Improvements in the Preparation and Treatment of Bromine for the Extraction of Gold from Ore or for other Purposes.
Year: 1888

page_text: Date of Application, 7th Dec., 1888
Complete Specification Left, 9th Sept., 1889-Accepted, 2nd Nov.,
1889
PROVISIONAL SPECIFICATION.
Improvements in the Preparation and Treatment of Bromine for
the Extraction of Gold from Ore or for other Purposes.
I, MATTHEW HENRY SIMPSON, of Halsey Street, in the County of Middlesex,
Metallurgical Engineer, do hereby declare the nature of this invention to be as
follows:-
My invention relates more especially to the extraction or separation of gold, by
what are known as wet processes from such auriferous materials as pyrites, or tailings
obtained in the ordinary gold washing processes, or other auriferous materials of the
like kind roasted or unroasted.
For such purpose, the use of bromine is very effective, but it is objectionable on
account of the difficulty and expense of safely conveying and keeping the bromine
in a liquid form; and my invention has for its object a novel method of preparing
and treating bromine so that it is obtained in a form easily transported and stored,
whilst when necessary it can be readily set free for the purpose of extracting gold in
the manner described.
I take a strong solution of a caustic base such as caustic soda, potash, or ammonia,
or the carbonates of these bases, or I employ the oxide, hydrate, or carbonate of any
other suitable base, and I saturate it with bromine thereby forming a hypobromate
or a mixture of bromide and bromate of the base, and I evaporate the solution to
dryness, obtaining a dry powdery material capable of being carried or transported
in boxes or barrels or other suitable vessels, which material forms a store from which
bromine can be obtained whenever desired. Of the several suitable bases capable
of being employed in the way described I prefer caustic soda.
To obtain bromine from this salt or mixture of salts, all that is required is to
dissolve the material in water and add to the solution an acid such as sulphuric
acid, when the bromine is at once set free or liberated.
This soda bromine material is easy of transport and without danger of breakage,
unlike liquid bromine, whilst from it liquid bromine may be obtained at any time
as aforesaid.
In order to obtain an acid material likewise easy of transport for the purpose of
liberating. the bromine from the soda-bromine material I take sodic or potassic
sulphate, and I treat it with sufficient sulphuric acid to form an acid sulphate heating
the mixture to expel all water. The mass is allowed to cool, when it solidifies and
may he broken up and packed in suitable boxes or barrels.
Instead of this solid acid material I employ free acid for my purpose when the
latter is to be had at a less cost.
The auriferous material to be treated is placed in barrels or other suitable vessels
capable of being hermetically sealed, and is then moistened with the requisite amount
A solution of the acid
of a solution of the soda-bromine compound described.
sulphate is next added in quantity sufficient to liberate the bromine, and the
containing vessel is closed and agitated occasionally for a few hours. The auriferous
material is then washed, and any excess of bromine present volatilized and condensed
and the solution containing the gold subjected to any known method for the
precipitation of the gold. Or, sometimes instead of operating simply as above
described, I add to the auriferous material with the soda bromine compound a
quantity of a carbonate such as sodic, carbonate, or chalk, a magnesic carbonate,
and upon addition of the acid material (in sufficient quantity to decompose the
carbonate as well as the soda bromine solution) pressure is obtained inside the vessel
to assist the action of the Bromine on the auriferous material. The quantity of
carbonate which I add depends upon the pressure required and the size of the
vessel.

page_text: Or, sometimes I make the bromine compound and the carbonate in one compound,
which is added to the moist ore and I then add the free acid or acid material
described, which materials are prepared in the manner described for convenience
of transport and to obtain intimate contact between the, particles of gold and
bromine.
The bromine compound prepared in the novel way described, may be used for
other purposes as well as the extraction of gold; as for instance, for use in
Photography.
Dated Ginis Tth day
day of December 1888.
EDWARDS & Co.
COMPLETE SPECIFICATION.
Improvements in the Preparation and Treatment of Bromine for
the Extraction of Gold from Ore or for other Purposes.
I, MATTHEW HENRY SIMPSON, of Halsey Street in the County of Middlesex,
Metallurgical Engineer, do hereby declare the nature of this invention and in what
manner the same is to be performed, to be particularly described and ascertained
in and by the following statement (that is to say) :-
My invention relates more especially to the extraction or separation of gold, by
what are known as wet processes, from such auriferous materials as pyrites, or
tailings obtained in the ordinary gold washing processes, or other auriferous materials
of the like kind, roasted or unroasted.
In such processes the use of bromine is well known and effective, but it is open
to inconvenience on account of the difficulty and expense of safely conveying and
keeping the bromine in a liquid form; and my invention has for its object a novel
method of preparing and treating bromine so that it is obtained in a form casily
transported and stored, whilst when necessary it can be readily set free. for the
purpose of extracting gold in the manner described, or for other purposes.
I take a strong solution of a caustic base such as caustic soda, potash, or ammonia,
or the carbonates of these bases, or I employ the oxide, hydrate, or carbonate of any
other suitable base, and I saturate it with bromine thereby forming a hypobromate
or a mixture of bromide and bromate of the base, and I evaporate the solution to
dryness, obtaining a dry powdery material capable of being carried or transported
in boxes or barrels or other suitable vessels and forming a store from which bromine
can be obtained whenever required. Of the several suitable bases capable of being
employed in the way described I prefer caustic soda.
In order to obtain the bromine from this salt or mixture of salts, all that is
required is to dissolve the material in water and add to the solution an acid such
as sulphuric acid, when the bromine is at once set free or liberated.
The soda-bromine material described is easy of transport and without danger,
unlike liquid bromine, whilst from it liquid bromine may be obtained at any time as
already described.
In order to obtain an acid material likewise easy of transport for the purpose of
liberating the bromine from the soda-bromine material I take sodic or potassic
sulphate, and treat it with sufficient sulphuric acid to form an acid sulphate, heating
the mixture to expel all water. The mass is allowed to cool, when it solidifies and
may be broken up and packed in suitable boxes or barrels.
Instead of this solid acid material, I employ free acid for my purpose when the
latter is to be had at a less cost.
When the bromine is to be used for the extraction of gold the auriferous material
to be treated is placed in barrels or other suitable vessels capable of being hermeti-
cally sealed and is then moistened with the requisite amount of a solution of the
soda-bromine compound described. A solution of the acid sulphate is next added
in quantity sufficient to liberate the bromine, and the containing vessel is closed and
agitated occasionally for a few hours. The auriferous material is then washed
and any excess of bromine present volatilized and condensed, and the solution

page_text: containing the gold subjected to any known method for the precipitation of the
gold.
Or sometimes instead of operating simply as above described, I add to the
auriferous material with the soda-bromine compound a quantity of a carbonate, such
as sodic carbonate, or chalk, or magnesic carbonate, and upon addition of the acid
material (in sufficient quantity to decompose the carbonate as well as the soda-
bromine solution,) pressure is obtained inside the vessel to render more perfect the
action of the Bromine on the auriferous material. The quantity of carbonate which
I add depends upon the pressure required and the size of the vessel.
Or sometimes I make the bromine compound and the carbonate in one compound,
which is added to the moist ore, and 1 then add the free acid or acid material
described, which materials are prepared in the manner described for convenience
of transport and to obtain intimate contact between the particles of gold and
bromine.
The bromine compound prepared in the novel way described, may be used for
other purposes as well as for the extraction of gold; as for instance, for use in
Photography.
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 :-
1. The method of combining bromine with caustic bases, or with the carbonate
of such bases, or with the oxide, hydrate or carbonate, of other suitable hases,
evaporating the mixture to dryness, so as to obtain a material containing bromine
capable of being readily transported, and from which the bromine can be set free
when required substantially as herein described.
2. In order to set free the bromine from such salt or mixture of salts when
required, the addition of an acid such as sulphuric acid, substantially as herein
described.
3. In order to obtain an acid material, in a convenient form for carriage, for the
purpose described, the treatment of sodic or potassic sulphate with sulphuric acid
to form an acid sulphate, heating the mixture to expel all water, allowing the .
mass to cool and solidify, and breaking it up into pieces convenient for packing,
substantially as herein described.
4. The addition to the bromine compound, of a suitable carbonate in order to
obtain pressure in the vessel in which the bromine is used for the extraction of
gold, substantially as herein described.
Dated this 29th day of August 1889.
EDWARDS & Co.,
35, Southampton Buildings, London, Agents for the Patentee.