PROCESS FOR THE RECOVERY OF TIN FROM TINPLATE SCRAP AND OTHER MATERIALS CONTAINING TIN, BUCH AS OXIDIZED METAL AND RESIDUES
Year: 1884

page_text: PROVISIONAL SPECIFICATION.
I, HERBERT, JOHN HADDAN, of 67, Strand, in the City of Westminster, Civil
Engineer, do hereby declare the nature of said invention for PROCESS FOR THE
RECOVERY OF TIN FROM TINPLATE SCRAP AND OTHER MATERIALS CONTAINING TIN,
BUCH AS OXIDIZED METAL AND RESIDUES, a communication to me from abroad
by Alfred Lambotte, Vice-President of the Tribunal of Commerce, of Bruxelles,
Belgium, to bo as follows:-
This invention has for its object to recover tin from tinnod iron and more
particularly from the waste of tinplate, but the process is also applicable to any
other material containing tin such as dross, chippings, oxidized metal, and residues.
According to circumstances these materials may preponderate so as to form the
principal part.
By this process the two metals may be separated by means of chlorine-gas, in
such manner, that the iron is recovered ready for smelting, and the tin in a
particularly pure (that is free from iron) and commercially useful state.
Attempts for separating tin from tiuplate by means of chlorine have been made
as early as 1854 by Panella, Seely and Higgin, but without success. The principal
difficulty in the application of chlorine consists in confining its effect to the tin
alone, without attacking the iron, and in preventing the formation of liquid stannic
chloride which acts on the iron, causing, under reduction to stannous chloride,
the formation of ferrous chloride.
The present invention has for its object to avoid these drawbacks.
:
1. By causing the chlorine to act only in a highly diluted state on the tinned
material, that is to say, mixed with air or other inert gases, in which state it does
not attack the iron; this is carried out by conducting a continuous current of
chlorine gas over the surface of the material, so as to simultaneously carry off the
vapours of stannic chloride which are generated, thereby preventing the close
contact of the latter with the bare iron.
2. By causing the chlorine to act at a temperature above the boiling point of the
stannic chloride, partly because tho re-action is too much retarded in the cold, and
further, in order to provent the condensation of the chloride.
3. By employing the chlorine in a certain dry state.

page_text: A further peculiarity of this invention consists in the condensation of the vapours
of stannic chloride, which takes place in such manner that the air or gas current,
charged with chloride vapours, is charged with so much moisture after leaving the
material, as is necessary for producing hydrated or crystallized stannic chloride,
which is more. easily condensed than dry stannic chloride; or by conducting the
current charged with chlorido vapours through a more or less concentrated
solution of stannic chloride.
The latter forms a superior binding substance, and in this way the concentration
of the solutions of stannic chloride may be automatically effected up to the point
of complete saturation or beyond it.
In carrying out this invention I proceed as follows:
The material to be untinned is introduced into a kind of cupola furnaces, or into
stone towers, or iron towers protected against radiation of heat, and which for the
purpose of continuous working are provided with movable grates or other
appliances for removing the untinned material.
The untinned material is removed below by a suitable motion of the grate bara
or other supports, while fresh material is filled in from above.
The chlorine gas, which is strongly diluted with air or other inert gases,
sufficiently dried and'. heated to the temperature necessary for the reaction, is
introduced at the lower part of the tower, and sucked through the mass of
material. The vapours of stannic chloride generated are immediately carried off
by the current.
. In order to recover crystallized salts directly from the vapours, the latter arò
charged in the upper part of the tower (left free for this purpose) with the water
necessary for crystallization, in the shape of aqueous vapours. The deposit of the
crystals takes place in spacious condensation chambers specially arranged for this
purpose. Or the dry vapours are conducted into the condensation chambers, the.
walls of which are kept moist for the purpose of causing the formation of crystals.
If it is not intended to recover the stannic chloride immediately as a crystallized
salt, the air or gas currents charged with chloride vapours may be conducted
through coke towers irrigated with water, through washing apparatus, standard
apparatus, or other appliances usually employed for similar purposes of absorption.
In this case the condensation of the stannic chloride may be assisted by the
addition of muriatic acid, or solutions of such chlorino compounds which form
with stannic chloride technically useful double salts, for instance sodic chloride
and ammonium chloride. This method serves at the same time to prevent the
decomposition of the stannic chloride during the evaporation of the obtained
solutions.
It is also advisable to cause the absorption of the stannic chloride vapours by a
solution of stannic chloride. The latter forms, until fully saturated, a highly
suitable binding substance, and permits an automatic and continuous condensation
of the chloride vapours and the concentration of the obtained solutions by means
of the methodical arrangements of apparatus generally used for such purposes.
For the purpose of crystallizing the stannic chloride contained in the obtained
solutions, the latter are evaporated by conducting a warm current of dry or moist
air through the same. By this process the water of the solution is removed,
without causing the decomposition of the stannic chloride.
The concentration may also be carried out in vacuo.
The above described process permits the utilization of the strongly diluted
gaseous chlorine obtained in various chemical processes, such as Deacon's, Weldon's,
and Solvay's.

page_text: COMPLETE SPECIFICATION.
I, HERBERT JOHN HADDAN, of 67, Strand, in the City of Westminster, Civil
Engineer, do hereby declare the nature of said invention for PROCESS FOR THE
RECOVERY OF TIN FROM TINPLATE SCRAP AND OTHER MATERIALS CONTAINING TIN,
SUCH AS OXIDIZED METAL AND RESIDUES, a communication to me from abroad
by Alfred Lambotte, Vice President of the Tribunal of Commerce, of Bruxelles,
Belgium, 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 its object to recover tin from tinned iron and more
particularly from the waste of tinplato, but the process is also applicable to other
material containing tin such as dross, chippings, oxydized metal, and residues.
According to circumstances these materials may preponderate so as to form the
principal part.
By this process the two metals may be separated by means of chlorine-gas in
such manner that the iron is recovered ready for smelting and the tin in a
particularly pure (that is free from iron) and commercially useful state.
Attempts for separating tin from tin plate by means of chlorine have been mado
as early as 1854 by Panella, Seely & Higgin, but without success.
The principal
difficulty in the application of chlorine consists in confining its effect to the tin
alone, without attacking the iron, and in preventing the formation of liquid
stannic chloride which acts on the iron causing, under reduction to stannous
chloride, the formation of ferrous chlorido.
.The present invention has for its object to avoid these drawbacks.
1. By causing the chlorine to act only in a highly diluted state on the tinned
material, that is. to say mixed with' air or other inert gases, in which state it docs
not attack the iron; this is carried out by conducting a continuous current of
chlorino gas over the surface of the material so as to simultaneously carry off the
vapours of stannic chloride which are gonorated, thereby preventing the close
contact of the latter with the bare iron.
2. By causing the chlorine to act at a temperature above the boiling point of tho
stannic chloride, partly because the reaction is too much retarded in the cold, and
further in order to prevent the condensation of the chloride.
3. By employing the chlorine in a certain dry state. A further peculiarity of
this invention consists in the condensation of the vapours of stannic chloride which
takes place in such manner that the air or gas current charged with chloride
vapours, is charged with so much moisturo after leaving the material as is necessary
for producing hydrated or crystallized stannic chloride which is more easily
condensed than dry stannic chloride; or by conducting the current charged with
chlorido vapours through a more or less concentrated solution of stannic chloride.
The latter forms a superior binding substance, and in this way the concentration

page_text: of the solutions of stannic chloride may be automatically effected up to the point
of complete saturation or beyond it.
In carrying out this invention I proceed as follows:
The material to be untinned is introduced into a kind of cupola furnaces, or into
stone towers, or iron towers protected against radiation of heat and which for the
purpose of continuous working are provided with movable graters or other
appliances for removing the untinned material.
The untioned material is removed below by a suitable motion of the grate bars
or other supports, while fresh material is filled in from above.
The chlorine gas which is strongly diluted with air or other inert gases,
sufficiently dried and heated to the temperature necessary for the reaction, is
introduced at the lower part of the tower, and sucked through the mass of material.
The vapours of stannic chloride generated are immediately carried off by the
current,
In order to recover crystallized salts directly from the vapours, the latter are
charged in the upper part of the tower (left free for this purpose) with the water
necessary for crystallization, in the shape of aqueous vapours. The deposit of tho
crystals takes place in spacious condensation chambers specially arranged for this
purpose. Or the dry vapours are conducted into the condensation chambers, the
walls of which are kept moist for the purpose of causing the formation of crystals.
If it is not intended to recover the stannic chloride immediately as a crystallized
salt, the air or gas currents charged with chloride vapours may be conducted
through coke towers irrigated with water, through washing apparatus, standard
apparatus or other appliances usually employed for similar purposes of absorption.
In this case the condensation of the stannic chloride may be assisted by tho
addition of muriatic acid or solutions of such chlorine compounds which form with
stannic chloride technically useful double salts, for instance sodic chloride and
ammonium chloride, This method serves at the same time to prevent the
decomposition of the stannic chloride during the evaporation of the obtained
solutions.
"
It is also advisable to cause the absorption of the stannic chlorido vapours by a
solution of stannic chloride. The latter forms until fully saturated a highly
suitable binding substance and permits an automatic and continuous condensation
of the chloride vapours and the concentration of the obtained solutions by means
of the methodical arrangements of apparatus generally used for such purposes.
For the purpose of crystallizing the stannic chloride contained in the obtained
solutions, the latter are evaporated by conducting a warm current of dry or moist
air through the same. By this process the water of the solution is removed
without causing the decomposition of the stannic chloridė.
The concentration may also be carried out in vacuo.
The above described process permits the utilization of the strongly_diluted
gaseous chlorine obtained in various chemical processes, such as Deacon's, Weldon's,
and Solvay's.
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 method of extracting tin from wasto tin-plate, and other tinned iron
articles, which consists in conducting over the articles to be thus treated a current
of chlorine gas diluted with air or other inert gases, at a temporature above the
boiling point. of stannic chloride.
2. The direct production of crystallized stannic chloride from the stannic
chloride vapours obtained as indicated under claim 1 by the supply of aqueous
vapours, or condensation in moist chambers.
8. The methodical absorption of the stannic chloride vapours by a stannic
chlorido solution of medium strength.

page_text: 4. The evaporation of the concentrated stannic chloride solution obtained, for the
formation of crystals, by conducting through the said solution a current of warm
air which may or may not have been previously dried.
5. In combination with the process described by claim 1, the employment of
processes of manufacture which yield diluted chlorine gas, such as Deacon's,
Weldon's or Solvay's process.
6. The treatment, by the described process, of any materials containing tin, for
the purpose of converting the tin into stannic chlorides and other technically useful
compounds.