Improvements in Obtaining Yellow Pigments.
Year: 1889

page_text: Date of Application, 30th Apr., 1889
Complete Specification Left, 28th Jan., 1890-Accepted, 1st Mar., 1890
PROVISIONAL SPECIFICATION.
Improvements in Obtaining Yellow Pigments.
I, JOHN MACFARLANE, of Ferencze Villa, Barrhead, in the County of Renfrew,
North Britain, Technical Chemist, do hereby declare the nature of this Invention to be
as follows, that is to say :-
My said Invention has for its object the manufacture of yellow pigments of various
shades in an improved manner.
In carrying out my Invention I employ a solution of ferrous sulphate to which
according to one modification I add carbonate of lime in a state of fine division or
made into a paste with water. The mixture is to be well agitated and exposed to air
for which purpose air, may be blown through it so as at once to agitate it and bring
all parts of it into contact with air. The result of the reaction is the formation of
hydrated oxide of iron mixed with sulphate of lime and also with some carbonate of
lime if the carbonate of lime has been added in excess. Various shades of yellow
are obtainable by using various proportions of ferrous sulphate and carbonate of
lime.
Instead of carbonate of lime any other carbonate of an alkaline earth may be
employed, the carbonate of lime being however preferable on account of its cheapness
and suitability. If a strongly colored pigment is wanted a carbonate of an alkali or
of a base the sulphate of which is soluble must be employed, and the sulphate formed
must be separated by washing.
Dated this Twenty-ninth day of April 1889.
EDMUND HUNT,
Applicant's Agent.
COMPLETE SPECIFICATION.
Improvements in Obtaining Yellow Pigments.
I, JOHN MACFARLANE, of Fereneze Villa, Barrhead, in the County of Renfrew,
North Britain, Technical 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, that is to say:-
My said Invention has for its object the manufacture of yellow pigments of various
shades in an improved manner.
In carrying out my Invention I employ a solution of ferrous sulphate to which
according to one modification I add carbonate of lime in a state of fine division or
made into a paste with water. The mixture is to be well agitated and exposed to air
for which purpose air may be blown through it so as at once to agitate it and bring
all parts of it into contact with air. The result of the reaction is the formation of
hydrated oxide of iron mixed with sulphate of lime and also with some carbonate of
lime if the carbonate of lime has been added in excess. Various shades of yellow are
obtainable by using various proportions of ferrous sulphate and carbonate of lime.
For obtaining an orange yellow I combine 34 parts by weight of crystallised ferrous
sulphate with 1 part of carbonate of lime. And for obtaining a light yellow I
combine part of ferrous sulphate with 1 part of carbonate of lime. The operation
may be effected in any convenient vessel, the ferrous sulphate being dissolved in
sufficient water and the carbonate of line being added in a state of fine division. For
the agitation and treatment with air the vessel may be provided with a pipe descending
nearly to the bottom and having at its lower end a rose or perforated part; and air
being made to pass through the pipe by a suitable pump or blower rises through the
solution and causes the yellow pigment to be rapidly formed. When the operation
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page_text: has been continued a sufficient length of time the liquid is decanted or otherwise
separated; and the pigment is washed and dried or finished in any suitable
manner.
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 :-
Forming yellow pigments by adding carbonate of lime to a solution of ferrous
sulphate, with agitation and exposure to air, substantially as hereinbefore described.
Dated this Twenty-seventh day of January 1890.
EDMUND HUNT,
Applicant's Agent.