A New or Improved Process for the Extraction and Recovery of Metals, and Especially for the Recovery of Tin from Tinned Iron Plate.
Year: 1887

page_text: Date of Application, 10th Mar., 1887
Complete Left, 7th Dec., 1887
Complete Accepted, 10th Mar., 1888
PROVISIONAL SPECIFICATION.
A New or Improved Process for the Extraction and Recovery of
Metals, and Especially for the Recovery of Tin from Tinned
Iron Plate.
I, CARL BERNHARD SCHULTZE of 23 Katharinenstrasse, Leipzig, in the Empire of
Germany, Doctor of Philosophy, do hereby declare the nature of my invention, to be
as follows:
This invention consists in a process for the extraction of metals from solutions, ores,
or mixinres containing various metal, the process being very applicable to the treat-
ment of factory waste containing metals and the like--and to the recovery of iron from
scrap tinned iron plate.
Diluted sulphuric acid or hydrochloric acid is added to the raw material by which
means everything soluble in these acids is extracted-If the solution contains much
zine or cobalt, the solution is allowed to filter over sheet zinc by which means copper.
bismuth, lead, tin, cadmium and nickel (if present) are first separated and afterwards
iron and cobalt as insoluble basic sulphates. If however the solution contains little
zine, then it is treated with a neutral or acid solution of sesquioxyde of iron or with a
free acid in which hydrated peroxyde or sesquioxyde of iron in some form is suspended
or with air and free acid or acid solution of a salt. If the mixture contains tin, copper,
If iron
bismuth, nickel or cobalt solutions of the oxydes of these are thereby formed.
is not present in the raw material the solution is brought into contact with iron and
the copper and bismuth are precipitated as metals. Lead, if present, is partly pre-
cipitated as metallic powder, and as sulphate of lead. The remaining solution is then
neutralized by the addition of metallic tin and with hydrated peroxyde of iron (or with
sesquioxyde of iron). Pure metallic iron is now brought into contact with the neutral
solution, by which means tin is deposited and afterwards nickel. Heat may be applied
at this stage of the process to expedite the re-action.
Any cobalt remaining may if desired be extracted as before described.
The undissolved residue of the raw material is well mixed with scraps of metallic
iron, in suitable tanks or vats, and diluting sulphuric acid poured over and lefi. in
contact with it for several weeks, during which period it may be several times turned
over, by this means insoluble metallic oxydes are converted into metals and soluble

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metallic oxydes and any iron present is converted into protoxyde of iron. Ultimately
oer, lead and bismuth are formed and solution of sulphates of tin, iron,
nckel, cobah. These latter sulphates are neutralized and the tin and nickel recovered
by addition of metallic iron as above described, and the cobalt also as before described.
The iron lyes resulting from this or other part of the process may be filtered over
heaps of waste of sheet iron by which means iron vitriol is formed which may be
purified by recrystallization.
In applying this process to lacquered tin plate, the lac-varnish is first removed,
preferably by means of sulphuric acid of specific gravity 15 to 184 heated to a
temperature of about 100° Centigrade.
11
HERBERT & Co.,
67, Strand, W.C.,
Agents to Applicant.
COMPLETE SPECIFICATION.
A New or Improved Process for the Extraction and Recovery of
Metals, and Especially for the Recovery of Tin from Tinned
Iron Plate.
I, CARL BERNHARD SCHULTZE, Dr. phil., of Troiha, Prussia, do hereby
declare the nature of this invention and in what manner the same is to be 2
performed, to be particularly described and ascertained in and by the following
statement:-
The process consists in the performance one after another of the operations which
are described in what follows under I to VII with the provision that the operations
under I, II and IV either singly or altogether need not be performed, if the nature 2
of the mixture of metals to be separated does not require it; and that on the other
hand operation VIII takes the place of operation III in so far as insoluble bioxyd of
tin is to be changed into a solution of soluble tin-salt.
The substances containing metals are treated with cold diluted sulfuric acid.
Residues free from zinc are resultant and a solution of sulfate of zinc containing
some iron, tin, cadmium, nickel, cobalt, copper.
This solution is digested with zine-ashes or other waste containing zinc oxyd, then
filtered over scraps or grains of zinc and finally graduated (sent to drop within the
free air) over scraps of zinc,

page_text: The acid solutions free from copper and bismuth, resultant in III or IV respectively
are treated with metallic tin and with hydrated peroxyd of iron (or with sesquioxyd of
iron) simultaneously.
The solution takes up equivalent quantities of both and saturates itself with them by
the formation of salts of protoxyds entirely neutral.
Pure metallic iron is now allowed to act again on the solutions of metallic salts
perfectly neutralised according to V or by other known methods, and containing tin,
nickel, cobalt, iron.
While the iron dissolves itself slowly, the tin is first separated as a metallic powder
and in splendid metal scales, after it finally any nickel present. A slight heating of the
solution expedites the reaction.-Cobalt is not precipitated by iron; if cobalt is

page_text: VIL. THE UTILIZATION OF THE IRON-VITRIOL-LYES.
The lyes of sulfate of iron which result from VI are graduated (sent to drop
within the free air) over heaps of waste of sheet iron. The excess of water evaporates
and iron-vitriol crystallises in the heaps which is rendered pure by recrystallisation or
is utilised direct.
VIII. THE TRANSFORMING OF INSOLUBLE BIOXYD OF TIN INTO SOLUBLE TIN SALT.
Substances containing insoluble bioxyd of tin, such as tin-ash, residuum of zinc-
chloride-production, tim-sione, are first treated with diluted sulfuric acid, and thus
everything soluble is drawn out of them. The insoluble residue containing the bioxyd
of tin is well mixed with metallic iron or tin, as thin as possible on account of the
greater surface, therefore advantageously with scraps of tinned iron plate, is filled
into low vats or low well tared and asphalted stone chests. Diluted sulfuric acid is
poured over it, and it is left to itself for some weeks, or it may be turned over several
times during this period. During this time on the one hand a slow reduction of the
insoluble bioxyd of tin into soluble protoxyd has taken place, on the other hand an
oxydation of the metallic iron and tin to protoxyd of iron and iin. The tin is
separated according to V and VI from the solution thus formed containing sulfate
of tin and iron.
Having accurately described and defined the essence of my invention and the
manner of executing the same I claim :
The described process for the separation and recovery of Zine Cobalt, Iron, Tin and
Nickel from all kinds of substances containing these meials, and especially for that
purpose:
1.) The application of waste of sheet-zinc as means of graduation for solutions of
impure zinc-salt for the purpose of oxydating and separating the iron- and cobalt-salts
as insoluble combinations.
2.) The application of heated sulfuric-acid of 1,5-1,84 spec. gravity to free waste
of varnished in plate from the lac-varnish.
3.) The application either of a solution of sesquioxyd of iron, or of hydrated sesqui-
oxyd of iron (or of sesquioxyd of iron) suspended in somo free acid along with the tin
to be dissolved, in order to dissolve the tin.
4.) The application of metallic tin in union with hydrated sesquioxyd of iron or with
sesquioxyd of iron to effect the neutralisation of acid solutions of tin.
5.) The application of metallic iron to precipitate the tin and nickel from acid
solutions after they have been neutralised.
6.) The application of metallic waste of sheet or wire as a means of graduation
for the purpose of cheaply freeing vitriol-solutions from water and of gaining vitriol in
sali crusts.
7.) The application of metallic iron or tin or of both (scraps of tinned iron plate)
in union with an acid to convert insoluble bioxyd of tin into soluble tin salt.”
Trotha, Prussia, 5th December 1887.
DR. CARL BERNHARD SCHULTZE.