imparting tints to carbonate of lead during
its manufacture, wherein a supplemental substance is connected with one of the
electrodes which substance is adapted to impart to the precipitate the desired shade
or tint.
3. The herein described process of manufacturing lead pigments, wherein a
substance adapted to impart to the precipitate the desired colour is added to the
electrolyte.
4. The several processes for producing light-blue, brown, and purple lead
pigments herein before described.

page_text: 5. Lead pigments produced electrolytically by using a composite basic electrode,
or by introducing a suitable dye into the electrolyte, or by using a composite
basic anode together with a suitable dye in the electrolyte substantially as
described.
Dated this 27th day of November 1894.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.