AN IMPROVED PROCESS FOR EXTRACTING PROVISIONAL SPECIFICATION
Year: 1882

page_text: LETTERS PATENT to Alfred Kirby Huntington of Kings College Strand and
Walter Edward Koch of Philbeach Gardens Kensington, both in the County of
Middlesex for an Invention of "AN IMPROVED PROCESS FOR EXTRACTING
PROVISIONAL SPECIFICATION left by the said Alfred Kirby Huntington
and Walter Edward Koch at the Office of the Commissioners of Patents on
the 11th August 1882.
ALFRED KIRBY HUNTINGTON of Kings College Strand and WALTER EDWARD
KOCH of Philbeach Gardens Kensington, both in the County of Middlesex
"AN
IMPROVED PROCESS FOR EXTRACTING PRECIOUS METALS FROM THEIR ORES
"
Our invention relates to a process for extracting precious metals from their ores.
For this purpose we employ by preference a rotative gas furnace which may be of
the regenerative kind, and we provide means of the usual kind for supplying an
oxidising flame by excess of air or a deoxidising flame by excess of carbonaceous
matter in the gas or in the charge. This furnace we charge with the ore or tailings
that are to be treated, the ore being preferably crushed so as to expose a large
surface in a subdivided condition. We expose the charge to the oxidating flame
at a sufficiently elevated temperature to decompose without fusing the ore and to
separate or drive off the greater part of the sulphur or other impurity present in
the ore.
We then lower the heat of the furnace and introduce metallic lead or
easily reducible lead ore or compounds of lead such as oxide or carbonate. The
lead when in a molten condition takes up the precious metal as an amalgam or alloy
and is afterwards separated from it by cupellation.
The lead may be employed for a number of successive charges until it becomes
sufficiently saturated with the extracted metal, and after cupellation the litharge
produced can be used to form fresh alloy.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Alfred Kirby Huntington and Walter Edward Koch in the Great Seal
Patent Office on the 10th February 1883.
ALFRED KIRBY HUNTINGTON of Kings College Strand and WALTER EDWARD
KOCH of Philbeach Gardens Kensington, both in the County of Middlesex
"AN
IMPROVED PROCESS FOR EXTRACTING PRECIOUS METALS FROM THEIR ORES
"
Our Invention relates to a process for extracting precious metals from their ores.
For this purpose we employ by preference a rotative gas furnace which may be of
the regenerative kind, and we provide means of the usual kind for supplying an
oxidising flame by excess of air or a deoxidising flame by excess of carbonaceous
matter in the gas or in the charge. This furnace we charge with the ore or tailings
that are to be treated, the ore being preferably crushed so as to expose a large
surface in a subdivided condition. We expose the charge to the oxidating flame
at a sufficiently elevated temperature to decompose without fusing the ore and to
separate or drive off the greater part of the sulphur or other impurity present in
the ore.
We then lower the heat of the furnace and introduce metallic lead or
easily reducible lead ore or compounds of lead, such as oxide or carbonate. The
lead when in a molten condition takes up the precious metal as an amalgam or
alloy and is afterwards separated from it by cupellation.
The lead may be employed for a number of successive charges until it becomes
sufficiently saturated with the extracted metal, and after cupellation the litharge
produced can be used to form fresh alloy.
In practically carrying out our invention, we find it more convenient to effect
the amalgamation in a vessel separate from that in which the calcination of the ore
is effected. Thus when the ore is sufficiently calcined under the oxidating flame
in the rotative furnace, as we can ascertain by testing a sample taken from the
furnace, we transfer it still hot to a pan or vessel arranged as follows. It is a close
vessel set in a flue to receive heat preferably from a gas flame. Within the vessel
there is a revolving agitator which keeps the calcined ore in agitation over a
quantity of lead which is molten and occupies the lower part of the pan; a pipe
leads from a gas producer to the upper part of the pan and an outlet pipe carries
the gas from the pan to the fire or furnace where it is burnt to heat the pan. Thus
while the ore remains agitated at a temperature insufficient to frit it in the presence
of the molten lead the carbonaceous or deoxydating gas from the producer is kept
circulating through the pan. The melted lead in the pan takes up the precious
metal from the ore, and when the extraction is carried sufficiently far a side door
of the pan is opened and the arms of the agitator throw out the residue of the ore
when a fresh charge of calcined ore can be introduced. The lead may continue in
the pan to receive the precious metal from a number of successive charges of ore,
until it is sufficiently saturated, when it is run off by a tapping hole to be treated
by cupellation, or otherwise to separate the precious metal from it. Although we
have mentioned lead as a suitable metal for taking up the precious metal from the
ore, it is to be understood that other metals that fuse at a moderate heat, such as
tin, antimony or zinc or alloys or mixtures of these may be employed. We find
that an alloy of lead and antimony is particularly suitable for the purpose.
"
It often happens that when the ore is ejected from the amalgamating pan a
quantity of the amalgamated metal in a state of fine division is carried with it.
We therefore dress this out in the usual way.

page_text: Having thus described the nature of our invention and in what manner the saine
is to be performed, we claim :—
The herein described process for extracting precious metal from ore by calcining
the ore and then subjecting the calcined ore to heat and agitation in a deoxydating
atmosphere in presence of melted metal such as lead, zinc or their equivalents.
In witness whereof I the said Alfred Kirby Huntington and Walter Edward
Koch have hereunto set our hands and seals this ninth day of February
in the year of our Lord One thousand eight hundred and eighty-three.
ALFRED KIRBY HUNTINGTON
(L.S.)
WALTER EDWARD KOCH
(J..S.)