A New or Improved Pigment or Paint.
Year: 1898

page_text: A New or Improved Pigment or Paint.
A communication from abroad by ALFRED B. KITTSON, and ARTHUR BENJAMIN
BROWNE, of Dorchester, County of Suffolk, and Cambridge, County of Middle-
sex, respectively, State of Massachusetts, United States of America, Chemists.
I, ALFRED GEORGE BROOKES, of 55 & 56, Chancery Lane, in the County of
London, Chartered Patent Agent, do hereby declare the nature of this invention
to be as follows:-
The protective properties of metallic paint, preventing oxidization and destruc-
tion due to exposure, have led to a very extended employment, such paint having
as its base or pigment the peroxide of iron.
If the peroxide is pure, it will be uniform in colour.
Where it is not uniform in colour it is due to the presence of materials not com-
posed of iron and subject to decomposition on exposure to the elements.
For some time there has been a wide-spread demand for a black, gray or other
coloured metallic paint of equal efficacy as the red, which should contain such
a small proportion of the colouring pigment as to be harmless.
With this end in view the natural black magnetic oxide of iron has been ground
and used as a pigment or base for paint, and iron or steel scale has been ground
and similarly used, but in each case with no practical success.
In both instances the crystalline character of the material is retained, no matter
how thoroughly ground, rendering it impossible for the vehicle to thoroughly
permeate the particles, and consequently detracting from its value as a protective
paint.
The commercial use of the natural magnetic oxide in the manner referred to
would be prohibited on account of the cost of grinding to the requisite fineness.
It is also open to the same objection as the red oxide, namely, its crystalline
character.
As to the scale, it is magnetic only on the exterior, and the interior is not the
black oxide of iron.
In our experiments to obtain a cheap black metallic paint superior in value to
the well known red paint, and which can be widely varied as to colour by the addi-
tion of a very small proportion of the desired pigment we have discovered that
amorphous black magnetic oxide of iron spongaceous in character can be cheaply
produced and used as a pigment or base for paint which will possess the desired
properties and characteristics.
Accordingly we use amorphous black magnetic oxide of iron as a pigment for
paint.
We pulverize the material, which may be roasted iron pyrites, the ash from
sulphuric acid manufacture, or other materials containing peroxide of iron.
After pulverizing the material it is heated in a revolving chamber in the presence
of a reducing gas, preferably carbon monoxide, which fills the chamber and is
brought into contact with the material therein.

page_text: The peroxide of iron is reduced thereby to a black magnetic oxide of iron, the
gas escaping as carbon dioxide, and the reduction may be performed by any well
known apparatus.
The chemical reaction is as follows: -3 Fe2O3 + CO = 2 Fe3O4 + CO₂, the
peroxide of iron in the material, whatever the latter may be, being reduced in
accordance with such reaction.
The magnetic oxide of iron is separated from the gangue and other impurities
by any of the various magnetic separators in common use, whereby a substantially
pure magnetic oxide is obtained, averaging 95 to 98% in purity.
.
This product is amorphous, spongy, friable, and easily ground into a fine powder,
after which it can be mixed with a suitable vehicle, such as oil, japan, etcetera, to
form a paint.
A dead black paint is thus obtained, applicable wherever it is desired to prevent
rust or corrosion, its base consisting of practically pure black magnetic oxide of
iron.
A fine slate gray is obtained by the addition of a very small proportion of baryta,
zinc white, or any similar substance which will not set up electrical action or be
decomposed by exposure to the elements.
The addition of small and varied quantities of chrome yellow gives various shades
of olive green, and a handsome blue may be obtained by an addition of cyanide
of potassium and the oxide of zinc.
The proportion of colouring matter added to the black paint is so small that
there is no appreciable deterioration in its qualities.
By these means there is obtained an improved paint comprising a base of non-
crystalline magnetic oxide of iron, and available for use with a proper vehicle.
as oil or japan.
The improved paint consisting of a base of spongy, friable, non-crystalline black
magnetic oxide of iron, a colouring matter, and a vehicle combined, forms a smooth
and completely mixed paint.
Another feature of the improved paint, is that it comprises a base of non-
crystalline spongy friable magnetic oxide of iron in the form of an impalpable
powder capable of thorough combination with a vehicle said vehicle being con-
bined with said base so as to permeate every particle thereof, as described.
Dated the 9th day of April 1898.
WM. BROOKES & SON,
55 & 56, Chancery Lane, London,
Agents for the Applicant.
A communication from abroad by ALFRED B. KITTSON, and ARTHUR BENJAMIN 4
BROWNE, of Dorchester, County of Suffolk, and Cambridge, County of Middle-
sex, respectively, State of Massachusetts, United States of America, Chemists.
I, ALFRED GEORGE BROOKES, of 55 & 56, Chancery Lane, in the County of
London, Chartered Patent Agent, do hereby declare the nature of this invention
and in what manner the same is to be performed, to be particularly described and 4
ascertained in and by the following statement:
The protective properties of metallic paint, preventing oxidization and destruc-
tion due to exposure, have led to a very extended employment, such paint having
as its base or pigment the peroxide of iron.

page_text: If the peroxide is pure, it will be uniform in color.
where it is not uniform in color it is due to the presence of materials not com-
posed of iron and subject to decomposition on exposure to the elements.
For some time there has been a wide-spread demand for a black, gray, or other
coloured metallic paint of equal efficacy as the red, which should contain such
a small proportion of the coloring pigment as to be harmless.
With this end in view the natural black magnetic oxide of iron has been ground
and used as a pigment or base for paint, and iron or steel scale has been ground
and similarly used, but in each case with no practical success.
In both instances the crystalline character of the material is retained, no matter
how thoroughly ground, rendering it impossible for the vehicle to thoroughly
permeate the particles, and consequently detracting from its value as a protective
paint.
The commercial use of the natural magnetic oxide in the manner referred to
would be prohibited on account of the cost of grinding to the requisite fineness.
It is also open to the same objection as the red oxide, namely, its crystalline
character.
As to the scale, it is magnetic only on the exterior, and the interior is not the
black oxide of iron.
In our experiments to obtain a cheap black metallic paint superior in value to
the well known red paint, and which can be widely varied as to color by the addi-
tion of a very small proportion of the desired pigment we have discovered that
amorphous black magnetic oxide of iron spongaceous in character can be cheaply
produced and used as a pigment or base for paint which will possess the desired
properties and characteristics.
In accordance therewith our invention consists in the use of amorphous black
magnetic oxide of iron as a pigment for paint, substantially as will be described.
Other features of our invention will be hereinafter described and particularly
pointed out in the claims.
In carrying out our invention we pulverize the material, which may be roasted
iron pyrites, the ash from sulphuric acid manufacture, or other materials contain-
ing peroxide of iron.
After pulverizing the material it is heated in a revolving chamber in the presence
of a reducing gas, preferably carbon monoxide, which fills the chamber and is
brought into contact with the material therein.
The peroxide of iron is reduced thereby to a black magnetic oxide of iron, the
gas escaping as carbon dioxide, and the reduction may be performed by any well
known apparatus.
=
The chemical reaction is as follows:-3 Fe₂O₂ + CO. 2 Fe,O, CO₂, the
peroxide of iron in the material, whatever the latter may be, being reduced in
accordance with such reaction.
The magnetic oxide of iron is separated from the gangue and other impurities
by any of the various magnetic separators in common use, whereby a substantially
pure magnetic oxide is obtained, averaging 95 to 98% in purity.
This product is amorphous, spongy, friable, and easily ground into a fine powder,
after which it can be mixed with a suitable vehicle, such as oil, japan, etcetera to
form a paint.
A dead black paint is thus obtained, applicable wherever it is desired to prevent
rust or corrosion its base consisting of practically pure black magnetic oxide of
iron.
A fine slate gray is obtained by the addition of a very small proportion of baryta,
zinc white, or any similar substance which will not set up electrical action or be
decomposed by exposure to the elements.
The addition of small and varied quantities of chrome yellow gives various shades
of olive green.
In practice the addition of about one part in weight of chrome yellow, either
dried or ground in oil, to twenty five parts of the above mentioned amorphous

page_text: product has been found to give a handsome olive green, and about one part to thirty
five a handsome bronze green, but the varying of proportions may be made to give
tints covering a wide range in the taste of the operator.
The proportion of coloring matter added to the black paint is so small that
there is no appreciable deterioration in its qualities.
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
1: A paint comprising a base of non-crystalline magnetic oxide of iron, and
a proper vehicle, as on or japan, substantially as described.
2: A paint consisting of a base of spongy, friable, non-crystalline black mag-
netic oxide of iron, a coloring matter, and a vehicle, combined to form a smooth
and completely mixed paint, substantially as described.
3: A paint comprising a base of non-crystalline spongy, friable magnetic oxide
of iron in the form of an impalpable powder, and a vehicle, said vehicle being
combined with said base so as to permeate every particle thereof, substantially as
described.
Dated the 10th dow of Tan1800
WM. BROOKES & SON,
55 & 56, Chancery Lane, London,
Agents for the Applicant.