UTILIZATION OF WASTE TIN, TIN PLATE, LEAD AND TERNE PLATE
Year: 1885

page_text: I, EDWIN RICHARDSON BLUNDSTONE, of 10 Wellington Mansions, North Bank,
St John's Wood, London, in the County of Middlesex, Gentleman do hereby
declare the nature of my invention for THE UTILIZATION OF WASTE TIN, TIN
PLATE, LEAD AND TERNE PLATE to be as follows:-
I successively treat quantities of Waste Tin or Lead or Tin plate or Terne
plate, with a hot solution of a salt of chromium (preferably the perchloride), until
no more Tin or Lead, as the case may be, is dissolved.
In the case of Tin or Terne plate, the Iron now remains stripped of its coating of
Tin or Lead respectively, and may be utilized as a source of the various com-
mercially important salts of Iron or be beaten into masses and then melted up.
On the other hand the saturated chromium liquor is drawn off and cooled.
Upon cooling, crystals of metallic Tin or Lead, as the case may be, separate from
the liquor.
Throughout the process contact with the air is avoided by suitable means.
Besides the Tin or Lead obtained as above narrated, a further quantity may be
thrown out by the use of a galvanic current, in the usual manner.
'
The metallic crystals are washed with acidulated water and may be melted up
and cast into ingots of suitable dimension.
The chromium liquor can now be again used to treat further quantities of metal
waste, its qualities remaining, in great measure, unimpaired by the operation, if
carefully carried out as indicated above.
Dated this twenty ninth day of September 1885.

page_text: с
son of Waste-un, Tin Plate, Lead, and Terne‐plate.
I, EDWIN RICHARDSON BLUNDSTONE of N° 10 Wellington Mansions, North Bank,
Regent's Park London, in the County of Middlesex, Gentleman do hereby declare
the nature of my invention for THE UTILISATION OF CERTAIN METAL WASTE AND
THE PRODUCTION OF CERTAIN METALLIC CRYSTALS and in what manner the same
is to be performed, to be particularly described and ascertained in and by the
following statement :-
The object of my invention is to produce, on the one hand, a peculiar and useful
form of Metallic Tin or Lead and, on the other, to utilize Waste Tin or Lead, whether
these metals are in the form of coating on other metals, (eg: Tin plate) or
otherwise.
My process is explained as follows
I successively treat quantities of Waste Tin or Lead or Tin plate or Terne
plate, with a hot solution of perchloride of chromium, (or other salt of chromium
having an analogous reaction) until a saturation point is reached.
In the case of Tin plate or of Terne plate the Iron, which forms the basis of these
fabricks, now remains stripped of its coating of Tin or of Lead respectively, and may
be utilized as a source of the various commercially important salts of Iron or may
be beaten up into masses preparatory to smelting.
On the other hand, the
saturated chromium liquor, having been drawn off into another vat, is allowed
to cool.
Upon cooling, crystals of Metallic Tin or Lead, as the case may be, separate from
the liquor.
These crystals may vary from a considerable size to a very fine dust of acicular
crystals, according to the degree of concentration and the rapidity of cooling and
the agitation or otherwise of the solution during cooling. In any case they are
of great purity.
The metallic crystals are separated from the chromium liquor, which is now in
a fit condition to treat further quantities of metallic waste: the qualities of the
solution being practically unimpaired by the operation, if carefully carried out.
It will be seen that the chemical changes which, occur during cooling, are the
reverse of those which occur during heating, of the chromium liquor in contact
with Tin or Lead.
Throughout the process, contact with the air is avoided, as much as possible,
and, to secure this end, covered vats etc are used so that carbonic acid or other
gas without action on the chemicals used in the process may be introduced to
replace the air which would otherwise be in contact with the chromium liquor.
Again, during the heating, the solution must be carefully sampled from time to
time, especially towards the end of the reaction to guard against the reaction going
too far with the production, in this case, of an insoluble hydrated oxychloride
which would contaminate the metallic crystals and necessitate the expense of their
purification.
The separation of the crystals from the chromium liquor and from the water,
with which they are washed, is readily effected, for owing to their weight, they
speedily sink to the bottom of the apparatus used.

page_text: The plant used is of the simplest and most ordinary character; as will have been
Been by the foregoing description of the process.
Two sets of large covered vats or tanks, one at a higher level than the other, of
any convenient size or shape, constructed of flags, sheets of enamelled-iron, copper,
wood lined by copper, or iron coated with copper, etc, and heated (preferably) by
steam, are necessary. With regard to the use of the neutral gas, which replaces
the air in the apparatus, all that is necessary is, for the vats to be covered, and for
there to be entrance pipes leading the carbonic acid gas near to or just under the
surface of the liquor, and exit pipes to take off any excess of gas or steam, in the
cover, or near the top, of the vat.
Expensive "gas tight" joints, between the vats and their covers and in other
places, are quite unnecessary, for no questions of pressure or risks of explosions are
involved in any part of the process.
The use of carbonic acid gas does not add materially to the expense of the
process, as only a small quantity is needed and it is a bye-product in the manu-
facture of quick lime.
It is believed that the minute and brilliant crystal dust will be of great use as
a decorative agent, in textile and paper fabrics, etc, besides its use as a chemical
agent, especially in glass manufacture:-the chemical properties of Tin and Lead
being greatly enhanced by the fine state of division of the metal. It may also be
used as a coating for other metals.
.>
Finally, owing to the higher prices which the metal, as produced by this process,
will command, it will be possible to utilize waste Tin plate and other metal much
more profitably than hitherto.
In many districts chromium chloride liquors are waste products, but in any
case, the substance is cheaply and easily manufactured from the commercial
bichromates and, it is to be remembered, that the chromium liquor suffers very
little waste (theoretically none), throughout the process I have here detailed.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I declare that what
I claim is
1. The use of a hot solution of perchloride (or other salt having a similar action)
of chromium, for dissolving Tin and Lead, with the subsequent cooling of the
solution, to precipitate the dissolved metal substantially as and for the purposes
specified.
2. The combination with such process as aforesaid of carbonic acid gas, or other
gas having no deleterious action on the chemicals used, to exclude and replace
the air during the operation, substantially as and for the purposes specified.
3. The production of metallic crystals of Tin and of Lead by the use of chromium
chloride solution as set forth.
4. The utilisation of Waste Tin and Lead, whether these metals are mixed with
or coating other metals, or otherwise, by treatment with chromium chloride solution,
in the absence of air, substantially as set forth.
Dated this twenty first day of June.