Improvements in Processes for Smelting and Treating Tin Ores, Slags, Slimes, and Furnace Debris containing Tin and other Products, and in Apparatus therefor.
Year: 1890

page_text: Date of Application, 7th Feb., 1890
Complete Specification Left, 7th Nov., 1890-Accepted, 7th Feb., 1991
PROVISIONAL SPECIFICATION.
Improvements in Processes for Smelting and Treating Tin Ores,
Slags, Slimes, and Furnace Debris containing Tin and other
Products, and in Apparatus therefor.
I, ALFRED JOHN CAMPION, of High Cliff Hotel, Cliftonville, Margate, Kent,
Financial Agent, do hereby declare the nature of this invention to be as
follows:-
The first part of my invention consists of improvements in the construction of
furnaces for smelting, reducing, and recovering tin ores, slags, slimes, and furnace
debris containing tin and other products. The improvements consist of constructing
a vertical or an upright furnace similar in some respects to the ordinary cupola
furnace used for smelting cast iron, but differs in having no direct artificial air blast
or blower.
The furnace or the shaft may vary in dimensions according to the material to be
treated.
Above the "well or hearth six or more conical holes are made in the sides of
the furnace, which communicate with the interior. The top of this furnace-which
I call the "facile" furnace-is closed in by a conical cap or hollow flue leading
into a chimney shaft of considerable interior dimensions, constructed to retain
metallic particles which may be carried over through the flue. The interior of the
hollow cap or flue leading to this shaft is provided with one or more pipes through
which jets of steam of high pressure pass. This causes a vacuum and suction draft
through the holes above mentioned near the bottom of the furnace, sufficient for all
the purposes of combustion and smelting. The charging hole is below the conical
cap or hollow flue and near the top of the furnace and is fitted with an air-tight
door which is only opened when fresh charges of fuel and material are added.
The second part of my invention consists of blending certain fluxes with tin ores,
slags, slimes, and furnace debris to be treated in the before mentioned and so called
"Facile Furnace" and these may vary with the nature of the materials to be
treated. Where slags or slimes or other furnace debris containing not less than
two and a half per cent. (2%) of tin accompanied by silicates and oxides of iron
and sometimes other metals have to be smelted, I treat the same in suitable
proportions in the furnace with what is commonly known as alkali manufacturers'
tank waste" which contains a large proportion of sulphide and oxys-sulphide of
lime, and other lime salts, the quantity used being in accordance with the
composition of the material treated, and the quantity of iron and silica therein.
The action of this flux is to separate the oxide of iron by the combination of the
same with the sulphur of the sulphide of calcium, forming the sulphide of iron and
setting the lime free, which combines with the silica and alumina and in combination
with the small portion of soda present in the "tank waste" makes a very fusible
slag. This liberates the oxide of tin from its combination with the iron silica &c.
in the slag or debris and allows it to become reduced by the fuel and collects in the
well of the furnace. Should the proportion of silica in the slags, slimes, or debris
be very large; I prefer to use in the smelting process sulphate of soda as a flux, or
a flux made by slaking quick-lime with a solution of sulphate of soda, carbonate of
soda, or any other salt of soda, in such proportions as may be found necessary for
the quantity of silica present. This combination renders the silicate slag very fluid,
and allows the reduced tin to readily settle in the well of the furnace.
Should the debris to be treated be in the form of slimes in a fine state of division,
or should the tin ore to be smelted be also in a fine state of division, which is
commonly the case, I press the same, together or separate, in suitable moulds having

page_text: first combined them with the particular flux to be used. These pressed blocks are
stacked until partially dry and then placed in the furnace, charging the same in the
ordinary way.
In reducing tin from slags and debris by the above mentioned processes a certain
amount of extraneous metals-notably nickel, cobalt, tungsten and sometimes
sulphide and bi-sulphide of tin are found in the metal tapped from the well of the
furnace and is consequently very hard. To remove sulphur from the bi-sulphide
and sulphide of tin, the so called "hard head "or metal is fused in a small "Facile"
furnace with the addition of oxide of iron, iron ore, or iron scale. This removes
the sulphur.
For the elimination of tungsten nickel, cobalt, and some other
oxidizable metals from the "hard head" or metal the same must be subsequently
fused in the "Facile" furnace with a proportion of nitrate of soda (Chili saltpetre)
or oxide of manganese or a mixture of both. When furnace debris known as dross
or skimmings has to be treated, and where it is found, as is commonly the case, that
the same contains silver gold and metals of the platinum group, even when the same
are in very minute proportions, the dross should be smelted in a small "Facile "
furnace with litharge, red lead, metallic lead, or substances containing oxides of
lead. The reduced lead combines with the above mentioned metals and any tin
present and the alloy will accumulate in the well of the furnace. This can be
cupelled and the mixed precious metals will remain behind in the "test
or bottom
of cupelling furnace, the lead and tin being oxidized and flowing off as litharge.
This can be used again with fresh dross until the lead becomes so charged with tin
that the cupelling action is retarded. In this case it is smelted in the same form of
furnace for solder. Where it is considered desirable to separate the reduced tin
from the lead that is combined with it, the same can be smelted with "tank
"which converts the lead into a sulphide regulus of lead leaving pure
waste
tin free.
"
All the forementioned fluxes and combinations can be used for smelting tin
ores or substances containing tin in any ordinary cupola or other furnaces if
required.
Dated this Fifth day
1000
ALFRED JOHN CAMPION.
COMPLETE SPECIFICATION.
Improvements in Processes for Smelting and Treating Tin Ores,
Slags, Slimes, and Furnace Debris containing Tin and other
Products, and in Apparatus therefor.
I, ALFRED JOHN CAMPION, of High Cliff Hotel, Cliftonville, Margate, in the
County of Kent, Financial Agent, 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 :-
In carrying my invention into practice I construct a furnace which I call the
"Facile furnace similar to the ordinary cupola furnaces used for melting cast iron,
but it differs in having no blower nor artificial air blast.
The shaft or body of the furnace may vary in size according to the material to
be melted therein. Above the hearth or well of the furnace which is
provided with a tap hole six or more conical holes are made in the sides of the
furnace on a level with the fuel zone which communicate with the interior. The
top of this furnace is closed in by a conical cap connected with a hollow flue leading
into the chamber of a chimney shaft of considerable interior dimensions constructed
to retain metallic particles which may be carried over through the flue. The
interior of the hollow cap and flue leading to the chamber of the shaft is provided
with one or more pipes through which jets of steam at high pressure are passed.
This causes a vacuum and suction draught through the holes above mentioned near
the bottom of the furnace sufficient for all the purposes of combustion and smelting.

page_text: The charging hole is below the conical cap and hollow flue and is fitted with an air
tight door which is only opened when fresh charges of fuel and material have to be
added.
:
In carrying out the second part of my invention I mix certain fluxes with tin
ores, slags slimes and furnace debris to be treated in the before mentioned furnace
and these will vary with the composition of the materials to be treated.
"
When slags slimes or other furnace debris containing a percentage of from 5 to
22 per cent. of tin combined with silicates and oxides of iron and other metals have to
be smelted, I treat the same in the furnace with what is commonly known as alkali
manufacturer's "tank waste which contains a large proportion of sulphide and
oxy-sulphide of lime and other lime salts, the quantities used being preferably double
the weight of "tank waste to the quantity of iron and silica previously ascer-
tained to be in the slag or debris. The action of this flux is to separate the oxide
of iron by the combination of the same with the sulphur of the sulphide of calcium
forming the sulphide of iron and setting the lime free which combines with the
silica and alumina and in combination with the small portion of soda present in the
"tank waste" makes a very fusible slag. This liberates the oxide of tin from its
combinations with the iron silica etcetera in the slag or debris and allows it to become
reduced by the fuel and collects in the well of the furnace. Should the proportion
of silica in the slags slimes or debris be very large say exceeding 40 per cent. I
sometimes prefer to use in the smelting process a flux made by slaking quicklime
with a saturated solution of sulphate of soda or carbonate of soda or any other salt.
of soda in the following proportions, namely, one part of the soda lime, so made.
by weight to each part of silica previously ascertained to be present in the material
to be treated. This combination renders the silicate slag very fluid and allows the
reduced tin to readily settle in the well of the furnace.
Should the debris to be treated be in the form of slimes which are in a fine state
of division, or should tin ores have to be treated which are generally in a fine state
of division also, I press the same together or separately, in suitable moulds of any
desired shape having first combined them with their proportion of the particular
fluxes to be used, which would generally be of from one quarter to one half of the
weight of the soda lime before mentioned to the weight of the slimes or ores to be
treated.
These pressed briquettes are then stacked and preferably exposed to a gentle.
heat such as the waste heat of a furnace or flue until partially dry and are
afterwards placed in the furnace and smelted, charging the same in the usual way..
In reducing tin from slags and debris by the above mentioned processes a certain
amount of extraneous metals, notably nickel cobalt tungsten arsenic and sometimes.
sulphide and bisulphide of tin are found in the metal tapped off from the well of the
furnace and is consequently very hard. To remove the sulphur from the bisulphide
and sulphide of tin the so called "hard head" or metal is fused in a small "Facile'
This removes
furnace with the addition of oxide of iron, iron ore, or iron scale.
the sulphur. For the elimination of tungsten nickel cobalt and some other
oxidizable metals from the "hard head" or metal the same must be subsequently
fused in the Facile furnace with a proportion of nitrate of soda (Chili saltpetre) or
oxide of manganese or a mixture of both in a proportion equal to the quantity of
arsenic weight for weight previously ascertained to be present.
}
When furnace debris known as dross or skimmings has to be treated and where it.
is found as is commonly the case that the same contains silver gold and metals.
of the platinum group even when the same are in very minute proportions, the dross
should be smelted in a small "Facile" furnace with litharge red lead metallic lead
or substances containing oxides of lead in proportion of from one half to an equal
weight of the skimmings to be treated. The reduced lead combines with the
above mentioned metals and any tin present and the alloy will accumulate in the.
well of the furnace, and any nickel and cobalt present will be found separated in
the form of a cake at the bottom of the alloy tapped from the bottom of the
furnace.
H
"

page_text: The alloy containing tin lead and the precious metals can be cupelled in the
ordinary way, and the mixed precious metals will remain behind in the test or
bottom of cupelling furnace, the lead and tin being oxidized and flowing off as
mixed oxide of tin and litharge.
This can be used again with fresh dross until the lead becomes so charged with
tin that the cupelling action is retarded. In this case it is smelted in the same
form of furnace with fuel for solder.
All the forementioned fluxes and combinations can be used for smelting tin ores
or substances containing tin in any ordinary cupola or other furnaces if required.
When it is desirable to separate tin from slags containing tin so as to form a
solder the slag is melted alone in any furnace and metallic lead is added which
sinks through the melted slag carrying with it the whole of the tin and other
metals excepting iron that may be present, the proportion of lead used being from
one third to one half by weight of the ascertained quantity of tin left in the slag.
This is a very simple and effective way of recovering tin from tin slags and furnace
debris.
In the sketch drawing annexed of the "Facile Furnace" the part of the sketch
marked A is the body of the furnace which I prefer and which should be made of
firebricks and fireclay and if necessary with a suitable casing or jacket, the
scale being inch to 1 foot throughout. The part marked B is the conical cap or
cover to the furnace which is made preferably of sheet iron lined with fireclay
and is fitted air tight to the furnace. The part marked C is the charging hopper
provided with a horizontal sliding door or cover marked G and a vertical closing
door of any suitable material such as iron coated with fireclay marked F. In
charging the furnace the sliding door or cover marked G is drawn back and the
charge of fuel and fluxes is inserted into the hopper C. The cover G is then
replaced and closed and the vertical sliding door F is raised which allows the charge
in the hopper C to drop into the furnace A. the arrangement being air tight all the
time. The parts marked D are the conical holes for the admission of air into the
body of the furnace marked A. The part marked E is the tapping hole at the bottom
of the well of the furnace marked J. The part marked H is the flue chamber into
which the metallic particles mechanically carried over settle. I is the manhole
door for clearing out any accumulation of settled particles in this flue chamber.
K is the steam pipe from the boiler leading into the connecting flue marked Linto
which it discharges the blast of steam into the flue chamber H. This has the
effect of creating a suction partial vacuum in the connecting flue L and the
furnace A which causes the atmospheric air to enter with more or less force
through the conical holes marked D which maintains the combustion of the fuel in
the furnace.
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:
1st. The construction and use of a furnace substantially as described the draught
for which is occasioned by the suction action of a steam jet introduced above the
charge in the furnace for smelting tin ores tin slimes tin slags and tin furnace
debris.
"
2nd. The smelting and treatment of tin ores, tin slimes tin slags and tin furnace
debris to separate the tin and other metals contained therein by the use of
alkali manufacturers' "tank waste as a fluxing agent substantially as set forth..
3rd. The smelting and treatment of tin ores, tin slimes tin slags and tin furnace
debris to separate the tin and other metals contained therein by the use of soda
lime substantially as described as a fluxing agent.
4th. The smelting and treatment of tin ores and tin slimes in a fine state of
division by moulding the same into briquettes with the fluxes to be used sul-
stantially as described.
5th. The smelting and treatment of hard furnace debris known as "hard

page_text: head" by the addition of oxide of iron, iron ore, or iron scale to remove the
sulphur and arsenic from the same substantially as described.
6th. The treatment of the metallic substances contained in the "hard head "
for the purpose of eliminating the same by the use of nitrate of soda (Chili
saltpetre) or oxides of manganese or a combination of the same substantially as set
forth.
7th. The smelting and treatment of tin dross or skimmings with lead or com-
pounds of lead to combine and separate tin and the precious metals substantially
as set forth.
8th. The separation of tin and other metals contained in tin slags and furnace
debris by fusing the same and treating the fused mass with metallic lead sub-
stantially as set forth.
Dated this Eighth day of February 1890.
ALFRED JOHN CAMPION.