IMPROVED METHODS OR PROCESSES OF REFINING IMPURE COPPER
Year: 1881

page_text: LETTERS PATENT to Henry Harris Lake, of the Firm of Haseltine, Lake,
and Co., Patent Agents, Southampton Buildings, London, for an Invention
of "IMPROVED METHODS OR PROCESSES OF REFINING IMPURE COPPER."
A communication from abroad by Claude Theodore James Vautin, of North
Fitzrov. Victoria, Australia, Assaver.
COMPLETE SPECIFICATION filed by the said Henry Harris Lake at the
Office of the Commissioners of Patents on the 21st December 1881.
HENRY HARRIS LAKE, of the Firm of Haseltine, Lake, and Co., Patent Agents,
Southampton Buildings, London. " IMPROVED METHODS OR PROCESSES OF
REFINING IMPURE COPPER." A communication from abroad by Claude Theodore
James Vautin, of North Fitzroy, Victoria, Australia, Assayer.
This Invention relates to the refining of impure commercial copper, and comprises
two improvements, one having reference to the removal of the impurities by
oxidizing them, and the other to their removal by chlorodizing them.
22
By "impure commercial copper I mean such as Spanish-copper or the Cobar-
copper of New South Wales.
Before proceeding to describe my first improvement relating to the removal of
the impurities by oxidizing them, I wish to state that I am aware that the ordinary
method of removing such impurities is by oxidation, but such ordinary method
leaves a large percentage of them behind, whereas my improved method either
wholly removes them, or reduces their percentage to a minimum, so that this
portion of the said Invention may be termed an improved process of oxidizing the
impurities in commercial copper in order to effect their removal, the practical
result being that the product of my process is of considerably more value than that
of the ordinary process. The ordinary method of oxidizing the impurities in
commercial copper is to melt the latter, and then by stirring or rabbling it to
bring as much of it as possible into contact with the oxygen of the atmosphere.
This however has proved to be a very imperfect process, and open to many
objections. My process is either to force oxygen alone or in combination with

page_text: other gases (and preferably in the form of atmospheric air) throughout the whole
mass, so as to oxidize the whole or very nearly the whole of the impurities at once,
which impurities then riso to the surface and are skimmed off. As an alternative
to the use of oxygen in a gaseous form I substitute oxygen-producing solids and
mix them thoroughly with the mass of melted metal to be purified. Metallic
oxides that yield up a portion or a whole of their oxygen under heat will, when
mixed with a suitable flux or re-agent, form such oxygen-producing-solids. As
examples :-
1 part binoxide of manganese
1 oxide of copper (copper scale)
"
"
may be mixed with 2 or 3 parts
of slacked lime or soda-ash.
1 sesqui-oxide of iron (hematite iron ore).
Each oxide and its flux must first be ground and thoroughly mixed, and then
the mixture should be thrown on the surface of the impure melted copper and
thoroughly rabbled into or mixed with it, after which the heat should be raised in
order to reduce the slag to as fluid a state as possible. When the slag is in a fit
state it must be carefully removed, and the ordinary operations of poling and
casting conducted as usual. Of these solid oxygen-producing materials I prefer
the mixture of oxide of copper and slack lime, and in the proportion of from two
to three per cent. of the weight of the copper under treatment, and I prefer the
use of the solid oxygen-producing materials to the gaseous.
My second improvement is an alternative of the first and is of especial value
where the copper to be treated contains bismuth. It consists essentially in such a
use of chlorine as will bring it into contact with all the particles of the impure
metal to be treated, with the object of taking up all the impurities and carrying
them away in the form of volatilized chlorides. I accomplish this in two different
ways, viz., either by forcing a current of chlorine or hydrochloric acid gas through
or into intimate contact with every particle of the impure melted copper, or by
intimately mixing therewith a chlorine-producing composition consisting of a
chloride and its re-agent. The best example of such a composition is found to be
produced by mixing one part of common salt (chloride of sodium) with from three
to three and a half parts of slacked lime. Whatever may be the chlorides and
re-agents constituting the composition, I first grind and then thoroughly mix the
component parts and use the mixture as follows; that is to say, after the slag has
been thoroughly skimmed off the copper under treatment, I introduce the said
mixture into the furnace in the proportion of from two to three per cent. of the
weight of the melted copper, and thoroughly rabble or stir it in with the object of
making it permeate the whole mass. I prefer to throw in this composition by
degrees, so as to prevent the waste of the chlorine, and if this is done effectually all
or very nearly all of the impurities will be expelled in the form of volatilized
chlorides. During this portion of the process the damper should be closed so as to
prevent any unnecessary waste of chlorine by the draught of the flue.
When a current of chlorine or hydrochloric acid gas is used, it must be forced
through or into intimate contact with the molten copper, and for this purpose
almost any shaped vessel may be used, such as a crucible or a "Bessemer"
converter.
With respect to the second improvement, I prefer to apply the chlorine in the
form of chlorine-producing compositions, of which a mixture of salt and slacked
lime appears to be the best.
Having thus fully described the said Invention as communicated to me by my
foreign correspondent, and the manner of performing the same, I wish it understood
that with respect to the first described improvement I do not claim broadly the use
and application of oxygen or atmospheric air to impure melted copper in order to
oxidize its impurities, as I am aware that the common method of refining is to
pass a current of atmospheric air over its surface, but I claim,-
First. Refining impure commercial copper by forcing a current of oxygen-gas
through it when in a molten state.
Second. Refining impure commercial copper by thoroughly stirring or rabbling

page_text: into it when molten an oxygen-producing mixture, substantially as herein
described.
Third. Refining impure commercial copper by forcing a current of chlorine
through or into intimate contact with it when in a molten state.
Fourth. Refining impure commercial copper by thoroughly stirring or rabbling
into it when molten a chlorine-producing mixture, substantially as herein
described.
In witness whereof, I, the said Henry Harris Lake, have hereunto set my
hand and seal, this Twenty first day of December, in the year of our
Lord One thousand eight hundred and eighty one.
HENRY H. LAKE. (L.S.)