IMPROVEMENTS IN PURIFYING TIN
Year: 1852

page_text: LETTERS PATENT to John Arthur Phillips, of 8, Upper Stamford
Street, Blackfriars, in the County of Surrey, for the Invention
of "IMPROVEMENTS IN PURIFYING TIN."
Sealed the 17th January 1858, and dated the 6th November 1852.
PROVISIONAL SPECIFICATION left by the said John Arthur Phillips
at the Office of the Commissioners of Patents, with his Petition,
on the 6th November 1852.
I, JOHN ARTHUR PHILLIPS, of 8, Upper Stamford St., Blackfriars,
in the County of Surrey, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN PURIFYING TIN" to be as follows:-
This Invention consists of causing tin to be melted and run into
water to obtain it in a finely granulated state, and in this condition it
is dissolved by muriatic acid, which is drawn off to separate any pre-
cipitated or deposited matter, such as tungsten; and into this solution
more granulated tin is introduced, which throws down antimony or
arsnic, if any. The liquor is again drawn off into another vessel, and
the tin is precipitated by zinc. The precipitated tin, after being washed,

page_text: is compressed into masses, and afterwards fused into ingots. The
solution of chloride of zinc is precipitated by chalk or lime. In case,
in the first solution, copper is present, it is separated by iron.
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 5th May 1853.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I,
JOHN ARTHUR PHILLIPS, of 8, Upper Stamford Street, Blackfriars, in
the County of Surrey, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Sixth day of November, in the
year of our Lord One thousand eight hundred and fifty-two, in the six-
teenth 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, adminis-
trators, 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,
éxercise, and vend, within the United Kingdom of Great Britain and
Ireland, the Channel Islands, and Isle of Man, an Invention for
"IMPROVEMENTS IN PURIFYING TIN," upon the condition (amongst others)
that I, the said John Arthur Phillips, by an instrument in writing
under my hand and seal, should particularly 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 John Arthur Phillips, do hereby
declare the nature of the said Invention, and in what manner the
same is to be performed, to be particularly described and ascertained
in and by the following statement thereof (that is to say):

page_text: This Invention consists of causing tin to be melted and run into water
to obtain it in a finely granulated state, and in this condition it is dis-
solved by muriatic acid, which is drawn off to separate any precipitated
or deposited matter, such as tungsten; and into this solution more
granulated tin is introduced, which throws down antimony or arsenic.
if any. The liquor is again drawn off into another vessel, and the tin
is precipitated by zinc. The precipitated tin, after being washed, is
compressed into masses, and afterwards fused into ingots. The solution
of chloride of zinc is precipitated by chalk or lime. In case, in the first
solution, copper is present, it is separated by iron.
And in order that
my said Invention may be more fully understood I will proceed to
describe the means pursued by mc.
The operations by which the above results are obtained are conducted
as follows:-
The impure tin to be operated upon is first fused, either in a furnace
or in an ordinary iron pot, and subsequently granulated by being
allowed to flow in a finely divided stream into a vessel containing a
large supply of cold water. The granulated metal thus obtained is
now acted on by hot hydrochloric acid in vessels of wood, stoneware, or
other suitable material, care being at the same time taken that a larger
quantity of the granulated metal be employed than is capable of being
dissolved by the amount of hydrochloric acid present. On attacking
the impure metal in this manner the tin is rapidly dissolved with
the evolution of large quantities of hydrogen gas, whilst the tungsten
remains undissolved in the form of a dense black powder, and the
greater portion of the arsenic escapes through flues (connected with the
apparatus) in the form of arseniuretted hydrogen gas. It is necessary
that during this operation the tin (as above stated) should be in slight
excess, since the tungsten at first precipitated is itself to a certain extent
soluble in free hydrochloric acid. The solution of chloride of tin thus
obtained is, after allowing the insoluble impurities to subside, carefully
drawn off into a second vessel containing a small quantity of the same
granulated impure tin, where it is allowed to cool. By this means any
traces of arsenic or antimony which may have failed to be eliminated
in combination with hydrogen gas will be precipitated, and a solution

page_text: of chloride of tin free from those metals is obtained. If copper should
bé present it may be precipitated by iron, as is well understood. Should
lead have been present in the metal originally operated on, any traces
of that body may be readily removed by adding to the solution drawn
off from the deposit of antimony and arsenic a small quantity either
of sulphuric acid or sulphate of zinc. The liquor drawn off from the
precipitate of sulphate of lead thus produced, or, in case of lead not
being present in the tin originally operated on, that drawn from the
deposit of antimony and arsenic in the second vessel, is now sufficiently
free from impurities, and the tin is precipitated from it in the metallic
form. To do this the purified chloride of tin is run off into a wooden
vessel in which are suspended large bars of zinc, by which the tin is
rapidly precipitated in the metallic form, whilst a solution of chloride
of zinc is the result. The spongy metallic tin thus obtained, and which
during the progress of the operation requires from time to time to be
removed from the surface of the zine by means of tin or wooden
scrapers, is afterwards carefully washed first in water containing a
small quantity of hydrochloric acid, and subsequently in water only.
After having been thus treated the spongy metallic tin obtained iş
first tightly pressed for the purpose of expelling the moisture which it
contains, and afterwards fused in an iron pot and cast into ignots. The
tin-thus obtained is found to be almost chemically pure. The undis-
solved tin remaining in the vessel in which the solution is effected
(after being separated by washing from the residual tungsten and other
impurities) is employed in succeeding operations in lieu of freshly
granulated metal. The chloride of zinc resulting from the precipitation
of the tin in the metallic form by the introduction of zinc is now heated
to boiling, and decomposed by the addition of either chalk or milk of
lime. The carbonate or oxide of zine thus obtained, although beauti-
fully white in color, is found not to possess that opacity (body) which
is necessary to render it applicable for the purposes of a pigment, and
consequently it has to undergo another process before it can be so em-
ployed. In order to afford to it this necessary amount of opacity, the
carefully washed precipitate obtained by the addition of the chalk or
milk of lime, after being collected in proper vessels and either totally or

page_text: partially dried, is heated to redness in a muffle shaped oven or furnace.
By this means the precipitate acquires a great degree of density, and
thereby gains a body much superior to that of zinc white manufactured
by the ordinary process. When the precipitation of the chloride of zinc
is effected by the use of lime water or milk of lime, the resulting zinc
white is entirely composed of oxide of zine; but when, on the contrary,
chalk is employed, the resulting pigment, even after calcination, retains
a certain proportion of carbonic acid. This mixture of carbonate and
oxide of zinc possesses a better body than the oxide itself, and is conse-
quently for many purposes to be preferred to the pure oxide.
Having thus described the nature of my Invention, I would have it
understood that what I claim is,-
First, the purification of impure varieties of tin by solution in hydro-
chloric acid, and subsequent precipitation by metallic zinc.
Second, I claim the preparation of zinc white by the decomposition
of chloride of zinc by means of chalk, lime water, or milk of lime, and
imparting body to the precipitates obtained by exposure to an elevated
temperature.
In witness whereof, I, the said John Arthur Phillips, have hereunto
set my hand and seal, this Fifth day of May, in the year of our
Lord One thousand eight hundred and fifty-three.
Witness,
S. CARPMAEL.
J. ARTHUR PHILLIPS. (L.s.)