IMPROVEMENTS IN THE PURIFICATION OF LEAD TO BE EMPLOYED FOR THE MANUFACTURE OF WHITE LEAD, RED LEAD, AND LITHARGE
Year: 1865

page_text: LETTERS PATENT to John Arthur Phillips, of No. 12, Earls's Court
Terrace, Kensington, in the County of Middlesex, for the Invention of
"IMPROVEMENTS IN THE PURIFICATION OF LEAD TO BE EMPLOYED FOR THE
MANUFACTURE OF WHITE LEAD, RED LEAD, AND LITHARGE."
Sealed the 1st August 1865, and dated the 4th February 1865.
PROVISIONAL SPECIFICATION left by the said John Arthur Phillips
at the Office of the Commissioners of Patents, with his Petition, on the
4th February 1865.
I, JOHN ARTHUR PHILLIPS, of No. 12, Earl's Court Terrace, Kensington,
in the County of Middlesex, do hereby declare the nature of the said Inven-
tion for "IMPROVEMENTS IN THE PURIFICATION OF LEAD TO BE EMPLOYED FOR THE
MANUFACTURE OF WHITE LEAD, RED LEAD, AND LITHARGE," to be as follows:-
In order to extract copper and other impurities from lead, that is to be
subsequently used for the manufacture of white lead, red lead, litharge, or any
other purpose for which metallic lead entirely free from copper is required, I
employ the following process:→
The lead to be treated is first fused in a suitable pot or furnace, and after-
wards alloyed with a small quantity of zinc. This alloy is then stirred, and
allowed slightly to cool, and the scum that rises to the surface is removed by
means of a perforated ladle or otherwise. This process may be repeated if neces-
sary. The proportion of zinc which I prefer to employ varies from one quarter
to one per cent. The lead remaining in the pot after the removal of the scum
will be free from copper, and nearly all other impurities, except a trace of
zine, and inay frequently be at once employed for the manufacture of white

page_text: lead, red lead, and litharge. When it is desirable to elimenate the last trace
of zinc this is effected in the usual way in the ordinary softening furnace.
The lead remaining in the scum is subsequently obtained by eliquation in a
furnace provided with an inclined hearth.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said John Arthur Phillips in the Great Seal Patent Office on the
3rd August 1865.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
ARTHUR PHILLIPS, of 12, Earl's Court Terrace, Kensington, in the County of
Middlesex, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Fourth day of February, in the year of our Lord
One thousand eight hundred and sixty-five, in the twenty-eighth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me, the
said John Arthur Phillips, Her special licence that I, the said John Arthur-
Phillips, my executors, administrators, and assigns, or such others as I, the
said John Arthur Phillips, 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, the Channel Islands, and Isle of Man, an Invention for "Iм-
PROVEMENTS IN THE PURIFICATION OF LEAD," upon the condition (amongst others)
that I, the said John Arthur Phillips, my executors or administrators,
by an instrument in writing under my, or their, or one of their bands and
seals, should particularly describe and ascertain the nature of the said Inven-
tion, 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 John Arthur Phillips, do hereby declare
the nature of my 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:-
In order to extract copper and other impurities from lead, which is to be
subsequently used for the manufacture of white lead, red lead, and litharge, or
any other purpose for which metallic lead practically free from copper is
required, I employ the following process:-
The lead to be treated, should it contain an available amount of silver, is

page_text: first desilverized by any of the methods of desilverization of practical applica-
tion, then fused in a suitable pot or furnace, and afterwards alloyed with a
small quantity of zinc. This alloy is stirred, and allowed slightly to cool, and
the scum that rises to the surface is removed by means of a perforated ladle, or
by other means if deemed more convenient. This process may be repeated if
necessary. The proportion of zinc which I prefer to employ varies from per
cent. to 1 per cent. The lead remaining in the pot after the removal of the
scum will be practically free from copper and nearly all other impurities
except zinc. To elimenate the last traces of zinc, the lead is calcined or
treated at a high temperature in an improving furnace, whilst over the surface
of the lead bath coal or other carbonaceous matter is from time to time thrown
for the purpose of preventing the formation of oxides. The zinc at the high
temperature employed is volatilized, and the lead remaining in the furnace
after the elimination of the zinc is tapped into a proper pot and subsequently
cast into moulds. The lead thus obtained is practically free from copper, and
nearly all other impurities, and is specially applicable to the manufacture of
white lead, red lead, and litharge. The lead contained in the scum taken from
the surface of the pot or furnace in which the mixture of zinc and lead has
been made is subsequently recovered by eliquation either in a pot or furnace.
Having now described the nature of my said Invention, and in what manner
the same is to be performed, I wish it to be understood that what I claim is,-
Firstly, the purification of desilverized lead, or lead which does not contain
an available amount of silver, by adding thereto zinc, and removing the scum
or dross rising to the surface of the bath.
Secondly, the removal of the last traces of zinc from lead so prepared by
subjecting it to a high temperature in a furnace, in the bottom of which it
forms a bath, covered by small coal or other carbonaceous matter.
In witness whereof, I hereunto set my hand and seal, this Nineteenth
day of July, in the year of our Lord One thousand eight hundred and
sixty-five.
JOHN ARTHUR PHILLIPS. (L.S.)
Witness,
WILLIAM S. HART,
Clerk to the General Patent Comp', Limited,
71, Fleet Street, London.