Year: 1886

page_text: Date of Application, 11th May, 1886
Complete Left, 11th Feb., 1887
Complete Accepted, 11th Mar., 1887
I ROBERT LAVENDER of Talywain near Pontypool Mon. Manufacturing Chemist do
hereby declare the nature of this invention to be as follows:-
I take copperas and spread it on heated iron plates; in this way I drive off the
water of crystallization. I then crush the material and spread it in thin layers of less
than an inch in thickness in cast iron trays and I introduce these trays into retoris
set in a furnace like gas retorts so that they can be evenly heated to a full red heat.
The retorts I employ have a vertical partition running from end to end and are provided
with ledges on which the trays when in the retort are supported. The retorts are
connected with a sulphuric acid chamber and provision is made for the free passage of
air through the retorts during the operation-this is a main feature in my invention and
is essential to the production of a pigment of high quality free from sulphur. The heat
in the retort causes the sulphuric acid of the copperas to be driven off as vapour and
this is carried by the current of air into the sulphuric acid chamber and here it is
condensed preferably together with other acid fumes introduced into the chamber as
in the ordinary manufacture of sulphuric acid. An exhauster of any convenient sort
draws the air from the chamber and through the retorts. I so arrange that when the
bulk of the sulphuric acid has been driven off from the copperas the passage connecting
the retort with the acid chamber may be closed whilst nevertheless the air curreni
through the retort is maintained either by connection with a high chimney or in other
convenient manner.
When the operation is complete the trays are withdrawn from the retori and allowed
to cool.
The pigment is then found ready for use and it does not require lixiviation or other
preliminary treatment.
For the purpose of deepening the color the pigment may when desired be exposed
to a subsequent firing.
The copperas for this manufacture is conveniently obtained from spent acid which
has been employed in the pickling of iron plate.
The sulphuric acid is thus recovered from the spent liquor and is available to be
used again and again in the pickling operations.
MADDMABI
Ca
GLADDMA IL.
Ca
Agents for the Applicant.

page_text: COMPLETE SPECIFICATION....
Improvements in the Manufacture of Oxide of Iron Pigment Color.
I, ROBERT LAVENDER of Talywain near Pontypool Mon. Manufacturing 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 take copperas and spread it on heated iron plates; in this way 1 drive off the water
of crystallization. I then crush the material and spread it in thin layers of less than
an inch in thickness in cast iron trays and I introduce these trays into retorts set in a
furnace like gas retorts and heat them to a full red heat but not beyond as overheating
must be carefully avoided. The retorts employ have a vertical partition running from
end to end and are provided with ledges on which the trays when in the retort are
supported. The retorts are connected with a sulphuric acid chamber and provision is
inade for the free passage of air through the retorts during the operation-this is a
main feature in my invention and is essential to the production of a pigment of high
quality free from sulphur. The heat in the retort causes the sulphuric acid of the
copperas to be driven off as vapour, and this is carried by the current of air into the
sulphuric acid chamber and here it is condensed preferably together with other acid
funes introduced into the chamber as in the ordinary manufacture of sulphuric acid.
An exhauster of any convenient sort draws the air from the chamber and through the
retorts. I so arrange that when the bulk of the sulphuric acid has been driven off
from the copperas the passage connecting the retort with the acid chamber may be
closed whilst nevertheless the air current through the retort is maintained either by
connection with a high chimney or in other convenient manner.
When the operation is complete the trays are withdrawn from the retort and allowed
to cool.
The pigment is then found ready for use and it does not require lixiviation or other
preliminary treatment.
For the purpose of deepening the color the pignient may when desired be exposed
to a subsequent firing.
The copperas for this manufacture is conveniently obtained from spent acid which
has been employed in the pickling of iron plate.
The sulphuric acid is thus recovered from the spent liquor and is available to be used
again and again in the pickling operations.
In order that my said. invention may be most fully understood and readily carried
into effect I will proceed to describe the drawings hereunto annexed.
.DESCRIPTION OF THE DRAWINGS.

page_text: back end of the retort. C, C, are ledges which support the shallow trays D D. E is
the outlet pipe to the sulphuric acid chamber.
The door of the retort has apertures for the admission of air preferably provided
with valves to regulate the supply.
Other arrangements of retort might be adopted but it is essential that the fumes
shall be taken off quickly and not be allowed to remain in contact with or to pass and
repass over the pulverized material.
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 :-
The manufacture of oxide of iron pigment colour by heating copperas or sulphate of
iron to drive off the water of crystallization then crushing or grinding the product and
exposing it in thin layers to heat in retorts with a free passage of air through them
substantially as described.
CARPMAEL & Co.,
Agents for the Applicant.