A Process for the Extraction of Tin from Tin Slags and Tin Refuse by Lead or its Salts, Carbonaceous Matter, Fluor Spar, or other suitable Fluxes.
Year: 1891

page_text: Date of Application, 27th June, 1891
Complete Specification Left, 26th Nov., 1891-Accepted, 16th Jan., 1892
PROVISIONAL SPECIFICATION.
A Process for the Extraction of Tin from Tin Slags and Tin Refuse
by Lead or its Salts, Carbonaceous Matter, Fluor Spar, or other
suitable Fluxes.
I FRANCIS HERBERT MASON of Number 128 Gower Street in the Parish of
Saint Pancras in the County of Middlesex Metallurgist do hereby declare the
nature of this invention to be as follows: :-
The tin slag or tin refuse is smelted in a furnace with litharge red lead lead
ashes lead refuse or other reducible lead salts carbon or carbonaceous matter and
fluor spar or other suitable fluxes varying with the nature of the tin slag or tin
refuse, the result is an alloy of lead and tin containing also iron and sometimes
copper the quantities and nature of the impurities (that is the substances other than
tin and lead) varying with the nature of the tin slag or tin refuse and the
temperature used in smelting.
This alloy is subjected to liquation and afterwards to poling.
The result is an alloy of tin and lead which can be made up to any proportion
required by the addition of these metals of tin and lead and goes into and is used
in the market as a solder.
די
FRANC. H. MASON.
COMPLETE SPECIFICATION.
A Process for the Extraction of Tin from Tin Slags and Tin Refuse
by Lead or its Salts, Carbonaceous Matter, Fluor Spar, or other
suitable Fluxes.
1 FRANCIS HERBERT MASON of 25 Margaretta Terrace Oakley Street Chelsea
in the County of Middlesex 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:-
I take tin slag or refuse from tin smelting and crush it so that the largest pieces
do not exceed the size of a walnut. I then add to the crushed material:
(1) Fluor spar or other suitable flux, the quantity of fluor spar or other suitable
flux being about fifteen per cent. in weight of the crushed material.
(2) Lead ashes or other suitable salts of lead in such a proportion that the lead
in such lead ashes or other suitable salts of lead is equal to three times the
estimated amount of tin in the tin slag or refuse above mentioned as being
crushed.
(3) Carbon in the form of anthracite or other carbonaceous matter in sufficient
quantity to reduce the tin salts and lead salts (in the mixture) to a metallic
state.
I throughly mix all the above substances and then charge such mixture into a
reverberatory or low blast furnace and raise the temperature of the furnace until
the mixture melts, the mixture is then kept at a uniform heat and well rabbled
until all bubbling ceases, a little anthracite is thrown into the charge, the mass
rabbled, and when bubbling has ceased, the metal is run out and cast into
ingots.
These ingots are then subjected to liquation in a liquating or ordinary rever-
beratory furnace which operation consists of placing the ingots close behind the
fire bridge and gradually raising the temperature of the furnace. The metal which

page_text: first flows away is kept separate from that which flows away afterwards as it will
probably not require poling. The temperature of the furnace is gradually raised
until most of the tin and lead has flowed away.
All the metal that has thus flowed away (except perhaps that which first flowed
away still contains impurities, that is metal other than tin and lead; the metal
that has flowed away is therefore heated in a kettle to a temperature well above its
melting point and green poles (preferably apple wood) are plunged in, this makes
the metal boil & gives a larger expanse of metal to the oxidizing influence of the
air, the length of time of this operation, (i.e. the poling) depends upon the purity
of the alloy, small ingots are cast from time to time, and the nature of their
fracture will enable the operator to tell when the poling can be terminated the
skim which collects upon the top of the mass in the kettle, in the operation is
skimmed off from time to time and the substance ultimately left on the kettle is an
alloy of tin and lead which goes into the market as solder.
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 reduction of tin from țin slag and tin refuse by fusion with suitable fluxes
and lead salts and carbon; the fluxes and lead salts have a tendency to set free the
tin oxide from its combination with silica, and the carbon then reduces the tin
oxide to a metallic state which is collected in the lead reduced from lead salts by
carbon during the fusion.
Dated the 26th day of November 1891.