AN IMPROVED MODE OF PRODUCING CHLORIDE OR OXYCHLORIDE OF LEAD AND TREATING THE SAME FOR MANUFACTURING WHITE LEAD
Year: 1867

page_text: LETTERS PATENT to William Robert Lake, of the "International Patent
Office," No. 8, Southampton Buildings; Chancery Lane, in the County of.
Middlesex, Consulting Engineer, for the Invention of "AN IMPROVED
MODE OF PRODUCING CHLORIDE OR OXYCHLORIDE OF LEAD AND TREATING THE
SAME FOR MANUFACTURING WHITE LEAD."-A communication from abroad by
Thomas Mara Fell and Ambrose George Fell, both of the City, County,
and State of New York, United States of America.
Sealed the 15th November 1867, and dated the 17th May 1867.
PROVISIONAL SPECIFICATION left by the said William Robert Lake at
the Office of the Commissioners of Patents, with his Petition, on the:
17th May 1867.
I, WILLIAM ROBERT LAKE, of the "International Patent Office," No. 8;
Southampton Buildings, Chancery Lane, in the County of Middlesex, Con-
sulting Engineer, do hereby declare the nature of the said Invention for
"AN IMPROVED MODE OF PRODUCING CHLORIDE, OR OXYCHLORIDE OF LEAD AND
TREATING THE SAME FOR MANUFACTURING WHITE LEAD," & communication, to be
as follows:-
By mixing and grinding together chloride of sodium and oxide of lead a
chloride or oxychloride of lead is formed, but this chloride is very imperfect
in its combination and requires a very long and tedious operation of grinding.

page_text: To obtain our improved chloride, or oxychloride of lead, chloride of sodium,
as free as possible from impurities, is used, to which is added. sufficient water
to take up the whole quantity. This solution is then heated and drained to
separate it from its impurities; oxide of lead is then ground and stirred in a
large vessel or mill with sufficient water to form a thin paste; heat is then
applied to this paste until it is brought up to a high temperature. The
chloride of sodium while still in a heated state is gradually added to this paste.
The mass occasionally becomes stiff owing to the quick action and combina-
tion necessitating the addition of water occasionally, and a thorough stirring
and grinding. It usually takes from two to three hours to mix the mass, when
it is allowed to stand to cool off and digest for from five to six hours or more
until perfect combination ensues. The contents of the vessel are now a chloride
or oxychloride of lead and a clear solution of soda. This chloride or oxy-
chloride is superior in quality to that derived by simply grinding the chloride
of sodium and oxide of lead as has been heretofore practised. This solution
is now drawn off and the chloride is well washed by water until every
remaining trace of soda (caustic) is removed; twenty per centum of chloride
of sodium we have found to be a good proportion for ordinary purposes. If a
much greater quantity than twenty per centum is added the resulting chloride
will be found of a dark color when manufactured into a pigment or white
lead, or used for mixing colors; such is also the case when a less quantity
than that above stated is added.
In place of chloride of sodium chloride of potash, lime, or other chlorid.s
may be substituted, but they are more expensive than the one first named;
this chloride, however, or a chloride derived in any known way, is not very
well adapted for the purposes of a pigment, being of an impure color and
partially soluble by the action of water. This chloride or oxychloride of lead
is consequently converted into a chloro-sulphate or white lead, which is a pure
white possessing a fine body, and is insoluble when mixed as a pigment. To
obtain this result the chloride or oxychloride is submitted to an intimate
contact with about forty per centum of sulphuric acid of sixty degrees in lead
lined glass, porcelain, or other suitable vessels at a temperate approaching the
boiling point; this part of the process requires great care, and as the acid
produces a powerful and quick action on the chloride it should be added in
small quantities from time to time during a period, say, from two to three
hours from the commencement until it is all put in; the mass then requires
digesting for several hours.
The next part of these improvements consists in treating a chloride or oxy-

page_text: chloride of lead in the manner now to be described, thereby producing a
superior white lead or carbonate of lead to be used as a pigment; the chloride
employed may be the one made as above described. Before drawing off the
soda from such chloride the mass is reduced to a thin paste by stirring, water
being added to thin it still further, if necessary; carbonic acid gas is then forced
into it, which causes a double action, namely, the carbonic acid unites with
the soda and forms bicarbonate of soda; then this bicarbonate of soda reacts
on the chloride of lead forming carbonate of lead and chloride of sodiuin; it is
then well washed in order to free it from the chloride of sodium and is afterwards
dried in the same way as practiced with ordinary white lead. The proportion
of carbonic acid found to answer well is about twenty-two per centum of the
weight of the litharge or oxide of lead used to form the chloride, but it is
usual to add the acid until the whole mass is converted. A supply of the acid
may be obtained by the usual method of burning limestone or marble in a
closed stove or furnace with coke, or by the combustion of any carbonaceous
substance, the gas being drawn from the generator and forced into the pasty
chloride by the usual mechanical contrivances.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said William Robert Lake in the Great Seal Patent Office on
the 16th November '1867.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
ROBERT LAKE, of the "International, Patent Office," No. 8, Southampton
Buildings, Chancery Lane, in the County of Middlesex, Consulting Engineer,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Seventeenth day of May, in the year of our Lord One
thousand eight hundred and sixty-seven, in the thirtieth year of Her reign,
did, for Herself, Her heirs and successors, give and grant unto me, the said
William Robert Lake, Her special licence that I, the said William Robert
Lake, my executors, administrators, and assigns, or such others as I, the said
William Robert Lake, my executors, administrators, and assigns, should at any
time agree with, and no others, from time to time and at all times thereafter
during the term therein expressed, should and lawfully might, make, use,
exercise, and vend, within the United Kingdom of Great Britain and Ireland,

page_text: the Channel Islands, and Isle of Man, an Invention for "AN IMPROVED MODE
OF PRODUCING CHLORIDE OR OXYCHLORIDE OF LEAD, AND TREATING THE SAME FOR
MANUFACTURING WHITE LEAD," upon the condition (amongst others.). that I, the
said William Robert Lake, my executors or administrators, by an instrument
in writing under my, or their, or one of their hands and seals, should par-
ticularly describe and ascertain the nature of the said Invention, and in what
manner the same was to be performed, and cause the same to be filed in the
Great Seal Patent Office within six calendar months next and immediately
after the date of the said Letters Patent.
NOW KNOW YE, that I, the said William Robert Lake, do hereby declare
the nature of the said Invention, and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement:-
.
By mixing and grinding together chloride of sodium and oxide of lead a
chloride or oxychloride of lead is formed, but this chloride is very imperfect
in its combination and requires a very long and tedious operation of grinding.
To obtain my improved chloride or oxychloride of lead I take chloride of
sodium as free as possible from impurities, and add sufficient water to take up
the whole quantity; this solution is then heated and drained to separate it
from its impurities. Oxide of lead is next ground and stirred in a large vessel.
or mill with sufficient water to form a thick paste; heat is then applied to this
paste until it is brought up to a high temperature. The chloride of sodium
while still in a heated state is gradually added to this paste. The mass
occasionally becomes stiff owing to the quick action and combination
necessitating the addition of water occasionally and a thorough stirring and
grinding. It usually takes from two to three hours to mix the mass, when it
is allowed to stand to cool off and digest for from five to six hours or more
until perfect combination ensues. The contents of the vessel are now a
chloride or oxychloride of lead and a clear solution of soda; this chloride or
oxychloride is superior in quality to that derived by simply grinding the
chloride of sodium and oxide of lead as has been heretofore practised. This
solution is now drawn off and the chloride is well washed by water until every
remaining trace of soda (caustic) is removed. Twenty per centum of chloride
of sodium has been found to be a good proportion for ordinary purposes; if a
much greater quantity than twenty per centum is added the resulting chloride
will be found of a dark colour when manufactured into a pigment or white
lead, or used for mixing colours; such is also the case when a less quantity
than that is added.
.

page_text: In place of chloride of sodium chloride of potash, lime, or other chlorides
may be substituted, but they are more expensive than the one first named.
This chloride, however, or a chloride derived in any known way is not very
well adapted for the purposes of a pigment, being of an impure colour and
partially soluble by the action of water. The said chloride or oxychloride of
lead is consequently converted into a chloro-sulphate or white lead which is
a pure white possessing a fine body, and is insoluble when mixed as a
pigment. To obtain this result the chloride or oxychloride is submitted to
an intimate contact with about forty per centum of sulphuric acid of sixty
degrees in lead lined glass, porcelain, or other suitable vessels, at a temperature
approaching the boiling point. This part of the process requires great care,'
and as the acid produces a powerful and quick action on the chloride it should
be added in small quantities from time to time during a period of two or three'
hours from the commencement until it is all put in; the mass then requires
digesting for several hours.
In practising this Invention on a large scale, I first dissolve four hundred'
pounds of the best quality of common salt, as free as possible from impurities,*
in sufficient water to take up the same, next two thousand pounds of oxide of
lead are well ground and stirred in a large vessel or mill and mixed with
enough water to form a thin paste, and heated from one hundred degrees to
the boiling point to facilitate the operation. The salt solution being also'
heated to more readily dissolve it, and being drained off from its impurities.
is now gradually added to the last-named mixture. The apparatus preferably
used by me for the purpose consists of a vessel lined with lead and constructed'
with a muller or stirrer, so that the material may be well mixed and ground.
Owing to the powerful and quick combination the mass becomes occasionally
very stiff, and this stiffness must. be counteracted by a thorough stirring and
grinding, and by the addition of small quantities of fresh water from time to
time. I usually occupy in mixing from about two to three hours, and then
let the mass cool and digest for from five to six hours or more until perfect
combination ensues. Instead of making it into a solution the salt, if known
to be pure, can be simply added to the mixture of oxide, and the whole well
stirred or ground and otherwise heated as before described; but I prefer a
solution as most salt. contains more or less impurities. The substance in the
vessel is now a chloride or oxychloride of lead, and a clear solution of soda
derived from the chloride of sodium; this solution is now drawn off as an
article of commerce, and the chloride is well washed by water until every
remaining trace of caustic soda is removed, and afterwards again heated to

page_text: the boiling point, and subjected to the action of sulphuric acid which is added
in small quantities, in manner as herein-before stated, the whole being then.
allowed to rest, cool, and digest for several hours; chloro-sulphate of lead is
thus obtained with free muriatic acid in. solution, which acid may be drawn off
as an article of commerce. The chloro-sulphate is now well washed in the
same manner, as practised for the removal of the canstic soda from the chloride
in order to free it from all traces of acid; it is then dried in the same manner
as practised with ordinary white lead. Instead of sulphuric acid any salt of
that acid of an equivalent quantity may be used, the result being chloro-
sulphate of lead, and a salt which can be subsequently washed out; but the
use of a salt of that acid would be more expensive than the acid itself.
I do not confine myself to the treatment of my improved chloride, as any
other chloride of lead can be successfully treated as above set forth.
The next part of my improvements consists in treating a chloride or oxy-
chloride of lead in the manner now to be described, to produce a superior
white lead or carbonate of lead to be used as a pigment; the chloride
employed may be that above described. Before draining off the sola from
such chloride the mass is reduced into a thin paste by stirring, water being
added to thin it still further if necessary; carbonic acid gas is then forced
into it, which gas causes the following double action:-The carbonic acid
unites with the soda forming bicarbonate of soda, then this bicarbonate of
soda reacts on the chloride of lead forming carbonate of lead and chloride of
sodium; the product is then well washed in order to free it from the chloride
of sodium, and is afterwards dried in the same way as practised with ordinary
white lead. The proportion of carbonic acid that is found to answer well is
about twenty-two per centum of the weight of the litharge or oxide of lead
used to form the chloride, but it is usual to add the acid until the whole mass
is converted. A supply of the acid may be obtained by the usual method of
burning limestone or marble in a closed stove or furnace with coke, or by
the combustion of any carbonaceous substance, the gas being drawn from
the generator and forced into the pasty chloride by the usual mechanical
contrivances.
Having thus fully described the said Invention as communicated to me
by my foreign correspondents, and shown how the same may be conveniently
and advantageously carried into practice, I claim,―
First, the treatment of oxide of lead with the chloride of sodium, or its
equivalent, substantially as described for the purpose of producing a superior
chloride or oxychloride of lead.

page_text: Second, the production of a chloro-sulphate or white lead from a chloride
or oxychloride of lead for the purpose and substantially as described.
Third, the production of a carbonate of lead from a chloride or oxychloride
of lead for the purpose and substantially in the manner described.
In witness whereof, I, the said William Robert Lake, have hereunto
set my hand and seal, this Sixteenth day of November, in the year of
our Lord One thousand eight hundred and sixty-seven.
0
WILLIAM ROBERT LAKE. (L.s.)
Witness,
THO. N. PALMER,
Clerk to Messrs. Haseltine, Lake, & Co.,
8, Southampton Buildings, W.C.