Year: 1888

page_text: I, ROBERT EDWARD CHATFIELD of Woodlands, Sewardstone in the County of
Essex, Manufacturing Chemist do hereby declare the nature of this invention' to be
as follows:-
My invention relates to the manufacture of an ammonia carbonate which is applic-
able as a baking powder. As it is desirable that this should be of great purity
I prefer in the first place to obtain pure ammonia by the following method.
I mix in a close vessel sulphate of ammonia or a solution thereof and magnesia
with an excess of water of solution and I apply heat gradually raising it to about
170° F. The sulphate of ammonia becomes decomposed, the ammonia passes off and
is condensed in aqueous solution. The magnesia combining with the sulphuric acid
becomes sulphate of magnesia more or less in solution, which may be crystallised for
the market as Epsom salts, or may be reconverted into magnesia by any know
process for that purpose. The weaker ammonia that comes off last may be used as
solvent in a subsequent operation.
I employ the aqueous solution of ammonia "thus obtained, or it may be a solution
otherwise obtained for the production of a carbonate applicable as a baking powder
in the following manner. Into a close vessel containing the ammonia solution,
preferably into its upper part above the solution, I admit carbonic acid gas in
quantity preferably less than what will give one equivalent of carbonic acid to two
equivalents of ammonia. "After the supply of carbonic acid is shut off, crystallisation
takes place. When the crystals are formed, I run off the mother liquor, which
may be used as solvent for ammonia in a subsequent operation; and I then,
preferably in the same vessel, pass a farther supply of carbonic acid gas through or
over the crystals.

page_text: By the absorption of carbonic acid the crystals are altered. becoming very friable,
and almost completely inodorous. This substance, which is an ammonia carbonate or a
mixture of carbonates can be used as a baking powder by mixing it with the flour and
water used for breadmaking.
COMPLETE SPECIFICATION.
Manufacture of an Ammonia Carbonate Applicable as Baking
Powder.
I, ROBERT EDWARD CHATFIELD of Woodlands, Sewardstone in the County of
Essex, 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:
My invention relates to the manufacture of an ammonia carbonate which is
applicable as a baking powder. As it is desirable that this should be of great purity.
I prefer in the first place to obtain pure ammonia by the following method:
I mix in a close vessel sulphate of ammonia or a solution thereof and magnesia
in excess along with water in large excess and I apply heat, gradually raising it to
about 240° F. The sulphate of ammonia becoines decomposed, the ammonia passes
off and is condensed in aqueous solution. The magnesia combining with the sulphuric
acid becomes sulphate of magnesia more or less in solution, which may be crystallised
for the market as Epsom Salts, or may be reconverted into magnesia by any known
process for that purpose. The weak ammonia that comes off last may be used partly
as solvent of the sulphate of ammonia in a subsequent operation, and partly instead of
water for absorption of ammonia subsequently evolved.
1
I employ the aqueous solution of ammonia thus obtained, or it may be a solution
otherwise obtained for the production of a carbonate applicable as a baking powder in
the following manner. Into a close vessel containing the ammonia solution, preferably
. into its upper part above the solution, I admit carbonic acid gas preferably in the
proportion by weight of 19 parts carbonic acid to 17 parts of gaseous ammonia.
After the supply of carbonic acid is shut off, crystallisation takes place. When
the crystals are formed, I run off the mother liquor, which may be used as
solvent for ammonia in a subsequent operation; and I then preferably in the
same vessel, pass a farther supply of carbonic acid gas through or over the crystals.

page_text: By the absorption of carbonic acid the crystals are altered becoming very friable,
and almost completely inodorous. This substance, which is an ammonia carbonate or
a mixture of carbonates can be used as a baking powder by mixing it with the flour
and water used for bread making.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
The manufacture of an ammonia carbonate applicable as a baking powder by treating
pure ammonia solution with carbonic acid as herein described.
1 1
1
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ABEL & IMRAY,
Agents for the Applicant.