Improvements in and connected with Furnaces for Recovering Tin from Tin Slag.
Year: 1890

page_text: Date of Application, 14th Apr., 1890-Accepted, 17th May,
1890
COMPLETE SPECIFICATION.
Improvements in and connected with Furnaces for Recovering Tin
from Tin Slag.
I, JAMESON LETCHER, of Llanhydrock House, Devoran, in the county of Cornwall,
Metallurgist, 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 consists in improvements in and connected with furnaces for
recovering tin from tin slag.
According to this invention the furnace in which the tin slag is smelted consists of
a vertical chamber constructed of fire-clay bricks or other suitable material. Air is
admitted to the furnace through apertures provided in the walls at a convenient and
suitable height from the base. Below the level of the air apertures and between them
and the base is an aperture which while the smelting process in progress is blocked
by fire clay. At intervals the fire clay blocking the said aperture is pierced and
the metal run out through the hole made therein.
At the top the furnace communicates by a throat with a long horizontal flue which
communicates with a chimney stack.
By the employment of the long horizontal flue communicating with a stack a
draught is maintained sufficiently powerful to melt the metal in the furnace without
the waste of coke, employed as fuel, obtaining in furnaces where a blast or jet of
steam is directed into the furnace.
The long flue also serves as a means for receiving particles of metal deposited
from the fumes passing through the flue on the way to the stack.
The accompanying drawing represents. in vertical section a furnace constructed
and arranged in accordance with this invention. The furnace consists of a
chamber a having walls of fire-clay, fire-brick or other like material. At a con-
venient and suitable height above the base of the structure are apertures b for
admitting air.
Below is an aperture c which while the smelting process is in progress is blocked
with clay. The tin-slag and the coke for smelting the same are charged into the
furnace through an aperture in the top which after the furnace has been charged is
closed by a cover or lid.
By the throat d the furnace communicates with a long flue e which is in
communication with a chimney stack.
The flue e receives the fumes from a series of furnaces and, by its employment, a
sufficient draught is maintained in the furnaces to separate the tin in the slag.
The waste of fuel hitherto obtaining consequent upon the employment of air
blasts or steam jets is obviated.
The flue e constitutes a collecting chamber for particles of tin deposited from the
fumes passing to the chimney.
Apertures, with covers g, are provided in the flue e for the purpose of recovering
such particles.
The molten tin is drawn off from the furnace at intervals through a hole made
for the purpose in the clay in the aperture c.
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:-
A furnace for smelting tin-slag, consisting of a vertical chamber such as a with

page_text: air-apertures b at a convenient height above the base, and tapping aperture c below
the air-apertures, the said furnace communicating by a throat d with a long flue e
(common to a series of such furnaces) communicating with a chimney stack,
substantially as herein before described with reference to the accompanying drawing.
Dated this 11th day of Anril 1890.
NICHOLAS WATTS,
Bristol Bank Buildings, Bristol, Agent.