Improvements in the Extraction of Metals from Ores and Slags, and the Débris from Smelting Works and other Manufacturing Works.
Year: 1889

page_text: Date of Application, 14th June, 1889
Complete Specification Left, 9th Aug., 1889-Accepted, 14th Sept., 1889
PROVISIONAL SPECIFICATION.
Improvements in the Extraction of Metals from Ores and Slags,
and the Débris from Smelting Works and other Manufacturing
Works.
I, JAMES SHEARS, of No. 8, Keppel Street, Russell Square, London, W.C.
Gentleman do hereby declare the nature of this Invention to be as follows:-
The nature of this my invention, is with the object of extracting metal from refuse
slag and the débris from smelting works, and the refuse from mining smelting and
other manufacturing works.
In the case of ores or slags containing tin oxide and other metals I reduce the
same to powder with or without roasting, according to the nature of the constituents.
Such powder is then boiled at a high temperature in a solution of caustic soda, with
or without an oxidizing agent. This treatment will decompose the powdered slag and
the silica combined therewith will be converted into a silicate of soda, which can be
precipitated in an insoluble form by a judicious admixture of Milk of Lime, which
must not be in excess of the quantity of Silica present. The liquor containing the
tin and other metals can be evaporated to dryness as stannate or stannite of soda and
smelted in the usual way to recover the pure metal or the solution may be treated by
electrolysis, which will throw down the pure tin at once and leave the soda in solution,
free.
Dated this Fourteenth day of T... 1000
JAMES SHEARS.
COMPLETE SPECIFICATION.
Improvements in the Extraction of Metals from Ores and Slags,
and the Debris from Smelting Works and other Manufacturing
Works.
I, JAMES SHEARS of 8 Keppel Street Russell Square, London Gentleman 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 Refuse Tin Slags accumulated in the neighbourhood of Tin Smelting Works
in Cornwall, and other places, where that Metal is reduced from raw ores have been
accumulated for many centuries, and only partially utilized. These are found to
contain a large proportion of Tin Oxide in the form of enamel, varying from ten to
twenty one per cent. The oxide of tin is combined with silica, oxide of iron, some
tungsten, and occasionally nickel and cobalt. The separation economically of the
various metals in these slags has long been a desideratum. By my process I fuse the
slags in the fine state of powder with any alkali, or carbonated alkali, preferably soda,
on account of its cheapness and in excess. This creates soluble silicate of soda or
other alkali; tungstate of soda, or other alkali; stannate of soda, or other alkali ;
and free peroxide of iron. This mass is dissolved in boiling water in suitable iron
vessels heated from underneath. When quite dissolved a portion of uncombined
silica, and the whole of the peroxide of iron (which is not affected by the alkali) with
nickel and cobalt fall to the bottom, and can be separated by decantation. The clear
fluid containing silicate of alkali, stannate and tungstate of alkali are heated in suit-
able iron pans or boilers and an electric current is passed through the solution from
suitable electrodes, immersed but isolated in such solution to the interior of the iron
pan. These electrodes may be of any material having the requisite conductivity. A
Γυ
AL

page_text: current of low tension electricity created by any of the well known means of pro-
ducing such low tension current, preferably by a dynamo machine, is passed through
the immersed electrodes which has the effect of eliminating the tin in a metallic form
on the interior surface of the iron pan in a crystaline powder, which can be collected
and melted into ingots of quite pure tin. The residual solutions of silicates of alkali,
and tungstate of alkali are treated with a dilute solution of milk of lime which
combines with the silica and alumina present, forming a double silicate of lime and
alumina, which being insoluble falls to the bottom of the vessel, and which is valuable
as a hydraulic cement. The alkali is recovered from this process in a caustic form,
and can be evaporated and used again. Should any nickel or cobalt be present in the
combination, it will be found mixed with the oxide of iron, the residue of the second
process, and can, if found desirable, be eliminated by any of the known processes for
recovering these materials. Should there be tungstate of alkali present, it will
crystalize from the caustic solution of alkali recovered during evaporation and can be
eliminated by the usual way of salting out.
Having now particularly described and ascertained the nature of my said inven-
tion and in whe manner the same is to be performed I declare that what I
claim is:
The recovery of oxides of tin in the metallic form and other metals in refuse tin
slags by means of fusion with caustic or carbonated alkalies, and the separation of
the various extraneous materials such as silica, oxide of iron, tungsten, or nickel and
cobalt by the precesses above described, being practical methods of accomplishing the
same not hitherto in use.
Doted thin N: L 1
1000