Year: 1887

page_text: Date of Application, 11th Nov., 1887
Complete Left, 16th June, 1888
Complete Accepted, 20th July, 1888
I, ALEXANDER ORR, of 98 Raeberry Street, Glasgow, in the County of Lanark,
North Britain, Analytical Chemist, do hereby declare the nature of this Invention to
be as follows, that is to say :-
My said Invention has for its object to improve and render more expeditious the
process for making white lead.
In carrying out my Invention according to one modification, I take litharge in a
finely ground condition and mix it with about an equal weight of water in any
suitable vessel, giving preference to a vessel which can be closed and will withstand
an internal pressure of about 5 or 6 pounds more than that of the atmosphere. I add
a small quantity of acetic acid and inject carbonic acid into the mixture which is kept
well stirred or agitated by any suitable mechanical appliance. When treated in this
way the litharge is converted into white lead in a much shorter time than in ordinary
processes.
A very small quantity of acetic acid is required, one pound for every hundred pounds
of litharge being sufficient. A corresponding proportion of neutral acetate of lead may
be used instead of acetic acid; or nitric acid or nitrate of lead may be used. And
instead of introducing oxide of lead in the form of litharge, the lead may be introduced
in the metallic form if arrangements are made for oxidising it within the vessel.
Dated this Tenth day of November 1887.
EDMUND HUNT,
Applicant's Agent.

page_text: "provements in Making
1, ALEXANDER ORR, lately of 98 Raeberry Street, Glasgow, in the County of
Lanark, North Britain, but now of 1 Park Terrace, Irvine, in the County of Ayr,
North Britain, Analytical Chemist, do hereby declare the nature of this invention
and in what manner the same is to be performed, to be particularly described ana
ascertained in and by the following statement, that is to say :-
My said Invention has for its object to improve and render more expeditious and
economical the process for making white lead.
My Invention consists in operating upon an oxide of lead with carbonic acid in the
presence of an extremely small quantity of acetic acid, or a suitable homologue of
acetic acid, or nitric acid, or a lead salt of any of such acids.
In carrying out my Invention according to one modification I take litharge in a
finely ground condition and mix it with about an equal weight of water in any suitable
vessel, giving preference to a vessel which can be closed and will withstand an internal
pressure of from 5 to 10 pounds more than that of the atmosphere. I add a small
quantity of acetic acid and inject carbonic acid into the mixture which is kept well
stirred or agitated by any suitable mechanical appliance. The mixture is heated in
any convenient manner so as to be kept at a temperature of from 120 to 150 degrees
Fahrenheit. When treated in this way the litharge is converted into white lead in a
much shorter time than in ordinary processes.
The vessel employed in which to conduct the process may be of various constructions,
I may however describe apparatus which will I believe answer satisfactorily. In this
apparatus the vessel is in the form of a polygonal barrel with its axis horizontal, and
with trunnions on its ends carried in suitable bearings. The trunnions are hollow
and through one of them there passes a shaft having on it inside the vessel a paddle
wheel for agitating the contents. The shaft is hollow and perforated and is at one end
connected through the trunnion with a pipe through which the carbonic acid is injected.
The trunnions are fitted with stuffing boxes to prevent leakage. Any convenient
power and gearing are employed to turn the vessel and the paddle wheel the vessel
being driven slowly in one direction and the paddle more quickly in the opposite
direction. The vessel is provided with a door for introducing and removing materials,
and which can be kept tightly closed whilst the vessel is in motion.
A very small quantity of acetic acid is required, one tenth of a pound for every
bundred pounds of litharge being sufficient. Instead of acetic acid, certain homologues
of acetic acid may be used, namely propionic acid, butyric acid, or valerianic acid; or
nitric acid may be used, or a corresponding quantity of a lead salt of any of the acids
named.
Instead of introducing litharge or oxide of lead into the vessel, the whole or part of
the lead may be introduced in the metallic state provided that arrangements are made
for oxidising it within the vessel.

page_text: 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 process of producing white lead in which carbonic acid is made to act on oxide
of lead in presence of water and of a very small proportion of acetic, propionic,
butyric, valerianic, or nitric acid; or a lead salt of any one or more of such acids, the
mixture being mechanically agitated and kept at a temperature of from 120 to
150 degrees Fahrenheit substantially as herein before described.
Dated this Fifteenth day of June 1888
EDMUND HUNT,
Applicant's Agent.