IMPROVEMENTS IN THE HUMID REDUCTION OF GOLD AND OTHER ORES
Year: 1886

page_text: Date of Application, 30th Oct., 1886
Complete Left, 27th July, 1887
Complete Accepted, 28th Oct., 1887
We JAMES EDDISBURY BAUGH, Accountant, and CHARLES HINKSMAN Mining
Engineer, both of 117 Great Russell Street, Bloomsbury, in the county of Middlesex
do hereby declare the nature of the said invention for "IMPROVEMENTS IN THE
HUMID REDUCTION OF GOLD AND OTHER ORES "to be as follows:-
The aim of all concentrating and reducing appliances, and operations has hitherto
been to separate gold, from other mineral and metallic substances, by direct means, in
the purest possible state.
This invention differs widely, inasmuch that no effort is made to extract the gold
pure, but to effect its concentration, with commercial success in combination with
copper, and other mineral and metallic substances. It is well known that chlorine
gas, generated by the agency of per-oxide of manganese, salt, and sulphuric acid;
will (when passed through pulverized and well calcined pyrites, in a moistened state
containing metallic gold) convert that metal into chloride of gold.
From the solution of chloride of gold in water, thus obtained, gold may be
precipitated almost pure, or highly concentrated, in the metallic form, either by
metallic iron or copper, or by a solution of ferrous sulphate, or it may be obtained in
the state of sulphide, by sulphuretted hydrogen. No metallic sulphides or arsenides
must, however, be present, as a portion of these substances would be transformed into
chlorides, causing very heavy and unnecessary expenditure of chlorine.
When most careful precautions are taken, the precipitate is extremely rich for gold,
but practical operations have proved that a large per centage of the gold is left in the
calcined ore, in an insoluble state, whilst it is difficult to precipitate more than a
small per centage of the gold held in solution in the water; unless dealing with a
strong solution of chloride of gold, which naturally does not occur, when calcined
ores contain only one or two ounces of gold to the ton.
The following description of our method of procedure will clearly illustrate the
nature of our invention and the mode of carrying it into effect.
After the calcination and chlorination of pyrites and other ores as effected by our
fuel saving and effective furnaces patented by us under the No. 11,776 dated the

page_text: 16th September 1886, we first ascertain by laboratory test or assay, whether the whole
of the gold has been converted into a soluble state, during the process of chlorination.
The object of our invention (which is totally at variance with all other processes) is
to convert metallic sulphides, especially copper, into chlorides, in order to secure
the whole of the gold from the ore under treatment although not in a highly
concentrated state.
When the gold is contained in the ore in the form of arsenide or sulphide, we find
it is converted simultaneously with the copper into chloride, whilst at the same time
the chlorine gas generated at a minimum of cost by our improved furnace (the
subject of the above named patent) always converts a large per centage, and often
the whole of the metallic gold into chloride of gold. When however the laboratory
test proves that a portion of the metallic gold still remains in the ore, we pass free
chlorine through it, in the ordinary manner, but at a trifling cost, by reason that the
sulphides have been already chloridized, leaving only a portion of the metallic gold
insoluble.
This is effected either by first leaching the metals held in solution, by the aid of
boiling brine, and afterwards chlorinating the remaining metallic gold, with the aid
of free chlorine gas, or by completing the chlorination of the gold, before commencing
lixiviation.
It is preferable to chloridize every portion of the gold, before washing out any of
the other chlorides, when the gold, silver, and copper may be precipitated together,
with boiling brine as the solvent, and metallic iron as the precipitant, the iron
precipitating the gold in combination with both silver and copper.
Pyrites, as a rule, contain a small per centage of copper, sufficient to act as the
assistant to precipitate the gold. But when no trace of copper exists in the ore
containing the precious metal, it is necessary to mix a small quantity of sulphide of
copper, under the first stage of chlorination, by the aid of fire and chloride of sodium,
as specified in our Patent No. 11,776 of 1886, in order that the gold may be
precipitated with the copper and silver contained in the solution, through the means
of the copper otherwise a large per centage of the gold would be practically
unrecovered in the liquor, unless chloride of copper were present in the solution, to
assist the metallic iron in the collection of the metallic gold from its chloride form.
Practical experience has proved that it is most difficult to economically and
profitably treat pyrites for gold separately or at least, it has proved that often more
than one half of the gold contained in the ore by fire assay, is never recovered by
the present known and applied methods for obtaining the gold in a pure state, or
highly concentrated form; this statement is confirmed by Mr. Gold Warden
Archibald's report on the minerals of Queensland, where he says that ore known by
fire assay to contain from 5 to 10 ozs. of gold to a ton, when treated at local batteries
produces only 2 ozs.
Our invention takes advantage of the hitherto considered obnoxious sulphide of
copper, and aims only at a moderate concentration, averaging 100 ozs. of gold per
ton, associated with the copper precipitate, instead of endeavouring to produce pure
gold at a great loss of the gold originally contained in the ore. At the same time we
secure both silver and copper, whenever it is present, thereby effecting the great
desideratum of the mining community, viz: the reduction of gold, silver, and copper,
with commercial success.
Datal the 20th 1
111000
A. C. HENDERSON,
46, Southampton Buildings,
Agent for James Eddisbury Baugh and
Charles Hinksman.

page_text: COMPLETE SPECIFICATION.
Improvements in the Humid Reduction of Gold and other Ores.
We JAMES EDDISBURY BAUGH, Accountant and CHARLES HINKSMAN, Mining
Engineer, both of 117 Great Russell Street Bloomsbury, in the county of Middlesex
do hereby declare the nature of the said invention for "IMPROVEMENTS IN THE
HUMID REDUCTION OF GOLD AND OTHER ORES "and in what manner the same is
to be performed, to be particularly described and ascertained in and by the following
statement :-
The aim of all concentrating and reducing appliances, and operations has hitherto
been to separate gold, from other mineral and metallic substances, by direct means in
the purest possible state.
This invention differs widely from all hitherto recognized modes of operation
inasmuch that no effort is made to extract the gold pure, but to effect its concentration
with economical and commercial success, in combination with copper, and other
mineral and metallic substances. It is well known that chlorine gas generated by
the agency of peroxide of manganese, salt, and sulphuric acid or many other long
since discovered, and recognized chemical agents for the production of chlorine, (will
when passed through pulverized and well calcined pyrites in a moistened state,
containing gold,) convert that metal into chloride of gold.
From the solution of gold in water thus obtained, gold may be precipitated almost
pure, or highly concentrated, in the metallic form, either by metallic iron or copper,
or by a solution of ferrous sulphate, or it may be obtained in the state of sulphide by
sulphuretted hydrogen.
No metallic sulphides or arsenides must, however be present, as a portion of these
substances would be transformed into chlorides, causing very heavy and unnecessary
expenditure of chlorine.
When most careful precautions are taken, the precipitate is extremely rich for gold,.
but practical operations have proved that a large per centage of the gold is left in
the calcined ore, in an insoluble state, whilst it is difficult to precipitate more than a
small per centage of the gold, held in solution in the water, unless dealing with a
strong solution of chloride of gold which naturally does not occur when calcined ores
contain only one or two ounces of gold to the ton.
The following description of our modus operandi will clearly illustrate the nature of
our invention, and the method of carrying it into effect.
After the calcination and chlorination of pyrites and other oros, as effected by our
fuel saving and effective furnaces, patented by us under the No. 11,776, bearing date
the 16th September 1886, we first ascertain by laboratory test or assay, whether
the whole of the gold has been converted into a soluble state, during the process of
chlorination.
The object of our invention (which is totally at variance with all other processes)

page_text: is to convert metallic sulphides, especially copper, into chlorides, in order to secure
the whole of the gold from the ore under treatment, although not in a highly
concentrated state.
When the gold is contained in the ore, in the form of arsenide or sulphide, we find
it is converted simultaneously with the copper into chloride, whilst at the same time
the chlorine gas generated at a minimum of cost, by our improved furnace (the subject
of the Patent above referred to) always converts a large per centage and often the
whole of the metallic gold into chloride of gold. When however the laboratory test
proves that a portion of the metallic gold still remains in the ore, we pass free chlorine
through it, in the oridnary manner, or preferably as hereinafter stated, and at a
trifling cost by reason that the sulphides have been already chloridized, leaving only
a portion of the metallic gold insoluble.
This is effected either by first leaching the metals held in solution, by the aid of
boiling brine, and afterwards chlorinating the remaining metallic gold with the aid
of free chlorine gas, or by completing the chlorination of the gold, before commencing
lixiviation.
It is preferable to chloridize every portion of the gold, before washing out any of
the other chlorides, when the gold, silver and copper may be precipitated together
with boiling brine as the solvent, and metallic iron or zinc as the precipitant, the iron
or zinc precipitating the gold in combination with both silver and copper.
Pyrites, as a rule contain a small per centage of copper, sufficient to act as the
assistant to precipitate the gold. But when no trace of copper exists in the ore
containing the precious metal, it is necessary to mix a small quantity of sulphide of
copper under the first stage of chlorination by the aid of fire, and chloride of sodium,
as described in our Patent No. 11,776 of 1886 in order that the gold may be
precipitated with the copper and silver contained in the solution, through the means
of the copper, otherwise a large per centage of the gold would be practically
unrecovered in the liquor, unless chloride of copper was present in the solution, to
assist the metallic iron in the collection of the metallic gold from its chloride form.
Practical experience has proved that it is most difficult to economically and
profitably treat pyrites for gold separately, or at least, it has proved that often more
than one half of the gold contained in the ore by fire-assay is never recovered by the
present known and applied methods for obtaining the gold in a pure state or highly
concentrated form.
This statement is confirmed by Mr. Gold-Warden Archibald's report on the
minerals of Queensland, where he says, that ore known by fire-assay to contain from
5 to 10 ozs. of gold to a ton, when treated at local batteries produces only 2 ozs.
We do not confine ourselves to any one form of generating free chlorine by the aid
of chemical, but prefer and claim the following, for the reason that it is the most
economical and effective, its adaptation is entirely new by our discovery of its use,
whilst the necessary ingredients are obtained by us as by-products in the working of
our fuel saving and effective furnaces the subject of the Patent already referred to.
The following is our method of manufacture-we pass water either through chloride
of lime or bleaching powder in or bleaching powder in order to obtain a strong
solution (without any expensive mechanical appliances) which we mix with diluted
sulphuric or sulphurous acid.
This mixture is then passed through the ores contained in the leaching tanks,
either with or without air tight tops, in order to effectually chlorinate any slight traces
of metals of commercial value, that may not have been rendered soluble by our
aforesaid Furnaces, in somewhat similar manner that smelters (by fire process)
invariably endeavour to obtain whatever may have been left in smelting residues
or slags.
By the use of ordinary damped lime placed in chambers in connection with flues
for the purpose, in combination with the Patent 11,776, and the waste chlorine from
the ores under chlorination, added to a shower of water for the production of
sulphurous acid from the sulphides under calcination, the two elements, chloride of
lime and sulphurous acid are obtained as by-products instead of entailing the

page_text: otherwise necessary (and in remote districts) expensive purchase of the required
chlorine producing chemical substances.
In order to accomplish this in conjunction with the Patent 11,776 instead of having
only a small sized-chimney from the Furnace described in that Patent, which is
sufficient when volatile matters are allowed to escape ad lib. we find it necessary to
connect the Furnace with a higher chimney to increase draught, and also a series of
flues and chambers in separate communication with the pyrites and the powdered
calcined ore.
At the same time we utilize the volatile matters in the chemical production of
cheap chlorine agencies, from substances which otherwise would be wasted.
We admit that the articles manufactured by us have little commercial value for
exportation purposes in competition with the richer products obtained from manu-
facturing chemical works, yet inasmuch as sulphuric acid is always well diluted with
water before being brought into direct association with chloride of lime, the Sul-
phurous Acid obtained by us is sufficiently strong for practical purposes of generating
chlorine for the chlorination of minerals in the near neighbourhood of the minerals
themselves.
The flues and chambers in communication with the Furnace No. 11776 and an
ordinary chimney of any desired height, are so arranged that the bulk of the sulphur,
under volatilization, from the rock pyrites, as fully described in the Patent No. 11776
is conducted through one channel or flue.
In association with this flue through which the sulphur is expelled, we build one or
more chambers to collect sulphurous acid.
This is obtained by passing water and repassing the same water, in showers from
the top to the bottom of the said chamber or chambers. The fumes from the sulphur
ores in contact with the showers of water produces sulphurous acid, which increases
in strength in accordance with the quantity of sulphur contained in the rock ores
under the process of calcination in the Furnace together with the number of times
the water is re-passed through the chamber or chambers.
Strong leaden, wooden, or other suitable water or acid tight receptacles are placed
at the bottom of the chambers to receive the said liquor, which is conveyed over and
over again, by hand or mechanical means to a similar receptacle at the top of the
chambers, space being left both below and above for the flue inlet and outlet to the
chimney. The top receptacle has however a false bottom of finely perforated holes
to allow the liquor to descend in shower form. When the original water is sufficiently
charged with sulphurous fumes to produce sulphurous acid of about the same strength
as manufactured sulphuric acid, diluted with about five times its weight of water, we
secure one of the two articles necessary to produce cheap free chlorine, without
entailing the great expense of purchase and carriage of sulphuric acid to mines in
remote districts.
The next requisition is chloride of lime. This article can always be purchased in
the market. Nevertheless its cost is a serious item delivered at most mining regions,
unless in the direct neighbourhood of chemical manufacturing districts. Moreover
where mineral abounds, ordinary lime is generally abundant and in near proximity,
therefore we utilize waste chlorine by converting ordinary lime into chloride
of lime.
Towards this end, we refer again to the Patent No. 11776 and draw attention to
the ores on the solid hearths undergoing the process of chlorination by the aid of
chloride of sodium and the calorific powers of the rock pyrites as fuel in the combined
stages simultaneously of calcination and chlorination.
The chamber or chambers for converting ordinary lime into chloride of lime are
separated from the sulphurous acid chambers by a distinct flue and are connected
with the waste chlorine gas escaping from the ores placed on the solid hearth under-
going the process of chlorination. These chambers are fitted with shelves with
perforated holes upon which are placed ordinary lime, sufficiently damped to attract
the affinity of the would be otherwise wasted chlorine, thereby culminating in the
second by-product, viz: chloride of lime, which is of sufficient chlorine producing

page_text: agency, in combination with the weak sulphurous acid, as above described, to answer
the purposes of free chlorine, when brought together in an ordinary retort, for
economically converting the insolubles of residues into solubles. The two by-products
sulphurous acid and chloride of lime are hence obtained not only from waste sub-
stances, but as a further novelty are secured simultaneously together at one operation
by separate flues and chambers, in conjunction with our aforesaid furnace, Patent
No. 11776.
We also claim the use of boiling or hot brine as the solvent for gold, silver, and
copper together; which has never before been attempted only on silver, or silver
and copper chlorides, as we find the boiling or hot brine to be far more effective
than ordinary cold water, always used as the solvent for the leaching of chloride
of gold.
Finally we claim the novelty of using iron or zinc, not for merely precipitating
copper, which is well known, but for the precipitation of gold, silver, and copper
together simultaneously with the greatest economy, when taking into consideration
the great value of the gold and silver, over and above the value of the copper, at
the same cost of iron or zinc that would be necessary to precipitate the copper alone.
Our invention takes advantage of the hitherto considered obnoxious sulphide of
copper, and aims only at a moderate concentration, averaging 100 ozs. of gold per
ton, associated with the copper precipitate, instead of endeavouring to produce pure
At the same time
gold at a great loss of the gold originally contained in the ore.
we secure both silver and copper whenever it is present (which in larger or smaller
quantities is almost invariably the case) thereby effecting the great desideratum of
the mining community viz: the reduction of gold, silver and copper with commercial
success.
Having now particularly described and ascertained the nature of our invention,
and in what manner the same is to be performed we declare that what we claim is :-
1st. The passing of water through chloride of lime or bleaching powder, in order
to obtain a strong solution, which we mix with diluted sulphuric, or sulphurous acid,
which without any expensive mechanical appliances, produces highly efficacious, and,
very ecouomical free chlorine gas.
2nd. The use of ordinary damped lime placed in chambers in connection with flues
for the purpose, in combination with our Patent Furnaces No. 11776-1886, and the
waste chlorine from the ores under chlorination, added to a shower of water for the
production of sulphurous acid from the sulphides under calcination, the two elements
chloride of lime and sulphurous acid for producing free chlorine gas being obtained
as by-products, much more economically than if chloride of lime or bleaching
powder and sulphuric, or sulphurous acid had to be purchased in the open market.
3rd. The use of boiling or hot brine, as an effective solvent for the lixiviation of
chloride of gold, in combination with silver and copper in preference to cold water
employed in all other known processes.
4th. The use of iron or zinc for the precipitation of gold, silver, and copper,
together simultaneously. The whole in the manner by the means and for the purposes
substantially as herein set forth.