Year: 1889

page_text: A communication from abroad by JOSEPH ALBERT BRADBURN, of Syracuse, Onondaga
County, State of New York, United States of America, Chemist.
I, WILLIAM PHILLIPS THOMPSON F.C.S., M.L.M.E., of the Agency for Foreign
Patent Solicitors, 6, Lord Street, Liverpool, and 6, Bank Street, Manchester, both in
the County of Lancaster, and 323, High Holborn, in the County of Middlesex, Civil
Engineer, 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 the processes for the manufacture of caustic soda or caustic
potash and bleaching powder in which common salt or potassium chloride is used as a
base for the several chemical reactions.
The object of this invention is to simplify the process and reduce the cost of
production. It consists in the several novel features hereinafter set forth and which
are specifically set forth in the claims hereunto annexed.
The first step of this process consists in the treatment of solium chloride or potassium
chloride in a still of stone or stone ware with nitric acid and peroxide of manganese
hydrated or not, or a manganate or permanganate of soda for the treatment of sodium
chloride or of potash, if potassium chloride is treated, and during such treatment
heated either by free steam or by steam pipes running through the still, these steam
pipes may be of stone ware or of iron enamelled on the outside.
If to two molecules of common salt, one of peroxide of manganese is added together
with four molecules of nitric acid, the chemical reaction with the treatment and heating
produces two molecules of nitrate of soda in conjunction with one molecule of nitrate
of manganese, one molecule of chloride and two molecules of water.
The chemical symbols representing this reaction when peroxide of manganese is
used, can be stated as follows.―

page_text: The chlorine is used in the ordinary way for the manufacture of bleaching powder.
This produces a spent liquor in the still containing nitrate of soda and nitrate of
manganese, and the next step or steps of the process are for the purpose of producing
from this liquor a concentrated solution of nitrate of soda.
As the second step of this process, caustic soda is added to precipitate the manganese,
which is also oxidized by blowing air through the mixture.
The mixture is then settled, decanted or filtered to remove the peroxide of
manganese (Mn 02) which leaves a concentrated solution of nitrate of soda
(Na NO₂).
The nitrate of soda is obtained by evaporation and mixing with two or three times
its weight of ferric oxide (Fe, O3) and this mixture is heated in a suitable furnace in
a current of air passing through the furnace, and the nitrous fumes which are evolved
mix with the air and are together passed over any of the oxidizing substances
mentioned above, namely peroxide of manganese in any form or a manganite,
manganate or permanganate of an alkali or alkaline earth whether heated or not.
To save the nitric acid present in this oxidized air current, it is passed into
a suitable receptacle and treated with water or steam, and the nitric acid is
condensed.
The mass remaining in the furnace is then removed and lixiviated which yields a
strong caustic soda liquid and ferric oxide to be used over again. If potassium chloride
has been used in the first place, then a caustic. potash liquor and ferric oxide are
obtained here.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, as communicated to me by
my foreign correspondent, I declare that what I claim is :-
The process for the manufacture of caustic soda or caustic potash and bleaching
powder consisting of the following steps
First. The treatment with nitric acid and peroxide of manganese or its chemical
equivalent of common salt or of potassium chloride in a still.
Second. The treatment of spent liquor with caustic soda or caustic potash and the
removal of the peroxide of manganese.
Third. The evaporation of the nitrate of soda or nitrate of potash, mixing with it
ferric oxide, and furnacing.
Fourth. Lixiviating the mass from the furnace.
Dated this 17th day of April 1889.