Cuttings or Scrap and from Metal Covered with Tin.
Year: 1887

page_text: Cuttings or Scrap and from Metal Covered with Tin.
I SEBASTIEN TOUSSAINT MONTAGNE merchant in Nantes, France, 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 is an improvement on the invention patented in England on the
27th day of February 1886 No. 2865, relating to the extraction of the tin from tinned
metal, by means of hydrochloric acid gas.
Our improvement consists in the following moans and apparatus.
The tinned scrap is placed, without however being pressed, into a series of brick-
work chambers lined with any suitable material capable of resisting the action of
acids, and sufficiently thick to retain heat for a long time.
These chambers are put into intercommunication by a system of piping, provided
with suitable valves capable of allowing the acid gas to pass successively into several
chambers before passing to the exit or chimney, completely exhausted by its passage
through material less and less attacked by the acid.
In the annexed drawing, 1, 2, 3 are the chambers, a the supply of hydrochloric acid
gas, b the pipes provided with valves c, c', c³ for leading the said gas into the
chambers, 63, 6 are pipes for putting the chambers 1, 2, 3 into intercommu-
nication d is the tank supplying water to the chambers through a perforated coil j,
e is the vat for collecting, by means of pipes f the liquor of protochloride of tin. 9 is
the pipe having valves h for allowing the exhausted gas to escape through the
chimney i and k is a generator supplying steam by the pipes provided with
valves m.
Let it be supposed, for the sake of clearness, that three chambers are employed and
that the gas passes successively through the chambers 1, 2 and 3. The gas first
reaches the chamber 1 (through the pipe b and valve c) in which the extraction will be
soonest completed. When the extraction has been effected, the chamber 1 is com-
pletely shut off by closing the valve c of the gas supply pipe 6 and the valve c' which
puts the said chamber 1 in communication with the chamber 2 is opened. The acid gas
will then first enter the chamber 2 by the valve c¹ and be led into the chamber
and thence to the chimney.

page_text: While the chamber 1 is shut off, a spray of fresh water is allowed to fall into the
same, from a perforated coil ; or otherwise. At the same time, in order to reach the
parts which are the least accessible, a jet of steam is supplied from a generator k by
pipes 1, the same being cooled by the spray of fresh water and forming vapor which
settles on all the surfaces covered with protochloride of tin and carries it off in
dissolution.
The condensation of all the hydrochloric acid gas is thus certain to be effected and
the chamber 1 can be opened for removing the metal deprived of tin and recharging
the same with a fresh lot of tinned scrap, without being inconvenienced by the acid
smell. When this is done, the chamber 1 is closed and is placed again in the circuit,
by opening the valve c' and thus making this chamber the last one, that is to say the
gas entering through the chamber 2 passes into the chamber 3 and then into the
chamber 1, whence it is directed to the escape or chimney i. The order of circulation
1, 2, 3 becomes 2, 3, 1. After the metal contained in the chamber 2 has become
exhausted, the circulation is again 3, 1, 2 and so on, in successive order.
I have supposed an example of three chambers, but this number may vary. The
principle of the methodical exhaustion remains the same.
The liquors of protochloride of tin are collected into a vat e; the said liquors are
precipitated either by means of zinc or iron, or by means of lime. When zinc is used,
a metallic sponge is obtained, which, when washed with pure water and then with
acidulated water is freed, from all trace of chloride of iron and of chloride of zinc; the
said sponge is then dried and when melted, produces very pure tin. By means of
lime, a deposit is obtained which is pressed, dried and finally treated like tin ore.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is:―
First. The arrangement of apparatus consisting in causing hydrochloric acid gas,
in a still hot state to pass successively into several chambers containing scrap, cuttings
or pieces of tinned metal, which is less and less attacked by the acid, for the purpose
of reducing, almost to the theoretical figure, the quantity of hydrochloric acid gas
consumed.
Second. The simultaneous employment, for the purpose of obtaining a complete
washing in the vessels in which is effected the reaction of the sheet iron or metal
covered with protochloride of tin, of cold water spray and of a jet of steam, thus
allowing the said protochloride to be got at and dissolved, on the parts of the scrap
or auttings which are the least accessible and also allowing of all the hydrochloric
acid gas being condensed.
Third. The treatment of the liquors of protochloride of tin by the means hereinbefore
described.
T 2
1
1 SM 1007