Year: 1886

page_text: I, GEORGE THOMPSON LEWIS, of the City and County of Philadelphia and State
of Pennsylvania, United States of America, Manufacturer, do hereby declare the
nature of this invention to be as follows: -
In the smelting of Tin Ore as usually performed there is a loss of from five to
fifteen per cent of tin by volatilization even if great care is taken to prevent it.
This loss is so serious that to reduce it to a minimum the smelting of tin ore
is very often done in a reverberatory furnace, though cupola furnaces are more
economical to work,
In smelting down scraps of tinned iron (Tin scraps) the tin is either entirely lost
unless it has first been removed by expensive chemical operations.
Tin fumes from smelting furnaces have hitherto been very incompletely recovered
by settling in long flues.
I have discovered that I can completely condense and arrest tin fumes from the
process of smelting tin ore, or from the process of refining of tin and the smelting
of "tin scraps," by forcing them into receptacles of wool, calico, or other similar
textile fabric, this textile fabric serving as a filtering medium and allowing the
gases to escape through the interstices while condensing the tin fumes.
I prefer to have my strainers made in the shape of bags or sacks and I force the
gases and metallic fumes from the furnace into these strainers, by a pump or
preferably by a fan blower, which sucks the gases and fumes from the exit of the
furnace through cooling flues, preferably of sheet iron, and then forces them into,
the textile strainers. By employing such a fume condenser less care is necessary
to keep the temperature low in the smelting furnace, and this has an economical
value; where salts of tin are in demand, it may even be an advantage to employ
a hot blast in the furnace so as to produce a large amount of tin fumes, which may
be used directly in making salts of tin.
Where "tin scraps "
.are melted down in a cupola furnace, I have found it advan-
tageous to use a rather low cupola furnace in order to as much as possible avoid
arresting the fumes of tin in the upper part of the furnace and further to have
a set of tuyeres about two feet above the regular tuyeres, in this manner the

page_text: volatilization of the tin is nearly complete and the fumes can be condensed in my
strainers, the metallic iron produced will also be of superior quality to the metal
produced in the usual manner from tinned iron scraps.
The accompanying drawing shows an ordinary tin smelting cupola furnace, "A,"
in connection with the fume condenser.
fuel
The furnace is furnished with a hood, B, open in front at, b, where the ore,
and fluxes are introduced into the furnace. The fan, D, draws the fumes and gases
from the hood, B, into the sheet iron pipes, c, c, c, and forces them into the bags, “e,"
which are fastened to the collars, g, on the pipe, H, the gases pass through the
interstices of the textile fabric, while the condensed metallic fumes gradually fall
down in the hoppers, f, from which they are emptied upon the floor or into suitable
receptacles.
The tin fumes collected in the flues and hoppers are either used directly in the
manufacture of salts of tin, or they are reduced to metal either by fire reduction
or by the wet process.

page_text: ז'
from Tinned Sheet Iron Scraps.
I, GEORGE THOMPSON LEWIS, of the City and County of Philadelphia, and State
of Pennsylvania, United States of America, Manufacturer, do hereby declare the
nature of my invention for "IMPROVEMENTS IN THE SMELTING OF TIN ORE AND
RECOVERING TIN FROM TINNED SHEET IRON SCRAPS" and in what manner the
same is to be performed, to be particularly described and ascertained in and by
the following statement:-
In the smelting of Tin Ore as usually performed, there is a loss of from five to
fifteen per cent of tin by volatilization even if great care is taken to prevent it.
This loss is so serious that to reduce it to a minimum the smelting of tin ore
is very often done in a reverberatory furnace, though cupola furnaces are more
economical to work.
In smelting down scraps of tinned iron (Tin scraps) the tin is either entirely
lost unless it has first been removed by expensive chemical operations.
Tin fumes from smelting furnaces have hitherto been very incompletely recovered
by settling in long flues.
:
I have discovered that I can completely condense and arrest tin fumes from the
process of smelting tin ore, or from the process of refining of tin and the smelting
of "tin scraps," by forcing them into receptacles of wool, calico or other similar
textile fabrics, this textile fabric serving as a filtering medium and allowing the
gases to escape through the interstices while condensing the tin fumes.
I prefer to have my strainers made in the shape of bags or sacks and I force
the gases and metallic fumes from the furnace into these strainers by a pump or
preferably by a fan blower, which sucks the gases and fumes from the exit of the
furnace through cooling flues, preferably of sheet iron, and then forces them into
the textile strainers.
By employing such a fume condenser less care is necessary to keep the tempe-
rature low in the smelting furnace, and this has an economical value; where salts
of tin are in demand, it may even be an advantage to employ a hot blast in
the furnace so as to produce a large amount of tin fumes, which may be used
directly in making salts of tin.
"
Where « tin scraps
are melted down in a cupola furnace, I have found it
advantageous to use a rather low cupola furnace in order to as much as possible
avoid arresting the fumes of tin in the upper part of the furnace and further
to have a set of tuyeres about 2 feet above the regular tuyeres, in this manner the
volatilization of the tin is nearly complete and the fumes can be condensed in my
strainers, the metallic iron produced will also be of superior quality to the metal
produced in the usual manner from tinned iron scraps.
The drawing filed with the Provisional Specification of this application shows an
ordinary tin smelting cupola furnace "A" in connection with the fume condenser.
The furnace is furnished with a hood B, open in front where the ore, fuel and
fluxes are introduced into the furnace. The fan D, draws the fumes and gases

page_text: from the hood B, into the sheet iron pipes c, c, c, and forces them into the
bags "e" which are fastened to the collars g, on the pipe H, the gases pass through
the interstices of the textile fabric, while the condensed metallic fumes gradually
fall down in the hoppers, f, from which they are emptied upon the floor or into.
suitable receptacles.
The tin fumes collected in the flues and hoppers are either used directly in the
manufacture of salts of tin, or they are reduced to metal either by fire reduction or
by the wet process.
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 combination of an ordinary tin smelting furnace with a series of cooling
flues and a fume condenser consisting of receptacles of woolen or other textile
fabric substantially as described and for the purpose set forth.
2. The process substantially as described of smelting tin ore in a cupola furnace
with a cold or hot blast connected with a fume condenser consisting of a series of
cooling pipes and receptacles of a textile fabric as described.
3. The within described process of separating tin and iròn in scraps of tinned
iron by exposing these scraps to a high heat in a cupola furnace in order to melt
the iron and volitalize the tin and finally condensing the tin fumes in strainers of
textile fabric substantially as set forth.
4. The within described process of treating scraps of tinned iron (to volatilize
a maximum of tin and produce a better quality of iron) by heating the said tin
scraps in a cupola furnace with a double set of tuyeres and condensing the escaping
tin fumes in strainers of textile fabric, substantially as herein set forth.