IMPROVE- MENTS IN SEPARATING THE METAL TIN FROM THE IRON IN TIN PLATE CUTTINGS AND SCRAPS, AND IN OBTAINING THE METALS TIN AND IRON SEPARATE FOR USE, ALSO IN THE MANUFACTURE OF SULPHATE OF AMMONIA, CHLORIDE OF 2 PROVISIONAL SPECIFICATION
Year: 1874

page_text: LETTERS PATENT to James Stuart, of 34, Church Lane, Limehouse,
in the County of Middlesex, Chemist, for the Invention of "IMPROVE-
MENTS IN SEPARATING THE METAL TIN FROM THE IRON IN TIN PLATE CUTTINGS
AND SCRAPS, AND IN OBTAINING THE METALS TIN AND IRON SEPARATE FOR
USE, ALSO IN THE MANUFACTURE OF SULPHATE OF AMMONIA, CHLORIDE OF
2
PROVISIONAL SPECIFICATION left by the said James Stuart at the
Office of the Commissioners of Patents, with his Petition, on the
14th April 1874.
I, JAMES STUART, of 34, Church Lane, Limehouse, in the County of
5 Middlesex, Chemist, do hereby declare the nature of the said Invention
for "IMPROVEMENTS IN SEPARATING THE METAL TIN FROM THE IRON IN TIN
PLATE CUTTINGS AND SCRAPS, AND IN OBTAINING THE METALS TIN AND IRON
SEPARATE FOR USE, ALSO IN THE MANUFACTURE OF SULPHATE OF AMMONIA,

page_text: CHLORIDE OF AMMONIUM, SULPHATE OF IRON, AND SULPHATE OF ZINC," to be as
follows:-
It consists in subjecting tin plate cuttings and scraps to the action of
dilute sulphuric acid and atmospheric air, or to the action of dilute
sulphuric acid and nitric acid, or dilute sulphuric acid and nitrous acid
or hydrochloric acid, and any of the above combinations or compounds
of oxygen and nitrogen, when certain actions and reactions take place,
and the tin is separated from the iron and remains in the acid solution,
and the iron is left perfectly free from tin. Ammonia is formed during
the action, and this uniting with a portion of the sulphuric acid, forms
sulphate of ammonia. Part of the iron is also converted into sulphate
of iron during the action, and these sulphates of ammonia and of iron
are obtained from the solution for use.
If I wish to obtain chloride of ammonium and the chlorides of tin,
of iron, and of zinc, I use hydrochloric acid instead of sulphuric acid. I
obtain the tin from the acid solution by placing in the liquor plates of
zine; this throws down the tin in the state of metal, which I collect,
wash, and melt in the usual way.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said James Stuart in the Great Seal Patent Office on
the 3rd October 1874.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JAMES
STUART, of No. 34, Church Lane, Limehouse, in the County of Middlesex,
Chemist, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Fourteenth day of April, in the year
of our Lord One thousand eight hundred and seventy-four, in the thirty-
seventh year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto me, the said James Stuart, Her special licence that I,
the said James Stuart, my executors, administrators, and assigns, or such
others as I, the said James Stuart, 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

page_text: United Kingdom of Great Britain and Ireland, the Channel Islands,
and Isle of Man, an Invention for "IMPROVEMENTS IN SEPARATING THE
METAL TIN FROM THE IRON IN TIN PLATE CUTTINGS AND SCRAPS, AND IN OBTAINING
THE METALS TIN AND IRON SEPARATE FOR USE, ALSO IN THE MANUFACTURE OF
SULPHATE OF AMMONIA, CHLORIDE OF AMMONIUM, SULPHATE OF IRON, AND SULPHATE
OP ZINC," upon the condition (amongst others) that I, the said James
Stuart, my executors or administrators, by an instrument in writing
under my, or their, or one of their hands and seals, 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 James Stuart, do hereby declare the
nature of my said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the
following statement :-
It consists in subjecting tin plate cuttings and scraps to the action of
dilute sulphuric acid and atmospheric air, or to the action of dilute
sulphuric acid and nitric acid, or dilute sulphuric acid and nitrous acid
or hydrochloric acid, and any of the above combinations or compounds of
oxygen and nitrogen, when certain actions and reactions take place, and
the tin is separated from the iron and remains in the acid solution, and
the iron is obtained perfectly free from tin for use. Ammonia is also
formed during the action, and this, uniting with a portion of the sulphuric
acid, forms sulphate of ammonia. Part of the iron is also converted into
sulphate of iron during the action, and these sulphates of ammonia and
of iron are obtained from the solution for use by evaporation in tho
usual way.
If I want to use sulphuric acid and atmospheric air to separate the
tin and iron in carrying out my Invention, I first open the tin plate
cuttings and scraps and sort them into two grades (light and heavy). I
then place. the sorted cuttings and scraps in a suitable perforated cylinder
or other receptacle of any convenient shape, which may be made of lead
or wood. This receptacle is immersed to the depth of half its diameter
or thereabouts in a tank or bath containing dilute sulphuric acid in the pro-
portion of twenty-five per cent. or thereabouts of acid to seventy-five per
cent. or thereabout of water. In this the perforated receptacle and its

page_text: contents is made to perform a slow rotary motion, during which the
atmospheric air enters amongst the tin cuttings and scraps, and the
oxygen of the air acting upon the tin oxydizes it, the acid dissolving the
oxyde as soon as formed, and the nitrogen of the air uniting with the
hydrogen evolved by the iron as it is dissolved forms ammonia. This
tank or bath may be used at the temperature of the atmosphere, or may be
heated by the introduction of steam, or heated air is preferable, when all
the tin is dissolved off from the iron. Time, one hour or more, according
to temperature. I then lift the perforated receptacle and its contents
out of the tank by means of a lifting or hoisting apparatus, and after the
acid has drained or dripped off it is placed in another tank containing
water (either hot or cold) in which a little chloride of sodium or chloride
of potassium has been dissolved, or to which a little hydrochloric acid
has been added. In this I well wash the iron, the solution dissolving off
the last traces of oxyde of tin, and the iron is left clean for use.
I use
the liquors in the tanks until they will act no more, when they are
replaced by fresh ones, or I add more acid and repeat the process as long
as desirable in the same liquors.
If I prefer to use the sulphuric acid and atmospheric air without a
rotary receptacle for the cuttings and scraps I use the acid tank with
the same strength of solution of acid and water or thereabout, and place
the cuttings and scraps in crates or other convenient receptacles, then
immerse them in the acid, liquid, and force atmospheric air, either cold
or heated, through and amongst the cuttings and scraps by using a
forcing air pump or pumps or other convenient means of forcing air
through them. This I continue until the tin is separated from the iron.
I then remove the crate or other receptacle to the tank containing the
solution of chloride of sodium or chloride of potassium or hydrochloric
acid, and wash the iron as before described. I use the liquors in the tanks
until they will act no more, and then replace them by fresh ones, or add
more acid and repeat the process as often as desirable in the same
liquors.
When I use dilute sulphuric acid and nitric acid or dilute sulphuric acid
and nitrous acid to separate the tin from the iron in the tin plate cuttings
and
scraps in carrying out my Invention for every ten hundredweight of
cuttings and scraps I wish to operate upon I prepare in a tank or other
suitable vessel a bath of a sufficient quantity of water (cold or hot) to
immerse that quantity of cuttings and scraps in; to this I add one hundred-

page_text: weight or thereabout of the sulphuric acid of commerce and twenty pounds
or thereabout of the nitric acid of commerce, or thirty pounds or there-
about of the nitrous acid of commerce. I then stir the whole together.
The tin plate cuttings and scraps may then be placed in crates or other
suitable receptacles and immersed in the liquor, or placed in the tank
without crates if preferable, when certain actions and reactions take
place, during which the tin is separated from the iron and remains in
solution, and the iron is obtained perfectly free from tin for use.
Sulphate of ammonia and sulphate of iron are also formed during the
action, and both remain in solution. When the iron is perfectly free
from tin, time, fifteen minutes to one hour, I then drain it as before
explained and place it in another tank containing water (hot or cold) in
which, as before, is dissolved a small quantity of chloride of sodium or
of chloride of potassium, or containing a small quantity of hydrochloric
acid. In this I wash the iron, and this frees it from the film of oxide of
tin remaining upon it, and the iron is obtained perfectly clean for use.
In the first tank or other vessel I then add to the liquor the same
quantity of the sulphuric acid and of nitric acid or of nitrous acid, and
proceed as before, operating on fresh tin plate cuttings and scraps and
this I repeat as often as desirable. When I have operated upon a suf-
ficient quantity of tin plate cuttings and scraps to yield a moderate
precipitate of metal tin I run the liquors from both tanks into another
and larger tank, and into the liquor I then place plates of zinc. This
throws down the tin in the state of metal, and this I collect and wash
and melt in the usual way.
If I wish to obtain chloride of ammonium and the chlorides of tin, of
iron, and of zinc, I then use hydrochloric acid instead of sulphuric acid,
and proceed as before explained. When all the tin has been precipitated
I run the clear liquor which now contains sulphate of zinc, sulphate of
ammonia, and sulphate of iron into proper evaporating vessels, when
it is concentrated, and the sulphate of iron, the sulphato of zinc,
and the sulphate of ammonia are crystallised out by three successive
evaporations and coolings in the usual way. If by the use of hydro-
chloric acid solutions of the different chlorides have been obtained
I (after separating the tin by treatment of zinc) prefer to precipitato
the oxides of zinc and iron from the clear solution with chalk or lime,
then to collect the oxydes, and wash and dry them for usc.
The liquor
then contains chloride of ammonium and chloride of calcium, and this I

page_text: then place in a proper still, then add more chalk or lime, and distil over
the ammonia in the usual way. I then remove the liquor, which is a
strong solution of chloride of calcium, to the evaporating vessel, when
it is evaporated to dryness, and then barrelled for use. I sometimes
prefer to make the nitric acid in the tank or vessel used, in which case I a
use the proper quantity of nitrate of soda and sulphuric acid, or of nitrate
of potass and sulphuric acid, or other nitrate and acid, to give the
quantity of nitric acid above stated or thereabout, using more or less of
the nitrates according to their purity. These I dissolve in the water,
then add the acid, and proceed as before explained.
I do not confine myself to the above quantities of acids used, nor to
any given quantity, altho' I find the quantities I have given act perfectly
well and yield all the results required, still the quantities may be some-
times varied according to the quality of the tin plate cuttings and scraps
with beneficial results, neither do I confine myself to any of the times
given above for separating the tin from the iron, or to any length of
time, because the time necessary is longer or shorter according to the
quantity of acids used in the liquor and the temperature at which the
working is conducted and the quality of the tin plate cuttings and
scraps.
I do not confine myself to the use of chalk or lime to precipitate the
oxyde of iron and zinc, but use any of the alkalies or so called alkaline
earths or their carbonates for that purpose, and also for the purpose of
obtaining the ammonia, although I prefer chalk or lime.
In witness whereof, I, the said James Stuart, have hereunto set my a
hand and scal, this Seventeenth day of June, in the year of our
Lord One thousand cight hundred and seventy-four.
Signed, sealed, and delivered
by the within-named James
Stuart, in the presence of
P. PYALL,
Clerk to E. J. Coates,
13, Bread St., E.C.
JAMES STUART.
(L.S.)