Improvement in the Treatment of Quartzose or Siliceous and Sulphuretted Ores Containing Gold, Silver, or Copper.
Year: 1888

page_text: Date of Application, 14th Nov., 1888
Complete Specification Left, 9th Aug., 1889-Accepted, 14th Sept., 1889
PROVISIONAL SPECIFICATION.
Improvement in the Treatment of Quartzose or Siliceous and
Sulphuretted Ores Containing Gold, Silver, or Copper.
I, HENRY BROCK FULTON of Bellfield, Kirkintilloch, in the county of Dumbarton
Scotland, a Fellow of the Chemical Society of London do hereby declare the nature
of my said invention to be as follows:-
In the ordinary operation of smelting sulphuretted ores containing copper, for the
production of regulus, it is customary to submit the ore as it comes from the mine,
to a preliminary calcination, so that it may be deprived of the greater part of its
sulphur, and that the iron originally combined with that sulphur may become oxidised.
This calcined mineral, mixed with suitable fluxes, is thereafter smelted, either in
a reverberatory furnace, heated by a coal fire, or in a blast furnace where coke.is
intermixed with the charge. The valuable metal is thereby concentrated in the form
of regulus or "matte," while iron and other undesired bases are separated by the
flux, as slag.
The
By my present invention these two distinct operations are combined in one.
sulphur of the ore is utilised as fuel, and the direct employment of carbonaceous fue!
is dispensed with.
The improvement is applicable to the treatment not only of sulphuretted ores
containing copper, silver or gold-to which siliceous material requires to be added
to ensure the formation of slag ;-but, conversely, it is applicable to the treatment
of quartzose or siliceous ores containing gold, silver or copper,
-to which sulphuretted
material requires to be added, to ensure the formation of regulus.
In either caso a considerable proportion of the sulphur present in the ore or flux, is
volatilised in the elementary state, while a still larger proportion of it escapes from
the furnace as sulphurous oxide. And, while the former may be condensed at once,
the latter may be treated by well-known methods, for the recovery of sulphur
therefrom.
The recovery of sulphur however, from the fumes and gases, issuing from
the furnace, forms no part of the improved treatment, and is not herein claimed
as such.
In the improved treatment, I employ a blast furnace which may be of the dimensions
and of the design shewn in the accompanying drawing, though other dimensions and
modifications of construction-even to the use of a water-jacketed furnace-may be
adopted. In connection therewith, I employ a heating oven or stove, to raise
the temperature of the blast introduced at the tuyeres of the furnace, to, from
420° Centigrade to 650° Centigrade, more or less.
This heating oven may be of the construction shewn in the accompanying drawing,
or it may be of any other suitable design.
No special construction either of furnace or of heating oven is necessary for the
improved treatment or is herein claimed for it.
The procedure in beginning operations may be thus generally described :-
Ignited coal and wood are introduced on the hearth of the furnace, by a door for
that purpose, and, when these are well lighted, the door is built up, covered, and
luted. A gentle blast is at first admitted, and a little coke is added by the charging
arrangement on the furnace top. Flame is allowed to blow out freely by the tap-hole
and slag spout, until the crucible of the furnace is thoroughly heated. Coke may be
further added, until it reaches a few inches above the tuyeres, and the blast is
strengthened and continued until the furnace appears dazzlingly white at the tuyeres.
It is then ready for beginning the improved treatment.
When, for example, the mineral to be treated is cupriferous iron-pyrites, containing

page_text: small quantities of gold and silver, the flux required is a siliceous one, and if circum-
stances admit of it, the most appropriate form in which it can be introduced, is, as
auriferous, argentiferous our cupriferous quartz. Failing this however, silica, or
highly siliceous substances of any convenient kind may be employed.
To begin with, a charge of 5 cwts. of crudo sulphuretted mineral, with which
2 cwts. of auriferous quartz or other siliceous matter has been intermixed, is
introduced by the charging hopper, and, as soon as this has become fairly ignited,
it is followed by other similar charges.
If the temperature of the blast be sufficiently maintained, the mixture soon begins
to melt. Charges are now repeated frequently, and, as material is thus added to the
furnace with greater rapidity than it is capable of working off, the furnace becomes
full about 12 hours after beginning the operation, the smelting meanwhile progressing
below. The sulphur of the mineral is now the only fuel employed, and regular
charges of 10 cwts. of mineral, mixed with 5 cwts. of flux may be given half-hourly,
more or less, according to the capacity of the furnace and the volume, pressure and
temperature of the blast.
The pressure of the blast should not be less than 2 lbs. per square inch, and, by
preference as much as 4 lbs. per square inch.
The molten product which at first collects in the crucible of the furnace is
imperfectly desulphurised, and iron is insufficiently removed from it; but, as mineral
which has passed successively through each zone of the furnace, comes to the tuyeres,
normal work begins.
The greater part of the sulphur which has not been volatilised, as well as of the
iron, becomes oxidised, the latter combining with quartz to form a slag of ferrous
silicate, and only a small proportion of sulphur and of iron remains unoxidised, to
combine with copper and the noble metals, as auriferous copper-regulus.
The slag and regulus are separated from one another in the ordinary way.
When metalliferous quartz has to be worked in large quantities, and not simply as
an auxiliary material in the treatment of sulphuretted ores, furnace charges for
treatment in the manner above specified, may be prepared by adding to it, iron-
pyrites whether or not this be cupriferous or auriferous-in such quantity only, as
will yield with the silica of the quartz, a slag of ferrous silicate with as much as
from 62 to 71 per cent. of silica.
Again, when mineral, such as poor copper-pyrites, is subjected to this improved
treatment, the flux is modified to suit the gangue of the mineral, and to form with
it a fusible slag. Thus, in presence of lime, the flux added, is by preference, siliceous
silicate of alumina, but the treatment remains the same.
In other instances, the mineral to be operated upon, may have, in a self-contained
condition, all the materials necessary for the improved treatment, and in any such
case, the broken mineral may be charged into the furnace without any addition of
flux whatever.
Siliceous and auriferous iron-pyrites is mineral of this kind, and the improved
treatment of it, differs in no way, from what has been described as the improved
treatment of cupriferous iron-pyrites.
Whatever be the class of mineral subjected to the improved treatment, if it does
not naturally possess in a self-contained condition, all the materials necessary for the
formation of a metallic regulus and a fusible slag, that which is awanting, or which
is present in insufficient quantity must be added to the furnace charge. Carbonaceous
fuel occasioning as it does, a reducing atmosphere within the furnace-must not be
employed, after, in starting, the temperature of the furnace has been sufficiently
raised. And for the maintenance of a smelting temperature, when sulphides only
are utilised as fuel, the air-blast supplied to the furnace must be heated far above
the normal temperature of the surrounding atmosphere, and preferably to a
temperature not less than 420° Centigrade.

page_text: COMPLETE SPECIFICATION.
Improvement in the Treatment of Quartzose or Siliceous and
Sulphuretted Ores Containing Gold, Silver, or Copper.
I, HENRY BROCK FULTON, late of Bellfield, Kirkintilloch, in the county of Dumbarton,
Scotland, and now residing at 33 St. Dunstan's Road, Hammersmith, in the county
of London or Middlesex, Fellow of the Chemical Society of London do hereby
declare the nature of my said invention and in what manner the same is to
be performed, to be particularly described and ascertained in and by the following
statement:-
In the ordinary treatment of ores containing copper, with or without silver or
gold, for the production of regulus, the operations consist of calcination of the
mineral, employing wood or other carbonaceous fuel for the purpose, and subsequent
fusion of the calcined ore with fluxes, effected also by the use of coal, charcoal, coke
or other carbonaceous fuel.
By my present invention these two distinct operations are combined in one. The
sulphur of the ore is utilised as fuel, and the direct employment of carbonaceous fuel
is dispensed with.
The improvement is applicable to the treatment not only of sulphuretted ores
containing copper, silver or gold-to which siliceous material has to be added to
ensure the formation of slag; but also to the treatment of quartzose or siliceous ores,
containing gold, silver or copper-to which sulphuretted material has to be added
to support combustion, and ensure the formation of regulus.
In the improved treatment I employ a blast furnace, the construction of which
may be modified to suit the requirements of the particular ore or mixture of ores
under treatment, and, in communication therewith I employ a heating oven to raise
the temperature of the blast supplied to the blast furnace, preferably to from
420° Centigrade to 650° Centigrade, more or less.
:-
The procedure in beginning operations may be thus generally described :-
As in all blast furnace operations, a preliminary heating of the dry furnace to a
smelting temperature is necessary, and this is accomplished in the usual way by
kindling a fire of wood or coals on the hearth, putting on at first a gentle blast,
partially filling the furnace with coke, and increasing the blast until the interior of
the furnace has attained a smelting temperature at the tuyeres. When this has been
accomplished, the improved treatment begins, and the employment of carbonaceous
fuel in the furnace thenceforth ceases.
1st. As an example, when the. mineral for treatment is cupriferous iron-pyrites,
containing small quantities of gold and silver, the required flux is a siliceous one,
and when convenient, the most appropriate form in which it can be employed is, as
auriferous, argentiferous or cupriferous quartz. When such material cannot be
conveniently obtained, silica, sandstone, or other highly siliceous substance may be
made use of.
Though an open-mouthed furnace may be employed, one with a closed top, such
as is shewn in the drawing accompanying the provisional specification, allows the
operations to be conducted with less inconvenience to the workinen, the charges being
thus introduced to the interior of the furnace, without permitting any escape of
sulphurous gas around the charging platform.
Until the furnace has become full, and the process progresses normally, 1 prefer
to feed light charges, somewhat deficient in silica, adding them more frequently
than is afterwards necessary. Successive charges consisting of 5 cwts. of crude
sulphuretted mineral, intermixed with 2 cwts. of siliceous material, may be thrown
gradually into the hopper on the furnace top, after having drawn back the sliding
cover A. by means of the lever B. When the hopper has been filled, the slide is
replaced over its mouth, and the charge is then allowed to drop into the furnace by

page_text: raising the lever D. which opens the bell-valve C. Closing the bell-valve again, the
sliding cover may be once more removed, and a further portion of the charge may
be similarly introduced into the furnace.
As the furnace begins to work more regularly the charges may be increased to
10 cwts. of mineral, mixed with 5 cwts. of siliceous flux, every half hour, if the
temperature of the blast be sufficiently maintained, and its pressure be kept at from
2 lbs. to 4 lbs. per square inch.
Apart from the dimensions of the furnace, particularly its area at the tuyeres--
the speed at which a furnace may be worked, and the degree to which the produced
regulus may be concentrated, depend largely on the temperature and pressure at
which the blast is maintained. With a very high pressure blast, most of the iron
may be oxidised and removed as slag, yielding a concentrated regulus with as much
as 80% of copper, containing the greater part of the noble metals introduced in
the charge.
Such a degree of concentration however entails a considerable loss of copper in the
slag, and I prefer when working to recover copper-to aim at the production of
regulus with about 35% of copper. When the concentration is thus limited, the
loss of copper in the slag is inconsiderable, and the slag can be thrown away. Should
further concentration be desired, I prefer to treat the regulus from this first operation
in a second furnace, in a similar way, reserving the slag from this second treatment
to be used over again in the earlier stage.
2nd. When material such as auriferous pyrites, free from, or holding but little
copper, is under treatment, the higher degree of concentration may be aimed at
without suffering any material loss of the noble metals in the slag.
3rd. When auriferous quartz has to be worked in large quantities, and not merely
as an auxiliary material, or flux, in the treatment of sulphuretted ores, furnace
charges for treatment as above specified, may be prepared by adding to it iron-
pyrites, whether or not this be cupriferous or auriferous,-in such quantity only
as will yield with the silica of the quartz, a slag of ferrous silicate with as much as
from 62% to 71% of silica.
4th. When the mineral under treatment is poor copper-pyrites, the flux employed
with it is modified to suit the gangue of the mineral, and to form with it a fusible
slag. Thus, in presence of lime, the flux I prefer is siliceous silicate of alumina,
the treatment being otherwise the same.
5th. When again, the mineral under treatment is siliceous pyrites,-holding gold
silver or copper, having in a self-contained condition all the materials necessary for
the improved treatment, the broken mineral may be charged into the furnace without
any addition of flux whatever, and the treatment of such, -as in the various instances
just specified, differs. in no way from what has been more fully described as the
improved treatment of cupriferous iron-pyrites.
Whatever be the class of mineral subjected to the improved treatment, if it does
not naturally possess in a self-contained condition, all the materials necessary for
supporting combustion, and for the formation of a metallic regulus, and a fusible
slag, that which is awanting, or which is present in insufficient quantity must be
added to the furnace charge. Carbonaceous fuel must not be employed during the
smelting, after, in starting, the temperature of the furnace has been sufficiently
raised. And, for the maintenance of a smelting temperature when the oxidation of
sulphur and iron only is available for the purpose, the air blast supplied to the furnace
must be heated far above the normal temperature of the surrounding atmosphere,
and preferably to a temperature not less than 420° Centigrade.
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 :-
An improvement in the treatment of quartzose or siliceous and sulphuretted ores

page_text: containing gold, silver or copper, by mixing them in proportions suitable for com-
bustion and for the production of metallic regulus and fusible slag, and smelting
such ore or mixture in a blast furnace supplied with a highly heated air blast, in the
absence of coke or other carbonaceous fuel, as is herein before setforth.
Dated this Ninth day of August 1889.
H. B. FULTON.