Improvements in Separating or Recovering Tin from Tin Plate, and Apparatus for the Purpose.
Year: 1892

page_text: Date of Application, 13th Apr., 1892
Complete Specification Left, 13th Feb., 1893-Accepted, 17th June, 1893
Improvements in Separating or Recovering Tin from Tin Plate, and
Apparatus for the Purpose.
We, JOHN FREDERICK DUKE of 141 Great Suffolk Street, Southwark in the
County of London, Engineer, and FREDERICK REDMAN of 20 High Holborn in
the County of London Manufacturer, do hereby declare the nature of this invention
to be as follows:-
This invention has for object the separating or recovering of tin from tin plate
such for instance as waste tin plate and tin plate strap and with this object we
take advantage of the fact that tin has a greater affinity for lead than for iron.
According to our invention the tin plate which should previously be compressed
into a more or less compact mass, is heated in a suitable vessel to a temperature
which is equal to or somewhat exceeds the melting point of lead and we then pour
molten lead into the vessel so as to cover the tin plate. We maintain the heat and
after a time the lead and tin become amalgamated or alloyed with each other, a
portion of the alloy adhering to or coating the iron.
We then run off from the
vessel so much of the alloy of lead and tin as does not adhere to the iron into
another vessel containing another charge of tin plate also heated to the melting
point of lead. The heat is maintained in this vessel also and the tin of the tin plate
therein becomes amalgamated or alloyed with the lead as in the previous vessel.
We then run off the molten alloy into a third vessel and so on for say six vessels
which are a number that can be advantageously employed. When the molten alloy
has been run off from the first vessel into the second we run more molten lead into
the first vessel so as to further reduce the porportion of tin in the alloy that remains
adhering to the iron, and we repeat this process up to say six successive charges,
always running off the molten alloy into the next vessel and so on throughout the
series of vessels. The relative positions of the several vessels should be changed
after every charge, that which was the second of the series becoming the first, the
third becoming the second and so on, a fresh vessel containing a charge of tin plate
being introduced at the bottom of the series.
The alloy of lead and tin obtained from the last vessel can be used as solder or
for other purposes, or if desired the two metals can be separated by any known
process.
In order to recover more tin or alloy of lead and tin from the iron in the last
vessel this vessel is put under a hydraulic or other press and the metal while still
heated is submitted to powerful pressure which has the effect of squeezing out or
recovering more of the tin and lead while the iron with any remaining tin and lead
is formed into a block or ingot.
The apparatus which constitutes part of this invention is the arrangement which
comprises the series of vessels in which the tin plate is heated and mixed with
molten metal, such vessels being strong enough to stand the powerful hydraulic
pressure applied as above explained and having outlets for running off the molten
metal from one vessel to the next; also means for altering the positions of the
vessels relatively to each other and the press adapted to produce powerful pressure
upon the materials in the vessels.
Dated this 13th day of April 1892.
J. C. MEWBURN,
55 & 56, Chancery Lane, London, Chartered Patent Agent.

page_text: COMPLETE SPECIFICATION.
Improvements in Separating or Recovering Tin from Tin Plate, and
Apparatus for the Purpose.
We, JOHN FREDERICK DUKE of 141 Great Suffolk Street, Southwark in the
County of London, Engineer, and Frederick REDMAN of 20 High Holborn in
the County of London, Manufacturer, do hereby declare the nature of this invention
and in what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement:-
This invention has for object the separating or recovering of tin from tin plate
such for instance as waste tin plate and tin plate scrap. To attain this object we
take advantage of the fact that tin has a greater affinity for lead than for iron.
According to our invention the tin plate, which should previously be compressed
into a more or less compact mass, is heated in a suitable vessel to a temperature
which is equal to or somewhat exceeds the melting point of lead and we then, or
before heating the tin plate, pour molten lead into the vessel so as to cover the tin
plate. We maintain the heat and after a time the lead and tin become amal-
gamated or alloyed with each other, a portion of the alloy adhering to or coating
the iron. We then run off from the vessel so much of the alloy of lead and tin as
does not adhere to the iron into another vessel. This other vessel is one containing
a charge of tin plate which has already been treated with molten lead like the tin
plate in the first mentioned vessel, the molten alloy of lead and tin having then
been run off into another vessel preceding it. The heat to the melting point of lead
is maintained in the second mentioned vessel and the alloy which coats the iron
becomes amalgamated or alloyed with the molten alloy that has been run into the
vessel. We then run off the molten alloy into a third vessel and so on for say six
vessels which are a number that can be advantageously employed. After the
molten alloy has been run off from the first vessel into the second we run molten
alloy into the first vessel, now become the second vessel, from a vessel which has
taken its place as first vessel so as to further reduce the proportion of tin in the
alloy that remains adhering to the iron, and we repeat this process up to say six
successive charges, always running off the molten alloy into the next vessel and so
on throughout the series of vessels. The relative positions of the several vessels
should be changed after every charge, the first or most advanced vessel of the
series being removed, that which was the second of the series becoming the first,
the third becoming the second and so on, a fresh vessel contaming a charge of tin
plate being introduced as the last vessel that is to say the vessel in which the tin
plate receives its first treatment with the molten lead.
The alloy of lead and tin obtained from the last vessel in which the tin plate is
treated can be used as solder or for other purposes, or if desired the two metals can
be separated by any known process.
In order to recover more tin or alloy of lead and tin from the iron in the last
vessel in which the tin plate is treated, either this vessel is put under a hydraulic
or other press and the metal while still heated is submitted to powerful pressure
which has the effect of squeezing out or recovering more of the tin and lead while
the iron with any remaining tin and lead is formed into a block or ingot suitable
for remelting or the contents of the vessel are turned out into another vessel in
which the metal is submitted to powerful pressure as just explained.
The apparatus which constitutes part of this invention is the arrangement which
comprises the series of vessels in which the tin plate is heated and mixed with
molten metal such vessels having outlets for running off the molten metal from
one vessel to the next; also means for altering the positions of the vessels relatively
to each other and the press adapted to produce powerful pressure upon the materials
in the vessels or in another or special vessel into which the vessels are emptied.
Figures 1 and 2 of the accompanying drawings are two vertical sections taken
5

page_text: 2
с
at right angles to each other of an apparatus specially designed for carrying out
the process or method of operation hereinbefore described. a is a furnace or
heating chamber which can be heated by any suitable means such for instance as
gas as indicated by the burner b. At one end of the chamber is an opening e for
the introduction of the vessels which are pushed into position along a guideway or
platform d. At the other end of the chamber is an opening e for the withdrawal
of the vessels which are removed along the guideway or platform f. This end
of the chamber is provided with doors g g to enable the outlet taps or valves of the
vessels to be got at and operated. ii are endless chains passing at the upper part
of their travel over sprocket wheels kk and at the lower part of their travel under
sprocket wheels 11. These lower sprockets wheels are mounted on a shaft m to
which rotary motion can be imparted by means of a windlass » so as to drive the
chains or instead of this windlass any other suitable power may be employed. The
chains i carry at intervals projecting arms p p to engage with undercut lugs or
other suitable devices 9 9 on the vessels as hereinafter described.
vessels; they are preferably made with sloping sides as shown to enable their
contents to be more readily turned out when the vessels are inverted. ss are
guides for the chains and formed preferably of H iron. t is a trough in which the
molten alloy run from the bottom vessel is received and from which it escapes by
the pipe or outlet u. are taps or valves to the vessels r. y is a hydraulic
press for pressing the iron from the last vessel while still heated in order to squeeze
out or recover more of the tin and lead and to form the iron with any remaining
tin and lead into a block or ingot. This pressure can be effected upon the iron
either when in the last vessel or in a special vessel into which the iron from the
last vessel is emptied. We prefer to employ a special vessel as otherwise the
vessels would require to be made very strong and heavy to enable them to
stand the powerful pressure to which they would have to be submitted.
2'
are the
The apparatus is used as follows:- Each vessel supplied with its compressed
charge of tin plate and filled with molten lead to above the level of the tin plate
is in its turn pushed through the opening c on to the platform d. When the chains
are caused to travel two of the arms pp that is to say one on each chain engage
with the lugs 9 on the vessel and lift it off the platform, and the vessel remains
suspended by the same two arms until in its turn it reaches and rests upon the
delivery platform f when it becomes freed from the arms and can be withdrawn.
The movement given to the chains and vessels is intermittent, say at intervals of
ten minutes, and each movement is only to an extent equal to the distance between
the suspension points of two of the vessels as will be understood on reference to the
figure. When the vessel has reached the position of the vessel marked 5 in Figure 1
the heat will have been maintained for more than a sufficient time (about ten
minutes generally suffices) for the lead and tin therein to have become amalgamated
or alloyed with each other. Then (assuming that the apparatus has been at work
some time and all the vessels in the chamber are charged) we open and close the
taps or valves of the vessels occupying the respective positions 10, 9, 8, 7, 6, 1 in
succession so as to run the molten metal in 10 into the trought and the molten
metal in 9, 8, 7, 6 and 5 respectively into the vessels next below. The vessel
occupying the position 10 is now withdrawn through the opening e, its contents are
turned out into another vessel or box which is then placed upon the follower of the
press y so that when forced up against the part of the press head more tin and
lead may be squeezed out or recovered and the iron with any remaining tin and
lead formed into a block or ingot suitable for remelting. The part of the press
is preferably kept heated by gas or otherwise so as to assist in maintaining the
heat of the tin plate or iron in the vessel or box.
Although we consider that the particular way shown and described of shifting
the vessels to the various positions they have to successively occupy is well
adapted for the purpose to be effected we do not limit ourselves thereto.
We have shown that the molten material is run successively into six vessels r
or in other words that each charge of tin plate is submitted to six successive

page_text: treatments by the molten material and we consider that this number is that by
The number of treatments
which the process can be most economically worked.
can however be varied as desired and be reduced to three or two or even to one
when we submit each charge of tin plate to only one treatment, successive charges
of tin plate can be treated in the same box and the molten material employed in
the treatment may either be lead or the alloy of lead and tin obtained by the
treatment of previous charges.
Having now particularly described and ascertained the of our said invention
and in what manner the same is to be performed we declare that what we
claim is
1. The process of separating or recovering tin from tin plate which consists in
submitting the tin plate to the action of molten lead while maintained at a
temperature equal to or exceeding the melting point of lead whereby the lead
becomes alloyed or amalgamated with the tin of the tin plate and in then running
off the molten alloy, into a suitable receiver, substantially as hereinbefore
described.
2. The process of separating or recovering tin from tin plate, which consists
in submitting a quantity of tin plate while maintained at a temperature equal to
or exceeding the melting point of lead to the action of molten lead and then to the
action, once or oftener, of molten alloy of lead and tin run from other quantities of
tin plate which are being similarly treated, and finally running off the resulting
molten alloy of lead and tin into a suitable receiver substantially as herein before
described.
3. The process of separating or recovering tin from tin plate, which consists in
submitting a quantity of tin plate while maintained at a temperature equal to or
exceeding the melting point of lead to the action of molten lead with or without
being subsequently submitted once or oftener to the action of molten alloy of lead
and tin un from other quantities of tin plate which are being similarly treated, in
running off the resulting molten alloy of lead and tin into a suitable receiver, and
in then submitting the tin plate to the action of a powerful press whereby a further
amount of alloy of lead and tin is squeezed out and recovered, all substantially as
hereinbefore described.
4. The arrangement of apparatus substantially as and for the purpose herein-
before described.
D
19th dow of Wahm 1902
J. C. MEWBURN,
55 & 56, Chancery Lane, London, Chartered Patent Agent.