Year: 1886

page_text: Date of Application, 27th Apr., 1886.
Complete Left, 26th Jan., 1887.
Complete Accepted, 8th Mar., 1887.
We JAMES HARGREAVES, Chemist, THOMAS ROBINSON, Iron. Founder, and JOHN
HARGREAVES Chemist, all of Victoria Road, Widnes in the County of Lancaster, do
hereby declare the nature of the said invention to be as follows :-
The objects of our invention are improvements in the treatment of pyrites for the
purpose of obtaining the sulphur and valuable metal therein contained, and in apparatus
employed therein.
We arrange a series of pyrites burners or chambers hereinafter referred to as burners
or chambers the body of the burners being made of brick or iron lined with brick.
When practicable we construct the burners and connections of brick, the burner having
an arched or dome roof. We work the series of burners in such a way that each
burner becomes the first intermediate and last of the series. When the object is to
obtain sulphurous acid we arrange the burners in two or more series when it is desired
to maintain as near as possible an equal temperature and strength of sulphurous acid
gas in the combustion chamber hereinafter referred to.
We heat the air before entering the pyrites burners to a suitable temperaturo and
pass the heated air first through the burner containing pyrites from which the sulphur
has been most nearly burned.
We obtain the heated air by means of regenerators packed with brick or other
suitable substance which may jointly act as heat reservoir and have catalytic action
upon the acid gases partially forming sulphurous into sulphuric acid and giving free
chlorine from hydrochloric acid through which regenerator the hot products of com-
bustion and air alternately pass. Along with the air injected into or aspirated through
the regenerator and which regenerator as also the burners we cover on the exterior
with iron or other suitable means taken to avoid leakage we inject hydrochloric,
sulphurous acid gas, or a mixture of the two gases, in sufficient quantity, to render
soluble the copper and other valuable metals contained in the pyrites and (when the
sulphurous acid is to be used in the manufacture of sulphate of soda by the direct process)

page_text: the necessary aqueous vapour required by the process for mixing with sulphurous acid
may also be injected.
In the case of four burners being used in a series the hot air and acid gases enter the
first burner containing pyrites from which the sulphur has been most nearly burned.
After the gases have passed through the burnt pyrites they are conducted by suitable
conduits to the second burner containing partially burned pyrites from which the air
now largely charged with sulphurous acid is passed through the pyrites contained in
the third burner, thence through the pyrites contained in the fourth burner. As the
gases issue from the fourth burner they will not only be found free from oxygen,
but to contain a large quantity of sulphur in the state of vapour which we oxidise in
any convenient form of combustion chamber by adding the necessary excess of air
required for the manufacture of sulphate of soda by the direct process, or for the
formation of sulphuric acid in lead chambers.
To complete the combustion of the sulphur vapour contained in the hot sulphurous
gas issuing from the series of burners, we, when very hot sulphurous acid is required
use the hot air supplied under pressure from the before mentioned heat regenerator.
Should it be desired to ultimately pass the sulphurous acid gas into chambers of
lead for the manufacture of sulphuric acid, or when for other reasons hydrochloric
acid gas cannot be directly mixed with the air to be used for burning the pyrites.
Under such circumstances we mix sulphurous acid with the air before it enters the
regenerator, or we disconnect the burner containing the pyrites most nearly burned
from the other burners in tho series, and for the purpose of rendering soluble the copper
and other valuable metals contained in the burnt pyrites we pass hot air or products
of combustion, chlorine and hydrochloric acid through the burnt pyrites and thence to
a suitable condenser where the acid gases are condensed and afterwards utilized for
dissolving the valuable metals contained in the pyrites.
Where ordinary pyrites burners are used for burning pyrites, we proceed to burn
the pyrites in the usual manner, and obtain the copper and other valuable metals
contained in the burnt pyrites soluble by a subsequent treatment as follows:-
The burnt pyrites is withdrawn from the ordinary pyrites burners in the usual
way, care being taken to separate the pieces of burnt pyrites from the dust pyrites
which is afterwards made into pieces. Or we dissolve the valuable metals contained
in the burnt pyrites dust by means of the solution of persalts of iron hereinafter
referred to. The pieces of burnt pyrites are put into a chamber or series of chambers
and hot air or products of combustion, together with the acid gases as hereinbefore
described are passed through the burnt pyrites maintained at a suitable temperature and
by the method of partially forming the hydrochloric or sulphurous acid gases into
chlorine and sulphuric acid before it is brought into contact with the burnt pyrites as
hereinbefore described.
It will be found more economical and practical to use a series of two or more
chambers for this purpose with suitable arrangements to avoid loss of heat therefrom.
The cool burnt pyrites from the ordinary pyrites burners most recently charged into
the chambers are brought into contact with the acid gas hereinbefore referred to, after
having passed through the burnt pyrites previously charged into the preceding
chambers.
Suitable connections are made to enable the hot gases to pass from one chamber to
another, and dampers to disconnect or connect each chamber from or to the series as
the contents of the chamber become ready for discharging, or after being recharged
with burnt pyrites.
In passing hot hydrochloric acid or chlorine gas through burnt pyrites to render the
valuable metals soluble; arsenic and antimony we volatilize, and ultimately pass to the
condenser and extract by suitable means from the condensed hydrochloric acid before.
it is utilized for dissolving the valuable metals contained in the pyrites.
For the purpose of more readily dissolving the chloride of silver and gold contained
in the pyrites without the use of chloride of sodium as ordinarily employed we utilize
the salts of iron and copper from the pyrites roasted as hereinafter described and we

page_text: obtain for this purpose the chlorides in a more concentrated form by the use of a series
of vats for dissolving the copper.
When it is desired to render soluble the valuable metals contained in the pyrites and
obtain the sulphur contained in the pyrites in a free state, we proceed as follows:-
The copper and other metals are rendered soluble and the sulphurous acid and sulphur
vapour evolved as hereinbefore described, and the strong sulphurous acid gas is
deoxidized and sulphur formed by mixing it with carbonic oxide or other reducing
gases the mixed gases passed through a suitable hot chamber, the vapourized sulphur
is cooled and passed into a chamber where the sulphur is deposited, and from which
the arsenic is removed by convenient methods. As will be evident the sulphur vapour
obtained along with the strong sulphurous acid as hereinbefore described may be con-
densed solid sulphur obtained without deoxidation of the sulphurous acid, and the
sulphurous acid conveyed for any useful purpose.
Or we obtain the sulphur in the solid form from sulphurous acid by passing one
portion of the stream of sulphurous acid along with sufficient air to maintain the fuel
contained in the gas producer at a temperature sufficient to complete the reaction.
This de oxidizing gas is mixed with the other portion of the sulphurous acid coming
from the pyrites burners in suitable quantity to deoxidize the sulphurous acid, and the
mixed gases passed through a suitable hot chamber, and the sulphur is recovered and
freed from arsenic as previously described.
The temperature of air or products of combustion and the acid gases entering the
first burner of the series containing pyrites most nearly burned, and also the temperatures
of the pyrites we regulate as follows:-
Whilst any kernals of unburnt pyrites remain in the burnt pyrites we pass air or
products of combustion together if desired with admixture of sulphurous or sulphuric
acid vapour, and maintain the burnt pyrites at a temperature suitable for readily
burning the sulphur contained in the centre of the pieces of pyrites. After the
sulphur in the pyrites has been burned we at suitable temperature mix with hot air or-
products of combustion and pass through the burnt pyrites hydrochloric acid, or
chlorine gases, with or without admixture of sulphur gases as herein before described,
and after the valuable metals have been rendered soluble they are extracted in con-
venient manner. When it is desired to avoid making the burnt or unburnt dust
pyrites into pieces as hereinbefore described, we burn or chlorinise the dust pyrites
in suitable dust burners, and form them into a separate series or connect one or moro
dust burners with the chambers hereinbefore described; each dust burner may be
chlorinised in the series or separated as hereinbefore described.
And we employ unburnt pyrites dust, sulphurous acid or other suitable means for
reducing the per salts of iron contained in the solution of copper. coming from the
lixiviating tanks before precipitating the copper.

page_text: COMPLETE SPECIFICATION.
Improvements in Treating Pyrites and in Apparatus Employed
therein.
We JAMES HARGREAVES of Peel House Lane, Farnworth Chemist, THOMAS
ROBINSON of Hope House Farnworth Ironfounder and JOHN HARGREAVES of Albert
Road, Widnes, Chemist all in the County of Lancaster do hereby declare the nature
of this invention and in what manner the same is to he performed, to be particularly
described and ascertained in and by the following statement :-
:-
Our invention relates to improvements in the treatment of pyrites for the purpose
of obtaining the sulphur and valuable metals therein contained and in apparatus
employed therein.
We employ a series of two or more burners, or chambers, hereinafter called burners.
The body of each burner is made of brick, or iron lined with brick and is preferably
arranged upon the principle of the more recently improved cylinder apparatus
employed in the Hargreaves and Robinson Sulphate of Soda process, each burner
having several charging holes in the roof or cover and the heated gases being caused
to pass downwards through the pyrites.
We prefer to construct the burners and
lined with jointed tiles to prevent leakage.
roof and is suitably braced with iron.
'
connection, of brick; the interior may be
Each brick burner has an arched or domed
We work the series in such a way that each burner (when more than two are
employed) becomes alternately, the first intermediate and last of the series.
To more clearly explain our system of treating pyrites and the apparatus we employ,
we will refer to the various improvements under seperate heads, though as will be
evident the treatment employed under one head is not unfrequently applicable under
another.
When the object is to obtain sulphurous acid from raw pyrites and to render the
valuable metals soluble, wo arrange the burners and work them in two or more series.
-We maintain as near as possible an equal temperature and strength of the sulphurous
acid gas in the combustion chamber hereinafter referred to.
We heat the air before it enters the pyrites burners to a temperature of about
1000° F the object being to thoroughly oxidise the sulphides, but preferably to
maintain a temperature below that at which the soluble salts of copper decompose.
The heated air is first passed to and through the burner containing pyrites most
nearly freed from sulphur. Cold air may be added to the hot gas on its passage from
the first to the second burner.
We obtain heated air for the first burner, by means of regenerators packed with
brick or other suitable substances acting as heat reservoirs and causing catalytic action
upon acid gases forming sulphurous into sulphuric acid and giving free chlorine from
hydrochloric acid through the regenerators hot products of combustion and air, or
acid gases alternately pass.
Along with the air injected or aspirated through the regenerators (and which

page_text: regenerators as also the burners may be covered on the outside with iron, or other
suitable means taken to prevent leakage) we pass hydrochloric, sulphurous acid, or a
mixture of the two gases in sufficient quantity to render soluble the copper and other
valuable metals contained in the pyrites and when the sulphurous acid is to be used in
the manufacture of sulphate of soda by 'the direct process the necessary aqueous vapour
required may be mixed in. We find that the addition of aqueous vapour increases
the proportion of sulphur vapour evolved.
When the object is to simultaneously burn pyrites to obtain sulphurous acid, obtain
the valuable metals soluble and pass the air and acid gases through the burners forming
the series, two or more burners are employed but we prefer four. Where four burners
are employed, the hot air and acid gases enter the first burner containing pyrites from
which the sulphur has been most nearly burned, from the first by suitable conduits,
they are conducted to the second burner containing partially burned pyrites from which
the air largely charged with sulphurous acid is passed through the pyrites contained
in the third, thence through the pyrites contained in the fourth burner. The gases
from the fourth burner will be found free from oxygen and containing a large quantity
of sulphur vapour, which we oxidise in any convenient form of combustion chamber
by adding thereto the necessary excess of air required for the manufacture of sulphate
of soda by the direct process, or of sulphuric acid in head chambers.
To avoid condensation of sulphur, we prefer to heat newly charged raw pyrites by
products of combustion, before passing sulphurous acid containing sulphur vapour
through such pyrites.
To obtain sulphurous acid of even strength and temperature we mix the sulphurous
acid from two or more series of burners and oxidise the sulphur vapour in the
combustion chamber hereinafter described.
To more thoroughly complete the combustion of the sulphur vapour contained in
the hot sulphurous acid coming from the series of burners, we use hot air supplied
under pressure from the before mentioned heat regenerators.
Should it be desired to ultimately pass the sulphurous acid into chambers of lead, to
yield sulphuric acid, or when for other reasons, hydrochloric acid gas, or chlorino,
cannot be directly mixed with the air to be used for burning the pyrites, we mix
sulphurous acid with the air preferably before it enters the regenerators. We find hot
burnt pyrites to have strong catalytics action upon sulphurous acid and air forming
sulphuric acid and soluble sulphate of copper. Should the pyrites contain gold, we
disconnect the burner containing the pyrites most nearly burned, from the other
burners in the series and for the purpose of rendering more completely soluble the
copper and other valuable metals, we pass hot air or products of combustion (if the
metallic sulphides are not already perfectly oxidised) chlorine and hydrochloric acid
through the burnt pyrites and thence to a suitable condenser, where the acid is
condensed and afterwards utilized for dissolving the valuable metals contained in the
treated pyrites.
We employ the following method for obtaining the residual sulphur in a useful
condition and rendering soluble the valuable metals contained in pyrites from which
the sulphur has been previously burned in ordinary pyrites burners.
Where ordinary pyrites burners are used, we proceed to burn the pyrites in the
usual manner and afterwards obtain any sulphur remaining in the mass by passing hot
air through it and afterwards render the valuable metals soluble by passing acid gases
through such pyrites.
The burnt pyrites is withdrawn from the ordinary pyrites burners in the usual way,
care being taken to separate the pieces from the dust pyrites. This is preferably done
by means of a circular revolving screen, separating the pyrites in two or preferably in
three or more sizes.
The sizes may be called dust, medium and large.
1st. Dust passing through a screenth to th of an inch mesh.
2nd. Medium passing through a mesh in. to 1 inch.
3rd. Large-not capable of passing through the before mentioned sizes.

page_text: we prefer
Great the pyrites of anerent sizes in
separate burners.
We treat the Dustburnt pyrites in separate, or series of dust burners, preferably
mechanical, or made into large pieces and treated like the large size pyrites.
⚫ Instead of treating the dust burnt pyrites with hot air and acid gases the valuable
metals may be rendered soluble by means of persalts of iron, or hot strong liquid
hydrochloric acid may be used which will form perchloride of iron.
The pieces of burnt pyrites are put into a burner or series of burners with suitable
arrangements to avoid loss of heat therefrom.
In practice we find it preferable to employ two series as hereinbefore mentioned for
obtaining sulphurous acid and to arrange the two series so as to be interchangeable,
that is, the burners of one set, shall be interchangeable with the burners of the other
set. Hot air or products of combustion with which may be mixed sulphur acid gases
are passed through the pyrites, contained in the series in which the sulphides of the
metals are being oxidised and the sulphur obtained as sulphirous or sulphuric acid gas.
-Through the other series containing pyrites which has been thoroughly oxidised is
passed cool or hot hydrochloric acid gas.
Owing to the high temperature required to oxidise the sulphides of the metals we
find it preferable not to pass hydrochloric acid or chlorine through the pyrites until
the sulphides have been oxidised.
In actual working we find that when the residual sulphur contained in burnt pyrites
is oxidised at a temperature between 900° to 1150° F-that practically the whole of
the sulphur is eliminated as sulphuric acid vapour which we condense.
When it is desired to obtain the copper from the pyrites as sulphate, we pass the
sulphuric acid vapour evolved from the first series through the oxidised pyrites con-
tained in the second series and thence to a condenser from which it may be employed
for lixiviating the pyrites, thus obtaining practically the whole of the copper as
sulphate.
Soluble iron salts in the pyrites may be reduced by passing hot aqueous vapour
over the pyrites.
We pass the acid gases through the pyrites at a temperature below that at which the
salts of the valuable metals are largely volatilized or the copper salts reduced, and
when the pyrites contain gold after being treated with acid gases we cool the pyrites
to below 400° F :-if not already below that temperature) and maintain the said
pyrites in an atmosphere of chlorine.
The cool burnt pyrites from the ordinary pyrites burners, charged into the burner to
undergo subsequent treatment as herein before referred to is warmed and has sulphuric
acid condensed thereon by having passed therethrough the sulphur acid gases herein-
before referred to, coming from the burnt pyrites previously charged and undergoing
oxidation.
Suitable connections are made to enable the hot gases to pass from one burner to
another and dampers to disconnect or connect each burner from or to the series as the
contents of the burners become ready for discharging, or after being charged with
burnt pyrites the regenerators are preferably enclosed in the mass of brickwork
surrounding the series of burners.
In passing hot hydrochloric acid through burnt pyrites to render the valuable metals
soluble, arsenic and antimony are volatilized and are passed along with the acid gases
to the condenser and are extracted by suitable means from the condensed hydrochloric
acid preferably before it is utilized for dissolving the valuable metals.
For the purpose of more readily dissolving the chloridos of silver and gold contained
in the pyrites, without the use of chloride of sodium as ordinarily employed, we
utilize the salts of iron and copper from the pyrites roasted as hereinbefore described
and we obtain for this purpose the chlorides or other salts of the metals, in a more
concentrated form, by the use of a series of vats for dissolving the copper contained
in the pyrites.
To expedite the solution of the valuable metals, the large pieces may be reduced in
size and the liquor in all the vats kept hot.

page_text: When it is desired to render soluble the valuable metals contained in pyrites and
obtain the sulphur in a free state, we proceed as follows:-
The copper and other valuable metals are rendered soluble and the sulphurous acid
and sulphur vapour evolved by passing hot air and aqueous vapour through a long
column of pyrites as hereinbefore described and the sulphurous acid gas is deoxidised
and free sulphur obtained by mixing the sulphurous acid with carbonic oxide, or other
reducing gases. We prefer to use the carbonic oxide and hydrogen known as water
gas, or to employ sulphuretted hydrogen. The mixed gases are passed through a
suitable hot chamber preferably packed with brick.
Sulphurous acid may be reduced, by passing the reducing gas into the hot column
of pyrites beyond the zone where all free oxygen has been absorbed.
Sulphur in the solid form may be obtained by passing one portion of the stream of
sulphurous acid gas along with sufficient air to maintain the fuel contained in the gas
producer at a temperature sufficient to complete the reaction, the deoxidising gas thus
formed is mixed with the other portion of sulphurous acid coming from the pyrites
burners insuitable quantity to deoxidise the sulphurous acid and the mixed gasses passed
through the hereinbefore mentioned hot chamber.
The sulphur is recovered and freed from arsenic.-We prefer to separate the arsenic
or form it into chloride whilst the sulphur is in the state of vapour.
To separate the arsenic we prefer to have sulphuretted hydrogen in excess and pass
the sulphur vapour through a hot filter formed of sulphide of calcium, or other alkaline
sulphide.
To form the arsenic into chloride of arsenic, we prefer to have the sulphurous acid
in excess and mix hydrochloric acid with the hot sulphur vapour.
The vapourized sulphur is cooled and passed into a suitable condensing chamber.
As will be evident the sulphur vapour obtained along with the sulphurous acid and
purified from arsenic as hereinbefore described may without tho use of reducing gases
be condensed, solid sulphur obtained, air added to the sulphurous acid gas and
conveyed for the manufacture of sulphuric acid, or other useful purpose.
Having now particularly described and ascertained the nature of this invention, and
in what manner the same is to be performed, we declare that what we claim is :-
1st A series of burners for the purpose described constructed of iron lined
substantially as described.
2nd A series of burners for the purpose described, constructed of brick having an
arched or domed roof.
3rd The joint use of two series of burners, substantially in the manner and for
the purpose described..
4th Oxidising and treating with acid gases, the dust from burnt pyrites in the
manner and for the purpose, substantially as described.
5th-Obtaining hot air by means of regenerators alternately heated by products
of combustion and employing the hot air so obtained for oxidising the sulphides
of the metals and subsequently passing acid gases through the pyrites, substantially as
described.
6th-Heating acid gases by means of regenerators by passing alternately products
of combustion and acid gases therethrough, substantially as set forth.
7th Regenerators alternately heated by means of products of combustion, serving
at the same time to heat air and acid gases and induce catalytic action upon the said
acid gases substantially in the manner and for the purpose set forth.
8th Injecting or aspirating air or acid gases through a regenerator or regenerators
and subsequently passing such air or acid gases through a series (that is from one to
the other) of burners substantially as described.
9th Passing a mixture of hot air and aqueous vapour through a column or
columns of pyrites for the purpose of obtaining sulphurous acid and sulphur vapour,
subsequently rendering the valuable metals soluble, substantially as described.
10th Obtaining volatilized sulphur along with sulphurous acid and employing a
combustion chamber for oxidising the sulphur vapour, substantially as described.

page_text: 11th Treating burnt pyrites to eliminate the residual sulphur and afterwards render
the valuable metals soluble by means of acid gases, substantially as described.
12th Separating burnt pyrites into sizes, subsequently treating the separated sizes
by passing hot air, or products of combustion through a column or columns of the
pieces, substantially as described.
13th Treating pyrites as described under claim 12. and afterwards rendering the
valuable metals soluble by means of acid gases, substantially as described.
14th Passing hot air, or hot air mixed with sulphurous acid at a temperature of
between 900°, and 1150 Fahr: through a column or columns of pyrites from which
sulphur has been previously burned to directly obtain any remaining sulphur as
sulphuric acid and so prepare the pyrites for subsequent treatment by means of
acid gases.
15th Treating pyrites by means of hot gaseous hydrochloric acid for the purpose of
rendering the valuable metals soluble, to eliminate arsenic and antimony by volatilizing
the same substantially as set forth.
16th Rendering soluble the valuable metals contained in pyrites by means of acid
gases as herein described, subsequently washing out the said valuable metals so rendered
soluble, in a series of tanks, substantially as described.
17th-Obtaining an increased quantity of soluble gold from pyrites by first passing
acid gases through or amongst the mass and afterwards maintaining the pyrites in an
atmosphere of chlorine at a temperature of not more than 400° Fahr. substantially as
described.
18th Obtaining or manufacturing sulphate of copper by passing sulphuric acid
vapour from pyrites through a column or columns of burnt pyrites, substantially as
set forth.
19th Separating dust pyrites, from burnt pyrites and treating such dust pyrites
for the purpose of obtaining the valuable metals therein contained in a soluble condition,
substantially as described.
20th-Obtaining sulphur in the solid form from pyrites and subsequently rendering
soluble the valuable metals in the said burnt pyrites, by means of hot air and acid gases
substantially as described.
21st Obtaining sulphur in the solid form from sulphurous acid and sulphur
vapour obtained as described, by deoxidising the sulphurous acid by means of
deoxidising gases in a hot chamber substantially as set forth.
22nd Treating pyrites for the purpose of jointly obtaining sulphur in the solid
form and sulphurous acid, the latter available generally and subsequent treatment of
the pyrites by means of acid gases, substantially as described.
JAMES JOHNSON,
Patent Office,
4, Clayton Square, Liverpool,
.Agent.