IMPROVE- MENTS IN THE MODE OF RECOVERING TIN FROM TIN SCRAP
Year: 1883

page_text: LETTERS PATENT to Edward Lawrence Cleaver of Red Lion Square in the
County of Middlesex Analytical Chemist, for an Invention of "IMPROVE-
MENTS IN THE MODE OF RECOVERING TIN FROM TIN SCRAP"
PROVISIONAL SPECIFICATION left by the said Edward Lawrence Cleaver
at the Office of the Commissioners of Patents on the 23rd October 1883.
EDWARD LAWRENCE CLEAVER of Red Lion Square in the County of Middlesex
Analytical Chemist "IMPROVEMENTS IN THE MODE OF RECOVERING TIN FROM
TIN SCRAP."
The object of this invention is to remove from pieces of waste tin plate, the tin
with which the iron plate has been coated during manufacture.
The amount of waste pieces of tin, or tin scrap as it is termed, arising in the
manufacture of utensils and articles of tin, is enormous, and many attempts
have been made to recover the tin from the scrap, but hitherto with little or
no success.
In carrying out my invention the tin scrap is first carefully looked over, and
all excess of dirt, is, so far as possible, removed therefrom. The cleaned scrap is
then thrown into either an acid or an alkaline bath, which is maintained at
a temperature of over 120° Fahrenheit. The effect of this soaking or boiling
is to dissolve the tin, which is held in solution in the acid or alkaline bath.
The time required to effect the removal of the tin will depend upon the strength
of the bath and the temperature at which it is maintained.
In preparing the bath the acid I prefer to employ is hydrochloric acid, which
may be used alone, or diluted with water or in combination with a metallic or
other salt.
The alkaline bath which it is preferred to use is a solution of caustic soda
or potash or a mixture of both and which may also be used with or without a
metallic salt.
As soon as the tin is entirely dissolved off the plate, the iron plate is removed,
and the solution is subjected to the action of a current of electricity produced by
a dynamo or other electrical generator.

page_text: The electrical action will cause the tin to deposit which deposit will be removed
from the bath and washed and may then be melted down and cast into ingots for
the market.
Instead of treating the tin scrap as above described it may be immersed in
a suitable bath of some solvent as above mentioned and connected to one pole
of the electrical generator, the other pole of the generator being connected to a
plate of metal or any suitable electrical conductor on which will be deposited
by the action of the electric current the tin contained in solution in the bath.
By varying the current of electricity and the composition of the bath the tin
may be deposited in a coherent form ready for the market.
When the tin scrap is soaked or boiled in a bath of hydrochloric acid or alkali
alone, the resultant will be pure tin but when a metallic salt such as a salt of
lead is added to the bath after the boiling operation and the iron plate has been
removed the precipitant will be a metallic alloy in this case of tin and load which
will be cast into ingots of suitable size and sold as solder.
It will of course be understood that other acids and alkalis may be used, but
I have found those above mentioned have given very good results.
In like manner other metallic salts may be used and will be added to the
bath either before or after the boiling according to the nature of the salt
employed.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Edward Lawrence Cleaver in the Patent Office on the 23rd April
1884.
EDWARD LAWRENCE CLEAVER of Red Lion Square in the County of Middlesex
Analytical Chemist IMPROVEMENTS IN THE MODE OF RECOVERING TIN. FROM
TIN SCRAP
"
38
The object of this Invention is to remove from pieces of waste tin plate the tin
with which the iron plate has been coated during manufacture
The amount of wasto pieces of tin or tin scrap as it is termed arising in
the manufacture of utensils and articles of tin is enormous and many attempts
have been made to recover the tin from the scrap but hitherto with little or no
success.
In carrying out my Invention the tin scrap is first carefully looked over and
all excess of dirt is so far as possible removed therefrom-The cleaned scrap is
then thrown into either an acid or an alkaline bath which is by preference
maintained at a temperature of over One hundred and twenty degrees
Fahrenheit. The effect of this treating or boiling is as is well known to
dissolve the tin off the scrap and it is then held in solution in the acid or
alkaline bath.
The time required to effect the removal of the tin will depend upon the strength
of the bath and the temperature at which it is maintained.
In preparing the bath the acid I prefer to employ is hydrochloric acid which
may be used alone or diluted with water or in combination with a metallic or
other salt.
The alkaline bath which it is preferred to use is a solution of Caustic soda or
potash or a mixture of both and which may also be used with or without a metallic
or other salt.
As soon as the tin is entirely dissolved off the plate the iron plate is removed
and the solution is subjected to the action of a current of electricity produced by
a dynamo or other electrical generator.
The electrical action will cause the tin to deposit which deposit will be removed
from the bath and washed and may then be melted down and cast into ingots for
the market.
Instead of treating the tin scrap as above described it may be immersed in a
suitable bath of some solvent as above mentioned and connected to one pole of the
electrical generator, the other pole of the generator being connected to a plate of
metal or any suitable electrical conductor on which will be deposited by the action
of the electric current the tin contained in solution in the bath.
By varying the current of electricity and the composition of the bath the tin
may be deposited in a coherent form ready for the market.
When the tin scrap is treated or boiled in a bath of hydrochloric acid or alkali
alone the resultant will be pure tin but when a metallic salt such as a salt of lead
is added to the bath after the boiling operation and the iron plate has been removed
the precipitant will be a metallic alloy in this case of tin and lead which will be
cast into ingots of suitable size and sold as solder.
It will of course be understood that other acids and alkalis may be used but I
have found those above mentioned have given very good results.
In like manner other metallic salts may be used and will be added to the
bath either before or after the boiling according to the nature of the salt
employed.

page_text: Having now described this Invention for " Improvements in the mode of
recovering tin from tin scrap" and explained the manner of carrying the same
into effect I claim :-
The recovery of tin from tin scrap by the combined use of. a chemical solvent
with currents of electricity in the manner above described:
In witness whereof I the said Edward Lawrence Cleaver have hereunto set
my hand and seal the twenty third day of April in the year of our Lord One
thousand eight hundred and eighty four.
ALT
בזבזיז מגל
UD VAN
MATURIT II VIT STATE LA
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(1.5.)