IMPROVEMENTS IN THE TREATMENT OF REGULUS OR MATTE, FOR THE EXTRACTION OF METALS CONTAINED THEREIN
Year: 1882

page_text: "
LETTERS PATENT to Edward Andrew Parnell of Swansea in the County of
Glamorgan for an invention of IMPROVEMENTS IN THE TREATMENT OF
REGULUS OR MATTE, FOR THE EXTRACTION OF METALS CONTAINED THEREIN
"
PROVISIONAL SPECIFICATION left by the said Edward Andrew Parnell
at the Office of the Commissioners of Patents on the 9th June 1882.
EDWARD ANDREW PARNELL of Swansea in the County of Glamorgan. IMPROVE-
MENTS IN THE TREATMENT OF REGULUS OR MATTE, FOR THE EXTRACTION OF
METALS CONTAINED THEREIN."
My improvements relate chiefly to the treatment of regulus or matte derived
from the smelting of pyretic ores consisting of sulphide of iron with more or less
sulphides of copper and other metals, and is specially intended for regulus derived
from argentiferous and auriferous pyrites. The regulus is obtained in the usual
way by smelting raw or partially calcined ores either in reverberatory furnaces or
cupolas.
Instead of subjecting such regulus to the usual "dry" methods of smelting and
refining, I treat the regulus with hydrochloric acid by the action of which the
sulphide of iron is decomposed with production of ferrous chloride and disengage-
ment of sulphuretted hydrogen gas, the latter may be made available as a source
of sulphur or sulphurous acid.
The sulphides of copper, lead silver and gold remain undissolved. By the use of
a slight excess of hydrochloric acid the iron may be entirely eliminated from the
insoluble sulphides; and the acid liquor thus obtained may be rendered perfectly
neutral by contact with fresh regulus. The insoluble sulphides, after filtration
and washing, are treated by the usual well known methods for the separation of
its various metals.
My improvements also include a modification of the preceding method which
may sometimes be desirable in which the solvent is a solution of ferric chloride.
When regulus containing sulphides of iron copper and lead is digested in a solution
of ferric chloride, both iron and copper are readily dissolved, with separation of

page_text: free sulphur, and reduction of the ferric chloride to ferrous chloride, sulphide of
lead is also decomposed by ferric chloride, yielding chloride of lead, which for the
most part remains undissolved, together with all the silver and gold which may
have been present in the regulus. From the solution copper may be precipitated
in the usual way, either as metallic copper or as sulphide, and the filtered liquid,
after addition of hydrochloric acid and exposure to air for oxidation to ferric
chloride may be used for treatment in the same way of fresh regulus.
In cases where it is desirable to dissolve both copper and iron from argentiferous
regulus, the preceding operation may be modified by causing a current of air to
permeate the mixture of regulus and ferric chloride with occasional addition of
hydrochloric acid and removal of a corresponding quantity of the solution of
ferrous and cupric chlorides.
Regulus derived from other sources then those to which I have herein referred
may also be profitably treated by the processes herein described, as for example,
the regulus obtained by the smelting, of cupriferous lead ores.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Edward Andrew Parnell in the Great Seal Patent Office on the
9th December 1882.
.
EDWARD ANDREW PARNELL of Swansea in the County of Glamorgan. "IMPROVE-
MENTS IN THE TREATMENT OF REGULUS OR MATTE FOR THE EXTRACTION OF
METALS CONTAINED THEREIN."
"
My improvements relate, in the first place to the treatment of regulus or matte
obtained from argentiferous and auriferous, pyrites, being the first product of the
smelting of such ores in the usual way, in reverberatory furnaces or cupolas. The
ores may be smelted in the raw state or with preliminary partial calcination; with
or without the addition of suitable fluxes according to the nature and proportion
of the gangue. The regulus thus obtained consists chiefly of proto sulphide of
iron, and generally contains, besides the precious metals more or less sulphide of
copper.
Instead of subjecting such regulus to the usual "dry" methods of smelting and
refining I treat it with hydrochloric acid. The sulphide of iron contained in the
regulus is thereby decomposed, with the production of ferrous chloride and dis-
engagement of sulphuretted hydrogen gas; the latter may be made available as a
source of sulphur or sulphurous acid by the ordinary well known methods.
By the use of a slight excess of hydrochloric acid, the iron may be almost
entirely eliminated from the insoluble sulphides, and the acid liquor thus obtained
may be rendered perfectly neutral by contact with fresh regulus.
The whole of the copper present in the regulus remains undissolved (so long
as sulphuretted hydrogen is present) as sulphide, together with all the silver
and gold.
If lead is present, that metal is dissolved to some extent, provided the acid is in
excess, and it is to be observed that if the solution of ferrous chloride is of
moderate strength, a notable quantity of lead remains in solution, even when the
excess of acid has been neutralized by fresh regulus, notwithstanding the presence
of sulphuretted hydrogen. The lead contained in such liquid may be completely
precipitated by metallic zinc, or more economically, by a solution of sulphide of
sodium.
In carrying out this process bydrochloric acid may be applied to the regulus
either in the gaseous state or as ordinary solution in water. I prefer the liquid
acid to the gaseous, as the former is more easily applied, and the action therewith
is more easily regulated. The strength of the liquid acid is not important, it may
be as low as 1060 sp. gr. but as the stronger acid acts more readily, I prefer to use
acid of sp. gr. 1.100 or upwards. The application of heat is not necessary when
the regulus contains less than 5% of copper, with a larger proportion of copper, it
is desirable to assist the action of the acid by moderate heating. The operation.
may be carried on either in a stone tank or in a tank made of oak or other hard
wood.
It will be obvious that the construction of the apparatus admits of considerable
variation. The most convenient form depends upon circumstances, particularly the
facility with which acid acts on the regulus and the quantity of regulus to be
operated upon. When the regulus is easily acted on, a tank may be employed.
of 5 to 6 feet in height to contain a layer of 3 to 4 feet in thickness of regulus
broken in pieces of about the size of a walnut, on a perforated false bottom. The
acid may be run through continuously. A large part of the insoluble sulphide is
carried through by the liquor in a finely divided state, and is allowed to settle in
an adjacent tank.

page_text: If the regulus is not decomposed with great facility by hydrochloric acid owing,
to the presence of say more than 5 p.c. of copper, it should be ground and the
mixture with acid agitated. A good method of agitation consists in placing the
mixture in a horizontal revolving cylinder, made of wood with a pipe through the
centre of one end to allow the egress of gas.
It is always desirable to treat the undissolved portion of the regulus with
excess of acid, and to neutralize the acid liquor therefrom by contact with fresh
regulus.
"
The insoluble sulphides (usually of copper and lead together with the precious
metals) after filtration and washing are either treated by the usual well known
methods for the separation of the various metals, or by an improved process herein
after described.
My improvements relate in the second place, to a wet process for treating
argentiferous and auriferous regulus, in which hydrochloric acid is used as the
solvent of the common metals not directly, but indirectly through the intervention
of ferric chloride. When regulus containing sulphides of iron copper and lead is
digested in a hot solution of ferric chloride, the sulphides are decomposed, with
formation of the corresponding chlorides separation of free sulphur, and reduction
of the ferric chloride to ferrous chloride: copper and iron are dissolved, lead only
partially The whole of the silver and gold are undissolved.
This method is applicable not only to regulus of the kind before referred to,
containing a small proportion of copper, but to regulus in which copper is the
principal constituent.
In carrying out this operation a convenient strength of ferric chloride solution
is about 1-150 sp gr. The regulus should be reduced to a fine powder. The
vessel employed may be either of stone or hard wood, with a rouser for agitation.
The application of heat is not necessary, but it is highly desirable, as it greatly
accelerates the decomposition. A steam jet may be conveniently employed for
that purpose. The undissolved portion consists of free sulphur, the precious metals
(a portion of the silver being as chloride) siliceous matter present in the regulus
and possibly chloride of lead and a small quantity of regulus not fully acted on.
It is collected on a filter washed dried and gently heated to sublime or burn the
sulphur, and the residue is treated by the usual well known methods for extracting
and refining precious metals.
From the solution thus obtained copper may be precipitated either as metallic
copper by iron, or as sulphide by sulphuretted hydrogen. A portion of the
supernatant or filtered liquor is used as a source of ferric chloride for subsequent
operation. For that purpose sufficient free hydrochloric acid is added to it to
correspond to one half the ferrous chloride present and the liquor is freely exposed
to the air in well known apparatus for a similar object until oxidation to ferric
chloride takes place. Another method of obtaining ferric chloride from the ferrous
chloride liquor is hereinafter described.
In the treatment of copper regulus by solution of ferric chloride in the manner
I have described the solution of copper which is thereby formed acts an important
part. The copper in the regulus is first converted to cuprous chloride. By further
action of ferric chloride and also by exposure to air (hydrochloric acid being
also present) the cuprous chloride becomes changed to cupric chloride. Now the
latter acts on fresh regulus in a manner analagous to ferric chloride that is to say
it becomes reduced to cuprous chloride and dissolves both copper and iron from the
regulus with separation of free sulphur. In the presence of hydrochloric acid the
cuprous chloride is held in solution and by access of air becomes again changed to
cupric chloride to react on fresh regulus In such a case the mixture of ferric
chloride and cupric chloride becomes the active solvent, and it is obvious that the
operation, if desirable on other grounds, may be commenced by solution of cupric
chloride without admixture of ferric chloride.
· The preceding operations may also be modified by first partially calcining the
regulus and afterwards treating it with hydrochloric acid. The ferric and cupric

page_text: chlorides thus produced react on the remaining sulphides; or the preliminary
calcination of the regulus may be complete and the ferric and cupric chlorides
obtained therefrom be made use of for acting on other raw regulus. Another
mode of treating argentiferous coppery regulus for separation of both copper and
iron analogous to the preceding is by means of ferric sulphate in the place of ferric
chloride. When such regulus in fine powder is digested in solution of ferric
sulphate reactions take place corresponding to those with ferric chloride. Both
copper and iron are dissolved with separation of free sulphur and reduction of
ferric sulphate to ferrous sulphate. Lead and the precious metals are not dissolved.
The presence of a little free sulphuric acid is desirable. This operation may be
conducted in a similar manner to that with ferric chloride liquor, with the exception
that instead of completing the operation in a tank I prefer evaporating the mixture
with regulus to dryness in a pan with surface heat and moderately heating it with
exposure to air whereby oxidation of the ferrous sulphate takes place and the ferric
sulphate reacts on more regulus. The temperature should not be so high as to
decompose ferric sulphate into oxide of iron and free sulphuric acid.
When describing my process for decomposing argentiferous regulus containing
only a small proportion of copper with hydrochloric acid I referred to an improved
method of separating copper from the argentiferous residue undissolved by bydro-
chloric acid namely by the use of a solution of ferric chloride cupric chloride
or ferric sulphate as above described. The light fine portion is acted on with
great facility; the gritty portion should be reduced to a fine powder before treat-
ment. Thus the first and second methods of treating regulus herein described
may be conjoined by first decomposing the regulus by hydrochloric acid with
disengagement of sulphuretted hydrogen and afterwards exposing freely to air the
ferrous chloride liquor thus obtained holding the undissolved sulphides, in suspension
(some free hydrochloric acid being also present) when the change takes place
described under the second head.
The preceding operations in which hydrochloric acid is used either directly by
the first method or indirectly by the second are specially adapted for localities
where hydrochloric acid is of little value, particularly the vicinity of Alkali Works
in which sulphate of soda is made by decomposing common salt with sulphuric
acid. In other localities it will be desirable to reproduce hydrochloric acid or
ferric chloride from the neutral ferrous chloride liquor. For that purpose, the
liquor is evaporated to dryness and the residue heated to dull redness either in an
open reverberatory furnace or in a muffle furnace in connection with an ordinary
coke tower for condensation.
If the object is to recover free hydrochloric acid, steam is brought into contact
with the charge in the furnace. This operation is already well known. But
when the object is to obtain ferric chloride no steam is introduced but air is
allowed to have free access. At a moderate heat ferric chloride is formed and
volatalized. The residue consists of oxide of iron (mostly ferric oxide). The ferric
chloride may be condensed for the most part in the solid state in adjacent cooling
chambers and the remainder by washing the escaping gas in a coke tower or other
well known condensing apparatus.
It will be obvious that in their manipulatory details, the processes herein
described admit of considerable variation I have pointed out the manner of con-
ducting the various operations under ordinary circumstances. I would however
have it distinctly understood that I do not confine myself to the precise details I
have mentioned. I would also have it understood that I am aware that hydro-
chloric acid, sulphuric acid, Ferric Chloride, and Ferric Sulphate have before been
employed in the extraction of iron and copper from sulphide ores both raw and
roasted but the material which I treat is a regulus or matte, that is to say a product
obtained by the fusion of the ores and which consists almost entirely of the metals
combined with sulphur the earthy constituents of the Ores having been almost
completely separated in the form of Slag. What I claim as my invention is
1st The treatment of regulus or matte with hydrochloric acid for the separation

page_text: from the valuable metals, of iron as ferrous chloride, and of sulphur as
sulphuretted hydrogen.
2nd The treatment of argentiferous and auriferous regulus with ferric chloride
and with cupric chloride, either together or separately, for the extraction of
iron and copper and separation of sulphur in the free state.
3rd The treatment of argentiferous and auriferous regulus with ferric sulphate
for a similar purpose.
4th The treatment of the mixed sulphides left undissolved when regulus is
digested in hydrochloric or sulphuric acid with ferric and cupric chlorides
together or separately.
5th The treatment of the aforesaid mixed sulphides, and of argentiferous and
auriferous regulus with ferric sulphate
6th The treatment of partially calcined regulus with hydrochloric acid-for the
separation of iron and copper in the manner herein described.
In witness whereof I the said Edward Andrew Parnell have hereunto set my
hand and seal this seventh day of December in the year of our Lord One
thousand eight hundred and eighty two.