Improvement in the Process of Precipitating Oxide of Tin from Solutions.
Year: 1892

page_text: Date of Application, 21st Sept., 1892
Complete Specification Left, 21st June, 1893-Accepted, 29th July, 1893
PROVISIONAL SPECIFICATION.
Improvement in the Process of Precipitating Oxide of Tin from
Solutions.
I, CAMILLE LÉON CHARLES BERTOU, of 11 Rue de St. Petersbourg, Paris, in
the Republic of France, Chemist, do hereby declare the nature of this invention
to be as follows:-
The object of this invention is the precipitation of tin in the form of an oxide
from solutions containing it either alone or mixed with other metals and is
especially designed for use upon the solutions of tin obtained by the process which
is the subject of my Patent No. 15174 dated 25th September 1890, according to
which scraps and waste of tin plate are placed in a bath at a temperature of about
50° C. composed of hydrochloric acid and a nitrate in which the proportion of the
nitrate is preferably about six per cent. of the weight of the acid, then adding more
of the scraps or waste in successive charges and in the meantime gradually raising
the temperature of the bath as it becomes more and more saturated with tin and
weaker in the nitrate.
This invention consists in precipitating the tin from the solution in the state of
of an oxide by the combined employment of a carbonate of an alkaline earth metal
and a carbonate of an alkali metal as hereinafter set forth. I choose by preference
carbonate of lime and carbonate of soda because of their cheapness and their light
atomic weight.
The process of precipitating may be performed in the bath in which the tin
solution to be treated has been obtained or in any suitable bath. While the
solution is maintained at a temperature near but below the boiling point and exposed
to the atmosphere, I add the carbonate of lime very gradually in small quantities
until the precipitation of the oxide of tin (which precipitates first) is completed in
order to precipitate afterwards in the state of oxide or carbonate any iron, zinc,
lead or copper which may be contained in the liquor. At the successive additions
of the carbonate of lime there will be observed a disengagement of carbonic acid
which indicates that all the tin has not been precipitated, but as soon as the
gaseous disengagement ceases, this part of the operation may be considered as
terminated. Then after the contents of the bath have been allowed to cool, the
precipitate is collected and is first washed with cold water and afterwards
suspended in water at any temperature below the ebullition point to which is added
gradually or in small quantities the carbonate of soda until the liquor shows a
slightly alkaline reaction when it may be known that the dechloridation is complete
and pure oxide of tin is obtained. All that now remains to be done is to transform
this oxide into metal which may be done with great facility by any of the known
means.
Dand this 1st down of Contamshee 1000
COMPLETE SPECIFICATION.
Improvement in the Process of Precipitating Oxide of Tin from
Solutions.
I, CAMILLE LÉON CHARLES BERTOU, of 11 Rue de St. Petersbourg, Paris, in
the Republic of France, Chemist, 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 :-
The object of this invention is the precipitation of tin in the form of an oxide

page_text: from solutions containing it either alone or mixed with other metals and is
especially designed for use upon the solutions of tin obtained by the process which
is the subject of my Patent No. 15174 dated 25th September 1890, according to
which scraps and waste of tin plates are placed in a bath at a temperature of about
50° C. composed of hydrochloric acid and a nitrate in which the proportion of the
nitrate is preferably about six per cent. of the weight of the acid, then adding more
of the scraps or waste in successive charges and in the meantime gradually raising
the temperature of the bath as it becomes more and more saturated with tin and
weaker in the nitrate.
This invention consists in precipitating the tin from the solution in the state of
an oxide by the combined employment of a carbonate of an alkaline earth metal
and a carbonate of an alkali metal as hereinafter set forth. I choose by preference
carbonate of lime and carbonate of soda because of their cheapness and their light
atomic weight.
The process of precipitating may be performed in the bath in which the tin
solution to be treated has been obtained or in any suitable bath. While the
solution is maintained at a temperature near but below the boiling point and exposed
to the atmosphere, I add the carbonate of lime very gradually in small quantities
until the precipitation of the tin (which precipitates first) is completed in order not
to precipitate afterwards in the state of oxide or carbonate any iron, zinc, lead or
copper which may be contained in the liquor. At the successive additions of the
carbonate of lime there will be observed a disengagement of carbonic acid which
indicates that all the tin has not been precipitated, but as soon as the gaseous
disengagement ceases, this part of the operation may be considered as terminated.
Then after the contents of the bath have been allowed to cool, the precipitate is
collected and is first washed with cold water and afterwards suspended in water at
any temperature below the ebullition point to which is added gradually or in small
quantities the carbonate of soda until the liquor shows a slightly alkaline reaction
when it may be known that the dechloridation is complete and pure oxide of tin is
obtained. All that now remains to be done is to transform this oxide into metal
which may be done with great facility by any of the known means.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is
The within described improvement in the process of precipitating tin in the form
of an oxide from solutions containing it, consisting in first adding carbonate of an
alkaline earth metal to the solution at a temperature nearly but below ebullition
and gradually continuing such addition until the precipitation of the tin is
completed, then allowing the liquor to cool and collecting the precipitate there-
from, next washing the precipitate with cold water and afterwards suspending the
washed precipitate in a solution of a carbonate of an alkali metal the strength of
which is gradually increased until it presents a slightly alkaline reaction.
Dated this 21st day of June 1893.
ALLISON BROS.,
Agents for the Applicant.