A New or Improved Method for Oxidising the Protosalts of Iron to the Persalts.
Year: 1894

page_text: Date of Application, 8th Sept., 1894
Complete Specification Left, 4th June, 1895-Accepted, 13th July, 1895
PROVISIONAL. SPECIFICATION.
A New or Improved Method for Oxidising the Protosalts of Iron to
the Persalts.
I, NORMAN MCCULLOCH, of 7 Melrose Street, Glasgow, in the County of
Lanark, North Britain, Chemist, 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 :—
This invention relates to a new or improved method for effecting the combination
of protoxide of iron in acid solution with free oxygen, such as atmospheric oxygen,
with consequent formation of a persalt of iron (which may be basic or normal
according to the proportion of acid in the original solution) by agitating the ferrous
solution with a sufficient volume of air in presence of a suitable proportion of either
nitric oxide (NO) or nitrogen peroxide (NO).
The function of these nitrogen oxides is to act as carriers of oxygen from the air
to the ferrous solution, or as catalytic agents.
This they effect through the well known property of nitric oxide (NO) to combine
directly with free oxygen to form nitrogen peroxide (NO) which is a powerful
oxidising body. The nitrogen peroxide (NO,) in presence of an iron protosalt
instantly parts with one half of its combined oxygen to the iron and is reduced
to nitric oxide (NO). This inherent power of regeneration theoretically enables
the nitrogen oxides specified to bring about the chemical combination of an infinitely
large proportion of oxygen and protosalt of iron and in practice it is observed
that the catalytic action of the aforementioned nitrogen oxides ceases only with
the conversion of those compounds to substances not possessed of this power to act
as oxygen carriers under the conditions, but, the loss of active nitrogen oxide from
this and other causes is small relative to the proportion of atmospheric oxygen
it can render practically available as an oxidant it having been found that one
volume of nitric oxide can influence the rapid chemical combination of at least
fourteen volumes of oxygen under the conditions described herein.
To practically apply the foregoing principle of oxidising ferrous salts with air,
various forms of apparatus may be employed, but I prefer to use an oxidising plant
as follows:-
I employ a cylindrical wooden vessel, about six feet in diameter and six feet
long, and closed at both ends with wooden lids. These lids are each fitted with
bearings for the axle of a wooden agitator which revolves in the interior of the
vessel. This agitator is fitted with wooden vanes so that by its revolving action
it not only effects a thorough commingling of the liquid and gaseous contents of
the vessel but a rapid replacement of the latter with external air when the air
holes, with which the ends and cylindrical side of the apparatus are pierced, are
opened.
Into this apparatus is conveyed an amount of ferrous solution commensurate
with the air capacity of the plant to contain sufficient oxygen to oxidise the iron,
and an amount of nitric oxide, or its equivalent in nitrogen peroxide, in the
proportion of about two and one third parts per one hundred parts of iron to he
oxidised. The agitator is then set to work until the dark chocolate colour of the
solution changes to reddish yellow which is a convenient indication that the
oxidation of the iron is complete. The liquid contents of the chamber are then

page_text: run off to make way for another portion of ferrous solution, and the air and nitric
oxide are renewed from time to time as required.
Details not touched upon in describing the above apparatus and the method of
its manipulation will be readily understood.
As most persalts of iron have a strongly corrosive action on metals generally
I prefer to use wood, or siliceous material, in constructing those parts of the above
apparatus, which come into contact with the iron salts and nitric oxides.
Dated this 7th day of September 1894.
JOHNSONS,
115 St. Vincent Street, Glasgow, Petitioner's Agents.
A New or Improved Method for Oxidising the Protosalts of Iron to
the Persalts.
I, NORMAN MCCULLOCH of 7 Melrose Street, Glasgow, in the County of
Lanark, North Britain, Chemist, 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 :- i
This invention relates to a method for effecting the combination of protoxide of
iron in acid solution with free oxygen such as atmospheric oxygen, with consequent
formation of a persalt of iron (which may be basic or normal according to the
proportion of acid in the original solution) by agitating the ferrous solution with a
sufficient volume of air in presence of a suitable proportion of either nitric
oxide (NO) or nitrogen peroxide (NO).
This
The function of these nitrogen oxides is to act as carriers of oxygen from the air
to the ferrous solution, or as catalytic agents. This they effect through the
well-known property of nitric oxide (NO) to combine directly with free oxygen to
form nitrogen peroxide (NO) which is a powerful oxidising body. The nitrogen
peroxide (NO),) in presence of an iron protosalt instantly parts, with one half of
its combined oxygen to the iron and is reduced to nitric oxide (NO).
inherent power of regeneration theoretically enables the nitrogen oxides specified
to bring about the chemical combination of an infinitely large proportion of
oxygen and protosalt of iron, and in practice it is observed that the catalytic
action of the aforementioned nitrogen oxides ceases only with the conversion of
those compounds to substances not possessed of this power to act as oxygen carriers
under the conditions, but the loss of active nitrogen oxides from this and other
causes is, small relative to the proportion of atmospheric oxygen it can render
practically available as an oxidant it having been found that one volume of nitric
oxide can influence the rapid chemical combination of at least fourteen volumes of
oxygen under the conditions described herein.
To practically apply the foregoing principle of oxidising ferrous salts with air,
many forms of apparatus naturally suggest themselves but excellent results have
been obtained by using as the "oxidising" plant a very simple apparatus of which
the following is a general but sufficiently particular description
It may consist of a cylindrical wooden vessel about six feet in diameter and
six feet long and closed at both ends with wooden, lids. These lids are each fitted
with bearings for the axle of a wooden agitator which revolves in the interior of
the vessel. This agitator is fitted with wooden vanes so that by its revolving
action it not only effects a thorough commingling of the liquid and gaseous
contents of the vessel but a rapid replacement of the latter with external air when
the air holes, with which the ends and cylindrical side of the apparatus are pierced,
are opened.

page_text: Into this apparatus is conveyed an amount of ferrous solution commensurate with
the air capacity of the plant to contain sufficient oxygen to oxidise the iron, and
an amount of nitric oxide, or its equivalent in nitrogen peroxide, in the proportion
of about two and one-third parts per one hundred parts of iron to be oxidised.
The agitator is then set to work until the dark chocolate colour of the solution
changes to reddish yellow which is a convenient indication that the oxidation of
the iron is complete. The liquid contents of the chamber are then run off to make
way for another portion of ferrous solution and the air and nitric oxide are renewed
from time to time as required.
Details not touched upon in describing the above apparatus and the method of
its manipulation will be readily understood.
I may mention here that as most persalts of iron have a strongly corrosive
action on the metals generally we are limited practically to the use of wood or
siliceous material, in constructing those parts of the above apparatus which come
into contact with the iron salts and nitric oxides.
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:-
The method of oxidising ferrous solutions by agitating the iron solution with
air in amount at least equivalent to effect the complete oxidation of the iron, and
in presence of nitric oxide or nitrogen peroxide, in the proportion of about two
and one-third parts nitric oxide or nitrogen peroxide per one hundred parts of
iron to be oxidised.
Dated this 31st dew of Man 1805
JOHNSONS,
115 St. Vincent Street, Glasgow, Applicant's Agents.