IMPROVEMENTS IN THE MANUFACTURE OF WHITE LEAD
Year: 1877

page_text: LETTERS PATENT to Farnham Maxwell Lyte, of the Scientific Club, Savile
Row, in the County of Middlesex, and at present of Paris, in the Republic of
France, for the Invention of "IMPROVEMENTS IN THE MANUFACTURE OF WHITE
LEAD."
Sealed the 25th January 1878, and dated the 29th November 1877.
•
PROVISIONAL SPECIFICATION left by the said Farnham Maxwell Lyte
at the Office of the Commissioners of Patents on the 29th November 1877.
FARNHAM MAXWELL LYTE, of the Scientific Club, Savile Row, in the County of
Middlesex, and at present of Paris, in the Republic of France.
"IMPROVEMENTS IN
THE MANUFACTURE OF WHITE LEAD."
In carrying into operation my improved method of manufacturing white lead I
proceed as follows:-In order to accelerate the process of manufacture I substitute
for the sheet lead now generally employed metallic lead, chemically precipitated as
obtained by reducing lead salts by an electro-negative metal, using by preference
metallic zinc for this reduction, used in the manner described in the Specifications
of Letters Patent granted to me, and dated 15th February 1877, and 23rd July
1877.
Sulphate or chloride of lead is dissolved in acidulated brine or in hydrochloric
acid, or these salts may be covered with brine or hydrochloric acid, and in either
case when bars or lumps of metallic zinc are placed in the mixture, the salts of lead
become reduced to metallic spongy lead, while a proportionate amount of zinc
passes into solution.
Other salts of lead, such as the nitrate, acetate, &c., may be similarly reduced
from their solutions to the state of spongy metallic lead. The spongy metallic lead
is placed in chambers, such as those wherein white lead is manufactured according
to the ordinary process, and is treated in the manner ordinarily employed for the
production of white lead. The lead in this finely divided state, as produced by

page_text: chemical reduction, I have found to be much more easily acted upon, and to be
more rapidly carbonated than lead in the ordinary state, as hitherto treated. In
the reduction of the spongy lead, zinc passes into solution in the proportion of about
1 part of zinc to every 3 parts of lead reduced, and may be recovered by precipi-
tation as rough oxide in a state fit for distillation and conversion into metallic zinc,
observing the precautions recommended in the Specifications of my previous Patents
above mentioned.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Farnham Maxwell Lyte in the Great Seal Patent Office on
the 29th May 1878.
FARNHAM MAXWELL LYTE, of the Scientific Club, Savile Row, in the County of
Middlesex, and at present of Paris, in the Republic of France. "IMPROVEMENTS IN
THE MANUFACTURE OF WHITE LEAD."
In carrying into operation my improved method of manufacturing white lead I
proceed as follows:-In order to accelerate the process of manufacture I substitute
for the sheet lead now generally employed metallic lead, chemically precipitated as
obtained by reducing lead salts by an electro-negative metal, using by preference
metallic zinc for this reduction, used in the manner described in the Specifications
of Letters Patent granted to me, and dated 15th February 1877, and 23rd July
1877.
Sulphate or chloride of lead is dissolved in acidulated brinė or in hydrochloric
acid, or these salts may be covered with brine or hydrochloric acid, and in either
case when bars or lumps of metallic zinc are placed in the mixture, the salts of lead
become reduced to metallic spongy lead, while a proportionate amount of zinc
passes into solution.
Other salts of lead, such as the nitrate, acetate, &c., may be similarly reduced
from their solutions to the state of spongy metallic lead. The spongy metallic lead
is placed in chambers, such as those wherein white lead is sometimes manufactured,
according to ordinary processes, or in chambers constructed on like principles, and
is treated in the manner ordinarily employed for the production of white lead. The
lead in this finely divided state, as produced by chemical reduction, I have found to
be much more easily acted upon, and to be more rapidly carbonated than lead in the
ordinary state, as hitherto treated. In the reduction of the spongy lead zinc passes
into solution in the proportion of about one part of zinc to every three parts of lead
reduced, and may be recovered by precipitation as rough oxide in a state fit for
distillation and conversion into metallic zinc, observing the proportions recommended
in the Specifications of my previous Patents above mentioned.
Among other processes for the conversion of the spongy lead into white lead may
be mentioned that of wetting the said spongy lead with a solution of lead acetate, or
of some other salts of lead, and exposing such mixture in a moist state in a chamber
to a current of mixed atmospheric air and carbonic acid gas, or to a mixture of

page_text: oxygen with carbonic acid gas; by such means the metallic lead becomes oxidized,
and the oxide thus produced absorbing carbonic acid becomes converted into the
basic carbonate, i.e., into white lead.
Having now described my Invention, and the manner of performing the same, I
declare that what I claim as my Invention to be protected by the herein-before in
part recited Letters Patent is, the substitution of finely divided metallic lead,
chemically produced by the reduction of lead salts by means of metallic zinc for the
sheets of lead or granulated lead, or other finely divided lead which have been
hitherto employed, or proposed to be employed, in manufacturing white lead.
In witness whereof, 1, the said Farnham Maxwell Lyte, have hereunto set my
hand and seal, this Twenty-ninth day of May, in the year of our Lord One
thousand eight hundred and seventy-eight.
F. MAXWELL LYTE. (L.S.)