An Improved Process of Separating Metals having Different Melting Points.
Year: 1895

page_text: Date of Application, 6th Dec., 1895-Accepted, 30th May, 1896
COMPLETE SPECIFICATION.
An Improved Process of Separating Metals having Different
Melting Points.
1, HERMANN LANGEN, of No. 22, Marktstrasse, Duisburg, Rhine Province, in
the Empire of Germany, Manufacturer, 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 object of this invention is to enable readily melting metals or metallic
compounds to be separated from metals or compounds of a higher point of fusion
by melting mechanically produced mixtures of such metals or compounds in
separate fractions or successive stages.
The melting operation should be performed in a medium calculated to prevent
the liquefying metals from combining with, or becoming completely alloyed to, the
metals that have not yet commenced to melt or liquefy, (i.e., metals which are
required to remain behind).
This has been impracticable hitherto. A mixture of chips of pewter and red
brass (tombac), for example, upon having been melted while exposed to the air,.
has been found to run together or fuse into a homogeneous mass or alloy,
practically unfit for any useful purpose.
By the improved process herein described the more readily melting metals,.
which it is desired to separate from metallic mixtures of the class referred to, may
be melted separately in a special fluid or gaseous medium. Amongst the mediums
of the fluid or melted class, those of a high boiling point, such as paraffin, have
been found best suited for the purposes of this invention; while among the gaseous.
mediums, all indifferent gases have proved suitable. Where it is desired to employ
fluids of a low boiling point, such boiling point may be raised, however, by
applying pressure in the course of the operation.
In carrying the invention into practice, the metallic mixtures are placed in the
liquid, such as melted paraffin, to be used as a medium; with which they are
mixed together. The fluid employed should be heated, either before or after being
mixed with the metal, to a temperature higher than that at which those of the
metals contained in the mixture which have the lowest melting points, will liquefy.
Then, in order to facilitate the fusion or union of all parts of the metal which has
been thus melted, the mixture is thoroughly stirred or shaken, after which the
melted metal together with the paraffin is drawn off. The solid metal remaining
behind is that which will melt at a higher temperature only, so that the two kinds
of metal are effectually separated from each other.
Where a medium in the form of gas is employed, such as carbonic acid gas or
any other gas which will remain indifferent in its action upon the metal at a
comparatively high temperature, the gas is conducted through the metallic
mixture; when the readily melting metals will, in the same way as before, liquefy,
and, by so doing, separate from the remaining metal or metals.
The process hereinbefore described may be carried into practice in various
ways.
I will hereafter describe a centrifugal machine, suitable for this purpose, it being
however understood that the process is not intended to be restricted to this
kind of apparatus, and that this apparatus is merely to further illustrate the
process.

page_text: .
The centrifugal machine is represented in the accompanying drawing in which
Figure 1 is a vertical section ;
Figure 2 shows one half of the apparatus in plan and
Figure 3 is a detail of the apparatus in section.
The casing of the centrifugal machine encloses an annular space a, which serves
as a heating chamber. The metal-chips, to be separated, are together with the
paraffin placed in the centrifugal drum b and are brought to a state of fusion
therein under the action of the heat from the heating chamber. That part of the
metal which during this part of the operation flows out of the centrifugal drum
through its perforations, is discharged from the casing of the centrifugal machine,
before the centrifugal action proper is commenced. By the latter the separation
of the refractory chips and of the molten metal still adhering thereto, is completed.
When this has been effected, the cover c of the casing is removed therefrom and
the whole centrifugal drum lifted out of the casing, in order that the remainder of
the chips may be discharged therefrom.
For lifting out the centrifugal drum b, I provide a cap d having a holding ring
(Figure 3) this being effected in such a manner that the cap is slid over the hub-
extremity of the drum and is by a rotary motion caused to form a kind of bayonet
joint therewith. The conduits e and e¹ serve for supplying and discharging
cooling water to and from the top bearing of the shaft of the centrifugal
machine.
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 separation of the different metals forming metallic mixtures, by melting one
or all of such metals in fractions or successive stages in a heated fluid with or
without the employment of pressure, or by means of a super-heated gas.
Dated this 6th day of December 1895.
HASELTINE, LAKE & Co.,
45 Southampton Buildings, London, W.C., Agents for the Applicant.