A New Manufacture of a Salt or Compound containing Bromine.
Year: 1897

page_text: PROVISIONAL SPECIFICATION.
A New Manufacture of a Salt or Compound containing Bromine.
I, BERTRAND CHase Hinman, of 22, Cliff Street, in the City, County and State
of New York, United States of America, Metallurgist, do hereby declare the nature
of this invention to be as follows:-
:-
This invention relates to a new manufacture of a salt containing bromine,
chlorine, oxygen and a base, the said salt being chiefly intended for the
extraction of gold from its ores or compounds.
The bromine exists either as bromate or as bromate in combination with bromide
the former being in excess and the salt due to its containing a preponderance of
bromate has an oxidising power greater than that which is required to decompose
its bromide.
This salt may be made as follows:
Into bromine I introduce chlorine to saturation and to this mixture I add a
solution of sodium hydroxide or any other alkaline hydrate, carbonate or equiva-
lent dissolved in water. The result is that a larger quantity of bromate is formed,
than would be obtained by merely adding the hydroxide of sodium to the bromine.
The reaction may be represented as follows:
Br₂+5 Cl₂+12 NaOH = 10 NaCl + 2 NaBrO, + 6 H₂O.
This reaction shows that all the bromine has been converted into bromate; if
however a lesser quantity of chlorine is employed a portion of the bromine will
be present as a bromide. The amount of bromide is dependent upon the amount
of chlorine introduced and may be altered as occasion requires.
A similar result may be obtained by introducing bromine into a solution of an
alkaline carbonate or equivalent, previously saturated with chlorine to the desired
extent.
Or I may introduce chlorine into an alkaline bromine, solution containing an
excess of alkali or equivalent.
In all these cases involving a combination of chlorine, bromine and a base if
the use of the chlorine be omitted the solution will consist of a mixture possessing
only such oxidising power as will just liberate its own bromine, but by the addition
of the chlorine a salt is produced containing such additional amount of bromate as
will ensure the desired excess of oxidising power.
If a dry salt suitable for shipment be desired, the water of solution is evaporated.
During this operation the temperature should be preserved below the point of
decomposition, but otherwise no special precaution is necessary.
In order to use this salt it merely suffices to redissolve it in water, and the
solution on coming in contact with an acid becomes at once active. The beneficial
result from the use of such a salt may best be shown in the treatment of ores.
It is well known that free bromine will to a greater or lesser degree enter into
combination with the bases or base constituents of the ore and produce bromides
and when there is no excess of available oxygen present to set the combined

page_text: bromine free it will continue to exist as bromide at the end of the leaching opera-
tion and can not be saved except by special chemical treatment.
If however the aforesaid salt be employed in the manner indicated, the salt by
virtue of its possessing an excess of available oxygen will decompose the bromides
which may have formed during the treatment, so that after the leaching, all the
bromine will be found in the free state and it can consequently be saved without
any further chemical treatment.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C.,
Agents for the Applicant.
A New Manufacture of a Salt or Compound containing Bromine.
I, BERTRAND CHASE HINMAN, of 22, Cliff Street, in the City, County and State
of New York, United States of America, Metallurgist, do hereby declare the nature
of this invention and in what manner the same is to be performed, to be particu-
larly described and ascertained in and by the following statement:
-
This invention relates to a new manufacture of a salt containing, bromine,
chlorine, oxygen and a base, the said salt being chiefly intended for the extraction
of gold from its ores or compounds.
The bromine exists either as bromate alone or as bromate in combination with
bromide; in the latter case the bromate must be in excess and the salt will conse-
quently possess an oxidising power greater than that which is required to decompose
its bromide.
This salt may be made as follows:-
Chlorine is introduced into bromine to saturation, and to this mixture is added
a solution of sodium hydrate or any other alkaline hydrate or carbonate, or
equivalent compound dissolved in water. In this way a larger quantity of bromate
is formed than would be obtained by merely adding the hydrate of sodium to
bromine alone.
The reaction may be represented as follows:-
Br₂+5 Cl₂+12 NaOH
=
10 NaCl + 2 NaBrO2 + 6 H₂O.
3
This reaction shows that all the bromine has been converted into bromate. If
however a lesser quantity of chlorine is employed, a portion of the bromine com-
bines with the base to form a bromide, the amount of which depends upon the
amount of chlorine introduced, and may be altered as occasion requires.
A similar result may be obtained by introducing bromine into a solution of an
alkaline carbonate or equivalent compound, previously saturated with chlorine
to the desired extent.
Or for the same purpose chlorine may be introduced into an alkaline bromine
solution containing an excess of alkali or its equivalent.
In all these cases involving a combination of chlorine, bromine, and a base, if
the use of the chlorine were omitted the solution would consist of a mixture
possessing only such oxidising power as will just liberate the bromine, from the
bromide originally used, but, by the addition of the chlorine, a salt is produced
containing such additional amount of bromate as will ensure the desired excess
of oxidising power to decompose any bromide that may have been subsequently
formed.
If a dry salt suitable for shipment be desired, the water of solution is evaporated.

page_text: During this operation the temperature should be preserved below the point of
decomposition of the bromate, but otherwise no special precaution is necessary.
In order to use this salt it merely suffices to re-dissolve it in water, and to allow
the solution to come into contact with an acid, such as sulphuric acid, sufficiently
powerful to decompose the bromate, and the said solution becomes at once active.
The beneficial result from the use of such a salt may best be shown in the treat-
ment of ores. It is well known that free bromine will to a greater or lesser degree
enter into combination with the bases of the ore and produce bromides and when
there is no excess of available oxygen present to set the combined bromine free,
it will continue to exist as bromide at the end of the leaching operation and cannot
be saved except by special chemical treatment.
If however the aforesaid salt be employed in the manner indicated, it will by
virtue of its possessing an excess of available oxygen, decompose the bromides
which may have formed during the treatment, so that after the leaching, all the
bromine will be found in the free state. Consequently the bromine can be saved
without any further chemical treatment.
Thus for example if the ore is to be leached with an acidified solution of the salt
of the composition previously described an addition of hydrochloric acid is made
before the solution is poured over the ore. This at once sets bromine free accord-
ing to the following reaction:
NaBr NaBro₁ + 6 HCI
=
6 NaCl + 3 H₂O + 3 Brą.
The solution ready to go upon the ore should contain as its active constituents
NaBrO, free Br., and HCl. As this free bromine enters into combination with
the bases of the ore forming bromides, they will at once be broken up, liberating
bromine again according to the reaction just shown, and this will continue as long
as any bromate remains in the solution, so that when the right amount of bromate
is present in the original salt solution employed, the filtrate which is drawn off
from the ore will contain the bromine entirely in the free state, with whatever
bases may have dissolved, and also the gold as chlorides.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is:-
1. As new products the hereindescribed salts containing bromine, chlorine,
oxygen and a base.
2. The several methods of producing the said salts substantially as hereinabove
described.
1
1000
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C.,
Agents for the Applicant.