A Method of Utilising certain Bye-products of Iron and Copper - Sulphides, and other Iron and Copper Ores, for the Production of Persulphate of Iron, to be used as a Disinfectant for the Purification of Sewage, and for other purposes.
Year: 1894

page_text: Date of Application, 30th June, 1894
Complete Specification Left, 7th Feb., 1895-Accepted, 9th Mar., 1895
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PROVISIONAL SPECIFICATION.
A Method of Utilising certain Bye-products of Iron and Copper
- Sulphides, and other Iron and Copper Ores, for the Production
of Persulphate of Iron, to be used as a Disinfectant for the
Purification of Sewage, and for other purposes.
We GEORGE DALTON of Regent Villas Headingley in the City of Leeds
Engineer and THOMAS BAWDEN PROVIS of 42 Aberdeen Park Highbury in the
County of Middlesex Mining Engineer, do hereby declare the nature of this
invention to be as follows
After iron and copper pyrites and other ores of iron and copper have been treated
for the extraction of sulphur copper and silver there remains a refuse containing &
large percentage of iron which having been exposed to a great heat in the
extraction process is peculiarly absorbent of oxygen and on being exposed to the
atmosphere rapidly becomes converted into peroxide of iron. Notwithstanding this
Our
the refuse produced as aforesaid has hitherto been mostly regarded as waste.
invention consists in converting it into persulphate of iron for use as a disinfectant,
or for the purification of sewage, or for the precipitation of solids from other
For this
solutions and for the manufacture of manures and for other purposes.
purpose we treat the refuse after sufficient oxidisation by natural or artificial means
with sulphuric acid in suitable vessels and by this means the ferruginous particles
become converted into persulphate of iron. Then by the application of heat we
drive off the superfluous moisture and what is then left may be pressed into briquets
or converted into a dry powder. By the foregoing method persulphate of iron may
be produced at a greatly reduced cost and manure of considerable value produced
at reduced cost. If great purity of the persulphate be desired the refuse after
leaving the roasting furnaces may be washed or re-smelted so as to effectuate the
almost complete removal of silica. In this refined state the persulphate may be
made up in the form of lozenges and used as a medicine in the same way as
persulphate is now used.
Dated this Twenty-second day of June 1894.
GEO. DALTUN.
THOMAS B. PROVIS.
COMPLETE SPECIFICATION.
A Method of Utilising certain Bye-products of Iron and Copper
Sulphides, and other Iron and Copper Ores, for the Production
of Persulphate of Iron, to be used as a Disinfectant for the
Purification of Sewage, and for other purposes.
We GEORGE DALTON of Regent Villas Headingley in the City of Leeds
Engineer and THOMAS BAWDEN PROVIS of 42 Aberdeen Park Highbury in the
County of Middlesex Mining Engineer do hereby declare the nature of this
nvention and in what manner the same is to be performed, to be particularly
escribed and ascertained in and by the following statement:-
After iron and copper pyrites and other ores of iron and copper have been treated

page_text: for the extraction of sulphur copper and silver there remains a refuse containing a
large percentage of iron which having been exposed to a great heat in the extraction
process is peculiarly absorbent of oxygen and on being exposed to the atmosphere
rapidly becomes converted into peroxide of iron. Notwithstanding this the refuse
produced as aforesaid has hitherto been mostly regarded as waste. Our invention
consists in converting it into persulphate of iron for use as a disinfectant or for the
purification of sewage or for the precipitation of solids from other solutions and for
the manufacture of manures and for other purposes. For this purpose we treat the
refuse after previous oxidisation by natural or artificial means with sulphuric acid in
suitable vessels and by this means the ferruginous particles become converted into
persulphate of iron.
Such being the nature of our invention we now proceed to describe in greater
detail the manner in which we carry the same into practical effect but we would
wish it to be understood that our invention is independent of the apparatus by which
it may be carried into effect and that we do not claim any form of apparatus as part
of our invention.
The refuse produced as aforesaid hereinafter for convenience sometimes called
protoxide of iron or more simply protoxide may be oxydised by simply turning over
with the shovel the heaps into which it is usually placed on leaving the extraction
furnaces so as to bring all parts of it into contact with the air. Another method is
to blow air through it.
After the protoxide or refuse has been thoroughly oxidised and thereby converted
into peroxide of iron it is placed in any suitable vessel preferably one composed of
or lined with material impervious to the action of acid and there mixed to saturation
with sulphuric acid and thoroughly stirred up so as to subject every part of it to
the action of the acid. The thorough saturation of the peroxide by the acid
converts it into persulphate. Usually the relative proportions of the ingredients
are 2000 lbs. of acid of the quality known as Twaddle 168 to 2240 lbs. of peroxide
refuse, but the protoxide or refuse varies in character and consequently also the
peroxide which therefore sometimes takes more and sometimes less acid to effect the
conversion. The quantity will also vary according to the strength of the acid used
and the quality of the finished product will vary according to the strength of the acid.
Enough acid must be used to convert it into a sort of paste without leaving any
superfluous fluid. The mixing may be effected in open vessels unless carbon or
metallic copper or other metals than oxide of iron be present in which case there
will be noxious fumes. In that case the mixing should be effected in closed vessels
or otherwise means should be provided to pass the fumes through a condenser.
And if there be any considerable amount of sulphurous acid in the furnes that may
be utilised for the manufacture of a sulphite as for instance the sulphite of soda.
If the mixing be effected in closed vessels then some or any existing form of
mechanical stirrer or mixer must be used. In open vessels the mixing may be
effected either by mechanical means or by hand labour. When the mixing has been
thoroughly effected the persulphate thereby obtained is subjected to the action of
heat to drive off the moisture. The drying may be effected by the application of
heat under the mixing vessel (any superfluous or unabsorbed acid being first drawn
off) or the persulphate may be removed from the mixing vessel and dried in separate
ovens or kilns. We use separate ovens so constructed that the fumes and smoke
from the fire are not permitted to come into contact with the drying persulphate.
When the persulphate is sufficiently dried it is withdrawn from the ovens and is
ready for use and is at once put into tubs or casks ready for the market when
intended to be used for precipitation of sewage or similar rough purposes. But
instead of being dried to absolute dryness the persulphate may be withdrawn from
the ovens whilst still containing some moisture and passed through suitable presses
and thereby made into briquets and then thoroughly dried out.
When greater
purity of the persulphate is desired the protoxide or refuse as it leaves the roasting
or smelting furnaces wherein it has been produced may be washed or resmelted so
as to effectuate the almost complete removal of silica before further treatment as
i

page_text: herein before described. If a still purer condition of the persulphate be desired then
the finished ordinary product obtained as aforesaid may be dissolved in water when
the sand and insoluble matter will settle and the persulphate will afterwards be
obtained in re-crystalised form by evaporation of the remaining solution. But even
after this treatment arsenic might still be present. To produce persulphate for
medical purposes the peroxides may be treated with hydro-chloric or other acid or
alkaline solvents to eliminate arsenic and other impurities and the residue then
treated with sulphuric acid. This method will not only bring out arsenic in
solution but will dissolve most of the lime away. Persulphate of iron obtained in
this way may be used in the form of lozenges or in any other way as a medicine
in the same way as persulphate of iron is now used.
It is essential that the protoxide of iron or raw material or refuse should be
thoroughly oxidised before treatment with the sulphuric acid in order to produce
tne persulphate at the least cost as if sulphuric acid be added before oxidisation it
will form protosulphate and nitric acid will then have to be used to convert that
into persulphate. This would be an additional process in the manufacture and add
to the cost.
We claim that by our method as hereinbefore described persulphate can be
produced at greatly reduced cost.
Persulphate of iron is not of itself useful as a manure. It is only when applied
to sewage that it becomes so through the resultant precipitate and because of the
ammonia which it fixes in the precipitate. By lessening the cost of persulphate we
lessen the cost of manures produced thereby.
Persulphate of iron is useful as a disinfectant because of its tendency to absorb
noxious gases and any floating organic matter.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed we declare that what we
claim is
1. The utilisation of the refuse or bye-products of iron and copper pyrites
or sulphides and other iron and copper ores after treatment of such ores for the
extraction of sulphur copper and silver and for the purpose of producing persulphate
of iron therefrom.
2. The utilisation of such refuse or bye-products as aforesaid by and for the
purpose of producing persulphate of iron therefrom by the methods hereinbefore
described or any chemically equivalent method or methods.
Dated this Ch 1
1005
GEO. DALTON.
THOMAS B. PROVIS.
Filed, on behalf of the applicants, by Thos. Dalton,
65, Albion Street, Leeds, Solicitor, their Agent.